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_OCL_Scalar_Widening,
141 ICR_Complex_Real_Conversion,
142 ICR_Conversion,
143 ICR_Conversion,
144 ICR_Writeback_Conversion,
145 ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
146 // it was omitted by the patch that added
147 // ICK_Zero_Event_Conversion
148 ICR_C_Conversion,
149 ICR_C_Conversion_Extension
150 };
151 return Rank[(int)Kind];
152 }
153
154 /// GetImplicitConversionName - Return the name of this kind of
155 /// implicit conversion.
GetImplicitConversionName(ImplicitConversionKind Kind)156 static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
157 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
158 "No conversion",
159 "Lvalue-to-rvalue",
160 "Array-to-pointer",
161 "Function-to-pointer",
162 "Function pointer conversion",
163 "Qualification",
164 "Integral promotion",
165 "Floating point promotion",
166 "Complex promotion",
167 "Integral conversion",
168 "Floating conversion",
169 "Complex conversion",
170 "Floating-integral conversion",
171 "Pointer conversion",
172 "Pointer-to-member conversion",
173 "Boolean conversion",
174 "Compatible-types conversion",
175 "Derived-to-base conversion",
176 "Vector conversion",
177 "Vector splat",
178 "Complex-real conversion",
179 "Block Pointer conversion",
180 "Transparent Union Conversion",
181 "Writeback conversion",
182 "OpenCL Zero Event Conversion",
183 "C specific type conversion",
184 "Incompatible pointer conversion"
185 };
186 return Name[Kind];
187 }
188
189 /// StandardConversionSequence - Set the standard conversion
190 /// sequence to the identity conversion.
setAsIdentityConversion()191 void StandardConversionSequence::setAsIdentityConversion() {
192 First = ICK_Identity;
193 Second = ICK_Identity;
194 Third = ICK_Identity;
195 DeprecatedStringLiteralToCharPtr = false;
196 QualificationIncludesObjCLifetime = false;
197 ReferenceBinding = false;
198 DirectBinding = false;
199 IsLvalueReference = true;
200 BindsToFunctionLvalue = false;
201 BindsToRvalue = false;
202 BindsImplicitObjectArgumentWithoutRefQualifier = false;
203 ObjCLifetimeConversionBinding = false;
204 CopyConstructor = nullptr;
205 }
206
207 /// getRank - Retrieve the rank of this standard conversion sequence
208 /// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
209 /// implicit conversions.
getRank() const210 ImplicitConversionRank StandardConversionSequence::getRank() const {
211 ImplicitConversionRank Rank = ICR_Exact_Match;
212 if (GetConversionRank(First) > Rank)
213 Rank = GetConversionRank(First);
214 if (GetConversionRank(Second) > Rank)
215 Rank = GetConversionRank(Second);
216 if (GetConversionRank(Third) > Rank)
217 Rank = GetConversionRank(Third);
218 return Rank;
219 }
220
221 /// isPointerConversionToBool - Determines whether this conversion is
222 /// a conversion of a pointer or pointer-to-member to bool. This is
223 /// used as part of the ranking of standard conversion sequences
224 /// (C++ 13.3.3.2p4).
isPointerConversionToBool() const225 bool StandardConversionSequence::isPointerConversionToBool() const {
226 // Note that FromType has not necessarily been transformed by the
227 // array-to-pointer or function-to-pointer implicit conversions, so
228 // check for their presence as well as checking whether FromType is
229 // a pointer.
230 if (getToType(1)->isBooleanType() &&
231 (getFromType()->isPointerType() ||
232 getFromType()->isMemberPointerType() ||
233 getFromType()->isObjCObjectPointerType() ||
234 getFromType()->isBlockPointerType() ||
235 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
236 return true;
237
238 return false;
239 }
240
241 /// isPointerConversionToVoidPointer - Determines whether this
242 /// conversion is a conversion of a pointer to a void pointer. This is
243 /// used as part of the ranking of standard conversion sequences (C++
244 /// 13.3.3.2p4).
245 bool
246 StandardConversionSequence::
isPointerConversionToVoidPointer(ASTContext & Context) const247 isPointerConversionToVoidPointer(ASTContext& Context) const {
248 QualType FromType = getFromType();
249 QualType ToType = getToType(1);
250
251 // Note that FromType has not necessarily been transformed by the
252 // array-to-pointer implicit conversion, so check for its presence
253 // and redo the conversion to get a pointer.
254 if (First == ICK_Array_To_Pointer)
255 FromType = Context.getArrayDecayedType(FromType);
256
257 if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
258 if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
259 return ToPtrType->getPointeeType()->isVoidType();
260
261 return false;
262 }
263
264 /// Skip any implicit casts which could be either part of a narrowing conversion
265 /// or after one in an implicit conversion.
IgnoreNarrowingConversion(ASTContext & Ctx,const Expr * Converted)266 static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx,
267 const Expr *Converted) {
268 // We can have cleanups wrapping the converted expression; these need to be
269 // preserved so that destructors run if necessary.
270 if (auto *EWC = dyn_cast<ExprWithCleanups>(Converted)) {
271 Expr *Inner =
272 const_cast<Expr *>(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr()));
273 return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(),
274 EWC->getObjects());
275 }
276
277 while (auto *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
278 switch (ICE->getCastKind()) {
279 case CK_NoOp:
280 case CK_IntegralCast:
281 case CK_IntegralToBoolean:
282 case CK_IntegralToFloating:
283 case CK_BooleanToSignedIntegral:
284 case CK_FloatingToIntegral:
285 case CK_FloatingToBoolean:
286 case CK_FloatingCast:
287 Converted = ICE->getSubExpr();
288 continue;
289
290 default:
291 return Converted;
292 }
293 }
294
295 return Converted;
296 }
297
298 /// Check if this standard conversion sequence represents a narrowing
299 /// conversion, according to C++11 [dcl.init.list]p7.
300 ///
301 /// \param Ctx The AST context.
302 /// \param Converted The result of applying this standard conversion sequence.
303 /// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the
304 /// value of the expression prior to the narrowing conversion.
305 /// \param ConstantType If this is an NK_Constant_Narrowing conversion, the
306 /// type of the expression prior to the narrowing conversion.
307 /// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
308 /// from floating point types to integral types should be ignored.
getNarrowingKind(ASTContext & Ctx,const Expr * Converted,APValue & ConstantValue,QualType & ConstantType,bool IgnoreFloatToIntegralConversion) const309 NarrowingKind StandardConversionSequence::getNarrowingKind(
310 ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
311 QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
312 assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++");
313
314 // C++11 [dcl.init.list]p7:
315 // A narrowing conversion is an implicit conversion ...
316 QualType FromType = getToType(0);
317 QualType ToType = getToType(1);
318
319 // A conversion to an enumeration type is narrowing if the conversion to
320 // the underlying type is narrowing. This only arises for expressions of
321 // the form 'Enum{init}'.
322 if (auto *ET = ToType->getAs<EnumType>())
323 ToType = ET->getDecl()->getIntegerType();
324
325 // Converting from capability to pointer/integral is always narrowing
326 if (FromType->isCHERICapabilityType(Ctx) && !ToType->isCHERICapabilityType(Ctx))
327 return NK_Type_Narrowing;
328
329 switch (Second) {
330 // 'bool' is an integral type; dispatch to the right place to handle it.
331 case ICK_Boolean_Conversion:
332 if (FromType->isRealFloatingType())
333 goto FloatingIntegralConversion;
334 if (FromType->isIntegralOrUnscopedEnumerationType())
335 goto IntegralConversion;
336 // -- from a pointer type or pointer-to-member type to bool, or
337 return NK_Type_Narrowing;
338
339 // -- from a floating-point type to an integer type, or
340 //
341 // -- from an integer type or unscoped enumeration type to a floating-point
342 // type, except where the source is a constant expression and the actual
343 // value after conversion will fit into the target type and will produce
344 // the original value when converted back to the original type, or
345 case ICK_Floating_Integral:
346 FloatingIntegralConversion:
347 if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
348 return NK_Type_Narrowing;
349 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
350 ToType->isRealFloatingType()) {
351 if (IgnoreFloatToIntegralConversion)
352 return NK_Not_Narrowing;
353 llvm::APSInt IntConstantValue;
354 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
355 assert(Initializer && "Unknown conversion expression");
356
357 // If it's value-dependent, we can't tell whether it's narrowing.
358 if (Initializer->isValueDependent())
359 return NK_Dependent_Narrowing;
360
361 if (Initializer->isIntegerConstantExpr(IntConstantValue, Ctx)) {
362 // Convert the integer to the floating type.
363 llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
364 Result.convertFromAPInt(IntConstantValue, IntConstantValue.isSigned(),
365 llvm::APFloat::rmNearestTiesToEven);
366 // And back.
367 llvm::APSInt ConvertedValue = IntConstantValue;
368 bool ignored;
369 Result.convertToInteger(ConvertedValue,
370 llvm::APFloat::rmTowardZero, &ignored);
371 // If the resulting value is different, this was a narrowing conversion.
372 if (IntConstantValue != ConvertedValue) {
373 ConstantValue = APValue(IntConstantValue);
374 ConstantType = Initializer->getType();
375 return NK_Constant_Narrowing;
376 }
377 } else {
378 // Variables are always narrowings.
379 return NK_Variable_Narrowing;
380 }
381 }
382 return NK_Not_Narrowing;
383
384 // -- from long double to double or float, or from double to float, except
385 // where the source is a constant expression and the actual value after
386 // conversion is within the range of values that can be represented (even
387 // if it cannot be represented exactly), or
388 case ICK_Floating_Conversion:
389 if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
390 Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
391 // FromType is larger than ToType.
392 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
393
394 // If it's value-dependent, we can't tell whether it's narrowing.
395 if (Initializer->isValueDependent())
396 return NK_Dependent_Narrowing;
397
398 if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
399 // Constant!
400 assert(ConstantValue.isFloat());
401 llvm::APFloat FloatVal = ConstantValue.getFloat();
402 // Convert the source value into the target type.
403 bool ignored;
404 llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
405 Ctx.getFloatTypeSemantics(ToType),
406 llvm::APFloat::rmNearestTiesToEven, &ignored);
407 // If there was no overflow, the source value is within the range of
408 // values that can be represented.
409 if (ConvertStatus & llvm::APFloat::opOverflow) {
410 ConstantType = Initializer->getType();
411 return NK_Constant_Narrowing;
412 }
413 } else {
414 return NK_Variable_Narrowing;
415 }
416 }
417 return NK_Not_Narrowing;
418
419 // -- from an integer type or unscoped enumeration type to an integer type
420 // that cannot represent all the values of the original type, except where
421 // the source is a constant expression and the actual value after
422 // conversion will fit into the target type and will produce the original
423 // value when converted back to the original type.
424 case ICK_Integral_Conversion:
425 IntegralConversion: {
426 assert(FromType->isIntegralOrUnscopedEnumerationType());
427 assert(ToType->isIntegralOrUnscopedEnumerationType());
428 const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
429 const unsigned FromWidth = Ctx.getIntWidth(FromType);
430 const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
431 const unsigned ToWidth = Ctx.getIntWidth(ToType);
432
433 if (FromWidth > ToWidth ||
434 (FromWidth == ToWidth && FromSigned != ToSigned) ||
435 (FromSigned && !ToSigned)) {
436 // Not all values of FromType can be represented in ToType.
437 llvm::APSInt InitializerValue;
438 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
439
440 // If it's value-dependent, we can't tell whether it's narrowing.
441 if (Initializer->isValueDependent())
442 return NK_Dependent_Narrowing;
443
444 if (!Initializer->isIntegerConstantExpr(InitializerValue, Ctx)) {
445 // Such conversions on variables are always narrowing.
446 return NK_Variable_Narrowing;
447 }
448 bool Narrowing = false;
449 if (FromWidth < ToWidth) {
450 // Negative -> unsigned is narrowing. Otherwise, more bits is never
451 // narrowing.
452 if (InitializerValue.isSigned() && InitializerValue.isNegative())
453 Narrowing = true;
454 } else {
455 // Add a bit to the InitializerValue so we don't have to worry about
456 // signed vs. unsigned comparisons.
457 InitializerValue = InitializerValue.extend(
458 InitializerValue.getBitWidth() + 1);
459 // Convert the initializer to and from the target width and signed-ness.
460 llvm::APSInt ConvertedValue = InitializerValue;
461 ConvertedValue = ConvertedValue.trunc(ToWidth);
462 ConvertedValue.setIsSigned(ToSigned);
463 ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
464 ConvertedValue.setIsSigned(InitializerValue.isSigned());
465 // If the result is different, this was a narrowing conversion.
466 if (ConvertedValue != InitializerValue)
467 Narrowing = true;
468 }
469 if (Narrowing) {
470 ConstantType = Initializer->getType();
471 ConstantValue = APValue(InitializerValue);
472 return NK_Constant_Narrowing;
473 }
474 }
475 return NK_Not_Narrowing;
476 }
477
478 default:
479 // Other kinds of conversions are not narrowings.
480 return NK_Not_Narrowing;
481 }
482 }
483
484 /// dump - Print this standard conversion sequence to standard
485 /// error. Useful for debugging overloading issues.
dump() const486 LLVM_DUMP_METHOD void StandardConversionSequence::dump() const {
487 raw_ostream &OS = llvm::errs();
488 bool PrintedSomething = false;
489 if (First != ICK_Identity) {
490 OS << GetImplicitConversionName(First);
491 PrintedSomething = true;
492 }
493
494 if (Second != ICK_Identity) {
495 if (PrintedSomething) {
496 OS << " -> ";
497 }
498 OS << GetImplicitConversionName(Second);
499
500 if (CopyConstructor) {
501 OS << " (by copy constructor)";
502 } else if (DirectBinding) {
503 OS << " (direct reference binding)";
504 } else if (ReferenceBinding) {
505 OS << " (reference binding)";
506 }
507 PrintedSomething = true;
508 }
509
510 if (Third != ICK_Identity) {
511 if (PrintedSomething) {
512 OS << " -> ";
513 }
514 OS << GetImplicitConversionName(Third);
515 PrintedSomething = true;
516 }
517
518 if (!PrintedSomething) {
519 OS << "No conversions required";
520 }
521 }
522
523 /// dump - Print this user-defined conversion sequence to standard
524 /// error. Useful for debugging overloading issues.
dump() const525 void UserDefinedConversionSequence::dump() const {
526 raw_ostream &OS = llvm::errs();
527 if (Before.First || Before.Second || Before.Third) {
528 Before.dump();
529 OS << " -> ";
530 }
531 if (ConversionFunction)
532 OS << '\'' << *ConversionFunction << '\'';
533 else
534 OS << "aggregate initialization";
535 if (After.First || After.Second || After.Third) {
536 OS << " -> ";
537 After.dump();
538 }
539 }
540
541 /// dump - Print this implicit conversion sequence to standard
542 /// error. Useful for debugging overloading issues.
dump() const543 void ImplicitConversionSequence::dump() const {
544 raw_ostream &OS = llvm::errs();
545 if (isStdInitializerListElement())
546 OS << "Worst std::initializer_list element conversion: ";
547 switch (ConversionKind) {
548 case StandardConversion:
549 OS << "Standard conversion: ";
550 Standard.dump();
551 break;
552 case UserDefinedConversion:
553 OS << "User-defined conversion: ";
554 UserDefined.dump();
555 break;
556 case EllipsisConversion:
557 OS << "Ellipsis conversion";
558 break;
559 case AmbiguousConversion:
560 OS << "Ambiguous conversion";
561 break;
562 case BadConversion:
563 OS << "Bad conversion";
564 break;
565 }
566
567 OS << "\n";
568 }
569
construct()570 void AmbiguousConversionSequence::construct() {
571 new (&conversions()) ConversionSet();
572 }
573
destruct()574 void AmbiguousConversionSequence::destruct() {
575 conversions().~ConversionSet();
576 }
577
578 void
copyFrom(const AmbiguousConversionSequence & O)579 AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
580 FromTypePtr = O.FromTypePtr;
581 ToTypePtr = O.ToTypePtr;
582 new (&conversions()) ConversionSet(O.conversions());
583 }
584
585 namespace {
586 // Structure used by DeductionFailureInfo to store
587 // template argument information.
588 struct DFIArguments {
589 TemplateArgument FirstArg;
590 TemplateArgument SecondArg;
591 };
592 // Structure used by DeductionFailureInfo to store
593 // template parameter and template argument information.
594 struct DFIParamWithArguments : DFIArguments {
595 TemplateParameter Param;
596 };
597 // Structure used by DeductionFailureInfo to store template argument
598 // information and the index of the problematic call argument.
599 struct DFIDeducedMismatchArgs : DFIArguments {
600 TemplateArgumentList *TemplateArgs;
601 unsigned CallArgIndex;
602 };
603 // Structure used by DeductionFailureInfo to store information about
604 // unsatisfied constraints.
605 struct CNSInfo {
606 TemplateArgumentList *TemplateArgs;
607 ConstraintSatisfaction Satisfaction;
608 };
609 }
610
611 /// Convert from Sema's representation of template deduction information
612 /// to the form used in overload-candidate information.
613 DeductionFailureInfo
MakeDeductionFailureInfo(ASTContext & Context,Sema::TemplateDeductionResult TDK,TemplateDeductionInfo & Info)614 clang::MakeDeductionFailureInfo(ASTContext &Context,
615 Sema::TemplateDeductionResult TDK,
616 TemplateDeductionInfo &Info) {
617 DeductionFailureInfo Result;
618 Result.Result = static_cast<unsigned>(TDK);
619 Result.HasDiagnostic = false;
620 switch (TDK) {
621 case Sema::TDK_Invalid:
622 case Sema::TDK_InstantiationDepth:
623 case Sema::TDK_TooManyArguments:
624 case Sema::TDK_TooFewArguments:
625 case Sema::TDK_MiscellaneousDeductionFailure:
626 case Sema::TDK_CUDATargetMismatch:
627 Result.Data = nullptr;
628 break;
629
630 case Sema::TDK_Incomplete:
631 case Sema::TDK_InvalidExplicitArguments:
632 Result.Data = Info.Param.getOpaqueValue();
633 break;
634
635 case Sema::TDK_DeducedMismatch:
636 case Sema::TDK_DeducedMismatchNested: {
637 // FIXME: Should allocate from normal heap so that we can free this later.
638 auto *Saved = new (Context) DFIDeducedMismatchArgs;
639 Saved->FirstArg = Info.FirstArg;
640 Saved->SecondArg = Info.SecondArg;
641 Saved->TemplateArgs = Info.take();
642 Saved->CallArgIndex = Info.CallArgIndex;
643 Result.Data = Saved;
644 break;
645 }
646
647 case Sema::TDK_NonDeducedMismatch: {
648 // FIXME: Should allocate from normal heap so that we can free this later.
649 DFIArguments *Saved = new (Context) DFIArguments;
650 Saved->FirstArg = Info.FirstArg;
651 Saved->SecondArg = Info.SecondArg;
652 Result.Data = Saved;
653 break;
654 }
655
656 case Sema::TDK_IncompletePack:
657 // FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
658 case Sema::TDK_Inconsistent:
659 case Sema::TDK_Underqualified: {
660 // FIXME: Should allocate from normal heap so that we can free this later.
661 DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
662 Saved->Param = Info.Param;
663 Saved->FirstArg = Info.FirstArg;
664 Saved->SecondArg = Info.SecondArg;
665 Result.Data = Saved;
666 break;
667 }
668
669 case Sema::TDK_SubstitutionFailure:
670 Result.Data = Info.take();
671 if (Info.hasSFINAEDiagnostic()) {
672 PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
673 SourceLocation(), PartialDiagnostic::NullDiagnostic());
674 Info.takeSFINAEDiagnostic(*Diag);
675 Result.HasDiagnostic = true;
676 }
677 break;
678
679 case Sema::TDK_ConstraintsNotSatisfied: {
680 CNSInfo *Saved = new (Context) CNSInfo;
681 Saved->TemplateArgs = Info.take();
682 Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
683 Result.Data = Saved;
684 break;
685 }
686
687 case Sema::TDK_Success:
688 case Sema::TDK_NonDependentConversionFailure:
689 llvm_unreachable("not a deduction failure");
690 }
691
692 return Result;
693 }
694
Destroy()695 void DeductionFailureInfo::Destroy() {
696 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
697 case Sema::TDK_Success:
698 case Sema::TDK_Invalid:
699 case Sema::TDK_InstantiationDepth:
700 case Sema::TDK_Incomplete:
701 case Sema::TDK_TooManyArguments:
702 case Sema::TDK_TooFewArguments:
703 case Sema::TDK_InvalidExplicitArguments:
704 case Sema::TDK_CUDATargetMismatch:
705 case Sema::TDK_NonDependentConversionFailure:
706 break;
707
708 case Sema::TDK_IncompletePack:
709 case Sema::TDK_Inconsistent:
710 case Sema::TDK_Underqualified:
711 case Sema::TDK_DeducedMismatch:
712 case Sema::TDK_DeducedMismatchNested:
713 case Sema::TDK_NonDeducedMismatch:
714 // FIXME: Destroy the data?
715 Data = nullptr;
716 break;
717
718 case Sema::TDK_SubstitutionFailure:
719 // FIXME: Destroy the template argument list?
720 Data = nullptr;
721 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
722 Diag->~PartialDiagnosticAt();
723 HasDiagnostic = false;
724 }
725 break;
726
727 case Sema::TDK_ConstraintsNotSatisfied:
728 // FIXME: Destroy the template argument list?
729 Data = nullptr;
730 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
731 Diag->~PartialDiagnosticAt();
732 HasDiagnostic = false;
733 }
734 break;
735
736 // Unhandled
737 case Sema::TDK_MiscellaneousDeductionFailure:
738 break;
739 }
740 }
741
getSFINAEDiagnostic()742 PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
743 if (HasDiagnostic)
744 return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
745 return nullptr;
746 }
747
getTemplateParameter()748 TemplateParameter DeductionFailureInfo::getTemplateParameter() {
749 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
750 case Sema::TDK_Success:
751 case Sema::TDK_Invalid:
752 case Sema::TDK_InstantiationDepth:
753 case Sema::TDK_TooManyArguments:
754 case Sema::TDK_TooFewArguments:
755 case Sema::TDK_SubstitutionFailure:
756 case Sema::TDK_DeducedMismatch:
757 case Sema::TDK_DeducedMismatchNested:
758 case Sema::TDK_NonDeducedMismatch:
759 case Sema::TDK_CUDATargetMismatch:
760 case Sema::TDK_NonDependentConversionFailure:
761 case Sema::TDK_ConstraintsNotSatisfied:
762 return TemplateParameter();
763
764 case Sema::TDK_Incomplete:
765 case Sema::TDK_InvalidExplicitArguments:
766 return TemplateParameter::getFromOpaqueValue(Data);
767
768 case Sema::TDK_IncompletePack:
769 case Sema::TDK_Inconsistent:
770 case Sema::TDK_Underqualified:
771 return static_cast<DFIParamWithArguments*>(Data)->Param;
772
773 // Unhandled
774 case Sema::TDK_MiscellaneousDeductionFailure:
775 break;
776 }
777
778 return TemplateParameter();
779 }
780
getTemplateArgumentList()781 TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
782 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
783 case Sema::TDK_Success:
784 case Sema::TDK_Invalid:
785 case Sema::TDK_InstantiationDepth:
786 case Sema::TDK_TooManyArguments:
787 case Sema::TDK_TooFewArguments:
788 case Sema::TDK_Incomplete:
789 case Sema::TDK_IncompletePack:
790 case Sema::TDK_InvalidExplicitArguments:
791 case Sema::TDK_Inconsistent:
792 case Sema::TDK_Underqualified:
793 case Sema::TDK_NonDeducedMismatch:
794 case Sema::TDK_CUDATargetMismatch:
795 case Sema::TDK_NonDependentConversionFailure:
796 return nullptr;
797
798 case Sema::TDK_DeducedMismatch:
799 case Sema::TDK_DeducedMismatchNested:
800 return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;
801
802 case Sema::TDK_SubstitutionFailure:
803 return static_cast<TemplateArgumentList*>(Data);
804
805 case Sema::TDK_ConstraintsNotSatisfied:
806 return static_cast<CNSInfo*>(Data)->TemplateArgs;
807
808 // Unhandled
809 case Sema::TDK_MiscellaneousDeductionFailure:
810 break;
811 }
812
813 return nullptr;
814 }
815
getFirstArg()816 const TemplateArgument *DeductionFailureInfo::getFirstArg() {
817 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
818 case Sema::TDK_Success:
819 case Sema::TDK_Invalid:
820 case Sema::TDK_InstantiationDepth:
821 case Sema::TDK_Incomplete:
822 case Sema::TDK_TooManyArguments:
823 case Sema::TDK_TooFewArguments:
824 case Sema::TDK_InvalidExplicitArguments:
825 case Sema::TDK_SubstitutionFailure:
826 case Sema::TDK_CUDATargetMismatch:
827 case Sema::TDK_NonDependentConversionFailure:
828 case Sema::TDK_ConstraintsNotSatisfied:
829 return nullptr;
830
831 case Sema::TDK_IncompletePack:
832 case Sema::TDK_Inconsistent:
833 case Sema::TDK_Underqualified:
834 case Sema::TDK_DeducedMismatch:
835 case Sema::TDK_DeducedMismatchNested:
836 case Sema::TDK_NonDeducedMismatch:
837 return &static_cast<DFIArguments*>(Data)->FirstArg;
838
839 // Unhandled
840 case Sema::TDK_MiscellaneousDeductionFailure:
841 break;
842 }
843
844 return nullptr;
845 }
846
getSecondArg()847 const TemplateArgument *DeductionFailureInfo::getSecondArg() {
848 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
849 case Sema::TDK_Success:
850 case Sema::TDK_Invalid:
851 case Sema::TDK_InstantiationDepth:
852 case Sema::TDK_Incomplete:
853 case Sema::TDK_IncompletePack:
854 case Sema::TDK_TooManyArguments:
855 case Sema::TDK_TooFewArguments:
856 case Sema::TDK_InvalidExplicitArguments:
857 case Sema::TDK_SubstitutionFailure:
858 case Sema::TDK_CUDATargetMismatch:
859 case Sema::TDK_NonDependentConversionFailure:
860 case Sema::TDK_ConstraintsNotSatisfied:
861 return nullptr;
862
863 case Sema::TDK_Inconsistent:
864 case Sema::TDK_Underqualified:
865 case Sema::TDK_DeducedMismatch:
866 case Sema::TDK_DeducedMismatchNested:
867 case Sema::TDK_NonDeducedMismatch:
868 return &static_cast<DFIArguments*>(Data)->SecondArg;
869
870 // Unhandled
871 case Sema::TDK_MiscellaneousDeductionFailure:
872 break;
873 }
874
875 return nullptr;
876 }
877
getCallArgIndex()878 llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
879 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
880 case Sema::TDK_DeducedMismatch:
881 case Sema::TDK_DeducedMismatchNested:
882 return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;
883
884 default:
885 return llvm::None;
886 }
887 }
888
shouldAddReversed(OverloadedOperatorKind Op)889 bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
890 OverloadedOperatorKind Op) {
891 if (!AllowRewrittenCandidates)
892 return false;
893 return Op == OO_EqualEqual || Op == OO_Spaceship;
894 }
895
shouldAddReversed(ASTContext & Ctx,const FunctionDecl * FD)896 bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
897 ASTContext &Ctx, const FunctionDecl *FD) {
898 if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator()))
899 return false;
900 // Don't bother adding a reversed candidate that can never be a better
901 // match than the non-reversed version.
902 return FD->getNumParams() != 2 ||
903 !Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(),
904 FD->getParamDecl(1)->getType()) ||
905 FD->hasAttr<EnableIfAttr>();
906 }
907
destroyCandidates()908 void OverloadCandidateSet::destroyCandidates() {
909 for (iterator i = begin(), e = end(); i != e; ++i) {
910 for (auto &C : i->Conversions)
911 C.~ImplicitConversionSequence();
912 if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
913 i->DeductionFailure.Destroy();
914 }
915 }
916
clear(CandidateSetKind CSK)917 void OverloadCandidateSet::clear(CandidateSetKind CSK) {
918 destroyCandidates();
919 SlabAllocator.Reset();
920 NumInlineBytesUsed = 0;
921 Candidates.clear();
922 Functions.clear();
923 Kind = CSK;
924 }
925
926 namespace {
927 class UnbridgedCastsSet {
928 struct Entry {
929 Expr **Addr;
930 Expr *Saved;
931 };
932 SmallVector<Entry, 2> Entries;
933
934 public:
save(Sema & S,Expr * & E)935 void save(Sema &S, Expr *&E) {
936 assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
937 Entry entry = { &E, E };
938 Entries.push_back(entry);
939 E = S.stripARCUnbridgedCast(E);
940 }
941
restore()942 void restore() {
943 for (SmallVectorImpl<Entry>::iterator
944 i = Entries.begin(), e = Entries.end(); i != e; ++i)
945 *i->Addr = i->Saved;
946 }
947 };
948 }
949
950 /// checkPlaceholderForOverload - Do any interesting placeholder-like
951 /// preprocessing on the given expression.
952 ///
953 /// \param unbridgedCasts a collection to which to add unbridged casts;
954 /// without this, they will be immediately diagnosed as errors
955 ///
956 /// Return true on unrecoverable error.
957 static bool
checkPlaceholderForOverload(Sema & S,Expr * & E,UnbridgedCastsSet * unbridgedCasts=nullptr)958 checkPlaceholderForOverload(Sema &S, Expr *&E,
959 UnbridgedCastsSet *unbridgedCasts = nullptr) {
960 if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) {
961 // We can't handle overloaded expressions here because overload
962 // resolution might reasonably tweak them.
963 if (placeholder->getKind() == BuiltinType::Overload) return false;
964
965 // If the context potentially accepts unbridged ARC casts, strip
966 // the unbridged cast and add it to the collection for later restoration.
967 if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
968 unbridgedCasts) {
969 unbridgedCasts->save(S, E);
970 return false;
971 }
972
973 // Go ahead and check everything else.
974 ExprResult result = S.CheckPlaceholderExpr(E);
975 if (result.isInvalid())
976 return true;
977
978 E = result.get();
979 return false;
980 }
981
982 // Nothing to do.
983 return false;
984 }
985
986 /// checkArgPlaceholdersForOverload - Check a set of call operands for
987 /// placeholders.
checkArgPlaceholdersForOverload(Sema & S,MultiExprArg Args,UnbridgedCastsSet & unbridged)988 static bool checkArgPlaceholdersForOverload(Sema &S,
989 MultiExprArg Args,
990 UnbridgedCastsSet &unbridged) {
991 for (unsigned i = 0, e = Args.size(); i != e; ++i)
992 if (checkPlaceholderForOverload(S, Args[i], &unbridged))
993 return true;
994
995 return false;
996 }
997
998 /// Determine whether the given New declaration is an overload of the
999 /// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
1000 /// New and Old cannot be overloaded, e.g., if New has the same signature as
1001 /// some function in Old (C++ 1.3.10) or if the Old declarations aren't
1002 /// functions (or function templates) at all. When it does return Ovl_Match or
1003 /// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
1004 /// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
1005 /// declaration.
1006 ///
1007 /// Example: Given the following input:
1008 ///
1009 /// void f(int, float); // #1
1010 /// void f(int, int); // #2
1011 /// int f(int, int); // #3
1012 ///
1013 /// When we process #1, there is no previous declaration of "f", so IsOverload
1014 /// will not be used.
1015 ///
1016 /// When we process #2, Old contains only the FunctionDecl for #1. By comparing
1017 /// the parameter types, we see that #1 and #2 are overloaded (since they have
1018 /// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
1019 /// unchanged.
1020 ///
1021 /// When we process #3, Old is an overload set containing #1 and #2. We compare
1022 /// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
1023 /// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
1024 /// functions are not part of the signature), IsOverload returns Ovl_Match and
1025 /// MatchedDecl will be set to point to the FunctionDecl for #2.
1026 ///
1027 /// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
1028 /// by a using declaration. The rules for whether to hide shadow declarations
1029 /// ignore some properties which otherwise figure into a function template's
1030 /// signature.
1031 Sema::OverloadKind
CheckOverload(Scope * S,FunctionDecl * New,const LookupResult & Old,NamedDecl * & Match,bool NewIsUsingDecl)1032 Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
1033 NamedDecl *&Match, bool NewIsUsingDecl) {
1034 for (LookupResult::iterator I = Old.begin(), E = Old.end();
1035 I != E; ++I) {
1036 NamedDecl *OldD = *I;
1037
1038 bool OldIsUsingDecl = false;
1039 if (isa<UsingShadowDecl>(OldD)) {
1040 OldIsUsingDecl = true;
1041
1042 // We can always introduce two using declarations into the same
1043 // context, even if they have identical signatures.
1044 if (NewIsUsingDecl) continue;
1045
1046 OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
1047 }
1048
1049 // A using-declaration does not conflict with another declaration
1050 // if one of them is hidden.
1051 if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
1052 continue;
1053
1054 // If either declaration was introduced by a using declaration,
1055 // we'll need to use slightly different rules for matching.
1056 // Essentially, these rules are the normal rules, except that
1057 // function templates hide function templates with different
1058 // return types or template parameter lists.
1059 bool UseMemberUsingDeclRules =
1060 (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
1061 !New->getFriendObjectKind();
1062
1063 if (FunctionDecl *OldF = OldD->getAsFunction()) {
1064 if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
1065 if (UseMemberUsingDeclRules && OldIsUsingDecl) {
1066 HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
1067 continue;
1068 }
1069
1070 if (!isa<FunctionTemplateDecl>(OldD) &&
1071 !shouldLinkPossiblyHiddenDecl(*I, New))
1072 continue;
1073
1074 Match = *I;
1075 return Ovl_Match;
1076 }
1077
1078 // Builtins that have custom typechecking or have a reference should
1079 // not be overloadable or redeclarable.
1080 if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
1081 Match = *I;
1082 return Ovl_NonFunction;
1083 }
1084 } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
1085 // We can overload with these, which can show up when doing
1086 // redeclaration checks for UsingDecls.
1087 assert(Old.getLookupKind() == LookupUsingDeclName);
1088 } else if (isa<TagDecl>(OldD)) {
1089 // We can always overload with tags by hiding them.
1090 } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
1091 // Optimistically assume that an unresolved using decl will
1092 // overload; if it doesn't, we'll have to diagnose during
1093 // template instantiation.
1094 //
1095 // Exception: if the scope is dependent and this is not a class
1096 // member, the using declaration can only introduce an enumerator.
1097 if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
1098 Match = *I;
1099 return Ovl_NonFunction;
1100 }
1101 } else {
1102 // (C++ 13p1):
1103 // Only function declarations can be overloaded; object and type
1104 // declarations cannot be overloaded.
1105 Match = *I;
1106 return Ovl_NonFunction;
1107 }
1108 }
1109
1110 // C++ [temp.friend]p1:
1111 // For a friend function declaration that is not a template declaration:
1112 // -- if the name of the friend is a qualified or unqualified template-id,
1113 // [...], otherwise
1114 // -- if the name of the friend is a qualified-id and a matching
1115 // non-template function is found in the specified class or namespace,
1116 // the friend declaration refers to that function, otherwise,
1117 // -- if the name of the friend is a qualified-id and a matching function
1118 // template is found in the specified class or namespace, the friend
1119 // declaration refers to the deduced specialization of that function
1120 // template, otherwise
1121 // -- the name shall be an unqualified-id [...]
1122 // If we get here for a qualified friend declaration, we've just reached the
1123 // third bullet. If the type of the friend is dependent, skip this lookup
1124 // until instantiation.
1125 if (New->getFriendObjectKind() && New->getQualifier() &&
1126 !New->getDescribedFunctionTemplate() &&
1127 !New->getDependentSpecializationInfo() &&
1128 !New->getType()->isDependentType()) {
1129 LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
1130 TemplateSpecResult.addAllDecls(Old);
1131 if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
1132 /*QualifiedFriend*/true)) {
1133 New->setInvalidDecl();
1134 return Ovl_Overload;
1135 }
1136
1137 Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
1138 return Ovl_Match;
1139 }
1140
1141 return Ovl_Overload;
1142 }
1143
IsOverload(FunctionDecl * New,FunctionDecl * Old,bool UseMemberUsingDeclRules,bool ConsiderCudaAttrs,bool ConsiderRequiresClauses)1144 bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
1145 bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs,
1146 bool ConsiderRequiresClauses) {
1147 // C++ [basic.start.main]p2: This function shall not be overloaded.
1148 if (New->isMain())
1149 return false;
1150
1151 // MSVCRT user defined entry points cannot be overloaded.
1152 if (New->isMSVCRTEntryPoint())
1153 return false;
1154
1155 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
1156 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
1157
1158 // C++ [temp.fct]p2:
1159 // A function template can be overloaded with other function templates
1160 // and with normal (non-template) functions.
1161 if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
1162 return true;
1163
1164 // Is the function New an overload of the function Old?
1165 QualType OldQType = Context.getCanonicalType(Old->getType());
1166 QualType NewQType = Context.getCanonicalType(New->getType());
1167
1168 // Compare the signatures (C++ 1.3.10) of the two functions to
1169 // determine whether they are overloads. If we find any mismatch
1170 // in the signature, they are overloads.
1171
1172 // If either of these functions is a K&R-style function (no
1173 // prototype), then we consider them to have matching signatures.
1174 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
1175 isa<FunctionNoProtoType>(NewQType.getTypePtr()))
1176 return false;
1177
1178 const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
1179 const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);
1180
1181 // The signature of a function includes the types of its
1182 // parameters (C++ 1.3.10), which includes the presence or absence
1183 // of the ellipsis; see C++ DR 357).
1184 if (OldQType != NewQType &&
1185 (OldType->getNumParams() != NewType->getNumParams() ||
1186 OldType->isVariadic() != NewType->isVariadic() ||
1187 !FunctionParamTypesAreEqual(OldType, NewType)))
1188 return true;
1189
1190 // C++ [temp.over.link]p4:
1191 // The signature of a function template consists of its function
1192 // signature, its return type and its template parameter list. The names
1193 // of the template parameters are significant only for establishing the
1194 // relationship between the template parameters and the rest of the
1195 // signature.
1196 //
1197 // We check the return type and template parameter lists for function
1198 // templates first; the remaining checks follow.
1199 //
1200 // However, we don't consider either of these when deciding whether
1201 // a member introduced by a shadow declaration is hidden.
1202 if (!UseMemberUsingDeclRules && NewTemplate &&
1203 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
1204 OldTemplate->getTemplateParameters(),
1205 false, TPL_TemplateMatch) ||
1206 !Context.hasSameType(Old->getDeclaredReturnType(),
1207 New->getDeclaredReturnType())))
1208 return true;
1209
1210 // If the function is a class member, its signature includes the
1211 // cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
1212 //
1213 // As part of this, also check whether one of the member functions
1214 // is static, in which case they are not overloads (C++
1215 // 13.1p2). While not part of the definition of the signature,
1216 // this check is important to determine whether these functions
1217 // can be overloaded.
1218 CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
1219 CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
1220 if (OldMethod && NewMethod &&
1221 !OldMethod->isStatic() && !NewMethod->isStatic()) {
1222 if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
1223 if (!UseMemberUsingDeclRules &&
1224 (OldMethod->getRefQualifier() == RQ_None ||
1225 NewMethod->getRefQualifier() == RQ_None)) {
1226 // C++0x [over.load]p2:
1227 // - Member function declarations with the same name and the same
1228 // parameter-type-list as well as member function template
1229 // declarations with the same name, the same parameter-type-list, and
1230 // the same template parameter lists cannot be overloaded if any of
1231 // them, but not all, have a ref-qualifier (8.3.5).
1232 Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
1233 << NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
1234 Diag(OldMethod->getLocation(), diag::note_previous_declaration);
1235 }
1236 return true;
1237 }
1238
1239 // We may not have applied the implicit const for a constexpr member
1240 // function yet (because we haven't yet resolved whether this is a static
1241 // or non-static member function). Add it now, on the assumption that this
1242 // is a redeclaration of OldMethod.
1243 auto OldQuals = OldMethod->getMethodQualifiers();
1244 auto NewQuals = NewMethod->getMethodQualifiers();
1245 if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
1246 !isa<CXXConstructorDecl>(NewMethod))
1247 NewQuals.addConst();
1248 // We do not allow overloading based off of '__restrict'.
1249 OldQuals.removeRestrict();
1250 NewQuals.removeRestrict();
1251 if (OldQuals != NewQuals)
1252 return true;
1253 }
1254
1255 // Though pass_object_size is placed on parameters and takes an argument, we
1256 // consider it to be a function-level modifier for the sake of function
1257 // identity. Either the function has one or more parameters with
1258 // pass_object_size or it doesn't.
1259 if (functionHasPassObjectSizeParams(New) !=
1260 functionHasPassObjectSizeParams(Old))
1261 return true;
1262
1263 // enable_if attributes are an order-sensitive part of the signature.
1264 for (specific_attr_iterator<EnableIfAttr>
1265 NewI = New->specific_attr_begin<EnableIfAttr>(),
1266 NewE = New->specific_attr_end<EnableIfAttr>(),
1267 OldI = Old->specific_attr_begin<EnableIfAttr>(),
1268 OldE = Old->specific_attr_end<EnableIfAttr>();
1269 NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
1270 if (NewI == NewE || OldI == OldE)
1271 return true;
1272 llvm::FoldingSetNodeID NewID, OldID;
1273 NewI->getCond()->Profile(NewID, Context, true);
1274 OldI->getCond()->Profile(OldID, Context, true);
1275 if (NewID != OldID)
1276 return true;
1277 }
1278
1279 if (getLangOpts().CUDA && ConsiderCudaAttrs) {
1280 // Don't allow overloading of destructors. (In theory we could, but it
1281 // would be a giant change to clang.)
1282 if (!isa<CXXDestructorDecl>(New)) {
1283 CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
1284 OldTarget = IdentifyCUDATarget(Old);
1285 if (NewTarget != CFT_InvalidTarget) {
1286 assert((OldTarget != CFT_InvalidTarget) &&
1287 "Unexpected invalid target.");
1288
1289 // Allow overloading of functions with same signature and different CUDA
1290 // target attributes.
1291 if (NewTarget != OldTarget)
1292 return true;
1293 }
1294 }
1295 }
1296
1297 if (ConsiderRequiresClauses) {
1298 Expr *NewRC = New->getTrailingRequiresClause(),
1299 *OldRC = Old->getTrailingRequiresClause();
1300 if ((NewRC != nullptr) != (OldRC != nullptr))
1301 // RC are most certainly different - these are overloads.
1302 return true;
1303
1304 if (NewRC) {
1305 llvm::FoldingSetNodeID NewID, OldID;
1306 NewRC->Profile(NewID, Context, /*Canonical=*/true);
1307 OldRC->Profile(OldID, Context, /*Canonical=*/true);
1308 if (NewID != OldID)
1309 // RCs are not equivalent - these are overloads.
1310 return true;
1311 }
1312 }
1313
1314 // The signatures match; this is not an overload.
1315 return false;
1316 }
1317
1318 /// Tries a user-defined conversion from From to ToType.
1319 ///
1320 /// Produces an implicit conversion sequence for when a standard conversion
1321 /// is not an option. See TryImplicitConversion for more information.
1322 static ImplicitConversionSequence
TryUserDefinedConversion(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion,bool AllowObjCConversionOnExplicit)1323 TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
1324 bool SuppressUserConversions,
1325 AllowedExplicit AllowExplicit,
1326 bool InOverloadResolution,
1327 bool CStyle,
1328 bool AllowObjCWritebackConversion,
1329 bool AllowObjCConversionOnExplicit) {
1330 ImplicitConversionSequence ICS;
1331
1332 if (SuppressUserConversions) {
1333 // We're not in the case above, so there is no conversion that
1334 // we can perform.
1335 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1336 return ICS;
1337 }
1338
1339 // Attempt user-defined conversion.
1340 OverloadCandidateSet Conversions(From->getExprLoc(),
1341 OverloadCandidateSet::CSK_Normal);
1342 switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
1343 Conversions, AllowExplicit,
1344 AllowObjCConversionOnExplicit)) {
1345 case OR_Success:
1346 case OR_Deleted:
1347 ICS.setUserDefined();
1348 // C++ [over.ics.user]p4:
1349 // A conversion of an expression of class type to the same class
1350 // type is given Exact Match rank, and a conversion of an
1351 // expression of class type to a base class of that type is
1352 // given Conversion rank, in spite of the fact that a copy
1353 // constructor (i.e., a user-defined conversion function) is
1354 // called for those cases.
1355 if (CXXConstructorDecl *Constructor
1356 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
1357 QualType FromCanon
1358 = S.Context.getCanonicalType(From->getType().getUnqualifiedType());
1359 QualType ToCanon
1360 = S.Context.getCanonicalType(ToType).getUnqualifiedType();
1361 if (Constructor->isCopyConstructor() &&
1362 (FromCanon == ToCanon ||
1363 S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
1364 // Turn this into a "standard" conversion sequence, so that it
1365 // gets ranked with standard conversion sequences.
1366 DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
1367 ICS.setStandard(ImplicitConversionSequence::MemsetToZero);
1368 ICS.Standard.setAsIdentityConversion();
1369 ICS.Standard.setFromType(From->getType());
1370 ICS.Standard.setAllToTypes(ToType);
1371 ICS.Standard.CopyConstructor = Constructor;
1372 ICS.Standard.FoundCopyConstructor = Found;
1373 if (ToCanon != FromCanon)
1374 ICS.Standard.Second = ICK_Derived_To_Base;
1375 }
1376 }
1377 break;
1378
1379 case OR_Ambiguous:
1380 ICS.setAmbiguous();
1381 ICS.Ambiguous.setFromType(From->getType());
1382 ICS.Ambiguous.setToType(ToType);
1383 for (OverloadCandidateSet::iterator Cand = Conversions.begin();
1384 Cand != Conversions.end(); ++Cand)
1385 if (Cand->Best)
1386 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
1387 break;
1388
1389 // Fall through.
1390 case OR_No_Viable_Function:
1391 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1392 break;
1393 }
1394
1395 return ICS;
1396 }
1397
1398 /// TryImplicitConversion - Attempt to perform an implicit conversion
1399 /// from the given expression (Expr) to the given type (ToType). This
1400 /// function returns an implicit conversion sequence that can be used
1401 /// to perform the initialization. Given
1402 ///
1403 /// void f(float f);
1404 /// void g(int i) { f(i); }
1405 ///
1406 /// this routine would produce an implicit conversion sequence to
1407 /// describe the initialization of f from i, which will be a standard
1408 /// conversion sequence containing an lvalue-to-rvalue conversion (C++
1409 /// 4.1) followed by a floating-integral conversion (C++ 4.9).
1410 //
1411 /// Note that this routine only determines how the conversion can be
1412 /// performed; it does not actually perform the conversion. As such,
1413 /// it will not produce any diagnostics if no conversion is available,
1414 /// but will instead return an implicit conversion sequence of kind
1415 /// "BadConversion".
1416 ///
1417 /// If @p SuppressUserConversions, then user-defined conversions are
1418 /// not permitted.
1419 /// If @p AllowExplicit, then explicit user-defined conversions are
1420 /// permitted.
1421 ///
1422 /// \param AllowObjCWritebackConversion Whether we allow the Objective-C
1423 /// writeback conversion, which allows __autoreleasing id* parameters to
1424 /// be initialized with __strong id* or __weak id* arguments.
1425 static ImplicitConversionSequence
TryImplicitConversion(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion,bool AllowObjCConversionOnExplicit)1426 TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
1427 bool SuppressUserConversions,
1428 AllowedExplicit AllowExplicit,
1429 bool InOverloadResolution,
1430 bool CStyle,
1431 bool AllowObjCWritebackConversion,
1432 bool AllowObjCConversionOnExplicit) {
1433 ImplicitConversionSequence ICS;
1434 if (IsStandardConversion(S, From, ToType, InOverloadResolution,
1435 ICS.Standard, CStyle, AllowObjCWritebackConversion)){
1436 ICS.setStandard(ImplicitConversionSequence::KeepState);
1437 return ICS;
1438 }
1439
1440 if (!S.getLangOpts().CPlusPlus) {
1441 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1442 return ICS;
1443 }
1444
1445 // C++ [over.ics.user]p4:
1446 // A conversion of an expression of class type to the same class
1447 // type is given Exact Match rank, and a conversion of an
1448 // expression of class type to a base class of that type is
1449 // given Conversion rank, in spite of the fact that a copy/move
1450 // constructor (i.e., a user-defined conversion function) is
1451 // called for those cases.
1452 QualType FromType = From->getType();
1453 if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
1454 (S.Context.hasSameUnqualifiedType(FromType, ToType) ||
1455 S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
1456 ICS.setStandard(ImplicitConversionSequence::MemsetToZero);
1457 ICS.Standard.setAsIdentityConversion();
1458 ICS.Standard.setFromType(FromType);
1459 ICS.Standard.setAllToTypes(ToType);
1460
1461 // We don't actually check at this point whether there is a valid
1462 // copy/move constructor, since overloading just assumes that it
1463 // exists. When we actually perform initialization, we'll find the
1464 // appropriate constructor to copy the returned object, if needed.
1465 ICS.Standard.CopyConstructor = nullptr;
1466
1467 // Determine whether this is considered a derived-to-base conversion.
1468 if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
1469 ICS.Standard.Second = ICK_Derived_To_Base;
1470
1471 return ICS;
1472 }
1473
1474 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
1475 AllowExplicit, InOverloadResolution, CStyle,
1476 AllowObjCWritebackConversion,
1477 AllowObjCConversionOnExplicit);
1478 }
1479
1480 ImplicitConversionSequence
TryImplicitConversion(Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion)1481 Sema::TryImplicitConversion(Expr *From, QualType ToType,
1482 bool SuppressUserConversions,
1483 AllowedExplicit AllowExplicit,
1484 bool InOverloadResolution,
1485 bool CStyle,
1486 bool AllowObjCWritebackConversion) {
1487 return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions,
1488 AllowExplicit, InOverloadResolution, CStyle,
1489 AllowObjCWritebackConversion,
1490 /*AllowObjCConversionOnExplicit=*/false);
1491 }
1492
1493 /// PerformImplicitConversion - Perform an implicit conversion of the
1494 /// expression From to the type ToType. Returns the
1495 /// converted expression. Flavor is the kind of conversion we're
1496 /// performing, used in the error message. If @p AllowExplicit,
1497 /// explicit user-defined conversions are permitted.
1498 ExprResult
PerformImplicitConversion(Expr * From,QualType ToType,AssignmentAction Action,bool AllowExplicit)1499 Sema::PerformImplicitConversion(Expr *From, QualType ToType,
1500 AssignmentAction Action, bool AllowExplicit) {
1501 ImplicitConversionSequence ICS;
1502 return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS);
1503 }
1504
1505 ExprResult
PerformImplicitConversion(Expr * From,QualType ToType,AssignmentAction Action,bool AllowExplicit,ImplicitConversionSequence & ICS)1506 Sema::PerformImplicitConversion(Expr *From, QualType ToType,
1507 AssignmentAction Action, bool AllowExplicit,
1508 ImplicitConversionSequence& ICS) {
1509 if (checkPlaceholderForOverload(*this, From))
1510 return ExprError();
1511
1512 // Objective-C ARC: Determine whether we will allow the writeback conversion.
1513 bool AllowObjCWritebackConversion
1514 = getLangOpts().ObjCAutoRefCount &&
1515 (Action == AA_Passing || Action == AA_Sending);
1516 if (getLangOpts().ObjC)
1517 CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
1518 From->getType(), From);
1519 ICS = ::TryImplicitConversion(*this, From, ToType,
1520 /*SuppressUserConversions=*/false,
1521 AllowExplicit ? AllowedExplicit::All
1522 : AllowedExplicit::None,
1523 /*InOverloadResolution=*/false,
1524 /*CStyle=*/false, AllowObjCWritebackConversion,
1525 /*AllowObjCConversionOnExplicit=*/false);
1526 return PerformImplicitConversion(From, ToType, ICS, Action);
1527 }
1528
1529 /// Determine whether the conversion from FromType to ToType is a valid
1530 /// conversion that strips "noexcept" or "noreturn" off the nested function
1531 /// type.
IsFunctionConversion(QualType FromType,QualType ToType,QualType & ResultTy)1532 bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
1533 QualType &ResultTy) {
1534 if (Context.hasSameUnqualifiedType(FromType, ToType))
1535 return false;
1536
1537 // Permit the conversion F(t __attribute__((noreturn))) -> F(t)
1538 // or F(t noexcept) -> F(t)
1539 // where F adds one of the following at most once:
1540 // - a pointer
1541 // - a member pointer
1542 // - a block pointer
1543 // Changes here need matching changes in FindCompositePointerType.
1544 CanQualType CanTo = Context.getCanonicalType(ToType);
1545 CanQualType CanFrom = Context.getCanonicalType(FromType);
1546 Type::TypeClass TyClass = CanTo->getTypeClass();
1547 if (TyClass != CanFrom->getTypeClass()) return false;
1548 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
1549 if (TyClass == Type::Pointer) {
1550 CanTo = CanTo.castAs<PointerType>()->getPointeeType();
1551 CanFrom = CanFrom.castAs<PointerType>()->getPointeeType();
1552 } else if (TyClass == Type::BlockPointer) {
1553 CanTo = CanTo.castAs<BlockPointerType>()->getPointeeType();
1554 CanFrom = CanFrom.castAs<BlockPointerType>()->getPointeeType();
1555 } else if (TyClass == Type::MemberPointer) {
1556 auto ToMPT = CanTo.castAs<MemberPointerType>();
1557 auto FromMPT = CanFrom.castAs<MemberPointerType>();
1558 // A function pointer conversion cannot change the class of the function.
1559 if (ToMPT->getClass() != FromMPT->getClass())
1560 return false;
1561 CanTo = ToMPT->getPointeeType();
1562 CanFrom = FromMPT->getPointeeType();
1563 } else {
1564 return false;
1565 }
1566
1567 TyClass = CanTo->getTypeClass();
1568 if (TyClass != CanFrom->getTypeClass()) return false;
1569 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
1570 return false;
1571 }
1572
1573 const auto *FromFn = cast<FunctionType>(CanFrom);
1574 FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();
1575
1576 const auto *ToFn = cast<FunctionType>(CanTo);
1577 FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();
1578
1579 bool Changed = false;
1580
1581 // Drop 'noreturn' if not present in target type.
1582 if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
1583 FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
1584 Changed = true;
1585 }
1586
1587 // Drop 'noexcept' if not present in target type.
1588 if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
1589 const auto *ToFPT = cast<FunctionProtoType>(ToFn);
1590 if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
1591 FromFn = cast<FunctionType>(
1592 Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
1593 EST_None)
1594 .getTypePtr());
1595 Changed = true;
1596 }
1597
1598 // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
1599 // only if the ExtParameterInfo lists of the two function prototypes can be
1600 // merged and the merged list is identical to ToFPT's ExtParameterInfo list.
1601 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
1602 bool CanUseToFPT, CanUseFromFPT;
1603 if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
1604 CanUseFromFPT, NewParamInfos) &&
1605 CanUseToFPT && !CanUseFromFPT) {
1606 FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
1607 ExtInfo.ExtParameterInfos =
1608 NewParamInfos.empty() ? nullptr : NewParamInfos.data();
1609 QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
1610 FromFPT->getParamTypes(), ExtInfo);
1611 FromFn = QT->getAs<FunctionType>();
1612 Changed = true;
1613 }
1614 }
1615
1616 if (!Changed)
1617 return false;
1618
1619 assert(QualType(FromFn, 0).isCanonical());
1620 if (QualType(FromFn, 0) != CanTo) return false;
1621
1622 ResultTy = ToType;
1623 return true;
1624 }
1625
1626 /// Determine whether the conversion from FromType to ToType is a valid
1627 /// vector conversion.
1628 ///
1629 /// \param ICK Will be set to the vector conversion kind, if this is a vector
1630 /// conversion.
IsVectorConversion(Sema & S,QualType FromType,QualType ToType,ImplicitConversionKind & ICK)1631 static bool IsVectorConversion(Sema &S, QualType FromType,
1632 QualType ToType, ImplicitConversionKind &ICK) {
1633 // We need at least one of these types to be a vector type to have a vector
1634 // conversion.
1635 if (!ToType->isVectorType() && !FromType->isVectorType())
1636 return false;
1637
1638 // Identical types require no conversions.
1639 if (S.Context.hasSameUnqualifiedType(FromType, ToType))
1640 return false;
1641
1642 // There are no conversions between extended vector types, only identity.
1643 if (ToType->isExtVectorType()) {
1644 // There are no conversions between extended vector types other than the
1645 // identity conversion.
1646 if (FromType->isExtVectorType())
1647 return false;
1648
1649 // Vector splat from any arithmetic type to a vector.
1650 if (FromType->isArithmeticType()) {
1651 ICK = ICK_Vector_Splat;
1652 return true;
1653 }
1654 }
1655
1656 // We can perform the conversion between vector types in the following cases:
1657 // 1)vector types are equivalent AltiVec and GCC vector types
1658 // 2)lax vector conversions are permitted and the vector types are of the
1659 // same size
1660 // 3)the destination type does not have the ARM MVE strict-polymorphism
1661 // attribute, which inhibits lax vector conversion for overload resolution
1662 // only
1663 if (ToType->isVectorType() && FromType->isVectorType()) {
1664 if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
1665 (S.isLaxVectorConversion(FromType, ToType) &&
1666 !ToType->hasAttr(attr::ArmMveStrictPolymorphism))) {
1667 ICK = ICK_Vector_Conversion;
1668 return true;
1669 }
1670 }
1671
1672 return false;
1673 }
1674
1675 static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
1676 bool InOverloadResolution,
1677 StandardConversionSequence &SCS,
1678 bool CStyle);
1679
1680 /// IsStandardConversion - Determines whether there is a standard
1681 /// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
1682 /// expression From to the type ToType. Standard conversion sequences
1683 /// only consider non-class types; for conversions that involve class
1684 /// types, use TryImplicitConversion. If a conversion exists, SCS will
1685 /// contain the standard conversion sequence required to perform this
1686 /// conversion and this routine will return true. Otherwise, this
1687 /// 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)1688 static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
1689 bool InOverloadResolution,
1690 StandardConversionSequence &SCS,
1691 bool CStyle,
1692 bool AllowObjCWritebackConversion) {
1693 QualType FromType = From->getType();
1694
1695 // Standard conversions (C++ [conv])
1696 SCS.setAsIdentityConversion();
1697 SCS.IncompatibleObjC = false;
1698 SCS.setFromType(FromType);
1699 SCS.CopyConstructor = nullptr;
1700
1701 // There are no standard conversions for class types in C++, so
1702 // abort early. When overloading in C, however, we do permit them.
1703 if (S.getLangOpts().CPlusPlus &&
1704 (FromType->isRecordType() || ToType->isRecordType()))
1705 return false;
1706
1707 // The first conversion can be an lvalue-to-rvalue conversion,
1708 // array-to-pointer conversion, or function-to-pointer conversion
1709 // (C++ 4p1).
1710
1711 if (FromType == S.Context.OverloadTy) {
1712 DeclAccessPair AccessPair;
1713 if (FunctionDecl *Fn
1714 = S.ResolveAddressOfOverloadedFunction(From, ToType, false,
1715 AccessPair)) {
1716 // We were able to resolve the address of the overloaded function,
1717 // so we can convert to the type of that function.
1718 FromType = Fn->getType();
1719 SCS.setFromType(FromType);
1720
1721 // we can sometimes resolve &foo<int> regardless of ToType, so check
1722 // if the type matches (identity) or we are converting to bool
1723 if (!S.Context.hasSameUnqualifiedType(
1724 S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
1725 QualType resultTy;
1726 // if the function type matches except for [[noreturn]], it's ok
1727 if (!S.IsFunctionConversion(FromType,
1728 S.ExtractUnqualifiedFunctionType(ToType), resultTy))
1729 // otherwise, only a boolean conversion is standard
1730 if (!ToType->isBooleanType())
1731 return false;
1732 }
1733
1734 // Check if the "from" expression is taking the address of an overloaded
1735 // function and recompute the FromType accordingly. Take advantage of the
1736 // fact that non-static member functions *must* have such an address-of
1737 // expression.
1738 CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
1739 if (Method && !Method->isStatic()) {
1740 assert(isa<UnaryOperator>(From->IgnoreParens()) &&
1741 "Non-unary operator on non-static member address");
1742 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()
1743 == UO_AddrOf &&
1744 "Non-address-of operator on non-static member address");
1745 const Type *ClassType
1746 = S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
1747 FromType = S.Context.getMemberPointerType(FromType, ClassType);
1748 } else if (isa<UnaryOperator>(From->IgnoreParens())) {
1749 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==
1750 UO_AddrOf &&
1751 "Non-address-of operator for overloaded function expression");
1752 FromType = S.Context.getPointerType(FromType);
1753 }
1754
1755 // Check that we've computed the proper type after overload resolution.
1756 // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
1757 // be calling it from within an NDEBUG block.
1758 assert(S.Context.hasSameType(
1759 FromType,
1760 S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()));
1761 } else {
1762 return false;
1763 }
1764 }
1765 // Lvalue-to-rvalue conversion (C++11 4.1):
1766 // A glvalue (3.10) of a non-function, non-array type T can
1767 // be converted to a prvalue.
1768 bool argIsLValue = From->isGLValue();
1769 if (argIsLValue &&
1770 !FromType->isFunctionType() && !FromType->isArrayType() &&
1771 S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
1772 SCS.First = ICK_Lvalue_To_Rvalue;
1773
1774 // C11 6.3.2.1p2:
1775 // ... if the lvalue has atomic type, the value has the non-atomic version
1776 // of the type of the lvalue ...
1777 if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
1778 FromType = Atomic->getValueType();
1779
1780 // If T is a non-class type, the type of the rvalue is the
1781 // cv-unqualified version of T. Otherwise, the type of the rvalue
1782 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
1783 // just strip the qualifiers because they don't matter.
1784 FromType = FromType.getUnqualifiedType();
1785 } else if (FromType->isArrayType()) {
1786 // Array-to-pointer conversion (C++ 4.2)
1787 SCS.First = ICK_Array_To_Pointer;
1788
1789 // An lvalue or rvalue of type "array of N T" or "array of unknown
1790 // bound of T" can be converted to an rvalue of type "pointer to
1791 // T" (C++ 4.2p1).
1792 FromType = S.Context.getArrayDecayedType(FromType);
1793
1794 if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
1795 // This conversion is deprecated in C++03 (D.4)
1796 SCS.DeprecatedStringLiteralToCharPtr = true;
1797
1798 // For the purpose of ranking in overload resolution
1799 // (13.3.3.1.1), this conversion is considered an
1800 // array-to-pointer conversion followed by a qualification
1801 // conversion (4.4). (C++ 4.2p2)
1802 SCS.Second = ICK_Identity;
1803 SCS.Third = ICK_Qualification;
1804 SCS.QualificationIncludesObjCLifetime = false;
1805 SCS.setAllToTypes(FromType);
1806 return true;
1807 }
1808 } else if (FromType->isFunctionType() && argIsLValue) {
1809 // Function-to-pointer conversion (C++ 4.3).
1810 SCS.First = ICK_Function_To_Pointer;
1811
1812 if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
1813 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
1814 if (!S.checkAddressOfFunctionIsAvailable(FD))
1815 return false;
1816
1817 // An lvalue of function type T can be converted to an rvalue of
1818 // type "pointer to T." The result is a pointer to the
1819 // function. (C++ 4.3p1).
1820 FromType = S.Context.getPointerType(FromType);
1821 } else {
1822 // We don't require any conversions for the first step.
1823 SCS.First = ICK_Identity;
1824 }
1825 SCS.setToType(0, FromType);
1826
1827 // The second conversion can be an integral promotion, floating
1828 // point promotion, integral conversion, floating point conversion,
1829 // floating-integral conversion, pointer conversion,
1830 // pointer-to-member conversion, or boolean conversion (C++ 4p1).
1831 // For overloading in C, this can also be a "compatible-type"
1832 // conversion.
1833 bool IncompatibleObjC = false;
1834 ImplicitConversionKind SecondICK = ICK_Identity;
1835 if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
1836 // The unqualified versions of the types are the same: there's no
1837 // conversion to do.
1838 SCS.Second = ICK_Identity;
1839 } else if (S.IsIntegralPromotion(From, FromType, ToType)) {
1840 // Integral promotion (C++ 4.5).
1841 SCS.Second = ICK_Integral_Promotion;
1842 FromType = ToType.getUnqualifiedType();
1843 } else if (S.IsFloatingPointPromotion(FromType, ToType)) {
1844 // Floating point promotion (C++ 4.6).
1845 SCS.Second = ICK_Floating_Promotion;
1846 FromType = ToType.getUnqualifiedType();
1847 } else if (S.IsComplexPromotion(FromType, ToType)) {
1848 // Complex promotion (Clang extension)
1849 SCS.Second = ICK_Complex_Promotion;
1850 FromType = ToType.getUnqualifiedType();
1851 } else if (ToType->isBooleanType() &&
1852 (FromType->isArithmeticType() ||
1853 FromType->isAnyPointerType() ||
1854 FromType->isBlockPointerType() ||
1855 FromType->isMemberPointerType())) {
1856 // Boolean conversions (C++ 4.12).
1857 SCS.Second = ICK_Boolean_Conversion;
1858 FromType = S.Context.BoolTy;
1859 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
1860 ToType->isIntegralType(S.Context)) {
1861 // Integral conversions (C++ 4.7).
1862 SCS.Second = ICK_Integral_Conversion;
1863 FromType = ToType.getUnqualifiedType();
1864 } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
1865 // Complex conversions (C99 6.3.1.6)
1866 SCS.Second = ICK_Complex_Conversion;
1867 FromType = ToType.getUnqualifiedType();
1868 } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
1869 (ToType->isAnyComplexType() && FromType->isArithmeticType())) {
1870 // Complex-real conversions (C99 6.3.1.7)
1871 SCS.Second = ICK_Complex_Real;
1872 FromType = ToType.getUnqualifiedType();
1873 } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
1874 // FIXME: disable conversions between long double and __float128 if
1875 // their representation is different until there is back end support
1876 // We of course allow this conversion if long double is really double.
1877
1878 // Conversions between bfloat and other floats are not permitted.
1879 if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty)
1880 return false;
1881 if (&S.Context.getFloatTypeSemantics(FromType) !=
1882 &S.Context.getFloatTypeSemantics(ToType)) {
1883 bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty &&
1884 ToType == S.Context.LongDoubleTy) ||
1885 (FromType == S.Context.LongDoubleTy &&
1886 ToType == S.Context.Float128Ty));
1887 if (Float128AndLongDouble &&
1888 (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) ==
1889 &llvm::APFloat::PPCDoubleDouble()))
1890 return false;
1891 }
1892 // Floating point conversions (C++ 4.8).
1893 SCS.Second = ICK_Floating_Conversion;
1894 FromType = ToType.getUnqualifiedType();
1895 } else if ((FromType->isRealFloatingType() &&
1896 ToType->isIntegralType(S.Context)) ||
1897 (FromType->isIntegralOrUnscopedEnumerationType() &&
1898 ToType->isRealFloatingType())) {
1899 // Conversions between bfloat and int are not permitted.
1900 if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
1901 return false;
1902
1903 // Floating-integral conversions (C++ 4.9).
1904 SCS.Second = ICK_Floating_Integral;
1905 FromType = ToType.getUnqualifiedType();
1906 } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
1907 SCS.Second = ICK_Block_Pointer_Conversion;
1908 } else if (AllowObjCWritebackConversion &&
1909 S.isObjCWritebackConversion(FromType, ToType, FromType)) {
1910 SCS.Second = ICK_Writeback_Conversion;
1911 } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
1912 FromType, IncompatibleObjC)) {
1913 // Pointer conversions (C++ 4.10).
1914 SCS.Second = ICK_Pointer_Conversion;
1915 SCS.IncompatibleObjC = IncompatibleObjC;
1916 FromType = FromType.getUnqualifiedType();
1917 } else if (S.IsMemberPointerConversion(From, FromType, ToType,
1918 InOverloadResolution, FromType)) {
1919 // Pointer to member conversions (4.11).
1920 SCS.Second = ICK_Pointer_Member;
1921 } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
1922 SCS.Second = SecondICK;
1923 FromType = ToType.getUnqualifiedType();
1924 } else if (!S.getLangOpts().CPlusPlus &&
1925 S.Context.typesAreCompatible(ToType, FromType)) {
1926 // Compatible conversions (Clang extension for C function overloading)
1927 SCS.Second = ICK_Compatible_Conversion;
1928 FromType = ToType.getUnqualifiedType();
1929 } else if (IsTransparentUnionStandardConversion(S, From, ToType,
1930 InOverloadResolution,
1931 SCS, CStyle)) {
1932 SCS.Second = ICK_TransparentUnionConversion;
1933 FromType = ToType;
1934 } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
1935 CStyle)) {
1936 // tryAtomicConversion has updated the standard conversion sequence
1937 // appropriately.
1938 return true;
1939 } else if (ToType->isEventT() &&
1940 From->isIntegerConstantExpr(S.getASTContext()) &&
1941 From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
1942 SCS.Second = ICK_Zero_Event_Conversion;
1943 FromType = ToType;
1944 } else if (ToType->isQueueT() &&
1945 From->isIntegerConstantExpr(S.getASTContext()) &&
1946 (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
1947 SCS.Second = ICK_Zero_Queue_Conversion;
1948 FromType = ToType;
1949 } else if (ToType->isSamplerT() &&
1950 From->isIntegerConstantExpr(S.getASTContext())) {
1951 SCS.Second = ICK_Compatible_Conversion;
1952 FromType = ToType;
1953 } else {
1954 // No second conversion required.
1955 SCS.Second = ICK_Identity;
1956 }
1957 SCS.setToType(1, FromType);
1958
1959 // The third conversion can be a function pointer conversion or a
1960 // qualification conversion (C++ [conv.fctptr], [conv.qual]).
1961 bool ObjCLifetimeConversion;
1962 if (S.IsFunctionConversion(FromType, ToType, FromType)) {
1963 // Function pointer conversions (removing 'noexcept') including removal of
1964 // 'noreturn' (Clang extension).
1965 SCS.Third = ICK_Function_Conversion;
1966 } else if (S.IsQualificationConversion(FromType, ToType, CStyle,
1967 ObjCLifetimeConversion)) {
1968 SCS.Third = ICK_Qualification;
1969 SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
1970 FromType = ToType;
1971 } else {
1972 // No conversion required
1973 SCS.Third = ICK_Identity;
1974 }
1975
1976 // C++ [over.best.ics]p6:
1977 // [...] Any difference in top-level cv-qualification is
1978 // subsumed by the initialization itself and does not constitute
1979 // a conversion. [...]
1980 QualType CanonFrom = S.Context.getCanonicalType(FromType);
1981 QualType CanonTo = S.Context.getCanonicalType(ToType);
1982 if (CanonFrom.getLocalUnqualifiedType()
1983 == CanonTo.getLocalUnqualifiedType() &&
1984 CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
1985 FromType = ToType;
1986 CanonFrom = CanonTo;
1987 }
1988
1989 SCS.setToType(2, FromType);
1990
1991 if (CanonFrom == CanonTo)
1992 return true;
1993
1994 // If we have not converted the argument type to the parameter type,
1995 // this is a bad conversion sequence, unless we're resolving an overload in C.
1996 if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
1997 return false;
1998
1999 ExprResult ER = ExprResult{From};
2000 Sema::AssignConvertType Conv =
2001 S.CheckSingleAssignmentConstraints(ToType, ER,
2002 /*Diagnose=*/false,
2003 /*DiagnoseCFAudited=*/false,
2004 /*ConvertRHS=*/false);
2005 ImplicitConversionKind SecondConv;
2006 switch (Conv) {
2007 case Sema::Compatible:
2008 SecondConv = ICK_C_Only_Conversion;
2009 break;
2010 // For our purposes, discarding qualifiers is just as bad as using an
2011 // incompatible pointer. Note that an IncompatiblePointer conversion can drop
2012 // qualifiers, as well.
2013 case Sema::CompatiblePointerDiscardsQualifiers:
2014 case Sema::IncompatiblePointer:
2015 case Sema::IncompatiblePointerSign:
2016 SecondConv = ICK_Incompatible_Pointer_Conversion;
2017 break;
2018 default:
2019 return false;
2020 }
2021
2022 // First can only be an lvalue conversion, so we pretend that this was the
2023 // second conversion. First should already be valid from earlier in the
2024 // function.
2025 SCS.Second = SecondConv;
2026 SCS.setToType(1, ToType);
2027
2028 // Third is Identity, because Second should rank us worse than any other
2029 // conversion. This could also be ICK_Qualification, but it's simpler to just
2030 // lump everything in with the second conversion, and we don't gain anything
2031 // from making this ICK_Qualification.
2032 SCS.Third = ICK_Identity;
2033 SCS.setToType(2, ToType);
2034 return true;
2035 }
2036
2037 static bool
IsTransparentUnionStandardConversion(Sema & S,Expr * From,QualType & ToType,bool InOverloadResolution,StandardConversionSequence & SCS,bool CStyle)2038 IsTransparentUnionStandardConversion(Sema &S, Expr* From,
2039 QualType &ToType,
2040 bool InOverloadResolution,
2041 StandardConversionSequence &SCS,
2042 bool CStyle) {
2043
2044 const RecordType *UT = ToType->getAsUnionType();
2045 if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
2046 return false;
2047 // The field to initialize within the transparent union.
2048 RecordDecl *UD = UT->getDecl();
2049 // It's compatible if the expression matches any of the fields.
2050 for (const auto *it : UD->fields()) {
2051 if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
2052 CStyle, /*AllowObjCWritebackConversion=*/false)) {
2053 ToType = it->getType();
2054 return true;
2055 }
2056 }
2057 return false;
2058 }
2059
2060 /// IsIntegralPromotion - Determines whether the conversion from the
2061 /// expression From (whose potentially-adjusted type is FromType) to
2062 /// ToType is an integral promotion (C++ 4.5). If so, returns true and
2063 /// sets PromotedType to the promoted type.
IsIntegralPromotion(Expr * From,QualType FromType,QualType ToType)2064 bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
2065 const BuiltinType *To = ToType->getAs<BuiltinType>();
2066 // All integers are built-in.
2067 if (!To) {
2068 return false;
2069 }
2070
2071 // An rvalue of type char, signed char, unsigned char, short int, or
2072 // unsigned short int can be converted to an rvalue of type int if
2073 // int can represent all the values of the source type; otherwise,
2074 // the source rvalue can be converted to an rvalue of type unsigned
2075 // int (C++ 4.5p1).
2076 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
2077 !FromType->isEnumeralType()) {
2078 if (// We can promote any signed, promotable integer type to an int
2079 (FromType->isSignedIntegerType() ||
2080 // We can promote any unsigned integer type whose size is
2081 // less than int to an int.
2082 Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
2083 return To->getKind() == BuiltinType::Int;
2084 }
2085
2086 return To->getKind() == BuiltinType::UInt;
2087 }
2088
2089 // C++11 [conv.prom]p3:
2090 // A prvalue of an unscoped enumeration type whose underlying type is not
2091 // fixed (7.2) can be converted to an rvalue a prvalue of the first of the
2092 // following types that can represent all the values of the enumeration
2093 // (i.e., the values in the range bmin to bmax as described in 7.2): int,
2094 // unsigned int, long int, unsigned long int, long long int, or unsigned
2095 // long long int. If none of the types in that list can represent all the
2096 // values of the enumeration, an rvalue a prvalue of an unscoped enumeration
2097 // type can be converted to an rvalue a prvalue of the extended integer type
2098 // with lowest integer conversion rank (4.13) greater than the rank of long
2099 // long in which all the values of the enumeration can be represented. If
2100 // there are two such extended types, the signed one is chosen.
2101 // C++11 [conv.prom]p4:
2102 // A prvalue of an unscoped enumeration type whose underlying type is fixed
2103 // can be converted to a prvalue of its underlying type. Moreover, if
2104 // integral promotion can be applied to its underlying type, a prvalue of an
2105 // unscoped enumeration type whose underlying type is fixed can also be
2106 // converted to a prvalue of the promoted underlying type.
2107 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
2108 // C++0x 7.2p9: Note that this implicit enum to int conversion is not
2109 // provided for a scoped enumeration.
2110 if (FromEnumType->getDecl()->isScoped())
2111 return false;
2112
2113 // We can perform an integral promotion to the underlying type of the enum,
2114 // even if that's not the promoted type. Note that the check for promoting
2115 // the underlying type is based on the type alone, and does not consider
2116 // the bitfield-ness of the actual source expression.
2117 if (FromEnumType->getDecl()->isFixed()) {
2118 QualType Underlying = FromEnumType->getDecl()->getIntegerType();
2119 return Context.hasSameUnqualifiedType(Underlying, ToType) ||
2120 IsIntegralPromotion(nullptr, Underlying, ToType);
2121 }
2122
2123 // We have already pre-calculated the promotion type, so this is trivial.
2124 if (ToType->isIntegerType() &&
2125 isCompleteType(From->getBeginLoc(), FromType))
2126 return Context.hasSameUnqualifiedType(
2127 ToType, FromEnumType->getDecl()->getPromotionType());
2128
2129 // C++ [conv.prom]p5:
2130 // If the bit-field has an enumerated type, it is treated as any other
2131 // value of that type for promotion purposes.
2132 //
2133 // ... so do not fall through into the bit-field checks below in C++.
2134 if (getLangOpts().CPlusPlus)
2135 return false;
2136 }
2137
2138 // C++0x [conv.prom]p2:
2139 // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
2140 // to an rvalue a prvalue of the first of the following types that can
2141 // represent all the values of its underlying type: int, unsigned int,
2142 // long int, unsigned long int, long long int, or unsigned long long int.
2143 // If none of the types in that list can represent all the values of its
2144 // underlying type, an rvalue a prvalue of type char16_t, char32_t,
2145 // or wchar_t can be converted to an rvalue a prvalue of its underlying
2146 // type.
2147 if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
2148 ToType->isIntegerType()) {
2149 // Determine whether the type we're converting from is signed or
2150 // unsigned.
2151 bool FromIsSigned = FromType->isSignedIntegerType();
2152 uint64_t FromSize = Context.getTypeSize(FromType);
2153
2154 // The types we'll try to promote to, in the appropriate
2155 // order. Try each of these types.
2156 QualType PromoteTypes[6] = {
2157 Context.IntTy, Context.UnsignedIntTy,
2158 Context.LongTy, Context.UnsignedLongTy ,
2159 Context.LongLongTy, Context.UnsignedLongLongTy
2160 };
2161 for (int Idx = 0; Idx < 6; ++Idx) {
2162 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
2163 if (FromSize < ToSize ||
2164 (FromSize == ToSize &&
2165 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
2166 // We found the type that we can promote to. If this is the
2167 // type we wanted, we have a promotion. Otherwise, no
2168 // promotion.
2169 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
2170 }
2171 }
2172 }
2173
2174 // An rvalue for an integral bit-field (9.6) can be converted to an
2175 // rvalue of type int if int can represent all the values of the
2176 // bit-field; otherwise, it can be converted to unsigned int if
2177 // unsigned int can represent all the values of the bit-field. If
2178 // the bit-field is larger yet, no integral promotion applies to
2179 // it. If the bit-field has an enumerated type, it is treated as any
2180 // other value of that type for promotion purposes (C++ 4.5p3).
2181 // FIXME: We should delay checking of bit-fields until we actually perform the
2182 // conversion.
2183 //
2184 // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
2185 // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
2186 // bit-fields and those whose underlying type is larger than int) for GCC
2187 // compatibility.
2188 if (From) {
2189 if (FieldDecl *MemberDecl = From->getSourceBitField()) {
2190 llvm::APSInt BitWidth;
2191 if (FromType->isIntegralType(Context) &&
2192 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, 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 return true;
2243
2244 // Half can be promoted to float.
2245 if (!getLangOpts().NativeHalfType &&
2246 FromBuiltin->getKind() == BuiltinType::Half &&
2247 ToBuiltin->getKind() == BuiltinType::Float)
2248 return true;
2249 }
2250
2251 return false;
2252 }
2253
2254 /// Determine if a conversion is a complex promotion.
2255 ///
2256 /// A complex promotion is defined as a complex -> complex conversion
2257 /// where the conversion between the underlying real types is a
2258 /// floating-point or integral promotion.
IsComplexPromotion(QualType FromType,QualType ToType)2259 bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
2260 const ComplexType *FromComplex = FromType->getAs<ComplexType>();
2261 if (!FromComplex)
2262 return false;
2263
2264 const ComplexType *ToComplex = ToType->getAs<ComplexType>();
2265 if (!ToComplex)
2266 return false;
2267
2268 return IsFloatingPointPromotion(FromComplex->getElementType(),
2269 ToComplex->getElementType()) ||
2270 IsIntegralPromotion(nullptr, FromComplex->getElementType(),
2271 ToComplex->getElementType());
2272 }
2273
2274 /// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
2275 /// the pointer type FromPtr to a pointer to type ToPointee, with the
2276 /// same type qualifiers as FromPtr has on its pointee type. ToType,
2277 /// if non-empty, will be a pointer to ToType that may or may not have
2278 /// the right set of qualifiers on its pointee.
2279 ///
2280 static QualType
BuildSimilarlyQualifiedPointerType(const Type * FromPtr,QualType ToPointee,QualType ToType,ASTContext & Context,bool StripObjCLifetime=false)2281 BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
2282 QualType ToPointee, QualType ToType,
2283 ASTContext &Context,
2284 bool StripObjCLifetime = false) {
2285 assert((FromPtr->getTypeClass() == Type::Pointer ||
2286 FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&
2287 "Invalid similarly-qualified pointer type");
2288
2289 /// Conversions to 'id' subsume cv-qualifier conversions.
2290 if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
2291 return ToType.getUnqualifiedType();
2292
2293 const bool FromIsCap = FromPtr->isCHERICapabilityType(Context);
2294 PointerInterpretationKind PIK = FromIsCap ? PIK_Capability : PIK_Integer;
2295 QualType CanonFromPointee
2296 = Context.getCanonicalType(FromPtr->getPointeeType());
2297 QualType CanonToPointee = Context.getCanonicalType(ToPointee);
2298 Qualifiers Quals = CanonFromPointee.getQualifiers();
2299
2300 if (StripObjCLifetime)
2301 Quals.removeObjCLifetime();
2302
2303 // Exact qualifier match -> return the pointer type we're converting to.
2304 if (CanonToPointee.getLocalQualifiers() == Quals) {
2305 // ToType is exactly what we need. Return it.
2306 // XXXAR: but only if the memory capability qualifier matches
2307 if (ToType->isCHERICapabilityType(Context) == FromIsCap && !ToType.isNull())
2308 return ToType.getUnqualifiedType();
2309
2310 // Build a pointer to ToPointee. It has the right qualifiers
2311 // already.
2312 if (isa<ObjCObjectPointerType>(ToType))
2313 return Context.getObjCObjectPointerType(ToPointee);
2314 return Context.getPointerType(ToPointee, PIK);
2315 }
2316
2317 // Just build a canonical type that has the right qualifiers.
2318 QualType QualifiedCanonToPointee
2319 = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
2320
2321 if (isa<ObjCObjectPointerType>(ToType))
2322 return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
2323 return Context.getPointerType(QualifiedCanonToPointee, PIK);
2324 }
2325
isNullPointerConstantForConversion(Expr * Expr,bool InOverloadResolution,ASTContext & Context)2326 static bool isNullPointerConstantForConversion(Expr *Expr,
2327 bool InOverloadResolution,
2328 ASTContext &Context) {
2329 // Handle value-dependent integral null pointer constants correctly.
2330 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
2331 if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
2332 Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
2333 return !InOverloadResolution;
2334
2335 return Expr->isNullPointerConstant(Context,
2336 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
2337 : Expr::NPC_ValueDependentIsNull);
2338 }
2339
2340 /// IsPointerConversion - Determines whether the conversion of the
2341 /// expression From, which has the (possibly adjusted) type FromType,
2342 /// can be converted to the type ToType via a pointer conversion (C++
2343 /// 4.10). If so, returns true and places the converted type (that
2344 /// might differ from ToType in its cv-qualifiers at some level) into
2345 /// ConvertedType.
2346 ///
2347 /// This routine also supports conversions to and from block pointers
2348 /// and conversions with Objective-C's 'id', 'id<protocols...>', and
2349 /// pointers to interfaces. FIXME: Once we've determined the
2350 /// appropriate overloading rules for Objective-C, we may want to
2351 /// split the Objective-C checks into a different routine; however,
2352 /// GCC seems to consider all of these conversions to be pointer
2353 /// conversions, so for now they live here. IncompatibleObjC will be
2354 /// set if the conversion is an allowed Objective-C conversion that
2355 /// should result in a warning.
IsPointerConversion(Expr * From,QualType FromType,QualType ToType,bool InOverloadResolution,QualType & ConvertedType,bool & IncompatibleObjC)2356 bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
2357 bool InOverloadResolution,
2358 QualType& ConvertedType,
2359 bool &IncompatibleObjC) {
2360 IncompatibleObjC = false;
2361 if (isObjCPointerConversion(FromType, ToType, ConvertedType,
2362 IncompatibleObjC))
2363 return true;
2364
2365 // Conversion from a null pointer constant to any Objective-C pointer type.
2366 if (ToType->isObjCObjectPointerType() &&
2367 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2368 ConvertedType = ToType;
2369 return true;
2370 }
2371
2372 // Blocks: Block pointers can be converted to void*.
2373 if (FromType->isBlockPointerType() && ToType->isPointerType() &&
2374 ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
2375 ConvertedType = ToType;
2376 return true;
2377 }
2378 // Blocks: A null pointer constant can be converted to a block
2379 // pointer type.
2380 if (ToType->isBlockPointerType() &&
2381 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2382 ConvertedType = ToType;
2383 return true;
2384 }
2385
2386 // If the left-hand-side is nullptr_t, the right side can be a null
2387 // pointer constant.
2388 if (ToType->isNullPtrType() &&
2389 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2390 ConvertedType = ToType;
2391 return true;
2392 }
2393
2394 const PointerType* ToTypePtr = ToType->getAs<PointerType>();
2395 if (!ToTypePtr)
2396 return false;
2397
2398 // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
2399 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2400 ConvertedType = ToType;
2401 return true;
2402 }
2403
2404 // Beyond this point, both types need to be pointers
2405 // , including objective-c pointers.
2406 QualType ToPointeeType = ToTypePtr->getPointeeType();
2407 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
2408 !getLangOpts().ObjCAutoRefCount) {
2409 ConvertedType = BuildSimilarlyQualifiedPointerType(
2410 FromType->getAs<ObjCObjectPointerType>(),
2411 ToPointeeType,
2412 ToType, Context);
2413 return true;
2414 }
2415 const PointerType *FromTypePtr = FromType->getAs<PointerType>();
2416 if (!FromTypePtr)
2417 return false;
2418
2419 QualType FromPointeeType = FromTypePtr->getPointeeType();
2420
2421 // If the unqualified pointee types are the same, this can't be a
2422 // pointer conversion, so don't do all of the work below.
2423 if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
2424 return false;
2425
2426 // An rvalue of type "pointer to cv T," where T is an object type,
2427 // can be converted to an rvalue of type "pointer to cv void" (C++
2428 // 4.10p2).
2429 if (FromPointeeType->isIncompleteOrObjectType() &&
2430 ToPointeeType->isVoidType()) {
2431 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2432 ToPointeeType,
2433 ToType, Context,
2434 /*StripObjCLifetime=*/true);
2435 assert(FromType->isCHERICapabilityType(Context) ==
2436 ConvertedType->isCHERICapabilityType(Context) &&
2437 "Converted type should retain capability/pointer");
2438 return true;
2439 }
2440
2441 // MSVC allows implicit function to void* type conversion.
2442 if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
2443 ToPointeeType->isVoidType()) {
2444 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2445 ToPointeeType,
2446 ToType, Context);
2447 return true;
2448 }
2449
2450 // When we're overloading in C, we allow a special kind of pointer
2451 // conversion for compatible-but-not-identical pointee types.
2452 if (!getLangOpts().CPlusPlus &&
2453 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
2454 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2455 ToPointeeType,
2456 ToType, Context);
2457 return true;
2458 }
2459
2460 // C++ [conv.ptr]p3:
2461 //
2462 // An rvalue of type "pointer to cv D," where D is a class type,
2463 // can be converted to an rvalue of type "pointer to cv B," where
2464 // B is a base class (clause 10) of D. If B is an inaccessible
2465 // (clause 11) or ambiguous (10.2) base class of D, a program that
2466 // necessitates this conversion is ill-formed. The result of the
2467 // conversion is a pointer to the base class sub-object of the
2468 // derived class object. The null pointer value is converted to
2469 // the null pointer value of the destination type.
2470 //
2471 // Note that we do not check for ambiguity or inaccessibility
2472 // here. That is handled by CheckPointerConversion.
2473 if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
2474 ToPointeeType->isRecordType() &&
2475 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
2476 IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
2477 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2478 ToPointeeType,
2479 ToType, Context);
2480 return true;
2481 }
2482
2483 if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
2484 Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
2485 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2486 ToPointeeType,
2487 ToType, Context);
2488 return true;
2489 }
2490
2491 return false;
2492 }
2493
2494 /// Adopt the given qualifiers for the given type.
AdoptQualifiers(ASTContext & Context,QualType T,Qualifiers Qs)2495 static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
2496 Qualifiers TQs = T.getQualifiers();
2497
2498 // Check whether qualifiers already match.
2499 if (TQs == Qs)
2500 return T;
2501
2502 if (Qs.compatiblyIncludes(TQs))
2503 return Context.getQualifiedType(T, Qs);
2504
2505 return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
2506 }
2507
2508 /// isObjCPointerConversion - Determines whether this is an
2509 /// Objective-C pointer conversion. Subroutine of IsPointerConversion,
2510 /// with the same arguments and return values.
isObjCPointerConversion(QualType FromType,QualType ToType,QualType & ConvertedType,bool & IncompatibleObjC)2511 bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
2512 QualType& ConvertedType,
2513 bool &IncompatibleObjC) {
2514 if (!getLangOpts().ObjC)
2515 return false;
2516
2517 // The set of qualifiers on the type we're converting from.
2518 Qualifiers FromQualifiers = FromType.getQualifiers();
2519
2520 // First, we handle all conversions on ObjC object pointer types.
2521 const ObjCObjectPointerType* ToObjCPtr =
2522 ToType->getAs<ObjCObjectPointerType>();
2523 const ObjCObjectPointerType *FromObjCPtr =
2524 FromType->getAs<ObjCObjectPointerType>();
2525
2526 if (ToObjCPtr && FromObjCPtr) {
2527 // If the pointee types are the same (ignoring qualifications),
2528 // then this is not a pointer conversion.
2529 if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
2530 FromObjCPtr->getPointeeType()))
2531 return false;
2532
2533 // Conversion between Objective-C pointers.
2534 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
2535 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
2536 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
2537 if (getLangOpts().CPlusPlus && LHS && RHS &&
2538 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
2539 FromObjCPtr->getPointeeType()))
2540 return false;
2541 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2542 ToObjCPtr->getPointeeType(),
2543 ToType, Context);
2544 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2545 return true;
2546 }
2547
2548 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
2549 // Okay: this is some kind of implicit downcast of Objective-C
2550 // interfaces, which is permitted. However, we're going to
2551 // complain about it.
2552 IncompatibleObjC = true;
2553 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2554 ToObjCPtr->getPointeeType(),
2555 ToType, Context);
2556 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2557 return true;
2558 }
2559 }
2560 // Beyond this point, both types need to be C pointers or block pointers.
2561 QualType ToPointeeType;
2562 if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
2563 ToPointeeType = ToCPtr->getPointeeType();
2564 else if (const BlockPointerType *ToBlockPtr =
2565 ToType->getAs<BlockPointerType>()) {
2566 // Objective C++: We're able to convert from a pointer to any object
2567 // to a block pointer type.
2568 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
2569 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2570 return true;
2571 }
2572 ToPointeeType = ToBlockPtr->getPointeeType();
2573 }
2574 else if (FromType->getAs<BlockPointerType>() &&
2575 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
2576 // Objective C++: We're able to convert from a block pointer type to a
2577 // pointer to any object.
2578 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2579 return true;
2580 }
2581 else
2582 return false;
2583
2584 QualType FromPointeeType;
2585 if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
2586 FromPointeeType = FromCPtr->getPointeeType();
2587 else if (const BlockPointerType *FromBlockPtr =
2588 FromType->getAs<BlockPointerType>())
2589 FromPointeeType = FromBlockPtr->getPointeeType();
2590 else
2591 return false;
2592
2593 // If we have pointers to pointers, recursively check whether this
2594 // is an Objective-C conversion.
2595 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
2596 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2597 IncompatibleObjC)) {
2598 // We always complain about this conversion.
2599 IncompatibleObjC = true;
2600 ConvertedType = Context.getPointerType(ConvertedType);
2601 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2602 return true;
2603 }
2604 // Allow conversion of pointee being objective-c pointer to another one;
2605 // as in I* to id.
2606 if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
2607 ToPointeeType->getAs<ObjCObjectPointerType>() &&
2608 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2609 IncompatibleObjC)) {
2610
2611 ConvertedType = Context.getPointerType(ConvertedType);
2612 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2613 return true;
2614 }
2615
2616 // If we have pointers to functions or blocks, check whether the only
2617 // differences in the argument and result types are in Objective-C
2618 // pointer conversions. If so, we permit the conversion (but
2619 // complain about it).
2620 const FunctionProtoType *FromFunctionType
2621 = FromPointeeType->getAs<FunctionProtoType>();
2622 const FunctionProtoType *ToFunctionType
2623 = ToPointeeType->getAs<FunctionProtoType>();
2624 if (FromFunctionType && ToFunctionType) {
2625 // If the function types are exactly the same, this isn't an
2626 // Objective-C pointer conversion.
2627 if (Context.getCanonicalType(FromPointeeType)
2628 == Context.getCanonicalType(ToPointeeType))
2629 return false;
2630
2631 // Perform the quick checks that will tell us whether these
2632 // function types are obviously different.
2633 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2634 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
2635 FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
2636 return false;
2637
2638 bool HasObjCConversion = false;
2639 if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
2640 Context.getCanonicalType(ToFunctionType->getReturnType())) {
2641 // Okay, the types match exactly. Nothing to do.
2642 } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
2643 ToFunctionType->getReturnType(),
2644 ConvertedType, IncompatibleObjC)) {
2645 // Okay, we have an Objective-C pointer conversion.
2646 HasObjCConversion = true;
2647 } else {
2648 // Function types are too different. Abort.
2649 return false;
2650 }
2651
2652 // Check argument types.
2653 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2654 ArgIdx != NumArgs; ++ArgIdx) {
2655 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2656 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2657 if (Context.getCanonicalType(FromArgType)
2658 == Context.getCanonicalType(ToArgType)) {
2659 // Okay, the types match exactly. Nothing to do.
2660 } else if (isObjCPointerConversion(FromArgType, ToArgType,
2661 ConvertedType, IncompatibleObjC)) {
2662 // Okay, we have an Objective-C pointer conversion.
2663 HasObjCConversion = true;
2664 } else {
2665 // Argument types are too different. Abort.
2666 return false;
2667 }
2668 }
2669
2670 if (HasObjCConversion) {
2671 // We had an Objective-C conversion. Allow this pointer
2672 // conversion, but complain about it.
2673 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2674 IncompatibleObjC = true;
2675 return true;
2676 }
2677 }
2678
2679 return false;
2680 }
2681
2682 /// Determine whether this is an Objective-C writeback conversion,
2683 /// used for parameter passing when performing automatic reference counting.
2684 ///
2685 /// \param FromType The type we're converting form.
2686 ///
2687 /// \param ToType The type we're converting to.
2688 ///
2689 /// \param ConvertedType The type that will be produced after applying
2690 /// this conversion.
isObjCWritebackConversion(QualType FromType,QualType ToType,QualType & ConvertedType)2691 bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
2692 QualType &ConvertedType) {
2693 if (!getLangOpts().ObjCAutoRefCount ||
2694 Context.hasSameUnqualifiedType(FromType, ToType))
2695 return false;
2696
2697 // Parameter must be a pointer to __autoreleasing (with no other qualifiers).
2698 QualType ToPointee;
2699 if (const PointerType *ToPointer = ToType->getAs<PointerType>())
2700 ToPointee = ToPointer->getPointeeType();
2701 else
2702 return false;
2703
2704 Qualifiers ToQuals = ToPointee.getQualifiers();
2705 if (!ToPointee->isObjCLifetimeType() ||
2706 ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
2707 !ToQuals.withoutObjCLifetime().empty())
2708 return false;
2709
2710 // Argument must be a pointer to __strong to __weak.
2711 QualType FromPointee;
2712 if (const PointerType *FromPointer = FromType->getAs<PointerType>())
2713 FromPointee = FromPointer->getPointeeType();
2714 else
2715 return false;
2716
2717 Qualifiers FromQuals = FromPointee.getQualifiers();
2718 if (!FromPointee->isObjCLifetimeType() ||
2719 (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
2720 FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
2721 return false;
2722
2723 // Make sure that we have compatible qualifiers.
2724 FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
2725 if (!ToQuals.compatiblyIncludes(FromQuals))
2726 return false;
2727
2728 // Remove qualifiers from the pointee type we're converting from; they
2729 // aren't used in the compatibility check belong, and we'll be adding back
2730 // qualifiers (with __autoreleasing) if the compatibility check succeeds.
2731 FromPointee = FromPointee.getUnqualifiedType();
2732
2733 // The unqualified form of the pointee types must be compatible.
2734 ToPointee = ToPointee.getUnqualifiedType();
2735 bool IncompatibleObjC;
2736 if (Context.typesAreCompatible(FromPointee, ToPointee))
2737 FromPointee = ToPointee;
2738 else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
2739 IncompatibleObjC))
2740 return false;
2741
2742 /// Construct the type we're converting to, which is a pointer to
2743 /// __autoreleasing pointee.
2744 FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
2745 ConvertedType = Context.getPointerType(FromPointee);
2746 return true;
2747 }
2748
IsBlockPointerConversion(QualType FromType,QualType ToType,QualType & ConvertedType)2749 bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
2750 QualType& ConvertedType) {
2751 QualType ToPointeeType;
2752 if (const BlockPointerType *ToBlockPtr =
2753 ToType->getAs<BlockPointerType>())
2754 ToPointeeType = ToBlockPtr->getPointeeType();
2755 else
2756 return false;
2757
2758 QualType FromPointeeType;
2759 if (const BlockPointerType *FromBlockPtr =
2760 FromType->getAs<BlockPointerType>())
2761 FromPointeeType = FromBlockPtr->getPointeeType();
2762 else
2763 return false;
2764 // We have pointer to blocks, check whether the only
2765 // differences in the argument and result types are in Objective-C
2766 // pointer conversions. If so, we permit the conversion.
2767
2768 const FunctionProtoType *FromFunctionType
2769 = FromPointeeType->getAs<FunctionProtoType>();
2770 const FunctionProtoType *ToFunctionType
2771 = ToPointeeType->getAs<FunctionProtoType>();
2772
2773 if (!FromFunctionType || !ToFunctionType)
2774 return false;
2775
2776 if (Context.hasSameType(FromPointeeType, ToPointeeType))
2777 return true;
2778
2779 // Perform the quick checks that will tell us whether these
2780 // function types are obviously different.
2781 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2782 FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
2783 return false;
2784
2785 FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
2786 FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
2787 if (FromEInfo != ToEInfo)
2788 return false;
2789
2790 bool IncompatibleObjC = false;
2791 if (Context.hasSameType(FromFunctionType->getReturnType(),
2792 ToFunctionType->getReturnType())) {
2793 // Okay, the types match exactly. Nothing to do.
2794 } else {
2795 QualType RHS = FromFunctionType->getReturnType();
2796 QualType LHS = ToFunctionType->getReturnType();
2797 if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
2798 !RHS.hasQualifiers() && LHS.hasQualifiers())
2799 LHS = LHS.getUnqualifiedType();
2800
2801 if (Context.hasSameType(RHS,LHS)) {
2802 // OK exact match.
2803 } else if (isObjCPointerConversion(RHS, LHS,
2804 ConvertedType, IncompatibleObjC)) {
2805 if (IncompatibleObjC)
2806 return false;
2807 // Okay, we have an Objective-C pointer conversion.
2808 }
2809 else
2810 return false;
2811 }
2812
2813 // Check argument types.
2814 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2815 ArgIdx != NumArgs; ++ArgIdx) {
2816 IncompatibleObjC = false;
2817 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2818 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2819 if (Context.hasSameType(FromArgType, ToArgType)) {
2820 // Okay, the types match exactly. Nothing to do.
2821 } else if (isObjCPointerConversion(ToArgType, FromArgType,
2822 ConvertedType, IncompatibleObjC)) {
2823 if (IncompatibleObjC)
2824 return false;
2825 // Okay, we have an Objective-C pointer conversion.
2826 } else
2827 // Argument types are too different. Abort.
2828 return false;
2829 }
2830
2831 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
2832 bool CanUseToFPT, CanUseFromFPT;
2833 if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
2834 CanUseToFPT, CanUseFromFPT,
2835 NewParamInfos))
2836 return false;
2837
2838 ConvertedType = ToType;
2839 return true;
2840 }
2841
2842 enum {
2843 ft_default,
2844 ft_different_class,
2845 ft_parameter_arity,
2846 ft_parameter_mismatch,
2847 ft_return_type,
2848 ft_qualifer_mismatch,
2849 ft_noexcept
2850 };
2851
2852 /// Attempts to get the FunctionProtoType from a Type. Handles
2853 /// MemberFunctionPointers properly.
tryGetFunctionProtoType(QualType FromType)2854 static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
2855 if (auto *FPT = FromType->getAs<FunctionProtoType>())
2856 return FPT;
2857
2858 if (auto *MPT = FromType->getAs<MemberPointerType>())
2859 return MPT->getPointeeType()->getAs<FunctionProtoType>();
2860
2861 return nullptr;
2862 }
2863
2864 /// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
2865 /// function types. Catches different number of parameter, mismatch in
2866 /// parameter types, and different return types.
HandleFunctionTypeMismatch(PartialDiagnostic & PDiag,QualType FromType,QualType ToType)2867 void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
2868 QualType FromType, QualType ToType) {
2869 // If either type is not valid, include no extra info.
2870 if (FromType.isNull() || ToType.isNull()) {
2871 PDiag << ft_default;
2872 return;
2873 }
2874
2875 // Get the function type from the pointers.
2876 if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
2877 const auto *FromMember = FromType->castAs<MemberPointerType>(),
2878 *ToMember = ToType->castAs<MemberPointerType>();
2879 if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
2880 PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
2881 << QualType(FromMember->getClass(), 0);
2882 return;
2883 }
2884 FromType = FromMember->getPointeeType();
2885 ToType = ToMember->getPointeeType();
2886 }
2887
2888 if (FromType->isPointerType())
2889 FromType = FromType->getPointeeType();
2890 if (ToType->isPointerType())
2891 ToType = ToType->getPointeeType();
2892
2893 // Remove references.
2894 FromType = FromType.getNonReferenceType();
2895 ToType = ToType.getNonReferenceType();
2896
2897 // Don't print extra info for non-specialized template functions.
2898 if (FromType->isInstantiationDependentType() &&
2899 !FromType->getAs<TemplateSpecializationType>()) {
2900 PDiag << ft_default;
2901 return;
2902 }
2903
2904 // No extra info for same types.
2905 if (Context.hasSameType(FromType, ToType)) {
2906 PDiag << ft_default;
2907 return;
2908 }
2909
2910 const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
2911 *ToFunction = tryGetFunctionProtoType(ToType);
2912
2913 // Both types need to be function types.
2914 if (!FromFunction || !ToFunction) {
2915 PDiag << ft_default;
2916 return;
2917 }
2918
2919 if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
2920 PDiag << ft_parameter_arity << ToFunction->getNumParams()
2921 << FromFunction->getNumParams();
2922 return;
2923 }
2924
2925 // Handle different parameter types.
2926 unsigned ArgPos;
2927 if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
2928 PDiag << ft_parameter_mismatch << ArgPos + 1
2929 << ToFunction->getParamType(ArgPos)
2930 << FromFunction->getParamType(ArgPos);
2931 return;
2932 }
2933
2934 // Handle different return type.
2935 if (!Context.hasSameType(FromFunction->getReturnType(),
2936 ToFunction->getReturnType())) {
2937 PDiag << ft_return_type << ToFunction->getReturnType()
2938 << FromFunction->getReturnType();
2939 return;
2940 }
2941
2942 if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
2943 PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
2944 << FromFunction->getMethodQuals();
2945 return;
2946 }
2947
2948 // Handle exception specification differences on canonical type (in C++17
2949 // onwards).
2950 if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
2951 ->isNothrow() !=
2952 cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
2953 ->isNothrow()) {
2954 PDiag << ft_noexcept;
2955 return;
2956 }
2957
2958 // Unable to find a difference, so add no extra info.
2959 PDiag << ft_default;
2960 }
2961
2962 /// FunctionParamTypesAreEqual - This routine checks two function proto types
2963 /// for equality of their argument types. Caller has already checked that
2964 /// they have same number of arguments. If the parameters are different,
2965 /// ArgPos will have the parameter index of the first different parameter.
FunctionParamTypesAreEqual(const FunctionProtoType * OldType,const FunctionProtoType * NewType,unsigned * ArgPos)2966 bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
2967 const FunctionProtoType *NewType,
2968 unsigned *ArgPos) {
2969 for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
2970 N = NewType->param_type_begin(),
2971 E = OldType->param_type_end();
2972 O && (O != E); ++O, ++N) {
2973 // Ignore address spaces in pointee type. This is to disallow overloading
2974 // on __ptr32/__ptr64 address spaces.
2975 QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
2976 QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());
2977
2978 if (!Context.hasSameType(Old, New)) {
2979 if (ArgPos)
2980 *ArgPos = O - OldType->param_type_begin();
2981 return false;
2982 }
2983 }
2984 return true;
2985 }
2986
2987 /// CheckPointerConversion - Check the pointer conversion from the
2988 /// expression From to the type ToType. This routine checks for
2989 /// ambiguous or inaccessible derived-to-base pointer
2990 /// conversions for which IsPointerConversion has already returned
2991 /// true. It returns true and produces a diagnostic if there was an
2992 /// error, or returns false otherwise.
CheckPointerConversion(Expr * From,QualType ToType,CastKind & Kind,CXXCastPath & BasePath,bool IgnoreBaseAccess,bool Diagnose)2993 bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
2994 CastKind &Kind,
2995 CXXCastPath& BasePath,
2996 bool IgnoreBaseAccess,
2997 bool Diagnose) {
2998 QualType FromType = From->getType();
2999 bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
3000
3001 Kind = CK_BitCast;
3002
3003 if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
3004 From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
3005 Expr::NPCK_ZeroExpression) {
3006 if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
3007 DiagRuntimeBehavior(From->getExprLoc(), From,
3008 PDiag(diag::warn_impcast_bool_to_null_pointer)
3009 << ToType << From->getSourceRange());
3010 else if (!isUnevaluatedContext())
3011 Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
3012 << ToType << From->getSourceRange();
3013 }
3014 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
3015 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
3016 QualType FromPointeeType = FromPtrType->getPointeeType(),
3017 ToPointeeType = ToPtrType->getPointeeType();
3018
3019 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
3020 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
3021 // We must have a derived-to-base conversion. Check an
3022 // ambiguous or inaccessible conversion.
3023 unsigned InaccessibleID = 0;
3024 unsigned AmbiguousID = 0;
3025 if (Diagnose) {
3026 InaccessibleID = diag::err_upcast_to_inaccessible_base;
3027 AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
3028 }
3029 if (CheckDerivedToBaseConversion(
3030 FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
3031 From->getExprLoc(), From->getSourceRange(), DeclarationName(),
3032 &BasePath, IgnoreBaseAccess))
3033 return true;
3034
3035 // The conversion was successful.
3036 Kind = CK_DerivedToBase;
3037 }
3038
3039 if (Diagnose && !IsCStyleOrFunctionalCast &&
3040 FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
3041 assert(getLangOpts().MSVCCompat &&
3042 "this should only be possible with MSVCCompat!");
3043 Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
3044 << From->getSourceRange();
3045 }
3046 }
3047 } else if (const ObjCObjectPointerType *ToPtrType =
3048 ToType->getAs<ObjCObjectPointerType>()) {
3049 if (const ObjCObjectPointerType *FromPtrType =
3050 FromType->getAs<ObjCObjectPointerType>()) {
3051 // Objective-C++ conversions are always okay.
3052 // FIXME: We should have a different class of conversions for the
3053 // Objective-C++ implicit conversions.
3054 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
3055 return false;
3056 } else if (FromType->isBlockPointerType()) {
3057 Kind = CK_BlockPointerToObjCPointerCast;
3058 } else {
3059 Kind = CK_CPointerToObjCPointerCast;
3060 }
3061 } else if (ToType->isBlockPointerType()) {
3062 if (!FromType->isBlockPointerType())
3063 Kind = CK_AnyPointerToBlockPointerCast;
3064 }
3065
3066 // We shouldn't fall into this case unless it's valid for other
3067 // reasons.
3068 if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
3069 Kind = CK_NullToPointer;
3070
3071 return false;
3072 }
3073
3074 /// IsMemberPointerConversion - Determines whether the conversion of the
3075 /// expression From, which has the (possibly adjusted) type FromType, can be
3076 /// converted to the type ToType via a member pointer conversion (C++ 4.11).
3077 /// If so, returns true and places the converted type (that might differ from
3078 /// ToType in its cv-qualifiers at some level) into ConvertedType.
IsMemberPointerConversion(Expr * From,QualType FromType,QualType ToType,bool InOverloadResolution,QualType & ConvertedType)3079 bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
3080 QualType ToType,
3081 bool InOverloadResolution,
3082 QualType &ConvertedType) {
3083 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
3084 if (!ToTypePtr)
3085 return false;
3086
3087 // A null pointer constant can be converted to a member pointer (C++ 4.11p1)
3088 if (From->isNullPointerConstant(Context,
3089 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
3090 : Expr::NPC_ValueDependentIsNull)) {
3091 ConvertedType = ToType;
3092 return true;
3093 }
3094
3095 // Otherwise, both types have to be member pointers.
3096 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
3097 if (!FromTypePtr)
3098 return false;
3099
3100 // A pointer to member of B can be converted to a pointer to member of D,
3101 // where D is derived from B (C++ 4.11p2).
3102 QualType FromClass(FromTypePtr->getClass(), 0);
3103 QualType ToClass(ToTypePtr->getClass(), 0);
3104
3105 if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
3106 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
3107 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
3108 ToClass.getTypePtr());
3109 return true;
3110 }
3111
3112 return false;
3113 }
3114
3115 /// CheckMemberPointerConversion - Check the member pointer conversion from the
3116 /// expression From to the type ToType. This routine checks for ambiguous or
3117 /// virtual or inaccessible base-to-derived member pointer conversions
3118 /// for which IsMemberPointerConversion has already returned true. It returns
3119 /// true and produces a diagnostic if there was an error, or returns false
3120 /// otherwise.
CheckMemberPointerConversion(Expr * From,QualType ToType,CastKind & Kind,CXXCastPath & BasePath,bool IgnoreBaseAccess)3121 bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
3122 CastKind &Kind,
3123 CXXCastPath &BasePath,
3124 bool IgnoreBaseAccess) {
3125 QualType FromType = From->getType();
3126 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
3127 if (!FromPtrType) {
3128 // This must be a null pointer to member pointer conversion
3129 assert(From->isNullPointerConstant(Context,
3130 Expr::NPC_ValueDependentIsNull) &&
3131 "Expr must be null pointer constant!");
3132 Kind = CK_NullToMemberPointer;
3133 return false;
3134 }
3135
3136 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
3137 assert(ToPtrType && "No member pointer cast has a target type "
3138 "that is not a member pointer.");
3139
3140 QualType FromClass = QualType(FromPtrType->getClass(), 0);
3141 QualType ToClass = QualType(ToPtrType->getClass(), 0);
3142
3143 // FIXME: What about dependent types?
3144 assert(FromClass->isRecordType() && "Pointer into non-class.");
3145 assert(ToClass->isRecordType() && "Pointer into non-class.");
3146
3147 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3148 /*DetectVirtual=*/true);
3149 bool DerivationOkay =
3150 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
3151 assert(DerivationOkay &&
3152 "Should not have been called if derivation isn't OK.");
3153 (void)DerivationOkay;
3154
3155 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
3156 getUnqualifiedType())) {
3157 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
3158 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
3159 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
3160 return true;
3161 }
3162
3163 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
3164 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
3165 << FromClass << ToClass << QualType(VBase, 0)
3166 << From->getSourceRange();
3167 return true;
3168 }
3169
3170 if (!IgnoreBaseAccess)
3171 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
3172 Paths.front(),
3173 diag::err_downcast_from_inaccessible_base);
3174
3175 // Must be a base to derived member conversion.
3176 BuildBasePathArray(Paths, BasePath);
3177 Kind = CK_BaseToDerivedMemberPointer;
3178 return false;
3179 }
3180
3181 /// Determine whether the lifetime conversion between the two given
3182 /// qualifiers sets is nontrivial.
isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,Qualifiers ToQuals)3183 static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
3184 Qualifiers ToQuals) {
3185 // Converting anything to const __unsafe_unretained is trivial.
3186 if (ToQuals.hasConst() &&
3187 ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
3188 return false;
3189
3190 return true;
3191 }
3192
3193 /// Perform a single iteration of the loop for checking if a qualification
3194 /// conversion is valid.
3195 ///
3196 /// Specifically, check whether any change between the qualifiers of \p
3197 /// FromType and \p ToType is permissible, given knowledge about whether every
3198 /// outer layer is const-qualified.
isQualificationConversionStep(QualType FromType,QualType ToType,bool CStyle,bool IsTopLevel,bool & PreviousToQualsIncludeConst,bool & ObjCLifetimeConversion)3199 static bool isQualificationConversionStep(QualType FromType, QualType ToType,
3200 bool CStyle, bool IsTopLevel,
3201 bool &PreviousToQualsIncludeConst,
3202 bool &ObjCLifetimeConversion) {
3203 Qualifiers FromQuals = FromType.getQualifiers();
3204 Qualifiers ToQuals = ToType.getQualifiers();
3205
3206 // Ignore __unaligned qualifier if this type is void.
3207 if (ToType.getUnqualifiedType()->isVoidType())
3208 FromQuals.removeUnaligned();
3209
3210 // Objective-C ARC:
3211 // Check Objective-C lifetime conversions.
3212 if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
3213 if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
3214 if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
3215 ObjCLifetimeConversion = true;
3216 FromQuals.removeObjCLifetime();
3217 ToQuals.removeObjCLifetime();
3218 } else {
3219 // Qualification conversions cannot cast between different
3220 // Objective-C lifetime qualifiers.
3221 return false;
3222 }
3223 }
3224
3225 // Allow addition/removal of GC attributes but not changing GC attributes.
3226 if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
3227 (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
3228 FromQuals.removeObjCGCAttr();
3229 ToQuals.removeObjCGCAttr();
3230 }
3231
3232 // -- for every j > 0, if const is in cv 1,j then const is in cv
3233 // 2,j, and similarly for volatile.
3234 if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
3235 return false;
3236
3237 // If address spaces mismatch:
3238 // - in top level it is only valid to convert to addr space that is a
3239 // superset in all cases apart from C-style casts where we allow
3240 // conversions between overlapping address spaces.
3241 // - in non-top levels it is not a valid conversion.
3242 if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
3243 (!IsTopLevel ||
3244 !(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
3245 (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
3246 return false;
3247
3248 // -- if the cv 1,j and cv 2,j are different, then const is in
3249 // every cv for 0 < k < j.
3250 if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
3251 !PreviousToQualsIncludeConst)
3252 return false;
3253
3254 // Keep track of whether all prior cv-qualifiers in the "to" type
3255 // include const.
3256 PreviousToQualsIncludeConst =
3257 PreviousToQualsIncludeConst && ToQuals.hasConst();
3258 return true;
3259 }
3260
3261 /// IsQualificationConversion - Determines whether the conversion from
3262 /// an rvalue of type FromType to ToType is a qualification conversion
3263 /// (C++ 4.4).
3264 ///
3265 /// \param ObjCLifetimeConversion Output parameter that will be set to indicate
3266 /// when the qualification conversion involves a change in the Objective-C
3267 /// object lifetime.
3268 bool
IsQualificationConversion(QualType FromType,QualType ToType,bool CStyle,bool & ObjCLifetimeConversion)3269 Sema::IsQualificationConversion(QualType FromType, QualType ToType,
3270 bool CStyle, bool &ObjCLifetimeConversion) {
3271 FromType = Context.getCanonicalType(FromType);
3272 ToType = Context.getCanonicalType(ToType);
3273 ObjCLifetimeConversion = false;
3274
3275 // If FromType and ToType are the same type, this is not a
3276 // qualification conversion.
3277 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
3278 return false;
3279
3280 // (C++ 4.4p4):
3281 // A conversion can add cv-qualifiers at levels other than the first
3282 // in multi-level pointers, subject to the following rules: [...]
3283 bool PreviousToQualsIncludeConst = true;
3284 bool UnwrappedAnyPointer = false;
3285 while (Context.UnwrapSimilarTypes(FromType, ToType)) {
3286 if (!isQualificationConversionStep(
3287 FromType, ToType, CStyle, !UnwrappedAnyPointer,
3288 PreviousToQualsIncludeConst, ObjCLifetimeConversion))
3289 return false;
3290 UnwrappedAnyPointer = true;
3291 }
3292
3293 // We are left with FromType and ToType being the pointee types
3294 // after unwrapping the original FromType and ToType the same number
3295 // of times. If we unwrapped any pointers, and if FromType and
3296 // ToType have the same unqualified type (since we checked
3297 // qualifiers above), then this is a qualification conversion.
3298 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
3299 }
3300
3301 /// - Determine whether this is a conversion from a scalar type to an
3302 /// atomic type.
3303 ///
3304 /// If successful, updates \c SCS's second and third steps in the conversion
3305 /// sequence to finish the conversion.
tryAtomicConversion(Sema & S,Expr * From,QualType ToType,bool InOverloadResolution,StandardConversionSequence & SCS,bool CStyle)3306 static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
3307 bool InOverloadResolution,
3308 StandardConversionSequence &SCS,
3309 bool CStyle) {
3310 const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
3311 if (!ToAtomic)
3312 return false;
3313
3314 StandardConversionSequence InnerSCS;
3315 if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
3316 InOverloadResolution, InnerSCS,
3317 CStyle, /*AllowObjCWritebackConversion=*/false))
3318 return false;
3319
3320 SCS.Second = InnerSCS.Second;
3321 SCS.setToType(1, InnerSCS.getToType(1));
3322 SCS.Third = InnerSCS.Third;
3323 SCS.QualificationIncludesObjCLifetime
3324 = InnerSCS.QualificationIncludesObjCLifetime;
3325 SCS.setToType(2, InnerSCS.getToType(2));
3326 return true;
3327 }
3328
isFirstArgumentCompatibleWithType(ASTContext & Context,CXXConstructorDecl * Constructor,QualType Type)3329 static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
3330 CXXConstructorDecl *Constructor,
3331 QualType Type) {
3332 const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
3333 if (CtorType->getNumParams() > 0) {
3334 QualType FirstArg = CtorType->getParamType(0);
3335 if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
3336 return true;
3337 }
3338 return false;
3339 }
3340
3341 static OverloadingResult
IsInitializerListConstructorConversion(Sema & S,Expr * From,QualType ToType,CXXRecordDecl * To,UserDefinedConversionSequence & User,OverloadCandidateSet & CandidateSet,bool AllowExplicit)3342 IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
3343 CXXRecordDecl *To,
3344 UserDefinedConversionSequence &User,
3345 OverloadCandidateSet &CandidateSet,
3346 bool AllowExplicit) {
3347 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3348 for (auto *D : S.LookupConstructors(To)) {
3349 auto Info = getConstructorInfo(D);
3350 if (!Info)
3351 continue;
3352
3353 bool Usable = !Info.Constructor->isInvalidDecl() &&
3354 S.isInitListConstructor(Info.Constructor);
3355 if (Usable) {
3356 // If the first argument is (a reference to) the target type,
3357 // suppress conversions.
3358 bool SuppressUserConversions = isFirstArgumentCompatibleWithType(
3359 S.Context, Info.Constructor, ToType);
3360 if (Info.ConstructorTmpl)
3361 S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
3362 /*ExplicitArgs*/ nullptr, From,
3363 CandidateSet, SuppressUserConversions,
3364 /*PartialOverloading*/ false,
3365 AllowExplicit);
3366 else
3367 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
3368 CandidateSet, SuppressUserConversions,
3369 /*PartialOverloading*/ false, AllowExplicit);
3370 }
3371 }
3372
3373 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3374
3375 OverloadCandidateSet::iterator Best;
3376 switch (auto Result =
3377 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3378 case OR_Deleted:
3379 case OR_Success: {
3380 // Record the standard conversion we used and the conversion function.
3381 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
3382 QualType ThisType = Constructor->getThisType();
3383 // Initializer lists don't have conversions as such.
3384 User.Before.setAsIdentityConversion();
3385 User.HadMultipleCandidates = HadMultipleCandidates;
3386 User.ConversionFunction = Constructor;
3387 User.FoundConversionFunction = Best->FoundDecl;
3388 User.After.setAsIdentityConversion();
3389 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3390 User.After.setAllToTypes(ToType);
3391 return Result;
3392 }
3393
3394 case OR_No_Viable_Function:
3395 return OR_No_Viable_Function;
3396 case OR_Ambiguous:
3397 return OR_Ambiguous;
3398 }
3399
3400 llvm_unreachable("Invalid OverloadResult!");
3401 }
3402
3403 /// Determines whether there is a user-defined conversion sequence
3404 /// (C++ [over.ics.user]) that converts expression From to the type
3405 /// ToType. If such a conversion exists, User will contain the
3406 /// user-defined conversion sequence that performs such a conversion
3407 /// and this routine will return true. Otherwise, this routine returns
3408 /// false and User is unspecified.
3409 ///
3410 /// \param AllowExplicit true if the conversion should consider C++0x
3411 /// "explicit" conversion functions as well as non-explicit conversion
3412 /// functions (C++0x [class.conv.fct]p2).
3413 ///
3414 /// \param AllowObjCConversionOnExplicit true if the conversion should
3415 /// allow an extra Objective-C pointer conversion on uses of explicit
3416 /// constructors. Requires \c AllowExplicit to also be set.
3417 static OverloadingResult
IsUserDefinedConversion(Sema & S,Expr * From,QualType ToType,UserDefinedConversionSequence & User,OverloadCandidateSet & CandidateSet,AllowedExplicit AllowExplicit,bool AllowObjCConversionOnExplicit)3418 IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
3419 UserDefinedConversionSequence &User,
3420 OverloadCandidateSet &CandidateSet,
3421 AllowedExplicit AllowExplicit,
3422 bool AllowObjCConversionOnExplicit) {
3423 assert(AllowExplicit != AllowedExplicit::None ||
3424 !AllowObjCConversionOnExplicit);
3425 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3426
3427 // Whether we will only visit constructors.
3428 bool ConstructorsOnly = false;
3429
3430 // If the type we are conversion to is a class type, enumerate its
3431 // constructors.
3432 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
3433 // C++ [over.match.ctor]p1:
3434 // When objects of class type are direct-initialized (8.5), or
3435 // copy-initialized from an expression of the same or a
3436 // derived class type (8.5), overload resolution selects the
3437 // constructor. [...] For copy-initialization, the candidate
3438 // functions are all the converting constructors (12.3.1) of
3439 // that class. The argument list is the expression-list within
3440 // the parentheses of the initializer.
3441 if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
3442 (From->getType()->getAs<RecordType>() &&
3443 S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
3444 ConstructorsOnly = true;
3445
3446 if (!S.isCompleteType(From->getExprLoc(), ToType)) {
3447 // We're not going to find any constructors.
3448 } else if (CXXRecordDecl *ToRecordDecl
3449 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
3450
3451 Expr **Args = &From;
3452 unsigned NumArgs = 1;
3453 bool ListInitializing = false;
3454 if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
3455 // But first, see if there is an init-list-constructor that will work.
3456 OverloadingResult Result = IsInitializerListConstructorConversion(
3457 S, From, ToType, ToRecordDecl, User, CandidateSet,
3458 AllowExplicit == AllowedExplicit::All);
3459 if (Result != OR_No_Viable_Function)
3460 return Result;
3461 // Never mind.
3462 CandidateSet.clear(
3463 OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3464
3465 // If we're list-initializing, we pass the individual elements as
3466 // arguments, not the entire list.
3467 Args = InitList->getInits();
3468 NumArgs = InitList->getNumInits();
3469 ListInitializing = true;
3470 }
3471
3472 for (auto *D : S.LookupConstructors(ToRecordDecl)) {
3473 auto Info = getConstructorInfo(D);
3474 if (!Info)
3475 continue;
3476
3477 bool Usable = !Info.Constructor->isInvalidDecl();
3478 if (!ListInitializing)
3479 Usable = Usable && Info.Constructor->isConvertingConstructor(
3480 /*AllowExplicit*/ true);
3481 if (Usable) {
3482 bool SuppressUserConversions = !ConstructorsOnly;
3483 if (SuppressUserConversions && ListInitializing) {
3484 SuppressUserConversions = false;
3485 if (NumArgs == 1) {
3486 // If the first argument is (a reference to) the target type,
3487 // suppress conversions.
3488 SuppressUserConversions = isFirstArgumentCompatibleWithType(
3489 S.Context, Info.Constructor, ToType);
3490 }
3491 }
3492 if (Info.ConstructorTmpl)
3493 S.AddTemplateOverloadCandidate(
3494 Info.ConstructorTmpl, Info.FoundDecl,
3495 /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
3496 CandidateSet, SuppressUserConversions,
3497 /*PartialOverloading*/ false,
3498 AllowExplicit == AllowedExplicit::All);
3499 else
3500 // Allow one user-defined conversion when user specifies a
3501 // From->ToType conversion via an static cast (c-style, etc).
3502 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
3503 llvm::makeArrayRef(Args, NumArgs),
3504 CandidateSet, SuppressUserConversions,
3505 /*PartialOverloading*/ false,
3506 AllowExplicit == AllowedExplicit::All);
3507 }
3508 }
3509 }
3510 }
3511
3512 // Enumerate conversion functions, if we're allowed to.
3513 if (ConstructorsOnly || isa<InitListExpr>(From)) {
3514 } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
3515 // No conversion functions from incomplete types.
3516 } else if (const RecordType *FromRecordType =
3517 From->getType()->getAs<RecordType>()) {
3518 if (CXXRecordDecl *FromRecordDecl
3519 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
3520 // Add all of the conversion functions as candidates.
3521 const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
3522 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3523 DeclAccessPair FoundDecl = I.getPair();
3524 NamedDecl *D = FoundDecl.getDecl();
3525 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
3526 if (isa<UsingShadowDecl>(D))
3527 D = cast<UsingShadowDecl>(D)->getTargetDecl();
3528
3529 CXXConversionDecl *Conv;
3530 FunctionTemplateDecl *ConvTemplate;
3531 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
3532 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3533 else
3534 Conv = cast<CXXConversionDecl>(D);
3535
3536 if (ConvTemplate)
3537 S.AddTemplateConversionCandidate(
3538 ConvTemplate, FoundDecl, ActingContext, From, ToType,
3539 CandidateSet, AllowObjCConversionOnExplicit,
3540 AllowExplicit != AllowedExplicit::None);
3541 else
3542 S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
3543 CandidateSet, AllowObjCConversionOnExplicit,
3544 AllowExplicit != AllowedExplicit::None);
3545 }
3546 }
3547 }
3548
3549 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3550
3551 OverloadCandidateSet::iterator Best;
3552 switch (auto Result =
3553 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3554 case OR_Success:
3555 case OR_Deleted:
3556 // Record the standard conversion we used and the conversion function.
3557 if (CXXConstructorDecl *Constructor
3558 = dyn_cast<CXXConstructorDecl>(Best->Function)) {
3559 // C++ [over.ics.user]p1:
3560 // If the user-defined conversion is specified by a
3561 // constructor (12.3.1), the initial standard conversion
3562 // sequence converts the source type to the type required by
3563 // the argument of the constructor.
3564 //
3565 QualType ThisType = Constructor->getThisType();
3566 if (isa<InitListExpr>(From)) {
3567 // Initializer lists don't have conversions as such.
3568 User.Before.setAsIdentityConversion();
3569 } else {
3570 if (Best->Conversions[0].isEllipsis())
3571 User.EllipsisConversion = true;
3572 else {
3573 User.Before = Best->Conversions[0].Standard;
3574 User.EllipsisConversion = false;
3575 }
3576 }
3577 User.HadMultipleCandidates = HadMultipleCandidates;
3578 User.ConversionFunction = Constructor;
3579 User.FoundConversionFunction = Best->FoundDecl;
3580 User.After.setAsIdentityConversion();
3581 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3582 User.After.setAllToTypes(ToType);
3583 return Result;
3584 }
3585 if (CXXConversionDecl *Conversion
3586 = dyn_cast<CXXConversionDecl>(Best->Function)) {
3587 // C++ [over.ics.user]p1:
3588 //
3589 // [...] If the user-defined conversion is specified by a
3590 // conversion function (12.3.2), the initial standard
3591 // conversion sequence converts the source type to the
3592 // implicit object parameter of the conversion function.
3593 User.Before = Best->Conversions[0].Standard;
3594 User.HadMultipleCandidates = HadMultipleCandidates;
3595 User.ConversionFunction = Conversion;
3596 User.FoundConversionFunction = Best->FoundDecl;
3597 User.EllipsisConversion = false;
3598
3599 // C++ [over.ics.user]p2:
3600 // The second standard conversion sequence converts the
3601 // result of the user-defined conversion to the target type
3602 // for the sequence. Since an implicit conversion sequence
3603 // is an initialization, the special rules for
3604 // initialization by user-defined conversion apply when
3605 // selecting the best user-defined conversion for a
3606 // user-defined conversion sequence (see 13.3.3 and
3607 // 13.3.3.1).
3608 User.After = Best->FinalConversion;
3609 return Result;
3610 }
3611 llvm_unreachable("Not a constructor or conversion function?");
3612
3613 case OR_No_Viable_Function:
3614 return OR_No_Viable_Function;
3615
3616 case OR_Ambiguous:
3617 return OR_Ambiguous;
3618 }
3619
3620 llvm_unreachable("Invalid OverloadResult!");
3621 }
3622
3623 bool
DiagnoseMultipleUserDefinedConversion(Expr * From,QualType ToType)3624 Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
3625 ImplicitConversionSequence ICS;
3626 OverloadCandidateSet CandidateSet(From->getExprLoc(),
3627 OverloadCandidateSet::CSK_Normal);
3628 OverloadingResult OvResult =
3629 IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
3630 CandidateSet, AllowedExplicit::None, false);
3631
3632 if (!(OvResult == OR_Ambiguous ||
3633 (OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
3634 return false;
3635
3636 auto Cands = CandidateSet.CompleteCandidates(
3637 *this,
3638 OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
3639 From);
3640 if (OvResult == OR_Ambiguous)
3641 Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
3642 << From->getType() << ToType << From->getSourceRange();
3643 else { // OR_No_Viable_Function && !CandidateSet.empty()
3644 if (!RequireCompleteType(From->getBeginLoc(), ToType,
3645 diag::err_typecheck_nonviable_condition_incomplete,
3646 From->getType(), From->getSourceRange()))
3647 Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
3648 << false << From->getType() << From->getSourceRange() << ToType;
3649 }
3650
3651 CandidateSet.NoteCandidates(
3652 *this, From, Cands);
3653 return true;
3654 }
3655
3656 /// Compare the user-defined conversion functions or constructors
3657 /// of two user-defined conversion sequences to determine whether any ordering
3658 /// is possible.
3659 static ImplicitConversionSequence::CompareKind
compareConversionFunctions(Sema & S,FunctionDecl * Function1,FunctionDecl * Function2)3660 compareConversionFunctions(Sema &S, FunctionDecl *Function1,
3661 FunctionDecl *Function2) {
3662 if (!S.getLangOpts().ObjC || !S.getLangOpts().CPlusPlus11)
3663 return ImplicitConversionSequence::Indistinguishable;
3664
3665 // Objective-C++:
3666 // If both conversion functions are implicitly-declared conversions from
3667 // a lambda closure type to a function pointer and a block pointer,
3668 // respectively, always prefer the conversion to a function pointer,
3669 // because the function pointer is more lightweight and is more likely
3670 // to keep code working.
3671 CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
3672 if (!Conv1)
3673 return ImplicitConversionSequence::Indistinguishable;
3674
3675 CXXConversionDecl *Conv2 = dyn_cast<CXXConversionDecl>(Function2);
3676 if (!Conv2)
3677 return ImplicitConversionSequence::Indistinguishable;
3678
3679 if (Conv1->getParent()->isLambda() && Conv2->getParent()->isLambda()) {
3680 bool Block1 = Conv1->getConversionType()->isBlockPointerType();
3681 bool Block2 = Conv2->getConversionType()->isBlockPointerType();
3682 if (Block1 != Block2)
3683 return Block1 ? ImplicitConversionSequence::Worse
3684 : ImplicitConversionSequence::Better;
3685 }
3686
3687 return ImplicitConversionSequence::Indistinguishable;
3688 }
3689
hasDeprecatedStringLiteralToCharPtrConversion(const ImplicitConversionSequence & ICS)3690 static bool hasDeprecatedStringLiteralToCharPtrConversion(
3691 const ImplicitConversionSequence &ICS) {
3692 return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
3693 (ICS.isUserDefined() &&
3694 ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
3695 }
3696
3697 /// CompareImplicitConversionSequences - Compare two implicit
3698 /// conversion sequences to determine whether one is better than the
3699 /// other or if they are indistinguishable (C++ 13.3.3.2).
3700 static ImplicitConversionSequence::CompareKind
CompareImplicitConversionSequences(Sema & S,SourceLocation Loc,const ImplicitConversionSequence & ICS1,const ImplicitConversionSequence & ICS2)3701 CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
3702 const ImplicitConversionSequence& ICS1,
3703 const ImplicitConversionSequence& ICS2)
3704 {
3705 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
3706 // conversion sequences (as defined in 13.3.3.1)
3707 // -- a standard conversion sequence (13.3.3.1.1) is a better
3708 // conversion sequence than a user-defined conversion sequence or
3709 // an ellipsis conversion sequence, and
3710 // -- a user-defined conversion sequence (13.3.3.1.2) is a better
3711 // conversion sequence than an ellipsis conversion sequence
3712 // (13.3.3.1.3).
3713 //
3714 // C++0x [over.best.ics]p10:
3715 // For the purpose of ranking implicit conversion sequences as
3716 // described in 13.3.3.2, the ambiguous conversion sequence is
3717 // treated as a user-defined sequence that is indistinguishable
3718 // from any other user-defined conversion sequence.
3719
3720 // String literal to 'char *' conversion has been deprecated in C++03. It has
3721 // been removed from C++11. We still accept this conversion, if it happens at
3722 // the best viable function. Otherwise, this conversion is considered worse
3723 // than ellipsis conversion. Consider this as an extension; this is not in the
3724 // standard. For example:
3725 //
3726 // int &f(...); // #1
3727 // void f(char*); // #2
3728 // void g() { int &r = f("foo"); }
3729 //
3730 // In C++03, we pick #2 as the best viable function.
3731 // In C++11, we pick #1 as the best viable function, because ellipsis
3732 // conversion is better than string-literal to char* conversion (since there
3733 // is no such conversion in C++11). If there was no #1 at all or #1 couldn't
3734 // convert arguments, #2 would be the best viable function in C++11.
3735 // If the best viable function has this conversion, a warning will be issued
3736 // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
3737
3738 if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
3739 hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
3740 hasDeprecatedStringLiteralToCharPtrConversion(ICS2))
3741 return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
3742 ? ImplicitConversionSequence::Worse
3743 : ImplicitConversionSequence::Better;
3744
3745 if (ICS1.getKindRank() < ICS2.getKindRank())
3746 return ImplicitConversionSequence::Better;
3747 if (ICS2.getKindRank() < ICS1.getKindRank())
3748 return ImplicitConversionSequence::Worse;
3749
3750 // The following checks require both conversion sequences to be of
3751 // the same kind.
3752 if (ICS1.getKind() != ICS2.getKind())
3753 return ImplicitConversionSequence::Indistinguishable;
3754
3755 ImplicitConversionSequence::CompareKind Result =
3756 ImplicitConversionSequence::Indistinguishable;
3757
3758 // Two implicit conversion sequences of the same form are
3759 // indistinguishable conversion sequences unless one of the
3760 // following rules apply: (C++ 13.3.3.2p3):
3761
3762 // List-initialization sequence L1 is a better conversion sequence than
3763 // list-initialization sequence L2 if:
3764 // - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
3765 // if not that,
3766 // - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T",
3767 // and N1 is smaller than N2.,
3768 // even if one of the other rules in this paragraph would otherwise apply.
3769 if (!ICS1.isBad()) {
3770 if (ICS1.isStdInitializerListElement() &&
3771 !ICS2.isStdInitializerListElement())
3772 return ImplicitConversionSequence::Better;
3773 if (!ICS1.isStdInitializerListElement() &&
3774 ICS2.isStdInitializerListElement())
3775 return ImplicitConversionSequence::Worse;
3776 }
3777
3778 if (ICS1.isStandard())
3779 // Standard conversion sequence S1 is a better conversion sequence than
3780 // standard conversion sequence S2 if [...]
3781 Result = CompareStandardConversionSequences(S, Loc,
3782 ICS1.Standard, ICS2.Standard);
3783 else if (ICS1.isUserDefined()) {
3784 // User-defined conversion sequence U1 is a better conversion
3785 // sequence than another user-defined conversion sequence U2 if
3786 // they contain the same user-defined conversion function or
3787 // constructor and if the second standard conversion sequence of
3788 // U1 is better than the second standard conversion sequence of
3789 // U2 (C++ 13.3.3.2p3).
3790 if (ICS1.UserDefined.ConversionFunction ==
3791 ICS2.UserDefined.ConversionFunction)
3792 Result = CompareStandardConversionSequences(S, Loc,
3793 ICS1.UserDefined.After,
3794 ICS2.UserDefined.After);
3795 else
3796 Result = compareConversionFunctions(S,
3797 ICS1.UserDefined.ConversionFunction,
3798 ICS2.UserDefined.ConversionFunction);
3799 }
3800
3801 return Result;
3802 }
3803
3804 // Per 13.3.3.2p3, compare the given standard conversion sequences to
3805 // determine if one is a proper subset of the other.
3806 static ImplicitConversionSequence::CompareKind
compareStandardConversionSubsets(ASTContext & Context,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3807 compareStandardConversionSubsets(ASTContext &Context,
3808 const StandardConversionSequence& SCS1,
3809 const StandardConversionSequence& SCS2) {
3810 ImplicitConversionSequence::CompareKind Result
3811 = ImplicitConversionSequence::Indistinguishable;
3812
3813 // the identity conversion sequence is considered to be a subsequence of
3814 // any non-identity conversion sequence
3815 if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
3816 return ImplicitConversionSequence::Better;
3817 else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
3818 return ImplicitConversionSequence::Worse;
3819
3820 if (SCS1.Second != SCS2.Second) {
3821 if (SCS1.Second == ICK_Identity)
3822 Result = ImplicitConversionSequence::Better;
3823 else if (SCS2.Second == ICK_Identity)
3824 Result = ImplicitConversionSequence::Worse;
3825 else
3826 return ImplicitConversionSequence::Indistinguishable;
3827 } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
3828 return ImplicitConversionSequence::Indistinguishable;
3829
3830 if (SCS1.Third == SCS2.Third) {
3831 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
3832 : ImplicitConversionSequence::Indistinguishable;
3833 }
3834
3835 if (SCS1.Third == ICK_Identity)
3836 return Result == ImplicitConversionSequence::Worse
3837 ? ImplicitConversionSequence::Indistinguishable
3838 : ImplicitConversionSequence::Better;
3839
3840 if (SCS2.Third == ICK_Identity)
3841 return Result == ImplicitConversionSequence::Better
3842 ? ImplicitConversionSequence::Indistinguishable
3843 : ImplicitConversionSequence::Worse;
3844
3845 return ImplicitConversionSequence::Indistinguishable;
3846 }
3847
3848 /// Determine whether one of the given reference bindings is better
3849 /// than the other based on what kind of bindings they are.
3850 static bool
isBetterReferenceBindingKind(const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3851 isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
3852 const StandardConversionSequence &SCS2) {
3853 // C++0x [over.ics.rank]p3b4:
3854 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
3855 // implicit object parameter of a non-static member function declared
3856 // without a ref-qualifier, and *either* S1 binds an rvalue reference
3857 // to an rvalue and S2 binds an lvalue reference *or S1 binds an
3858 // lvalue reference to a function lvalue and S2 binds an rvalue
3859 // reference*.
3860 //
3861 // FIXME: Rvalue references. We're going rogue with the above edits,
3862 // because the semantics in the current C++0x working paper (N3225 at the
3863 // time of this writing) break the standard definition of std::forward
3864 // and std::reference_wrapper when dealing with references to functions.
3865 // Proposed wording changes submitted to CWG for consideration.
3866 if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
3867 SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
3868 return false;
3869
3870 return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
3871 SCS2.IsLvalueReference) ||
3872 (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
3873 !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
3874 }
3875
3876 enum class FixedEnumPromotion {
3877 None,
3878 ToUnderlyingType,
3879 ToPromotedUnderlyingType
3880 };
3881
3882 /// Returns kind of fixed enum promotion the \a SCS uses.
3883 static FixedEnumPromotion
getFixedEnumPromtion(Sema & S,const StandardConversionSequence & SCS)3884 getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {
3885
3886 if (SCS.Second != ICK_Integral_Promotion)
3887 return FixedEnumPromotion::None;
3888
3889 QualType FromType = SCS.getFromType();
3890 if (!FromType->isEnumeralType())
3891 return FixedEnumPromotion::None;
3892
3893 EnumDecl *Enum = FromType->getAs<EnumType>()->getDecl();
3894 if (!Enum->isFixed())
3895 return FixedEnumPromotion::None;
3896
3897 QualType UnderlyingType = Enum->getIntegerType();
3898 if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
3899 return FixedEnumPromotion::ToUnderlyingType;
3900
3901 return FixedEnumPromotion::ToPromotedUnderlyingType;
3902 }
3903
3904 /// CompareStandardConversionSequences - Compare two standard
3905 /// conversion sequences to determine whether one is better than the
3906 /// other or if they are indistinguishable (C++ 13.3.3.2p3).
3907 static ImplicitConversionSequence::CompareKind
CompareStandardConversionSequences(Sema & S,SourceLocation Loc,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3908 CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
3909 const StandardConversionSequence& SCS1,
3910 const StandardConversionSequence& SCS2)
3911 {
3912 // Standard conversion sequence S1 is a better conversion sequence
3913 // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
3914
3915 // -- S1 is a proper subsequence of S2 (comparing the conversion
3916 // sequences in the canonical form defined by 13.3.3.1.1,
3917 // excluding any Lvalue Transformation; the identity conversion
3918 // sequence is considered to be a subsequence of any
3919 // non-identity conversion sequence) or, if not that,
3920 if (ImplicitConversionSequence::CompareKind CK
3921 = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
3922 return CK;
3923
3924 // -- the rank of S1 is better than the rank of S2 (by the rules
3925 // defined below), or, if not that,
3926 ImplicitConversionRank Rank1 = SCS1.getRank();
3927 ImplicitConversionRank Rank2 = SCS2.getRank();
3928 if (Rank1 < Rank2)
3929 return ImplicitConversionSequence::Better;
3930 else if (Rank2 < Rank1)
3931 return ImplicitConversionSequence::Worse;
3932
3933 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
3934 // are indistinguishable unless one of the following rules
3935 // applies:
3936
3937 // A conversion that is not a conversion of a pointer, or
3938 // pointer to member, to bool is better than another conversion
3939 // that is such a conversion.
3940 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
3941 return SCS2.isPointerConversionToBool()
3942 ? ImplicitConversionSequence::Better
3943 : ImplicitConversionSequence::Worse;
3944
3945 // C++14 [over.ics.rank]p4b2:
3946 // This is retroactively applied to C++11 by CWG 1601.
3947 //
3948 // A conversion that promotes an enumeration whose underlying type is fixed
3949 // to its underlying type is better than one that promotes to the promoted
3950 // underlying type, if the two are different.
3951 FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
3952 FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
3953 if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
3954 FEP1 != FEP2)
3955 return FEP1 == FixedEnumPromotion::ToUnderlyingType
3956 ? ImplicitConversionSequence::Better
3957 : ImplicitConversionSequence::Worse;
3958
3959 // C++ [over.ics.rank]p4b2:
3960 //
3961 // If class B is derived directly or indirectly from class A,
3962 // conversion of B* to A* is better than conversion of B* to
3963 // void*, and conversion of A* to void* is better than conversion
3964 // of B* to void*.
3965 bool SCS1ConvertsToVoid
3966 = SCS1.isPointerConversionToVoidPointer(S.Context);
3967 bool SCS2ConvertsToVoid
3968 = SCS2.isPointerConversionToVoidPointer(S.Context);
3969 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
3970 // Exactly one of the conversion sequences is a conversion to
3971 // a void pointer; it's the worse conversion.
3972 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
3973 : ImplicitConversionSequence::Worse;
3974 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
3975 // Neither conversion sequence converts to a void pointer; compare
3976 // their derived-to-base conversions.
3977 if (ImplicitConversionSequence::CompareKind DerivedCK
3978 = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
3979 return DerivedCK;
3980 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
3981 !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
3982 // Both conversion sequences are conversions to void
3983 // pointers. Compare the source types to determine if there's an
3984 // inheritance relationship in their sources.
3985 QualType FromType1 = SCS1.getFromType();
3986 QualType FromType2 = SCS2.getFromType();
3987
3988 // Adjust the types we're converting from via the array-to-pointer
3989 // conversion, if we need to.
3990 if (SCS1.First == ICK_Array_To_Pointer)
3991 FromType1 = S.Context.getArrayDecayedType(FromType1);
3992 if (SCS2.First == ICK_Array_To_Pointer)
3993 FromType2 = S.Context.getArrayDecayedType(FromType2);
3994
3995 QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
3996 QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
3997
3998 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
3999 return ImplicitConversionSequence::Better;
4000 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4001 return ImplicitConversionSequence::Worse;
4002
4003 // Objective-C++: If one interface is more specific than the
4004 // other, it is the better one.
4005 const ObjCObjectPointerType* FromObjCPtr1
4006 = FromType1->getAs<ObjCObjectPointerType>();
4007 const ObjCObjectPointerType* FromObjCPtr2
4008 = FromType2->getAs<ObjCObjectPointerType>();
4009 if (FromObjCPtr1 && FromObjCPtr2) {
4010 bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
4011 FromObjCPtr2);
4012 bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
4013 FromObjCPtr1);
4014 if (AssignLeft != AssignRight) {
4015 return AssignLeft? ImplicitConversionSequence::Better
4016 : ImplicitConversionSequence::Worse;
4017 }
4018 }
4019 }
4020
4021 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4022 // Check for a better reference binding based on the kind of bindings.
4023 if (isBetterReferenceBindingKind(SCS1, SCS2))
4024 return ImplicitConversionSequence::Better;
4025 else if (isBetterReferenceBindingKind(SCS2, SCS1))
4026 return ImplicitConversionSequence::Worse;
4027 }
4028
4029 // Compare based on qualification conversions (C++ 13.3.3.2p3,
4030 // bullet 3).
4031 if (ImplicitConversionSequence::CompareKind QualCK
4032 = CompareQualificationConversions(S, SCS1, SCS2))
4033 return QualCK;
4034
4035 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4036 // C++ [over.ics.rank]p3b4:
4037 // -- S1 and S2 are reference bindings (8.5.3), and the types to
4038 // which the references refer are the same type except for
4039 // top-level cv-qualifiers, and the type to which the reference
4040 // initialized by S2 refers is more cv-qualified than the type
4041 // to which the reference initialized by S1 refers.
4042 QualType T1 = SCS1.getToType(2);
4043 QualType T2 = SCS2.getToType(2);
4044 T1 = S.Context.getCanonicalType(T1);
4045 T2 = S.Context.getCanonicalType(T2);
4046 Qualifiers T1Quals, T2Quals;
4047 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4048 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4049 if (UnqualT1 == UnqualT2) {
4050 // Objective-C++ ARC: If the references refer to objects with different
4051 // lifetimes, prefer bindings that don't change lifetime.
4052 if (SCS1.ObjCLifetimeConversionBinding !=
4053 SCS2.ObjCLifetimeConversionBinding) {
4054 return SCS1.ObjCLifetimeConversionBinding
4055 ? ImplicitConversionSequence::Worse
4056 : ImplicitConversionSequence::Better;
4057 }
4058
4059 // If the type is an array type, promote the element qualifiers to the
4060 // type for comparison.
4061 if (isa<ArrayType>(T1) && T1Quals)
4062 T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
4063 if (isa<ArrayType>(T2) && T2Quals)
4064 T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
4065 if (T2.isMoreQualifiedThan(T1))
4066 return ImplicitConversionSequence::Better;
4067 if (T1.isMoreQualifiedThan(T2))
4068 return ImplicitConversionSequence::Worse;
4069 }
4070 }
4071
4072 // In Microsoft mode, prefer an integral conversion to a
4073 // floating-to-integral conversion if the integral conversion
4074 // is between types of the same size.
4075 // For example:
4076 // void f(float);
4077 // void f(int);
4078 // int main {
4079 // long a;
4080 // f(a);
4081 // }
4082 // Here, MSVC will call f(int) instead of generating a compile error
4083 // as clang will do in standard mode.
4084 if (S.getLangOpts().MSVCCompat && SCS1.Second == ICK_Integral_Conversion &&
4085 SCS2.Second == ICK_Floating_Integral &&
4086 S.Context.getTypeSize(SCS1.getFromType()) ==
4087 S.Context.getTypeSize(SCS1.getToType(2)))
4088 return ImplicitConversionSequence::Better;
4089
4090 // Prefer a compatible vector conversion over a lax vector conversion
4091 // For example:
4092 //
4093 // typedef float __v4sf __attribute__((__vector_size__(16)));
4094 // void f(vector float);
4095 // void f(vector signed int);
4096 // int main() {
4097 // __v4sf a;
4098 // f(a);
4099 // }
4100 // Here, we'd like to choose f(vector float) and not
4101 // report an ambiguous call error
4102 if (SCS1.Second == ICK_Vector_Conversion &&
4103 SCS2.Second == ICK_Vector_Conversion) {
4104 bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4105 SCS1.getFromType(), SCS1.getToType(2));
4106 bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4107 SCS2.getFromType(), SCS2.getToType(2));
4108
4109 if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
4110 return SCS1IsCompatibleVectorConversion
4111 ? ImplicitConversionSequence::Better
4112 : ImplicitConversionSequence::Worse;
4113 }
4114
4115 return ImplicitConversionSequence::Indistinguishable;
4116 }
4117
4118 /// CompareQualificationConversions - Compares two standard conversion
4119 /// sequences to determine whether they can be ranked based on their
4120 /// qualification conversions (C++ 13.3.3.2p3 bullet 3).
4121 static ImplicitConversionSequence::CompareKind
CompareQualificationConversions(Sema & S,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)4122 CompareQualificationConversions(Sema &S,
4123 const StandardConversionSequence& SCS1,
4124 const StandardConversionSequence& SCS2) {
4125 // C++ 13.3.3.2p3:
4126 // -- S1 and S2 differ only in their qualification conversion and
4127 // yield similar types T1 and T2 (C++ 4.4), respectively, and the
4128 // cv-qualification signature of type T1 is a proper subset of
4129 // the cv-qualification signature of type T2, and S1 is not the
4130 // deprecated string literal array-to-pointer conversion (4.2).
4131 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
4132 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
4133 return ImplicitConversionSequence::Indistinguishable;
4134
4135 // FIXME: the example in the standard doesn't use a qualification
4136 // conversion (!)
4137 QualType T1 = SCS1.getToType(2);
4138 QualType T2 = SCS2.getToType(2);
4139 T1 = S.Context.getCanonicalType(T1);
4140 T2 = S.Context.getCanonicalType(T2);
4141 assert(!T1->isReferenceType() && !T2->isReferenceType());
4142 Qualifiers T1Quals, T2Quals;
4143 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4144 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4145
4146 // If the types are the same, we won't learn anything by unwrapping
4147 // them.
4148 if (UnqualT1 == UnqualT2)
4149 return ImplicitConversionSequence::Indistinguishable;
4150
4151 ImplicitConversionSequence::CompareKind Result
4152 = ImplicitConversionSequence::Indistinguishable;
4153
4154 // Objective-C++ ARC:
4155 // Prefer qualification conversions not involving a change in lifetime
4156 // to qualification conversions that do not change lifetime.
4157 if (SCS1.QualificationIncludesObjCLifetime !=
4158 SCS2.QualificationIncludesObjCLifetime) {
4159 Result = SCS1.QualificationIncludesObjCLifetime
4160 ? ImplicitConversionSequence::Worse
4161 : ImplicitConversionSequence::Better;
4162 }
4163
4164 while (S.Context.UnwrapSimilarTypes(T1, T2)) {
4165 // Within each iteration of the loop, we check the qualifiers to
4166 // determine if this still looks like a qualification
4167 // conversion. Then, if all is well, we unwrap one more level of
4168 // pointers or pointers-to-members and do it all again
4169 // until there are no more pointers or pointers-to-members left
4170 // to unwrap. This essentially mimics what
4171 // IsQualificationConversion does, but here we're checking for a
4172 // strict subset of qualifiers.
4173 if (T1.getQualifiers().withoutObjCLifetime() ==
4174 T2.getQualifiers().withoutObjCLifetime())
4175 // The qualifiers are the same, so this doesn't tell us anything
4176 // about how the sequences rank.
4177 // ObjC ownership quals are omitted above as they interfere with
4178 // the ARC overload rule.
4179 ;
4180 else if (T2.isMoreQualifiedThan(T1)) {
4181 // T1 has fewer qualifiers, so it could be the better sequence.
4182 if (Result == ImplicitConversionSequence::Worse)
4183 // Neither has qualifiers that are a subset of the other's
4184 // qualifiers.
4185 return ImplicitConversionSequence::Indistinguishable;
4186
4187 Result = ImplicitConversionSequence::Better;
4188 } else if (T1.isMoreQualifiedThan(T2)) {
4189 // T2 has fewer qualifiers, so it could be the better sequence.
4190 if (Result == ImplicitConversionSequence::Better)
4191 // Neither has qualifiers that are a subset of the other's
4192 // qualifiers.
4193 return ImplicitConversionSequence::Indistinguishable;
4194
4195 Result = ImplicitConversionSequence::Worse;
4196 } else {
4197 // Qualifiers are disjoint.
4198 return ImplicitConversionSequence::Indistinguishable;
4199 }
4200
4201 // If the types after this point are equivalent, we're done.
4202 if (S.Context.hasSameUnqualifiedType(T1, T2))
4203 break;
4204 }
4205
4206 // Check that the winning standard conversion sequence isn't using
4207 // the deprecated string literal array to pointer conversion.
4208 switch (Result) {
4209 case ImplicitConversionSequence::Better:
4210 if (SCS1.DeprecatedStringLiteralToCharPtr)
4211 Result = ImplicitConversionSequence::Indistinguishable;
4212 break;
4213
4214 case ImplicitConversionSequence::Indistinguishable:
4215 break;
4216
4217 case ImplicitConversionSequence::Worse:
4218 if (SCS2.DeprecatedStringLiteralToCharPtr)
4219 Result = ImplicitConversionSequence::Indistinguishable;
4220 break;
4221 }
4222
4223 return Result;
4224 }
4225
4226 /// CompareDerivedToBaseConversions - Compares two standard conversion
4227 /// sequences to determine whether they can be ranked based on their
4228 /// various kinds of derived-to-base conversions (C++
4229 /// [over.ics.rank]p4b3). As part of these checks, we also look at
4230 /// conversions between Objective-C interface types.
4231 static ImplicitConversionSequence::CompareKind
CompareDerivedToBaseConversions(Sema & S,SourceLocation Loc,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)4232 CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
4233 const StandardConversionSequence& SCS1,
4234 const StandardConversionSequence& SCS2) {
4235 QualType FromType1 = SCS1.getFromType();
4236 QualType ToType1 = SCS1.getToType(1);
4237 QualType FromType2 = SCS2.getFromType();
4238 QualType ToType2 = SCS2.getToType(1);
4239
4240 // Adjust the types we're converting from via the array-to-pointer
4241 // conversion, if we need to.
4242 if (SCS1.First == ICK_Array_To_Pointer)
4243 FromType1 = S.Context.getArrayDecayedType(FromType1);
4244 if (SCS2.First == ICK_Array_To_Pointer)
4245 FromType2 = S.Context.getArrayDecayedType(FromType2);
4246
4247 // Canonicalize all of the types.
4248 FromType1 = S.Context.getCanonicalType(FromType1);
4249 ToType1 = S.Context.getCanonicalType(ToType1);
4250 FromType2 = S.Context.getCanonicalType(FromType2);
4251 ToType2 = S.Context.getCanonicalType(ToType2);
4252
4253 // C++ [over.ics.rank]p4b3:
4254 //
4255 // If class B is derived directly or indirectly from class A and
4256 // class C is derived directly or indirectly from B,
4257 //
4258 // Compare based on pointer conversions.
4259 if (SCS1.Second == ICK_Pointer_Conversion &&
4260 SCS2.Second == ICK_Pointer_Conversion &&
4261 /*FIXME: Remove if Objective-C id conversions get their own rank*/
4262 FromType1->isPointerType() && FromType2->isPointerType() &&
4263 ToType1->isPointerType() && ToType2->isPointerType()) {
4264 QualType FromPointee1 =
4265 FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4266 QualType ToPointee1 =
4267 ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4268 QualType FromPointee2 =
4269 FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4270 QualType ToPointee2 =
4271 ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4272
4273 // -- conversion of C* to B* is better than conversion of C* to A*,
4274 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4275 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4276 return ImplicitConversionSequence::Better;
4277 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4278 return ImplicitConversionSequence::Worse;
4279 }
4280
4281 // -- conversion of B* to A* is better than conversion of C* to A*,
4282 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
4283 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4284 return ImplicitConversionSequence::Better;
4285 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4286 return ImplicitConversionSequence::Worse;
4287 }
4288 } else if (SCS1.Second == ICK_Pointer_Conversion &&
4289 SCS2.Second == ICK_Pointer_Conversion) {
4290 const ObjCObjectPointerType *FromPtr1
4291 = FromType1->getAs<ObjCObjectPointerType>();
4292 const ObjCObjectPointerType *FromPtr2
4293 = FromType2->getAs<ObjCObjectPointerType>();
4294 const ObjCObjectPointerType *ToPtr1
4295 = ToType1->getAs<ObjCObjectPointerType>();
4296 const ObjCObjectPointerType *ToPtr2
4297 = ToType2->getAs<ObjCObjectPointerType>();
4298
4299 if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
4300 // Apply the same conversion ranking rules for Objective-C pointer types
4301 // that we do for C++ pointers to class types. However, we employ the
4302 // Objective-C pseudo-subtyping relationship used for assignment of
4303 // Objective-C pointer types.
4304 bool FromAssignLeft
4305 = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
4306 bool FromAssignRight
4307 = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
4308 bool ToAssignLeft
4309 = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
4310 bool ToAssignRight
4311 = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
4312
4313 // A conversion to an a non-id object pointer type or qualified 'id'
4314 // type is better than a conversion to 'id'.
4315 if (ToPtr1->isObjCIdType() &&
4316 (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
4317 return ImplicitConversionSequence::Worse;
4318 if (ToPtr2->isObjCIdType() &&
4319 (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
4320 return ImplicitConversionSequence::Better;
4321
4322 // A conversion to a non-id object pointer type is better than a
4323 // conversion to a qualified 'id' type
4324 if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
4325 return ImplicitConversionSequence::Worse;
4326 if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
4327 return ImplicitConversionSequence::Better;
4328
4329 // A conversion to an a non-Class object pointer type or qualified 'Class'
4330 // type is better than a conversion to 'Class'.
4331 if (ToPtr1->isObjCClassType() &&
4332 (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
4333 return ImplicitConversionSequence::Worse;
4334 if (ToPtr2->isObjCClassType() &&
4335 (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
4336 return ImplicitConversionSequence::Better;
4337
4338 // A conversion to a non-Class object pointer type is better than a
4339 // conversion to a qualified 'Class' type.
4340 if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
4341 return ImplicitConversionSequence::Worse;
4342 if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
4343 return ImplicitConversionSequence::Better;
4344
4345 // -- "conversion of C* to B* is better than conversion of C* to A*,"
4346 if (S.Context.hasSameType(FromType1, FromType2) &&
4347 !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
4348 (ToAssignLeft != ToAssignRight)) {
4349 if (FromPtr1->isSpecialized()) {
4350 // "conversion of B<A> * to B * is better than conversion of B * to
4351 // C *.
4352 bool IsFirstSame =
4353 FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
4354 bool IsSecondSame =
4355 FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
4356 if (IsFirstSame) {
4357 if (!IsSecondSame)
4358 return ImplicitConversionSequence::Better;
4359 } else if (IsSecondSame)
4360 return ImplicitConversionSequence::Worse;
4361 }
4362 return ToAssignLeft? ImplicitConversionSequence::Worse
4363 : ImplicitConversionSequence::Better;
4364 }
4365
4366 // -- "conversion of B* to A* is better than conversion of C* to A*,"
4367 if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
4368 (FromAssignLeft != FromAssignRight))
4369 return FromAssignLeft? ImplicitConversionSequence::Better
4370 : ImplicitConversionSequence::Worse;
4371 }
4372 }
4373
4374 // Ranking of member-pointer types.
4375 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
4376 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
4377 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
4378 const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
4379 const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
4380 const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
4381 const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
4382 const Type *FromPointeeType1 = FromMemPointer1->getClass();
4383 const Type *ToPointeeType1 = ToMemPointer1->getClass();
4384 const Type *FromPointeeType2 = FromMemPointer2->getClass();
4385 const Type *ToPointeeType2 = ToMemPointer2->getClass();
4386 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
4387 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
4388 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
4389 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
4390 // conversion of A::* to B::* is better than conversion of A::* to C::*,
4391 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4392 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4393 return ImplicitConversionSequence::Worse;
4394 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4395 return ImplicitConversionSequence::Better;
4396 }
4397 // conversion of B::* to C::* is better than conversion of A::* to C::*
4398 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
4399 if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4400 return ImplicitConversionSequence::Better;
4401 else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4402 return ImplicitConversionSequence::Worse;
4403 }
4404 }
4405
4406 if (SCS1.Second == ICK_Derived_To_Base) {
4407 // -- conversion of C to B is better than conversion of C to A,
4408 // -- binding of an expression of type C to a reference of type
4409 // B& is better than binding an expression of type C to a
4410 // reference of type A&,
4411 if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4412 !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4413 if (S.IsDerivedFrom(Loc, ToType1, ToType2))
4414 return ImplicitConversionSequence::Better;
4415 else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
4416 return ImplicitConversionSequence::Worse;
4417 }
4418
4419 // -- conversion of B to A is better than conversion of C to A.
4420 // -- binding of an expression of type B to a reference of type
4421 // A& is better than binding an expression of type C to a
4422 // reference of type A&,
4423 if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4424 S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4425 if (S.IsDerivedFrom(Loc, FromType2, FromType1))
4426 return ImplicitConversionSequence::Better;
4427 else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
4428 return ImplicitConversionSequence::Worse;
4429 }
4430 }
4431
4432 return ImplicitConversionSequence::Indistinguishable;
4433 }
4434
4435 /// Determine whether the given type is valid, e.g., it is not an invalid
4436 /// C++ class.
isTypeValid(QualType T)4437 static bool isTypeValid(QualType T) {
4438 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
4439 return !Record->isInvalidDecl();
4440
4441 return true;
4442 }
4443
withoutUnaligned(ASTContext & Ctx,QualType T)4444 static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
4445 if (!T.getQualifiers().hasUnaligned())
4446 return T;
4447
4448 Qualifiers Q;
4449 T = Ctx.getUnqualifiedArrayType(T, Q);
4450 Q.removeUnaligned();
4451 return Ctx.getQualifiedType(T, Q);
4452 }
4453
4454 /// CompareReferenceRelationship - Compare the two types T1 and T2 to
4455 /// determine whether they are reference-compatible,
4456 /// reference-related, or incompatible, for use in C++ initialization by
4457 /// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
4458 /// type, and the first type (T1) is the pointee type of the reference
4459 /// type being initialized.
4460 Sema::ReferenceCompareResult
CompareReferenceRelationship(SourceLocation Loc,QualType OrigT1,QualType OrigT2,ReferenceConversions * ConvOut)4461 Sema::CompareReferenceRelationship(SourceLocation Loc,
4462 QualType OrigT1, QualType OrigT2,
4463 ReferenceConversions *ConvOut) {
4464 assert(!OrigT1->isReferenceType() &&
4465 "T1 must be the pointee type of the reference type");
4466 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type");
4467
4468 QualType T1 = Context.getCanonicalType(OrigT1);
4469 QualType T2 = Context.getCanonicalType(OrigT2);
4470 Qualifiers T1Quals, T2Quals;
4471 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
4472 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
4473
4474 ReferenceConversions ConvTmp;
4475 ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
4476 Conv = ReferenceConversions();
4477
4478 // C++2a [dcl.init.ref]p4:
4479 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
4480 // reference-related to "cv2 T2" if T1 is similar to T2, or
4481 // T1 is a base class of T2.
4482 // "cv1 T1" is reference-compatible with "cv2 T2" if
4483 // a prvalue of type "pointer to cv2 T2" can be converted to the type
4484 // "pointer to cv1 T1" via a standard conversion sequence.
4485
4486 // Check for standard conversions we can apply to pointers: derived-to-base
4487 // conversions, ObjC pointer conversions, and function pointer conversions.
4488 // (Qualification conversions are checked last.)
4489 QualType ConvertedT2;
4490 if (UnqualT1 == UnqualT2) {
4491 // Nothing to do.
4492 } else if (isCompleteType(Loc, OrigT2) &&
4493 isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
4494 IsDerivedFrom(Loc, UnqualT2, UnqualT1))
4495 Conv |= ReferenceConversions::DerivedToBase;
4496 else if (UnqualT1->isObjCObjectOrInterfaceType() &&
4497 UnqualT2->isObjCObjectOrInterfaceType() &&
4498 Context.canBindObjCObjectType(UnqualT1, UnqualT2))
4499 Conv |= ReferenceConversions::ObjC;
4500 else if (UnqualT2->isFunctionType() &&
4501 IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
4502 Conv |= ReferenceConversions::Function;
4503 // No need to check qualifiers; function types don't have them.
4504 return Ref_Compatible;
4505 }
4506 bool ConvertedReferent = Conv != 0;
4507
4508 // We can have a qualification conversion. Compute whether the types are
4509 // similar at the same time.
4510 bool PreviousToQualsIncludeConst = true;
4511 bool TopLevel = true;
4512 do {
4513 if (T1 == T2)
4514 break;
4515
4516 // We will need a qualification conversion.
4517 Conv |= ReferenceConversions::Qualification;
4518
4519 // Track whether we performed a qualification conversion anywhere other
4520 // than the top level. This matters for ranking reference bindings in
4521 // overload resolution.
4522 if (!TopLevel)
4523 Conv |= ReferenceConversions::NestedQualification;
4524
4525 // MS compiler ignores __unaligned qualifier for references; do the same.
4526 T1 = withoutUnaligned(Context, T1);
4527 T2 = withoutUnaligned(Context, T2);
4528
4529 // If we find a qualifier mismatch, the types are not reference-compatible,
4530 // but are still be reference-related if they're similar.
4531 bool ObjCLifetimeConversion = false;
4532 if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
4533 PreviousToQualsIncludeConst,
4534 ObjCLifetimeConversion))
4535 return (ConvertedReferent || Context.hasSimilarType(T1, T2))
4536 ? Ref_Related
4537 : Ref_Incompatible;
4538
4539 // FIXME: Should we track this for any level other than the first?
4540 if (ObjCLifetimeConversion)
4541 Conv |= ReferenceConversions::ObjCLifetime;
4542
4543 TopLevel = false;
4544 } while (Context.UnwrapSimilarTypes(T1, T2));
4545
4546 // At this point, if the types are reference-related, we must either have the
4547 // same inner type (ignoring qualifiers), or must have already worked out how
4548 // to convert the referent.
4549 return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
4550 ? Ref_Compatible
4551 : Ref_Incompatible;
4552 }
4553
4554 /// Look for a user-defined conversion to a value reference-compatible
4555 /// with DeclType. Return true if something definite is found.
4556 static bool
FindConversionForRefInit(Sema & S,ImplicitConversionSequence & ICS,QualType DeclType,SourceLocation DeclLoc,Expr * Init,QualType T2,bool AllowRvalues,bool AllowExplicit)4557 FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
4558 QualType DeclType, SourceLocation DeclLoc,
4559 Expr *Init, QualType T2, bool AllowRvalues,
4560 bool AllowExplicit) {
4561 assert(T2->isRecordType() && "Can only find conversions of record types.");
4562 auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());
4563
4564 OverloadCandidateSet CandidateSet(
4565 DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4566 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4567 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4568 NamedDecl *D = *I;
4569 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4570 if (isa<UsingShadowDecl>(D))
4571 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4572
4573 FunctionTemplateDecl *ConvTemplate
4574 = dyn_cast<FunctionTemplateDecl>(D);
4575 CXXConversionDecl *Conv;
4576 if (ConvTemplate)
4577 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4578 else
4579 Conv = cast<CXXConversionDecl>(D);
4580
4581 if (AllowRvalues) {
4582 // If we are initializing an rvalue reference, don't permit conversion
4583 // functions that return lvalues.
4584 if (!ConvTemplate && DeclType->isRValueReferenceType()) {
4585 const ReferenceType *RefType
4586 = Conv->getConversionType()->getAs<LValueReferenceType>();
4587 if (RefType && !RefType->getPointeeType()->isFunctionType())
4588 continue;
4589 }
4590
4591 if (!ConvTemplate &&
4592 S.CompareReferenceRelationship(
4593 DeclLoc,
4594 Conv->getConversionType()
4595 .getNonReferenceType()
4596 .getUnqualifiedType(),
4597 DeclType.getNonReferenceType().getUnqualifiedType()) ==
4598 Sema::Ref_Incompatible)
4599 continue;
4600 } else {
4601 // If the conversion function doesn't return a reference type,
4602 // it can't be considered for this conversion. An rvalue reference
4603 // is only acceptable if its referencee is a function type.
4604
4605 const ReferenceType *RefType =
4606 Conv->getConversionType()->getAs<ReferenceType>();
4607 if (!RefType ||
4608 (!RefType->isLValueReferenceType() &&
4609 !RefType->getPointeeType()->isFunctionType()))
4610 continue;
4611 }
4612
4613 if (ConvTemplate)
4614 S.AddTemplateConversionCandidate(
4615 ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4616 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4617 else
4618 S.AddConversionCandidate(
4619 Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4620 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4621 }
4622
4623 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4624
4625 OverloadCandidateSet::iterator Best;
4626 switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
4627 case OR_Success:
4628 // C++ [over.ics.ref]p1:
4629 //
4630 // [...] If the parameter binds directly to the result of
4631 // applying a conversion function to the argument
4632 // expression, the implicit conversion sequence is a
4633 // user-defined conversion sequence (13.3.3.1.2), with the
4634 // second standard conversion sequence either an identity
4635 // conversion or, if the conversion function returns an
4636 // entity of a type that is a derived class of the parameter
4637 // type, a derived-to-base Conversion.
4638 if (!Best->FinalConversion.DirectBinding)
4639 return false;
4640
4641 ICS.setUserDefined();
4642 ICS.UserDefined.Before = Best->Conversions[0].Standard;
4643 ICS.UserDefined.After = Best->FinalConversion;
4644 ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
4645 ICS.UserDefined.ConversionFunction = Best->Function;
4646 ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
4647 ICS.UserDefined.EllipsisConversion = false;
4648 assert(ICS.UserDefined.After.ReferenceBinding &&
4649 ICS.UserDefined.After.DirectBinding &&
4650 "Expected a direct reference binding!");
4651 return true;
4652
4653 case OR_Ambiguous:
4654 ICS.setAmbiguous();
4655 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
4656 Cand != CandidateSet.end(); ++Cand)
4657 if (Cand->Best)
4658 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
4659 return true;
4660
4661 case OR_No_Viable_Function:
4662 case OR_Deleted:
4663 // There was no suitable conversion, or we found a deleted
4664 // conversion; continue with other checks.
4665 return false;
4666 }
4667
4668 llvm_unreachable("Invalid OverloadResult!");
4669 }
4670
4671 /// Compute an implicit conversion sequence for reference
4672 /// initialization.
4673 static ImplicitConversionSequence
TryReferenceInit(Sema & S,Expr * Init,QualType DeclType,SourceLocation DeclLoc,bool SuppressUserConversions,bool AllowExplicit)4674 TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
4675 SourceLocation DeclLoc,
4676 bool SuppressUserConversions,
4677 bool AllowExplicit) {
4678 assert(DeclType->isReferenceType() && "Reference init needs a reference");
4679
4680 // Most paths end in a failed conversion.
4681 ImplicitConversionSequence ICS;
4682 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4683
4684 QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
4685 QualType T2 = Init->getType();
4686
4687 // If the initializer is the address of an overloaded function, try
4688 // to resolve the overloaded function. If all goes well, T2 is the
4689 // type of the resulting function.
4690 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
4691 DeclAccessPair Found;
4692 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
4693 false, Found))
4694 T2 = Fn->getType();
4695 }
4696
4697 // Compute some basic properties of the types and the initializer.
4698 bool isRValRef = DeclType->isRValueReferenceType();
4699 Expr::Classification InitCategory = Init->Classify(S.Context);
4700
4701 Sema::ReferenceConversions RefConv;
4702 Sema::ReferenceCompareResult RefRelationship =
4703 S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);
4704
4705 auto SetAsReferenceBinding = [&](bool BindsDirectly) {
4706 ICS.setStandard(ImplicitConversionSequence::MemsetToZero);
4707 ICS.Standard.First = ICK_Identity;
4708 // FIXME: A reference binding can be a function conversion too. We should
4709 // consider that when ordering reference-to-function bindings.
4710 ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
4711 ? ICK_Derived_To_Base
4712 : (RefConv & Sema::ReferenceConversions::ObjC)
4713 ? ICK_Compatible_Conversion
4714 : ICK_Identity;
4715 // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
4716 // a reference binding that performs a non-top-level qualification
4717 // conversion as a qualification conversion, not as an identity conversion.
4718 ICS.Standard.Third = (RefConv &
4719 Sema::ReferenceConversions::NestedQualification)
4720 ? ICK_Qualification
4721 : ICK_Identity;
4722 ICS.Standard.setFromType(T2);
4723 ICS.Standard.setToType(0, T2);
4724 ICS.Standard.setToType(1, T1);
4725 ICS.Standard.setToType(2, T1);
4726 ICS.Standard.ReferenceBinding = true;
4727 ICS.Standard.DirectBinding = BindsDirectly;
4728 ICS.Standard.IsLvalueReference = !isRValRef;
4729 ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
4730 ICS.Standard.BindsToRvalue = InitCategory.isRValue();
4731 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4732 ICS.Standard.ObjCLifetimeConversionBinding =
4733 (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
4734 ICS.Standard.CopyConstructor = nullptr;
4735 ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
4736 };
4737
4738 // C++0x [dcl.init.ref]p5:
4739 // A reference to type "cv1 T1" is initialized by an expression
4740 // of type "cv2 T2" as follows:
4741
4742 // -- If reference is an lvalue reference and the initializer expression
4743 if (!isRValRef) {
4744 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is
4745 // reference-compatible with "cv2 T2," or
4746 //
4747 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
4748 if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
4749 // C++ [over.ics.ref]p1:
4750 // When a parameter of reference type binds directly (8.5.3)
4751 // to an argument expression, the implicit conversion sequence
4752 // is the identity conversion, unless the argument expression
4753 // has a type that is a derived class of the parameter type,
4754 // in which case the implicit conversion sequence is a
4755 // derived-to-base Conversion (13.3.3.1).
4756 SetAsReferenceBinding(/*BindsDirectly=*/true);
4757
4758 // Nothing more to do: the inaccessibility/ambiguity check for
4759 // derived-to-base conversions is suppressed when we're
4760 // computing the implicit conversion sequence (C++
4761 // [over.best.ics]p2).
4762 return ICS;
4763 }
4764
4765 // -- has a class type (i.e., T2 is a class type), where T1 is
4766 // not reference-related to T2, and can be implicitly
4767 // converted to an lvalue of type "cv3 T3," where "cv1 T1"
4768 // is reference-compatible with "cv3 T3" 92) (this
4769 // conversion is selected by enumerating the applicable
4770 // conversion functions (13.3.1.6) and choosing the best
4771 // one through overload resolution (13.3)),
4772 if (!SuppressUserConversions && T2->isRecordType() &&
4773 S.isCompleteType(DeclLoc, T2) &&
4774 RefRelationship == Sema::Ref_Incompatible) {
4775 if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4776 Init, T2, /*AllowRvalues=*/false,
4777 AllowExplicit))
4778 return ICS;
4779 }
4780 }
4781
4782 // -- Otherwise, the reference shall be an lvalue reference to a
4783 // non-volatile const type (i.e., cv1 shall be const), or the reference
4784 // shall be an rvalue reference.
4785 if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified()))
4786 return ICS;
4787
4788 // -- If the initializer expression
4789 //
4790 // -- is an xvalue, class prvalue, array prvalue or function
4791 // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
4792 if (RefRelationship == Sema::Ref_Compatible &&
4793 (InitCategory.isXValue() ||
4794 (InitCategory.isPRValue() &&
4795 (T2->isRecordType() || T2->isArrayType())) ||
4796 (InitCategory.isLValue() && T2->isFunctionType()))) {
4797 // In C++11, this is always a direct binding. In C++98/03, it's a direct
4798 // binding unless we're binding to a class prvalue.
4799 // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
4800 // allow the use of rvalue references in C++98/03 for the benefit of
4801 // standard library implementors; therefore, we need the xvalue check here.
4802 SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
4803 !(InitCategory.isPRValue() || T2->isRecordType()));
4804 return ICS;
4805 }
4806
4807 // -- has a class type (i.e., T2 is a class type), where T1 is not
4808 // reference-related to T2, and can be implicitly converted to
4809 // an xvalue, class prvalue, or function lvalue of type
4810 // "cv3 T3", where "cv1 T1" is reference-compatible with
4811 // "cv3 T3",
4812 //
4813 // then the reference is bound to the value of the initializer
4814 // expression in the first case and to the result of the conversion
4815 // in the second case (or, in either case, to an appropriate base
4816 // class subobject).
4817 if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4818 T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
4819 FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4820 Init, T2, /*AllowRvalues=*/true,
4821 AllowExplicit)) {
4822 // In the second case, if the reference is an rvalue reference
4823 // and the second standard conversion sequence of the
4824 // user-defined conversion sequence includes an lvalue-to-rvalue
4825 // conversion, the program is ill-formed.
4826 if (ICS.isUserDefined() && isRValRef &&
4827 ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
4828 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4829
4830 return ICS;
4831 }
4832
4833 // A temporary of function type cannot be created; don't even try.
4834 if (T1->isFunctionType())
4835 return ICS;
4836
4837 // -- Otherwise, a temporary of type "cv1 T1" is created and
4838 // initialized from the initializer expression using the
4839 // rules for a non-reference copy initialization (8.5). The
4840 // reference is then bound to the temporary. If T1 is
4841 // reference-related to T2, cv1 must be the same
4842 // cv-qualification as, or greater cv-qualification than,
4843 // cv2; otherwise, the program is ill-formed.
4844 if (RefRelationship == Sema::Ref_Related) {
4845 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
4846 // we would be reference-compatible or reference-compatible with
4847 // added qualification. But that wasn't the case, so the reference
4848 // initialization fails.
4849 //
4850 // Note that we only want to check address spaces and cvr-qualifiers here.
4851 // ObjC GC, lifetime and unaligned qualifiers aren't important.
4852 Qualifiers T1Quals = T1.getQualifiers();
4853 Qualifiers T2Quals = T2.getQualifiers();
4854 T1Quals.removeObjCGCAttr();
4855 T1Quals.removeObjCLifetime();
4856 T2Quals.removeObjCGCAttr();
4857 T2Quals.removeObjCLifetime();
4858 // MS compiler ignores __unaligned qualifier for references; do the same.
4859 T1Quals.removeUnaligned();
4860 T2Quals.removeUnaligned();
4861 if (!T1Quals.compatiblyIncludes(T2Quals))
4862 return ICS;
4863 }
4864
4865 // If at least one of the types is a class type, the types are not
4866 // related, and we aren't allowed any user conversions, the
4867 // reference binding fails. This case is important for breaking
4868 // recursion, since TryImplicitConversion below will attempt to
4869 // create a temporary through the use of a copy constructor.
4870 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4871 (T1->isRecordType() || T2->isRecordType()))
4872 return ICS;
4873
4874 // If T1 is reference-related to T2 and the reference is an rvalue
4875 // reference, the initializer expression shall not be an lvalue.
4876 if (RefRelationship >= Sema::Ref_Related &&
4877 isRValRef && Init->Classify(S.Context).isLValue())
4878 return ICS;
4879
4880 // C++ [over.ics.ref]p2:
4881 // When a parameter of reference type is not bound directly to
4882 // an argument expression, the conversion sequence is the one
4883 // required to convert the argument expression to the
4884 // underlying type of the reference according to
4885 // 13.3.3.1. Conceptually, this conversion sequence corresponds
4886 // to copy-initializing a temporary of the underlying type with
4887 // the argument expression. Any difference in top-level
4888 // cv-qualification is subsumed by the initialization itself
4889 // and does not constitute a conversion.
4890 ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
4891 AllowedExplicit::None,
4892 /*InOverloadResolution=*/false,
4893 /*CStyle=*/false,
4894 /*AllowObjCWritebackConversion=*/false,
4895 /*AllowObjCConversionOnExplicit=*/false);
4896
4897 // Of course, that's still a reference binding.
4898 if (ICS.isStandard()) {
4899 ICS.Standard.ReferenceBinding = true;
4900 ICS.Standard.IsLvalueReference = !isRValRef;
4901 ICS.Standard.BindsToFunctionLvalue = false;
4902 ICS.Standard.BindsToRvalue = true;
4903 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4904 ICS.Standard.ObjCLifetimeConversionBinding = false;
4905 } else if (ICS.isUserDefined()) {
4906 const ReferenceType *LValRefType =
4907 ICS.UserDefined.ConversionFunction->getReturnType()
4908 ->getAs<LValueReferenceType>();
4909
4910 // C++ [over.ics.ref]p3:
4911 // Except for an implicit object parameter, for which see 13.3.1, a
4912 // standard conversion sequence cannot be formed if it requires [...]
4913 // binding an rvalue reference to an lvalue other than a function
4914 // lvalue.
4915 // Note that the function case is not possible here.
4916 if (DeclType->isRValueReferenceType() && LValRefType) {
4917 // FIXME: This is the wrong BadConversionSequence. The problem is binding
4918 // an rvalue reference to a (non-function) lvalue, not binding an lvalue
4919 // reference to an rvalue!
4920 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
4921 return ICS;
4922 }
4923
4924 ICS.UserDefined.After.ReferenceBinding = true;
4925 ICS.UserDefined.After.IsLvalueReference = !isRValRef;
4926 ICS.UserDefined.After.BindsToFunctionLvalue = false;
4927 ICS.UserDefined.After.BindsToRvalue = !LValRefType;
4928 ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4929 ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
4930 }
4931
4932 return ICS;
4933 }
4934
4935 static ImplicitConversionSequence
4936 TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
4937 bool SuppressUserConversions,
4938 bool InOverloadResolution,
4939 bool AllowObjCWritebackConversion,
4940 bool AllowExplicit = false);
4941
4942 /// TryListConversion - Try to copy-initialize a value of type ToType from the
4943 /// initializer list From.
4944 static ImplicitConversionSequence
TryListConversion(Sema & S,InitListExpr * From,QualType ToType,bool SuppressUserConversions,bool InOverloadResolution,bool AllowObjCWritebackConversion)4945 TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
4946 bool SuppressUserConversions,
4947 bool InOverloadResolution,
4948 bool AllowObjCWritebackConversion) {
4949 // C++11 [over.ics.list]p1:
4950 // When an argument is an initializer list, it is not an expression and
4951 // special rules apply for converting it to a parameter type.
4952
4953 ImplicitConversionSequence Result;
4954 Result.setBad(BadConversionSequence::no_conversion, From, ToType);
4955
4956 // We need a complete type for what follows. Incomplete types can never be
4957 // initialized from init lists.
4958 if (!S.isCompleteType(From->getBeginLoc(), ToType))
4959 return Result;
4960
4961 // Per DR1467:
4962 // If the parameter type is a class X and the initializer list has a single
4963 // element of type cv U, where U is X or a class derived from X, the
4964 // implicit conversion sequence is the one required to convert the element
4965 // to the parameter type.
4966 //
4967 // Otherwise, if the parameter type is a character array [... ]
4968 // and the initializer list has a single element that is an
4969 // appropriately-typed string literal (8.5.2 [dcl.init.string]), the
4970 // implicit conversion sequence is the identity conversion.
4971 if (From->getNumInits() == 1) {
4972 if (ToType->isRecordType()) {
4973 QualType InitType = From->getInit(0)->getType();
4974 if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
4975 S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
4976 return TryCopyInitialization(S, From->getInit(0), ToType,
4977 SuppressUserConversions,
4978 InOverloadResolution,
4979 AllowObjCWritebackConversion);
4980 }
4981 // FIXME: Check the other conditions here: array of character type,
4982 // initializer is a string literal.
4983 if (ToType->isArrayType()) {
4984 InitializedEntity Entity =
4985 InitializedEntity::InitializeParameter(S.Context, ToType,
4986 /*Consumed=*/false);
4987 if (S.CanPerformCopyInitialization(Entity, From)) {
4988 Result.setAsIdentityConversion(ToType);
4989 return Result;
4990 }
4991 }
4992 }
4993
4994 // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
4995 // C++11 [over.ics.list]p2:
4996 // If the parameter type is std::initializer_list<X> or "array of X" and
4997 // all the elements can be implicitly converted to X, the implicit
4998 // conversion sequence is the worst conversion necessary to convert an
4999 // element of the list to X.
5000 //
5001 // C++14 [over.ics.list]p3:
5002 // Otherwise, if the parameter type is "array of N X", if the initializer
5003 // list has exactly N elements or if it has fewer than N elements and X is
5004 // default-constructible, and if all the elements of the initializer list
5005 // can be implicitly converted to X, the implicit conversion sequence is
5006 // the worst conversion necessary to convert an element of the list to X.
5007 //
5008 // FIXME: We're missing a lot of these checks.
5009 bool toStdInitializerList = false;
5010 QualType X;
5011 if (ToType->isArrayType())
5012 X = S.Context.getAsArrayType(ToType)->getElementType();
5013 else
5014 toStdInitializerList = S.isStdInitializerList(ToType, &X);
5015 if (!X.isNull()) {
5016 for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) {
5017 Expr *Init = From->getInit(i);
5018 ImplicitConversionSequence ICS =
5019 TryCopyInitialization(S, Init, X, SuppressUserConversions,
5020 InOverloadResolution,
5021 AllowObjCWritebackConversion);
5022 // If a single element isn't convertible, fail.
5023 if (ICS.isBad()) {
5024 Result = ICS;
5025 break;
5026 }
5027 // Otherwise, look for the worst conversion.
5028 if (Result.isBad() || CompareImplicitConversionSequences(
5029 S, From->getBeginLoc(), ICS, Result) ==
5030 ImplicitConversionSequence::Worse)
5031 Result = ICS;
5032 }
5033
5034 // For an empty list, we won't have computed any conversion sequence.
5035 // Introduce the identity conversion sequence.
5036 if (From->getNumInits() == 0) {
5037 Result.setAsIdentityConversion(ToType);
5038 }
5039
5040 Result.setStdInitializerListElement(toStdInitializerList);
5041 return Result;
5042 }
5043
5044 // C++14 [over.ics.list]p4:
5045 // C++11 [over.ics.list]p3:
5046 // Otherwise, if the parameter is a non-aggregate class X and overload
5047 // resolution chooses a single best constructor [...] the implicit
5048 // conversion sequence is a user-defined conversion sequence. If multiple
5049 // constructors are viable but none is better than the others, the
5050 // implicit conversion sequence is a user-defined conversion sequence.
5051 if (ToType->isRecordType() && !ToType->isAggregateType()) {
5052 // This function can deal with initializer lists.
5053 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
5054 AllowedExplicit::None,
5055 InOverloadResolution, /*CStyle=*/false,
5056 AllowObjCWritebackConversion,
5057 /*AllowObjCConversionOnExplicit=*/false);
5058 }
5059
5060 // C++14 [over.ics.list]p5:
5061 // C++11 [over.ics.list]p4:
5062 // Otherwise, if the parameter has an aggregate type which can be
5063 // initialized from the initializer list [...] the implicit conversion
5064 // sequence is a user-defined conversion sequence.
5065 if (ToType->isAggregateType()) {
5066 // Type is an aggregate, argument is an init list. At this point it comes
5067 // down to checking whether the initialization works.
5068 // FIXME: Find out whether this parameter is consumed or not.
5069 InitializedEntity Entity =
5070 InitializedEntity::InitializeParameter(S.Context, ToType,
5071 /*Consumed=*/false);
5072 if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
5073 From)) {
5074 Result.setUserDefined();
5075 Result.UserDefined.Before.setAsIdentityConversion();
5076 // Initializer lists don't have a type.
5077 Result.UserDefined.Before.setFromType(QualType());
5078 Result.UserDefined.Before.setAllToTypes(QualType());
5079
5080 Result.UserDefined.After.setAsIdentityConversion();
5081 Result.UserDefined.After.setFromType(ToType);
5082 Result.UserDefined.After.setAllToTypes(ToType);
5083 Result.UserDefined.ConversionFunction = nullptr;
5084 }
5085 return Result;
5086 }
5087
5088 // C++14 [over.ics.list]p6:
5089 // C++11 [over.ics.list]p5:
5090 // Otherwise, if the parameter is a reference, see 13.3.3.1.4.
5091 if (ToType->isReferenceType()) {
5092 // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
5093 // mention initializer lists in any way. So we go by what list-
5094 // initialization would do and try to extrapolate from that.
5095
5096 QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();
5097
5098 // If the initializer list has a single element that is reference-related
5099 // to the parameter type, we initialize the reference from that.
5100 if (From->getNumInits() == 1) {
5101 Expr *Init = From->getInit(0);
5102
5103 QualType T2 = Init->getType();
5104
5105 // If the initializer is the address of an overloaded function, try
5106 // to resolve the overloaded function. If all goes well, T2 is the
5107 // type of the resulting function.
5108 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
5109 DeclAccessPair Found;
5110 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
5111 Init, ToType, false, Found))
5112 T2 = Fn->getType();
5113 }
5114
5115 // Compute some basic properties of the types and the initializer.
5116 Sema::ReferenceCompareResult RefRelationship =
5117 S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);
5118
5119 if (RefRelationship >= Sema::Ref_Related) {
5120 return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
5121 SuppressUserConversions,
5122 /*AllowExplicit=*/false);
5123 }
5124 }
5125
5126 // Otherwise, we bind the reference to a temporary created from the
5127 // initializer list.
5128 Result = TryListConversion(S, From, T1, SuppressUserConversions,
5129 InOverloadResolution,
5130 AllowObjCWritebackConversion);
5131 if (Result.isFailure())
5132 return Result;
5133 assert(!Result.isEllipsis() &&
5134 "Sub-initialization cannot result in ellipsis conversion.");
5135
5136 // Can we even bind to a temporary?
5137 if (ToType->isRValueReferenceType() ||
5138 (T1.isConstQualified() && !T1.isVolatileQualified())) {
5139 StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
5140 Result.UserDefined.After;
5141 SCS.ReferenceBinding = true;
5142 SCS.IsLvalueReference = ToType->isLValueReferenceType();
5143 SCS.BindsToRvalue = true;
5144 SCS.BindsToFunctionLvalue = false;
5145 SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
5146 SCS.ObjCLifetimeConversionBinding = false;
5147 } else
5148 Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
5149 From, ToType);
5150 return Result;
5151 }
5152
5153 // C++14 [over.ics.list]p7:
5154 // C++11 [over.ics.list]p6:
5155 // Otherwise, if the parameter type is not a class:
5156 if (!ToType->isRecordType()) {
5157 // - if the initializer list has one element that is not itself an
5158 // initializer list, the implicit conversion sequence is the one
5159 // required to convert the element to the parameter type.
5160 unsigned NumInits = From->getNumInits();
5161 if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
5162 Result = TryCopyInitialization(S, From->getInit(0), ToType,
5163 SuppressUserConversions,
5164 InOverloadResolution,
5165 AllowObjCWritebackConversion);
5166 // - if the initializer list has no elements, the implicit conversion
5167 // sequence is the identity conversion.
5168 else if (NumInits == 0) {
5169 Result.setAsIdentityConversion(ToType);
5170 }
5171 return Result;
5172 }
5173
5174 // C++14 [over.ics.list]p8:
5175 // C++11 [over.ics.list]p7:
5176 // In all cases other than those enumerated above, no conversion is possible
5177 return Result;
5178 }
5179
5180 /// TryCopyInitialization - Try to copy-initialize a value of type
5181 /// ToType from the expression From. Return the implicit conversion
5182 /// sequence required to pass this argument, which may be a bad
5183 /// conversion sequence (meaning that the argument cannot be passed to
5184 /// a parameter of this type). If @p SuppressUserConversions, then we
5185 /// do not permit any user-defined conversion sequences.
5186 static ImplicitConversionSequence
TryCopyInitialization(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,bool InOverloadResolution,bool AllowObjCWritebackConversion,bool AllowExplicit)5187 TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
5188 bool SuppressUserConversions,
5189 bool InOverloadResolution,
5190 bool AllowObjCWritebackConversion,
5191 bool AllowExplicit) {
5192 if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
5193 return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
5194 InOverloadResolution,AllowObjCWritebackConversion);
5195
5196 if (ToType->isReferenceType())
5197 return TryReferenceInit(S, From, ToType,
5198 /*FIXME:*/ From->getBeginLoc(),
5199 SuppressUserConversions, AllowExplicit);
5200
5201 return TryImplicitConversion(S, From, ToType,
5202 SuppressUserConversions,
5203 AllowedExplicit::None,
5204 InOverloadResolution,
5205 /*CStyle=*/false,
5206 AllowObjCWritebackConversion,
5207 /*AllowObjCConversionOnExplicit=*/false);
5208 }
5209
TryCopyInitialization(const CanQualType FromQTy,const CanQualType ToQTy,Sema & S,SourceLocation Loc,ExprValueKind FromVK)5210 static bool TryCopyInitialization(const CanQualType FromQTy,
5211 const CanQualType ToQTy,
5212 Sema &S,
5213 SourceLocation Loc,
5214 ExprValueKind FromVK) {
5215 OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
5216 ImplicitConversionSequence ICS =
5217 TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
5218
5219 return !ICS.isBad();
5220 }
5221
5222 /// TryObjectArgumentInitialization - Try to initialize the object
5223 /// parameter of the given member function (@c Method) from the
5224 /// expression @p From.
5225 static ImplicitConversionSequence
TryObjectArgumentInitialization(Sema & S,SourceLocation Loc,QualType FromType,Expr::Classification FromClassification,CXXMethodDecl * Method,CXXRecordDecl * ActingContext)5226 TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
5227 Expr::Classification FromClassification,
5228 CXXMethodDecl *Method,
5229 CXXRecordDecl *ActingContext) {
5230 QualType ClassType = S.Context.getTypeDeclType(ActingContext);
5231 // [class.dtor]p2: A destructor can be invoked for a const, volatile or
5232 // const volatile object.
5233 Qualifiers Quals = Method->getMethodQualifiers();
5234 if (isa<CXXDestructorDecl>(Method)) {
5235 Quals.addConst();
5236 Quals.addVolatile();
5237 }
5238
5239 QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
5240
5241 // Set up the conversion sequence as a "bad" conversion, to allow us
5242 // to exit early.
5243 ImplicitConversionSequence ICS;
5244
5245 // We need to have an object of class type.
5246 if (const PointerType *PT = FromType->getAs<PointerType>()) {
5247 FromType = PT->getPointeeType();
5248
5249 // When we had a pointer, it's implicitly dereferenced, so we
5250 // better have an lvalue.
5251 assert(FromClassification.isLValue());
5252 }
5253
5254 assert(FromType->isRecordType());
5255
5256 // C++0x [over.match.funcs]p4:
5257 // For non-static member functions, the type of the implicit object
5258 // parameter is
5259 //
5260 // - "lvalue reference to cv X" for functions declared without a
5261 // ref-qualifier or with the & ref-qualifier
5262 // - "rvalue reference to cv X" for functions declared with the &&
5263 // ref-qualifier
5264 //
5265 // where X is the class of which the function is a member and cv is the
5266 // cv-qualification on the member function declaration.
5267 //
5268 // However, when finding an implicit conversion sequence for the argument, we
5269 // are not allowed to perform user-defined conversions
5270 // (C++ [over.match.funcs]p5). We perform a simplified version of
5271 // reference binding here, that allows class rvalues to bind to
5272 // non-constant references.
5273
5274 // First check the qualifiers.
5275 QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
5276 if (ImplicitParamType.getCVRQualifiers()
5277 != FromTypeCanon.getLocalCVRQualifiers() &&
5278 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
5279 ICS.setBad(BadConversionSequence::bad_qualifiers,
5280 FromType, ImplicitParamType);
5281 return ICS;
5282 }
5283
5284 if (FromTypeCanon.hasAddressSpace()) {
5285 Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
5286 Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
5287 if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
5288 ICS.setBad(BadConversionSequence::bad_qualifiers,
5289 FromType, ImplicitParamType);
5290 return ICS;
5291 }
5292 }
5293
5294 // Check that we have either the same type or a derived type. It
5295 // affects the conversion rank.
5296 QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
5297 ImplicitConversionKind SecondKind;
5298 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
5299 SecondKind = ICK_Identity;
5300 } else if (S.IsDerivedFrom(Loc, FromType, ClassType))
5301 SecondKind = ICK_Derived_To_Base;
5302 else {
5303 ICS.setBad(BadConversionSequence::unrelated_class,
5304 FromType, ImplicitParamType);
5305 return ICS;
5306 }
5307
5308 // Check the ref-qualifier.
5309 switch (Method->getRefQualifier()) {
5310 case RQ_None:
5311 // Do nothing; we don't care about lvalueness or rvalueness.
5312 break;
5313
5314 case RQ_LValue:
5315 if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
5316 // non-const lvalue reference cannot bind to an rvalue
5317 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
5318 ImplicitParamType);
5319 return ICS;
5320 }
5321 break;
5322
5323 case RQ_RValue:
5324 if (!FromClassification.isRValue()) {
5325 // rvalue reference cannot bind to an lvalue
5326 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
5327 ImplicitParamType);
5328 return ICS;
5329 }
5330 break;
5331 }
5332
5333 // Success. Mark this as a reference binding.
5334 // XXXAR: FIXME: DO CHERI CHECK
5335 ICS.setStandard(ImplicitConversionSequence::MemsetToZero);
5336 ICS.Standard.setAsIdentityConversion();
5337 ICS.Standard.Second = SecondKind;
5338 ICS.Standard.setFromType(FromType);
5339 ICS.Standard.setAllToTypes(ImplicitParamType);
5340 ICS.Standard.ReferenceBinding = true;
5341 ICS.Standard.DirectBinding = true;
5342 ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
5343 ICS.Standard.BindsToFunctionLvalue = false;
5344 ICS.Standard.BindsToRvalue = FromClassification.isRValue();
5345 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
5346 = (Method->getRefQualifier() == RQ_None);
5347 return ICS;
5348 }
5349
5350 /// PerformObjectArgumentInitialization - Perform initialization of
5351 /// the implicit object parameter for the given Method with the given
5352 /// expression.
5353 ExprResult
PerformObjectArgumentInitialization(Expr * From,NestedNameSpecifier * Qualifier,NamedDecl * FoundDecl,CXXMethodDecl * Method)5354 Sema::PerformObjectArgumentInitialization(Expr *From,
5355 NestedNameSpecifier *Qualifier,
5356 NamedDecl *FoundDecl,
5357 CXXMethodDecl *Method) {
5358 QualType FromRecordType, DestType;
5359 QualType ImplicitParamRecordType =
5360 Method->getThisType()->castAs<PointerType>()->getPointeeType();
5361
5362 Expr::Classification FromClassification;
5363 if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
5364 FromRecordType = PT->getPointeeType();
5365 DestType = Method->getThisType();
5366 FromClassification = Expr::Classification::makeSimpleLValue();
5367 } else {
5368 FromRecordType = From->getType();
5369 DestType = ImplicitParamRecordType;
5370 FromClassification = From->Classify(Context);
5371
5372 // When performing member access on an rvalue, materialize a temporary.
5373 if (From->isRValue()) {
5374 From = CreateMaterializeTemporaryExpr(FromRecordType, From,
5375 Method->getRefQualifier() !=
5376 RefQualifierKind::RQ_RValue);
5377 }
5378 }
5379
5380 // Note that we always use the true parent context when performing
5381 // the actual argument initialization.
5382 ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
5383 *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
5384 Method->getParent());
5385 if (ICS.isBad()) {
5386 switch (ICS.Bad.Kind) {
5387 case BadConversionSequence::bad_qualifiers: {
5388 Qualifiers FromQs = FromRecordType.getQualifiers();
5389 Qualifiers ToQs = DestType.getQualifiers();
5390 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
5391 if (CVR) {
5392 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
5393 << Method->getDeclName() << FromRecordType << (CVR - 1)
5394 << From->getSourceRange();
5395 Diag(Method->getLocation(), diag::note_previous_decl)
5396 << Method->getDeclName();
5397 return ExprError();
5398 }
5399 break;
5400 }
5401
5402 case BadConversionSequence::lvalue_ref_to_rvalue:
5403 case BadConversionSequence::rvalue_ref_to_lvalue: {
5404 bool IsRValueQualified =
5405 Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
5406 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
5407 << Method->getDeclName() << FromClassification.isRValue()
5408 << IsRValueQualified;
5409 Diag(Method->getLocation(), diag::note_previous_decl)
5410 << Method->getDeclName();
5411 return ExprError();
5412 }
5413
5414 case BadConversionSequence::no_conversion:
5415 case BadConversionSequence::unrelated_class:
5416 break;
5417 }
5418
5419 return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
5420 << ImplicitParamRecordType << FromRecordType
5421 << From->getSourceRange();
5422 }
5423
5424 if (ICS.Standard.Second == ICK_Derived_To_Base) {
5425 ExprResult FromRes =
5426 PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
5427 if (FromRes.isInvalid())
5428 return ExprError();
5429 From = FromRes.get();
5430 }
5431
5432 if (!Context.hasSameType(From->getType(), DestType)) {
5433 CastKind CK;
5434 QualType PteeTy = DestType->getPointeeType();
5435 LangAS DestAS =
5436 PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
5437 if (FromRecordType.getAddressSpace() != DestAS)
5438 CK = CK_AddressSpaceConversion;
5439 else
5440 CK = CK_NoOp;
5441 From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
5442 }
5443 return From;
5444 }
5445
5446 /// TryContextuallyConvertToBool - Attempt to contextually convert the
5447 /// expression From to bool (C++0x [conv]p3).
5448 static ImplicitConversionSequence
TryContextuallyConvertToBool(Sema & S,Expr * From)5449 TryContextuallyConvertToBool(Sema &S, Expr *From) {
5450 // C++ [dcl.init]/17.8:
5451 // - Otherwise, if the initialization is direct-initialization, the source
5452 // type is std::nullptr_t, and the destination type is bool, the initial
5453 // value of the object being initialized is false.
5454 if (From->getType()->isNullPtrType())
5455 return ImplicitConversionSequence::getNullptrToBool(From->getType(),
5456 S.Context.BoolTy,
5457 From->isGLValue());
5458
5459 // All other direct-initialization of bool is equivalent to an implicit
5460 // conversion to bool in which explicit conversions are permitted.
5461 return TryImplicitConversion(S, From, S.Context.BoolTy,
5462 /*SuppressUserConversions=*/false,
5463 AllowedExplicit::Conversions,
5464 /*InOverloadResolution=*/false,
5465 /*CStyle=*/false,
5466 /*AllowObjCWritebackConversion=*/false,
5467 /*AllowObjCConversionOnExplicit=*/false);
5468 }
5469
5470 /// PerformContextuallyConvertToBool - Perform a contextual conversion
5471 /// of the expression From to bool (C++0x [conv]p3).
PerformContextuallyConvertToBool(Expr * From)5472 ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
5473 if (checkPlaceholderForOverload(*this, From))
5474 return ExprError();
5475
5476 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
5477 if (!ICS.isBad())
5478 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
5479
5480 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
5481 return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
5482 << From->getType() << From->getSourceRange();
5483 return ExprError();
5484 }
5485
5486 /// Check that the specified conversion is permitted in a converted constant
5487 /// expression, according to C++11 [expr.const]p3. Return true if the conversion
5488 /// is acceptable.
CheckConvertedConstantConversions(Sema & S,StandardConversionSequence & SCS)5489 static bool CheckConvertedConstantConversions(Sema &S,
5490 StandardConversionSequence &SCS) {
5491 // Since we know that the target type is an integral or unscoped enumeration
5492 // type, most conversion kinds are impossible. All possible First and Third
5493 // conversions are fine.
5494 switch (SCS.Second) {
5495 case ICK_Identity:
5496 case ICK_Function_Conversion:
5497 case ICK_Integral_Promotion:
5498 case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
5499 case ICK_Zero_Queue_Conversion:
5500 return true;
5501
5502 case ICK_Boolean_Conversion:
5503 // Conversion from an integral or unscoped enumeration type to bool is
5504 // classified as ICK_Boolean_Conversion, but it's also arguably an integral
5505 // conversion, so we allow it in a converted constant expression.
5506 //
5507 // FIXME: Per core issue 1407, we should not allow this, but that breaks
5508 // a lot of popular code. We should at least add a warning for this
5509 // (non-conforming) extension.
5510 return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
5511 SCS.getToType(2)->isBooleanType();
5512
5513 case ICK_Pointer_Conversion:
5514 case ICK_Pointer_Member:
5515 // C++1z: null pointer conversions and null member pointer conversions are
5516 // only permitted if the source type is std::nullptr_t.
5517 return SCS.getFromType()->isNullPtrType();
5518
5519 case ICK_Floating_Promotion:
5520 case ICK_Complex_Promotion:
5521 case ICK_Floating_Conversion:
5522 case ICK_Complex_Conversion:
5523 case ICK_Floating_Integral:
5524 case ICK_Compatible_Conversion:
5525 case ICK_Derived_To_Base:
5526 case ICK_Vector_Conversion:
5527 case ICK_Vector_Splat:
5528 case ICK_Complex_Real:
5529 case ICK_Block_Pointer_Conversion:
5530 case ICK_TransparentUnionConversion:
5531 case ICK_Writeback_Conversion:
5532 case ICK_Zero_Event_Conversion:
5533 case ICK_C_Only_Conversion:
5534 case ICK_Incompatible_Pointer_Conversion:
5535 return false;
5536
5537 case ICK_Lvalue_To_Rvalue:
5538 case ICK_Array_To_Pointer:
5539 case ICK_Function_To_Pointer:
5540 llvm_unreachable("found a first conversion kind in Second");
5541
5542 case ICK_Qualification:
5543 llvm_unreachable("found a third conversion kind in Second");
5544
5545 case ICK_Num_Conversion_Kinds:
5546 break;
5547 }
5548
5549 llvm_unreachable("unknown conversion kind");
5550 }
5551
5552 /// CheckConvertedConstantExpression - Check that the expression From is a
5553 /// converted constant expression of type T, perform the conversion and produce
5554 /// the converted expression, per C++11 [expr.const]p3.
CheckConvertedConstantExpression(Sema & S,Expr * From,QualType T,APValue & Value,Sema::CCEKind CCE,bool RequireInt)5555 static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
5556 QualType T, APValue &Value,
5557 Sema::CCEKind CCE,
5558 bool RequireInt) {
5559 assert(S.getLangOpts().CPlusPlus11 &&
5560 "converted constant expression outside C++11");
5561
5562 if (checkPlaceholderForOverload(S, From))
5563 return ExprError();
5564
5565 // C++1z [expr.const]p3:
5566 // A converted constant expression of type T is an expression,
5567 // implicitly converted to type T, where the converted
5568 // expression is a constant expression and the implicit conversion
5569 // sequence contains only [... list of conversions ...].
5570 // C++1z [stmt.if]p2:
5571 // If the if statement is of the form if constexpr, the value of the
5572 // condition shall be a contextually converted constant expression of type
5573 // bool.
5574 ImplicitConversionSequence ICS =
5575 CCE == Sema::CCEK_ConstexprIf || CCE == Sema::CCEK_ExplicitBool
5576 ? TryContextuallyConvertToBool(S, From)
5577 : TryCopyInitialization(S, From, T,
5578 /*SuppressUserConversions=*/false,
5579 /*InOverloadResolution=*/false,
5580 /*AllowObjCWritebackConversion=*/false,
5581 /*AllowExplicit=*/false);
5582 StandardConversionSequence *SCS = nullptr;
5583 switch (ICS.getKind()) {
5584 case ImplicitConversionSequence::StandardConversion:
5585 SCS = &ICS.Standard;
5586 break;
5587 case ImplicitConversionSequence::UserDefinedConversion:
5588 // We are converting to a non-class type, so the Before sequence
5589 // must be trivial.
5590 SCS = &ICS.UserDefined.After;
5591 break;
5592 case ImplicitConversionSequence::AmbiguousConversion:
5593 case ImplicitConversionSequence::BadConversion:
5594 if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
5595 return S.Diag(From->getBeginLoc(),
5596 diag::err_typecheck_converted_constant_expression)
5597 << From->getType() << From->getSourceRange() << T;
5598 return ExprError();
5599
5600 case ImplicitConversionSequence::EllipsisConversion:
5601 llvm_unreachable("ellipsis conversion in converted constant expression");
5602 }
5603
5604 // Check that we would only use permitted conversions.
5605 if (!CheckConvertedConstantConversions(S, *SCS)) {
5606 return S.Diag(From->getBeginLoc(),
5607 diag::err_typecheck_converted_constant_expression_disallowed)
5608 << From->getType() << From->getSourceRange() << T;
5609 }
5610 // [...] and where the reference binding (if any) binds directly.
5611 if (SCS->ReferenceBinding && !SCS->DirectBinding) {
5612 return S.Diag(From->getBeginLoc(),
5613 diag::err_typecheck_converted_constant_expression_indirect)
5614 << From->getType() << From->getSourceRange() << T;
5615 }
5616
5617 ExprResult Result =
5618 S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
5619 if (Result.isInvalid())
5620 return Result;
5621
5622 // C++2a [intro.execution]p5:
5623 // A full-expression is [...] a constant-expression [...]
5624 Result =
5625 S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
5626 /*DiscardedValue=*/false, /*IsConstexpr=*/true);
5627 if (Result.isInvalid())
5628 return Result;
5629
5630 // Check for a narrowing implicit conversion.
5631 APValue PreNarrowingValue;
5632 QualType PreNarrowingType;
5633 switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
5634 PreNarrowingType)) {
5635 case NK_Dependent_Narrowing:
5636 // Implicit conversion to a narrower type, but the expression is
5637 // value-dependent so we can't tell whether it's actually narrowing.
5638 case NK_Variable_Narrowing:
5639 // Implicit conversion to a narrower type, and the value is not a constant
5640 // expression. We'll diagnose this in a moment.
5641 case NK_Not_Narrowing:
5642 break;
5643
5644 case NK_Constant_Narrowing:
5645 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5646 << CCE << /*Constant*/ 1
5647 << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
5648 break;
5649
5650 case NK_Type_Narrowing:
5651 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5652 << CCE << /*Constant*/ 0 << From->getType() << T;
5653 break;
5654 }
5655
5656 if (Result.get()->isValueDependent()) {
5657 Value = APValue();
5658 return Result;
5659 }
5660
5661 // Check the expression is a constant expression.
5662 SmallVector<PartialDiagnosticAt, 8> Notes;
5663 Expr::EvalResult Eval;
5664 Eval.Diag = &Notes;
5665 Expr::ConstExprUsage Usage = CCE == Sema::CCEK_TemplateArg
5666 ? Expr::EvaluateForMangling
5667 : Expr::EvaluateForCodeGen;
5668
5669 if (!Result.get()->EvaluateAsConstantExpr(Eval, Usage, S.Context) ||
5670 (RequireInt && !Eval.Val.isInt())) {
5671 // The expression can't be folded, so we can't keep it at this position in
5672 // the AST.
5673 Result = ExprError();
5674 } else {
5675 Value = Eval.Val;
5676
5677 if (Notes.empty()) {
5678 // It's a constant expression.
5679 return ConstantExpr::Create(S.Context, Result.get(), Value);
5680 }
5681 }
5682
5683 // It's not a constant expression. Produce an appropriate diagnostic.
5684 if (Notes.size() == 1 &&
5685 Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr)
5686 S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
5687 else {
5688 S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
5689 << CCE << From->getSourceRange();
5690 for (unsigned I = 0; I < Notes.size(); ++I)
5691 S.Diag(Notes[I].first, Notes[I].second);
5692 }
5693 return ExprError();
5694 }
5695
CheckConvertedConstantExpression(Expr * From,QualType T,APValue & Value,CCEKind CCE)5696 ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5697 APValue &Value, CCEKind CCE) {
5698 return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false);
5699 }
5700
CheckConvertedConstantExpression(Expr * From,QualType T,llvm::APSInt & Value,CCEKind CCE)5701 ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5702 llvm::APSInt &Value,
5703 CCEKind CCE) {
5704 assert(T->isIntegralOrEnumerationType() && "unexpected converted const type");
5705
5706 APValue V;
5707 auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true);
5708 if (!R.isInvalid() && !R.get()->isValueDependent())
5709 Value = V.getInt();
5710 return R;
5711 }
5712
5713
5714 /// dropPointerConversions - If the given standard conversion sequence
5715 /// involves any pointer conversions, remove them. This may change
5716 /// the result type of the conversion sequence.
dropPointerConversion(StandardConversionSequence & SCS)5717 static void dropPointerConversion(StandardConversionSequence &SCS) {
5718 if (SCS.Second == ICK_Pointer_Conversion) {
5719 SCS.Second = ICK_Identity;
5720 SCS.Third = ICK_Identity;
5721 SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
5722 }
5723 }
5724
5725 /// TryContextuallyConvertToObjCPointer - Attempt to contextually
5726 /// convert the expression From to an Objective-C pointer type.
5727 static ImplicitConversionSequence
TryContextuallyConvertToObjCPointer(Sema & S,Expr * From)5728 TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
5729 // Do an implicit conversion to 'id'.
5730 QualType Ty = S.Context.getObjCIdType();
5731 ImplicitConversionSequence ICS
5732 = TryImplicitConversion(S, From, Ty,
5733 // FIXME: Are these flags correct?
5734 /*SuppressUserConversions=*/false,
5735 AllowedExplicit::Conversions,
5736 /*InOverloadResolution=*/false,
5737 /*CStyle=*/false,
5738 /*AllowObjCWritebackConversion=*/false,
5739 /*AllowObjCConversionOnExplicit=*/true);
5740
5741 // Strip off any final conversions to 'id'.
5742 switch (ICS.getKind()) {
5743 case ImplicitConversionSequence::BadConversion:
5744 case ImplicitConversionSequence::AmbiguousConversion:
5745 case ImplicitConversionSequence::EllipsisConversion:
5746 break;
5747
5748 case ImplicitConversionSequence::UserDefinedConversion:
5749 dropPointerConversion(ICS.UserDefined.After);
5750 break;
5751
5752 case ImplicitConversionSequence::StandardConversion:
5753 dropPointerConversion(ICS.Standard);
5754 break;
5755 }
5756
5757 return ICS;
5758 }
5759
5760 /// PerformContextuallyConvertToObjCPointer - Perform a contextual
5761 /// conversion of the expression From to an Objective-C pointer type.
5762 /// Returns a valid but null ExprResult if no conversion sequence exists.
PerformContextuallyConvertToObjCPointer(Expr * From)5763 ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
5764 if (checkPlaceholderForOverload(*this, From))
5765 return ExprError();
5766
5767 QualType Ty = Context.getObjCIdType();
5768 ImplicitConversionSequence ICS =
5769 TryContextuallyConvertToObjCPointer(*this, From);
5770 if (!ICS.isBad())
5771 return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
5772 return ExprResult();
5773 }
5774
5775 /// Determine whether the provided type is an integral type, or an enumeration
5776 /// type of a permitted flavor.
match(QualType T)5777 bool Sema::ICEConvertDiagnoser::match(QualType T) {
5778 return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
5779 : T->isIntegralOrUnscopedEnumerationType();
5780 }
5781
5782 static ExprResult
diagnoseAmbiguousConversion(Sema & SemaRef,SourceLocation Loc,Expr * From,Sema::ContextualImplicitConverter & Converter,QualType T,UnresolvedSetImpl & ViableConversions)5783 diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
5784 Sema::ContextualImplicitConverter &Converter,
5785 QualType T, UnresolvedSetImpl &ViableConversions) {
5786
5787 if (Converter.Suppress)
5788 return ExprError();
5789
5790 Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
5791 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
5792 CXXConversionDecl *Conv =
5793 cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
5794 QualType ConvTy = Conv->getConversionType().getNonReferenceType();
5795 Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
5796 }
5797 return From;
5798 }
5799
5800 static bool
diagnoseNoViableConversion(Sema & SemaRef,SourceLocation Loc,Expr * & From,Sema::ContextualImplicitConverter & Converter,QualType T,bool HadMultipleCandidates,UnresolvedSetImpl & ExplicitConversions)5801 diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
5802 Sema::ContextualImplicitConverter &Converter,
5803 QualType T, bool HadMultipleCandidates,
5804 UnresolvedSetImpl &ExplicitConversions) {
5805 if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
5806 DeclAccessPair Found = ExplicitConversions[0];
5807 CXXConversionDecl *Conversion =
5808 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
5809
5810 // The user probably meant to invoke the given explicit
5811 // conversion; use it.
5812 QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
5813 std::string TypeStr;
5814 ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());
5815
5816 Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
5817 << FixItHint::CreateInsertion(From->getBeginLoc(),
5818 "static_cast<" + TypeStr + ">(")
5819 << FixItHint::CreateInsertion(
5820 SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
5821 Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);
5822
5823 // If we aren't in a SFINAE context, build a call to the
5824 // explicit conversion function.
5825 if (SemaRef.isSFINAEContext())
5826 return true;
5827
5828 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
5829 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
5830 HadMultipleCandidates);
5831 if (Result.isInvalid())
5832 return true;
5833 // Record usage of conversion in an implicit cast.
5834 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
5835 CK_UserDefinedConversion, Result.get(),
5836 nullptr, Result.get()->getValueKind());
5837 }
5838 return false;
5839 }
5840
recordConversion(Sema & SemaRef,SourceLocation Loc,Expr * & From,Sema::ContextualImplicitConverter & Converter,QualType T,bool HadMultipleCandidates,DeclAccessPair & Found)5841 static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
5842 Sema::ContextualImplicitConverter &Converter,
5843 QualType T, bool HadMultipleCandidates,
5844 DeclAccessPair &Found) {
5845 CXXConversionDecl *Conversion =
5846 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
5847 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
5848
5849 QualType ToType = Conversion->getConversionType().getNonReferenceType();
5850 if (!Converter.SuppressConversion) {
5851 if (SemaRef.isSFINAEContext())
5852 return true;
5853
5854 Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
5855 << From->getSourceRange();
5856 }
5857
5858 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
5859 HadMultipleCandidates);
5860 if (Result.isInvalid())
5861 return true;
5862 // Record usage of conversion in an implicit cast.
5863 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
5864 CK_UserDefinedConversion, Result.get(),
5865 nullptr, Result.get()->getValueKind());
5866 return false;
5867 }
5868
finishContextualImplicitConversion(Sema & SemaRef,SourceLocation Loc,Expr * From,Sema::ContextualImplicitConverter & Converter)5869 static ExprResult finishContextualImplicitConversion(
5870 Sema &SemaRef, SourceLocation Loc, Expr *From,
5871 Sema::ContextualImplicitConverter &Converter) {
5872 if (!Converter.match(From->getType()) && !Converter.Suppress)
5873 Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
5874 << From->getSourceRange();
5875
5876 return SemaRef.DefaultLvalueConversion(From);
5877 }
5878
5879 static void
collectViableConversionCandidates(Sema & SemaRef,Expr * From,QualType ToType,UnresolvedSetImpl & ViableConversions,OverloadCandidateSet & CandidateSet)5880 collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
5881 UnresolvedSetImpl &ViableConversions,
5882 OverloadCandidateSet &CandidateSet) {
5883 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
5884 DeclAccessPair FoundDecl = ViableConversions[I];
5885 NamedDecl *D = FoundDecl.getDecl();
5886 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
5887 if (isa<UsingShadowDecl>(D))
5888 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5889
5890 CXXConversionDecl *Conv;
5891 FunctionTemplateDecl *ConvTemplate;
5892 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
5893 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5894 else
5895 Conv = cast<CXXConversionDecl>(D);
5896
5897 if (ConvTemplate)
5898 SemaRef.AddTemplateConversionCandidate(
5899 ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
5900 /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true);
5901 else
5902 SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
5903 ToType, CandidateSet,
5904 /*AllowObjCConversionOnExplicit=*/false,
5905 /*AllowExplicit*/ true);
5906 }
5907 }
5908
5909 /// Attempt to convert the given expression to a type which is accepted
5910 /// by the given converter.
5911 ///
5912 /// This routine will attempt to convert an expression of class type to a
5913 /// type accepted by the specified converter. In C++11 and before, the class
5914 /// must have a single non-explicit conversion function converting to a matching
5915 /// type. In C++1y, there can be multiple such conversion functions, but only
5916 /// one target type.
5917 ///
5918 /// \param Loc The source location of the construct that requires the
5919 /// conversion.
5920 ///
5921 /// \param From The expression we're converting from.
5922 ///
5923 /// \param Converter Used to control and diagnose the conversion process.
5924 ///
5925 /// \returns The expression, converted to an integral or enumeration type if
5926 /// successful.
PerformContextualImplicitConversion(SourceLocation Loc,Expr * From,ContextualImplicitConverter & Converter)5927 ExprResult Sema::PerformContextualImplicitConversion(
5928 SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
5929 // We can't perform any more checking for type-dependent expressions.
5930 if (From->isTypeDependent())
5931 return From;
5932
5933 // Process placeholders immediately.
5934 if (From->hasPlaceholderType()) {
5935 ExprResult result = CheckPlaceholderExpr(From);
5936 if (result.isInvalid())
5937 return result;
5938 From = result.get();
5939 }
5940
5941 // If the expression already has a matching type, we're golden.
5942 QualType T = From->getType();
5943 if (Converter.match(T))
5944 return DefaultLvalueConversion(From);
5945
5946 // FIXME: Check for missing '()' if T is a function type?
5947
5948 // We can only perform contextual implicit conversions on objects of class
5949 // type.
5950 const RecordType *RecordTy = T->getAs<RecordType>();
5951 if (!RecordTy || !getLangOpts().CPlusPlus) {
5952 if (!Converter.Suppress)
5953 Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
5954 return From;
5955 }
5956
5957 // We must have a complete class type.
5958 struct TypeDiagnoserPartialDiag : TypeDiagnoser {
5959 ContextualImplicitConverter &Converter;
5960 Expr *From;
5961
5962 TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
5963 : Converter(Converter), From(From) {}
5964
5965 void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
5966 Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
5967 }
5968 } IncompleteDiagnoser(Converter, From);
5969
5970 if (Converter.Suppress ? !isCompleteType(Loc, T)
5971 : RequireCompleteType(Loc, T, IncompleteDiagnoser))
5972 return From;
5973
5974 // Look for a conversion to an integral or enumeration type.
5975 UnresolvedSet<4>
5976 ViableConversions; // These are *potentially* viable in C++1y.
5977 UnresolvedSet<4> ExplicitConversions;
5978 const auto &Conversions =
5979 cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
5980
5981 bool HadMultipleCandidates =
5982 (std::distance(Conversions.begin(), Conversions.end()) > 1);
5983
5984 // To check that there is only one target type, in C++1y:
5985 QualType ToType;
5986 bool HasUniqueTargetType = true;
5987
5988 // Collect explicit or viable (potentially in C++1y) conversions.
5989 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5990 NamedDecl *D = (*I)->getUnderlyingDecl();
5991 CXXConversionDecl *Conversion;
5992 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
5993 if (ConvTemplate) {
5994 if (getLangOpts().CPlusPlus14)
5995 Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5996 else
5997 continue; // C++11 does not consider conversion operator templates(?).
5998 } else
5999 Conversion = cast<CXXConversionDecl>(D);
6000
6001 assert((!ConvTemplate || getLangOpts().CPlusPlus14) &&
6002 "Conversion operator templates are considered potentially "
6003 "viable in C++1y");
6004
6005 QualType CurToType = Conversion->getConversionType().getNonReferenceType();
6006 if (Converter.match(CurToType) || ConvTemplate) {
6007
6008 if (Conversion->isExplicit()) {
6009 // FIXME: For C++1y, do we need this restriction?
6010 // cf. diagnoseNoViableConversion()
6011 if (!ConvTemplate)
6012 ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
6013 } else {
6014 if (!ConvTemplate && getLangOpts().CPlusPlus14) {
6015 if (ToType.isNull())
6016 ToType = CurToType.getUnqualifiedType();
6017 else if (HasUniqueTargetType &&
6018 (CurToType.getUnqualifiedType() != ToType))
6019 HasUniqueTargetType = false;
6020 }
6021 ViableConversions.addDecl(I.getDecl(), I.getAccess());
6022 }
6023 }
6024 }
6025
6026 if (getLangOpts().CPlusPlus14) {
6027 // C++1y [conv]p6:
6028 // ... An expression e of class type E appearing in such a context
6029 // is said to be contextually implicitly converted to a specified
6030 // type T and is well-formed if and only if e can be implicitly
6031 // converted to a type T that is determined as follows: E is searched
6032 // for conversion functions whose return type is cv T or reference to
6033 // cv T such that T is allowed by the context. There shall be
6034 // exactly one such T.
6035
6036 // If no unique T is found:
6037 if (ToType.isNull()) {
6038 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6039 HadMultipleCandidates,
6040 ExplicitConversions))
6041 return ExprError();
6042 return finishContextualImplicitConversion(*this, Loc, From, Converter);
6043 }
6044
6045 // If more than one unique Ts are found:
6046 if (!HasUniqueTargetType)
6047 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6048 ViableConversions);
6049
6050 // If one unique T is found:
6051 // First, build a candidate set from the previously recorded
6052 // potentially viable conversions.
6053 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6054 collectViableConversionCandidates(*this, From, ToType, ViableConversions,
6055 CandidateSet);
6056
6057 // Then, perform overload resolution over the candidate set.
6058 OverloadCandidateSet::iterator Best;
6059 switch (CandidateSet.BestViableFunction(*this, Loc, Best)) {
6060 case OR_Success: {
6061 // Apply this conversion.
6062 DeclAccessPair Found =
6063 DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess());
6064 if (recordConversion(*this, Loc, From, Converter, T,
6065 HadMultipleCandidates, Found))
6066 return ExprError();
6067 break;
6068 }
6069 case OR_Ambiguous:
6070 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6071 ViableConversions);
6072 case OR_No_Viable_Function:
6073 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6074 HadMultipleCandidates,
6075 ExplicitConversions))
6076 return ExprError();
6077 LLVM_FALLTHROUGH;
6078 case OR_Deleted:
6079 // We'll complain below about a non-integral condition type.
6080 break;
6081 }
6082 } else {
6083 switch (ViableConversions.size()) {
6084 case 0: {
6085 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6086 HadMultipleCandidates,
6087 ExplicitConversions))
6088 return ExprError();
6089
6090 // We'll complain below about a non-integral condition type.
6091 break;
6092 }
6093 case 1: {
6094 // Apply this conversion.
6095 DeclAccessPair Found = ViableConversions[0];
6096 if (recordConversion(*this, Loc, From, Converter, T,
6097 HadMultipleCandidates, Found))
6098 return ExprError();
6099 break;
6100 }
6101 default:
6102 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6103 ViableConversions);
6104 }
6105 }
6106
6107 return finishContextualImplicitConversion(*this, Loc, From, Converter);
6108 }
6109
6110 /// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is
6111 /// an acceptable non-member overloaded operator for a call whose
6112 /// arguments have types T1 (and, if non-empty, T2). This routine
6113 /// implements the check in C++ [over.match.oper]p3b2 concerning
6114 /// enumeration types.
IsAcceptableNonMemberOperatorCandidate(ASTContext & Context,FunctionDecl * Fn,ArrayRef<Expr * > Args)6115 static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context,
6116 FunctionDecl *Fn,
6117 ArrayRef<Expr *> Args) {
6118 QualType T1 = Args[0]->getType();
6119 QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType();
6120
6121 if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType()))
6122 return true;
6123
6124 if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType()))
6125 return true;
6126
6127 const auto *Proto = Fn->getType()->castAs<FunctionProtoType>();
6128 if (Proto->getNumParams() < 1)
6129 return false;
6130
6131 if (T1->isEnumeralType()) {
6132 QualType ArgType = Proto->getParamType(0).getNonReferenceType();
6133 if (Context.hasSameUnqualifiedType(T1, ArgType))
6134 return true;
6135 }
6136
6137 if (Proto->getNumParams() < 2)
6138 return false;
6139
6140 if (!T2.isNull() && T2->isEnumeralType()) {
6141 QualType ArgType = Proto->getParamType(1).getNonReferenceType();
6142 if (Context.hasSameUnqualifiedType(T2, ArgType))
6143 return true;
6144 }
6145
6146 return false;
6147 }
6148
6149 /// AddOverloadCandidate - Adds the given function to the set of
6150 /// candidate functions, using the given function call arguments. If
6151 /// @p SuppressUserConversions, then don't allow user-defined
6152 /// conversions via constructors or conversion operators.
6153 ///
6154 /// \param PartialOverloading true if we are performing "partial" overloading
6155 /// based on an incomplete set of function arguments. This feature is used by
6156 /// 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)6157 void Sema::AddOverloadCandidate(
6158 FunctionDecl *Function, DeclAccessPair FoundDecl, ArrayRef<Expr *> Args,
6159 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
6160 bool PartialOverloading, bool AllowExplicit, bool AllowExplicitConversions,
6161 ADLCallKind IsADLCandidate, ConversionSequenceList EarlyConversions,
6162 OverloadCandidateParamOrder PO) {
6163 const FunctionProtoType *Proto
6164 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>());
6165 assert(Proto && "Functions without a prototype cannot be overloaded");
6166 assert(!Function->getDescribedFunctionTemplate() &&
6167 "Use AddTemplateOverloadCandidate for function templates");
6168
6169 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
6170 if (!isa<CXXConstructorDecl>(Method)) {
6171 // If we get here, it's because we're calling a member function
6172 // that is named without a member access expression (e.g.,
6173 // "this->f") that was either written explicitly or created
6174 // implicitly. This can happen with a qualified call to a member
6175 // function, e.g., X::f(). We use an empty type for the implied
6176 // object argument (C++ [over.call.func]p3), and the acting context
6177 // is irrelevant.
6178 AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(),
6179 Expr::Classification::makeSimpleLValue(), Args,
6180 CandidateSet, SuppressUserConversions,
6181 PartialOverloading, EarlyConversions, PO);
6182 return;
6183 }
6184 // We treat a constructor like a non-member function, since its object
6185 // argument doesn't participate in overload resolution.
6186 }
6187
6188 if (!CandidateSet.isNewCandidate(Function, PO))
6189 return;
6190
6191 // C++11 [class.copy]p11: [DR1402]
6192 // A defaulted move constructor that is defined as deleted is ignored by
6193 // overload resolution.
6194 CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function);
6195 if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() &&
6196 Constructor->isMoveConstructor())
6197 return;
6198
6199 // Overload resolution is always an unevaluated context.
6200 EnterExpressionEvaluationContext Unevaluated(
6201 *this, Sema::ExpressionEvaluationContext::Unevaluated);
6202
6203 // C++ [over.match.oper]p3:
6204 // if no operand has a class type, only those non-member functions in the
6205 // lookup set that have a first parameter of type T1 or "reference to
6206 // (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there
6207 // is a right operand) a second parameter of type T2 or "reference to
6208 // (possibly cv-qualified) T2", when T2 is an enumeration type, are
6209 // candidate functions.
6210 if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator &&
6211 !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args))
6212 return;
6213
6214 // Add this candidate
6215 OverloadCandidate &Candidate =
6216 CandidateSet.addCandidate(Args.size(), EarlyConversions);
6217 Candidate.FoundDecl = FoundDecl;
6218 Candidate.Function = Function;
6219 Candidate.Viable = true;
6220 Candidate.RewriteKind =
6221 CandidateSet.getRewriteInfo().getRewriteKind(Function, PO);
6222 Candidate.IsSurrogate = false;
6223 Candidate.IsADLCandidate = IsADLCandidate;
6224 Candidate.IgnoreObjectArgument = false;
6225 Candidate.ExplicitCallArguments = Args.size();
6226
6227 // Explicit functions are not actually candidates at all if we're not
6228 // allowing them in this context, but keep them around so we can point
6229 // to them in diagnostics.
6230 if (!AllowExplicit && ExplicitSpecifier::getFromDecl(Function).isExplicit()) {
6231 Candidate.Viable = false;
6232 Candidate.FailureKind = ovl_fail_explicit;
6233 return;
6234 }
6235
6236 if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() &&
6237 !Function->getAttr<TargetAttr>()->isDefaultVersion()) {
6238 Candidate.Viable = false;
6239 Candidate.FailureKind = ovl_non_default_multiversion_function;
6240 return;
6241 }
6242
6243 if (Constructor) {
6244 // C++ [class.copy]p3:
6245 // A member function template is never instantiated to perform the copy
6246 // of a class object to an object of its class type.
6247 QualType ClassType = Context.getTypeDeclType(Constructor->getParent());
6248 if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() &&
6249 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) ||
6250 IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(),
6251 ClassType))) {
6252 Candidate.Viable = false;
6253 Candidate.FailureKind = ovl_fail_illegal_constructor;
6254 return;
6255 }
6256
6257 // C++ [over.match.funcs]p8: (proposed DR resolution)
6258 // A constructor inherited from class type C that has a first parameter
6259 // of type "reference to P" (including such a constructor instantiated
6260 // from a template) is excluded from the set of candidate functions when
6261 // constructing an object of type cv D if the argument list has exactly
6262 // one argument and D is reference-related to P and P is reference-related
6263 // to C.
6264 auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl());
6265 if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 &&
6266 Constructor->getParamDecl(0)->getType()->isReferenceType()) {
6267 QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType();
6268 QualType C = Context.getRecordType(Constructor->getParent());
6269 QualType D = Context.getRecordType(Shadow->getParent());
6270 SourceLocation Loc = Args.front()->getExprLoc();
6271 if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) &&
6272 (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) {
6273 Candidate.Viable = false;
6274 Candidate.FailureKind = ovl_fail_inhctor_slice;
6275 return;
6276 }
6277 }
6278
6279 // Check that the constructor is capable of constructing an object in the
6280 // destination address space.
6281 if (!Qualifiers::isAddressSpaceSupersetOf(
6282 Constructor->getMethodQualifiers().getAddressSpace(),
6283 CandidateSet.getDestAS())) {
6284 Candidate.Viable = false;
6285 Candidate.FailureKind = ovl_fail_object_addrspace_mismatch;
6286 }
6287 }
6288
6289 unsigned NumParams = Proto->getNumParams();
6290
6291 // (C++ 13.3.2p2): A candidate function having fewer than m
6292 // parameters is viable only if it has an ellipsis in its parameter
6293 // list (8.3.5).
6294 if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
6295 !Proto->isVariadic()) {
6296 Candidate.Viable = false;
6297 Candidate.FailureKind = ovl_fail_too_many_arguments;
6298 return;
6299 }
6300
6301 // (C++ 13.3.2p2): A candidate function having more than m parameters
6302 // is viable only if the (m+1)st parameter has a default argument
6303 // (8.3.6). For the purposes of overload resolution, the
6304 // parameter list is truncated on the right, so that there are
6305 // exactly m parameters.
6306 unsigned MinRequiredArgs = Function->getMinRequiredArguments();
6307 if (Args.size() < MinRequiredArgs && !PartialOverloading) {
6308 // Not enough arguments.
6309 Candidate.Viable = false;
6310 Candidate.FailureKind = ovl_fail_too_few_arguments;
6311 return;
6312 }
6313
6314 // (CUDA B.1): Check for invalid calls between targets.
6315 if (getLangOpts().CUDA)
6316 if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
6317 // Skip the check for callers that are implicit members, because in this
6318 // case we may not yet know what the member's target is; the target is
6319 // inferred for the member automatically, based on the bases and fields of
6320 // the class.
6321 if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) {
6322 Candidate.Viable = false;
6323 Candidate.FailureKind = ovl_fail_bad_target;
6324 return;
6325 }
6326
6327 if (Function->getTrailingRequiresClause()) {
6328 ConstraintSatisfaction Satisfaction;
6329 if (CheckFunctionConstraints(Function, Satisfaction) ||
6330 !Satisfaction.IsSatisfied) {
6331 Candidate.Viable = false;
6332 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
6333 return;
6334 }
6335 }
6336
6337 // Determine the implicit conversion sequences for each of the
6338 // arguments.
6339 for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
6340 unsigned ConvIdx =
6341 PO == OverloadCandidateParamOrder::Reversed ? 1 - ArgIdx : ArgIdx;
6342 if (Candidate.Conversions[ConvIdx].isInitialized()) {
6343 // We already formed a conversion sequence for this parameter during
6344 // template argument deduction.
6345 } else if (ArgIdx < NumParams) {
6346 // (C++ 13.3.2p3): for F to be a viable function, there shall
6347 // exist for each argument an implicit conversion sequence
6348 // (13.3.3.1) that converts that argument to the corresponding
6349 // parameter of F.
6350 QualType ParamType = Proto->getParamType(ArgIdx);
6351 Candidate.Conversions[ConvIdx] = TryCopyInitialization(
6352 *this, Args[ArgIdx], ParamType, SuppressUserConversions,
6353 /*InOverloadResolution=*/true,
6354 /*AllowObjCWritebackConversion=*/
6355 getLangOpts().ObjCAutoRefCount, AllowExplicitConversions);
6356 if (Candidate.Conversions[ConvIdx].isBad()) {
6357 Candidate.Viable = false;
6358 Candidate.FailureKind = ovl_fail_bad_conversion;
6359 return;
6360 }
6361 } else {
6362 // (C++ 13.3.2p2): For the purposes of overload resolution, any
6363 // argument for which there is no corresponding parameter is
6364 // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
6365 Candidate.Conversions[ConvIdx].setEllipsis();
6366 }
6367 }
6368
6369 if (EnableIfAttr *FailedAttr =
6370 CheckEnableIf(Function, CandidateSet.getLocation(), Args)) {
6371 Candidate.Viable = false;
6372 Candidate.FailureKind = ovl_fail_enable_if;
6373 Candidate.DeductionFailure.Data = FailedAttr;
6374 return;
6375 }
6376
6377 if (LangOpts.OpenCL && isOpenCLDisabledDecl(Function)) {
6378 Candidate.Viable = false;
6379 Candidate.FailureKind = ovl_fail_ext_disabled;
6380 return;
6381 }
6382 }
6383
6384 ObjCMethodDecl *
SelectBestMethod(Selector Sel,MultiExprArg Args,bool IsInstance,SmallVectorImpl<ObjCMethodDecl * > & Methods)6385 Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
6386 SmallVectorImpl<ObjCMethodDecl *> &Methods) {
6387 if (Methods.size() <= 1)
6388 return nullptr;
6389
6390 for (unsigned b = 0, e = Methods.size(); b < e; b++) {
6391 bool Match = true;
6392 ObjCMethodDecl *Method = Methods[b];
6393 unsigned NumNamedArgs = Sel.getNumArgs();
6394 // Method might have more arguments than selector indicates. This is due
6395 // to addition of c-style arguments in method.
6396 if (Method->param_size() > NumNamedArgs)
6397 NumNamedArgs = Method->param_size();
6398 if (Args.size() < NumNamedArgs)
6399 continue;
6400
6401 for (unsigned i = 0; i < NumNamedArgs; i++) {
6402 // We can't do any type-checking on a type-dependent argument.
6403 if (Args[i]->isTypeDependent()) {
6404 Match = false;
6405 break;
6406 }
6407
6408 ParmVarDecl *param = Method->parameters()[i];
6409 Expr *argExpr = Args[i];
6410 assert(argExpr && "SelectBestMethod(): missing expression");
6411
6412 // Strip the unbridged-cast placeholder expression off unless it's
6413 // a consumed argument.
6414 if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
6415 !param->hasAttr<CFConsumedAttr>())
6416 argExpr = stripARCUnbridgedCast(argExpr);
6417
6418 // If the parameter is __unknown_anytype, move on to the next method.
6419 if (param->getType() == Context.UnknownAnyTy) {
6420 Match = false;
6421 break;
6422 }
6423
6424 ImplicitConversionSequence ConversionState
6425 = TryCopyInitialization(*this, argExpr, param->getType(),
6426 /*SuppressUserConversions*/false,
6427 /*InOverloadResolution=*/true,
6428 /*AllowObjCWritebackConversion=*/
6429 getLangOpts().ObjCAutoRefCount,
6430 /*AllowExplicit*/false);
6431 // This function looks for a reasonably-exact match, so we consider
6432 // incompatible pointer conversions to be a failure here.
6433 if (ConversionState.isBad() ||
6434 (ConversionState.isStandard() &&
6435 ConversionState.Standard.Second ==
6436 ICK_Incompatible_Pointer_Conversion)) {
6437 Match = false;
6438 break;
6439 }
6440 }
6441 // Promote additional arguments to variadic methods.
6442 if (Match && Method->isVariadic()) {
6443 for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
6444 if (Args[i]->isTypeDependent()) {
6445 Match = false;
6446 break;
6447 }
6448 ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
6449 nullptr);
6450 if (Arg.isInvalid()) {
6451 Match = false;
6452 break;
6453 }
6454 }
6455 } else {
6456 // Check for extra arguments to non-variadic methods.
6457 if (Args.size() != NumNamedArgs)
6458 Match = false;
6459 else if (Match && NumNamedArgs == 0 && Methods.size() > 1) {
6460 // Special case when selectors have no argument. In this case, select
6461 // one with the most general result type of 'id'.
6462 for (unsigned b = 0, e = Methods.size(); b < e; b++) {
6463 QualType ReturnT = Methods[b]->getReturnType();
6464 if (ReturnT->isObjCIdType())
6465 return Methods[b];
6466 }
6467 }
6468 }
6469
6470 if (Match)
6471 return Method;
6472 }
6473 return nullptr;
6474 }
6475
convertArgsForAvailabilityChecks(Sema & S,FunctionDecl * Function,Expr * ThisArg,SourceLocation CallLoc,ArrayRef<Expr * > Args,Sema::SFINAETrap & Trap,bool MissingImplicitThis,Expr * & ConvertedThis,SmallVectorImpl<Expr * > & ConvertedArgs)6476 static bool convertArgsForAvailabilityChecks(
6477 Sema &S, FunctionDecl *Function, Expr *ThisArg, SourceLocation CallLoc,
6478 ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap, bool MissingImplicitThis,
6479 Expr *&ConvertedThis, SmallVectorImpl<Expr *> &ConvertedArgs) {
6480 if (ThisArg) {
6481 CXXMethodDecl *Method = cast<CXXMethodDecl>(Function);
6482 assert(!isa<CXXConstructorDecl>(Method) &&
6483 "Shouldn't have `this` for ctors!");
6484 assert(!Method->isStatic() && "Shouldn't have `this` for static methods!");
6485 ExprResult R = S.PerformObjectArgumentInitialization(
6486 ThisArg, /*Qualifier=*/nullptr, Method, Method);
6487 if (R.isInvalid())
6488 return false;
6489 ConvertedThis = R.get();
6490 } else {
6491 if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) {
6492 (void)MD;
6493 assert((MissingImplicitThis || MD->isStatic() ||
6494 isa<CXXConstructorDecl>(MD)) &&
6495 "Expected `this` for non-ctor instance methods");
6496 }
6497 ConvertedThis = nullptr;
6498 }
6499
6500 // Ignore any variadic arguments. Converting them is pointless, since the
6501 // user can't refer to them in the function condition.
6502 unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size());
6503
6504 // Convert the arguments.
6505 for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) {
6506 ExprResult R;
6507 R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
6508 S.Context, Function->getParamDecl(I)),
6509 SourceLocation(), Args[I]);
6510
6511 if (R.isInvalid())
6512 return false;
6513
6514 ConvertedArgs.push_back(R.get());
6515 }
6516
6517 if (Trap.hasErrorOccurred())
6518 return false;
6519
6520 // Push default arguments if needed.
6521 if (!Function->isVariadic() && Args.size() < Function->getNumParams()) {
6522 for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) {
6523 ParmVarDecl *P = Function->getParamDecl(i);
6524 if (!P->hasDefaultArg())
6525 return false;
6526 ExprResult R = S.BuildCXXDefaultArgExpr(CallLoc, Function, P);
6527 if (R.isInvalid())
6528 return false;
6529 ConvertedArgs.push_back(R.get());
6530 }
6531
6532 if (Trap.hasErrorOccurred())
6533 return false;
6534 }
6535 return true;
6536 }
6537
CheckEnableIf(FunctionDecl * Function,SourceLocation CallLoc,ArrayRef<Expr * > Args,bool MissingImplicitThis)6538 EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function,
6539 SourceLocation CallLoc,
6540 ArrayRef<Expr *> Args,
6541 bool MissingImplicitThis) {
6542 auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>();
6543 if (EnableIfAttrs.begin() == EnableIfAttrs.end())
6544 return nullptr;
6545
6546 SFINAETrap Trap(*this);
6547 SmallVector<Expr *, 16> ConvertedArgs;
6548 // FIXME: We should look into making enable_if late-parsed.
6549 Expr *DiscardedThis;
6550 if (!convertArgsForAvailabilityChecks(
6551 *this, Function, /*ThisArg=*/nullptr, CallLoc, Args, Trap,
6552 /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs))
6553 return *EnableIfAttrs.begin();
6554
6555 for (auto *EIA : EnableIfAttrs) {
6556 APValue Result;
6557 // FIXME: This doesn't consider value-dependent cases, because doing so is
6558 // very difficult. Ideally, we should handle them more gracefully.
6559 if (EIA->getCond()->isValueDependent() ||
6560 !EIA->getCond()->EvaluateWithSubstitution(
6561 Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
6562 return EIA;
6563
6564 if (!Result.isInt() || !Result.getInt().getBoolValue())
6565 return EIA;
6566 }
6567 return nullptr;
6568 }
6569
6570 template <typename CheckFn>
diagnoseDiagnoseIfAttrsWith(Sema & S,const NamedDecl * ND,bool ArgDependent,SourceLocation Loc,CheckFn && IsSuccessful)6571 static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND,
6572 bool ArgDependent, SourceLocation Loc,
6573 CheckFn &&IsSuccessful) {
6574 SmallVector<const DiagnoseIfAttr *, 8> Attrs;
6575 for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) {
6576 if (ArgDependent == DIA->getArgDependent())
6577 Attrs.push_back(DIA);
6578 }
6579
6580 // Common case: No diagnose_if attributes, so we can quit early.
6581 if (Attrs.empty())
6582 return false;
6583
6584 auto WarningBegin = std::stable_partition(
6585 Attrs.begin(), Attrs.end(),
6586 [](const DiagnoseIfAttr *DIA) { return DIA->isError(); });
6587
6588 // Note that diagnose_if attributes are late-parsed, so they appear in the
6589 // correct order (unlike enable_if attributes).
6590 auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin),
6591 IsSuccessful);
6592 if (ErrAttr != WarningBegin) {
6593 const DiagnoseIfAttr *DIA = *ErrAttr;
6594 S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage();
6595 S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
6596 << DIA->getParent() << DIA->getCond()->getSourceRange();
6597 return true;
6598 }
6599
6600 for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end()))
6601 if (IsSuccessful(DIA)) {
6602 S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage();
6603 S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
6604 << DIA->getParent() << DIA->getCond()->getSourceRange();
6605 }
6606
6607 return false;
6608 }
6609
diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl * Function,const Expr * ThisArg,ArrayRef<const Expr * > Args,SourceLocation Loc)6610 bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
6611 const Expr *ThisArg,
6612 ArrayRef<const Expr *> Args,
6613 SourceLocation Loc) {
6614 return diagnoseDiagnoseIfAttrsWith(
6615 *this, Function, /*ArgDependent=*/true, Loc,
6616 [&](const DiagnoseIfAttr *DIA) {
6617 APValue Result;
6618 // It's sane to use the same Args for any redecl of this function, since
6619 // EvaluateWithSubstitution only cares about the position of each
6620 // argument in the arg list, not the ParmVarDecl* it maps to.
6621 if (!DIA->getCond()->EvaluateWithSubstitution(
6622 Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
6623 return false;
6624 return Result.isInt() && Result.getInt().getBoolValue();
6625 });
6626 }
6627
diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl * ND,SourceLocation Loc)6628 bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
6629 SourceLocation Loc) {
6630 return diagnoseDiagnoseIfAttrsWith(
6631 *this, ND, /*ArgDependent=*/false, Loc,
6632 [&](const DiagnoseIfAttr *DIA) {
6633 bool Result;
6634 return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) &&
6635 Result;
6636 });
6637 }
6638
6639 /// Add all of the function declarations in the given function set to
6640 /// the overload candidate set.
AddFunctionCandidates(const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,TemplateArgumentListInfo * ExplicitTemplateArgs,bool SuppressUserConversions,bool PartialOverloading,bool FirstArgumentIsBase)6641 void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
6642 ArrayRef<Expr *> Args,
6643 OverloadCandidateSet &CandidateSet,
6644 TemplateArgumentListInfo *ExplicitTemplateArgs,
6645 bool SuppressUserConversions,
6646 bool PartialOverloading,
6647 bool FirstArgumentIsBase) {
6648 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
6649 NamedDecl *D = F.getDecl()->getUnderlyingDecl();
6650 ArrayRef<Expr *> FunctionArgs = Args;
6651
6652 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
6653 FunctionDecl *FD =
6654 FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
6655
6656 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
6657 QualType ObjectType;
6658 Expr::Classification ObjectClassification;
6659 if (Args.size() > 0) {
6660 if (Expr *E = Args[0]) {
6661 // Use the explicit base to restrict the lookup:
6662 ObjectType = E->getType();
6663 // Pointers in the object arguments are implicitly dereferenced, so we
6664 // always classify them as l-values.
6665 if (!ObjectType.isNull() && ObjectType->isPointerType())
6666 ObjectClassification = Expr::Classification::makeSimpleLValue();
6667 else
6668 ObjectClassification = E->Classify(Context);
6669 } // .. else there is an implicit base.
6670 FunctionArgs = Args.slice(1);
6671 }
6672 if (FunTmpl) {
6673 AddMethodTemplateCandidate(
6674 FunTmpl, F.getPair(),
6675 cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
6676 ExplicitTemplateArgs, ObjectType, ObjectClassification,
6677 FunctionArgs, CandidateSet, SuppressUserConversions,
6678 PartialOverloading);
6679 } else {
6680 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
6681 cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
6682 ObjectClassification, FunctionArgs, CandidateSet,
6683 SuppressUserConversions, PartialOverloading);
6684 }
6685 } else {
6686 // This branch handles both standalone functions and static methods.
6687
6688 // Slice the first argument (which is the base) when we access
6689 // static method as non-static.
6690 if (Args.size() > 0 &&
6691 (!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) &&
6692 !isa<CXXConstructorDecl>(FD)))) {
6693 assert(cast<CXXMethodDecl>(FD)->isStatic());
6694 FunctionArgs = Args.slice(1);
6695 }
6696 if (FunTmpl) {
6697 AddTemplateOverloadCandidate(FunTmpl, F.getPair(),
6698 ExplicitTemplateArgs, FunctionArgs,
6699 CandidateSet, SuppressUserConversions,
6700 PartialOverloading);
6701 } else {
6702 AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet,
6703 SuppressUserConversions, PartialOverloading);
6704 }
6705 }
6706 }
6707 }
6708
6709 /// AddMethodCandidate - Adds a named decl (which is some kind of
6710 /// 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)6711 void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
6712 Expr::Classification ObjectClassification,
6713 ArrayRef<Expr *> Args,
6714 OverloadCandidateSet &CandidateSet,
6715 bool SuppressUserConversions,
6716 OverloadCandidateParamOrder PO) {
6717 NamedDecl *Decl = FoundDecl.getDecl();
6718 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext());
6719
6720 if (isa<UsingShadowDecl>(Decl))
6721 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl();
6722
6723 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) {
6724 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) &&
6725 "Expected a member function template");
6726 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext,
6727 /*ExplicitArgs*/ nullptr, ObjectType,
6728 ObjectClassification, Args, CandidateSet,
6729 SuppressUserConversions, false, PO);
6730 } else {
6731 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext,
6732 ObjectType, ObjectClassification, Args, CandidateSet,
6733 SuppressUserConversions, false, None, PO);
6734 }
6735 }
6736
6737 /// AddMethodCandidate - Adds the given C++ member function to the set
6738 /// of candidate functions, using the given function call arguments
6739 /// and the object argument (@c Object). For example, in a call
6740 /// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
6741 /// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
6742 /// allow user-defined conversions via constructors or conversion
6743 /// operators.
6744 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)6745 Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
6746 CXXRecordDecl *ActingContext, QualType ObjectType,
6747 Expr::Classification ObjectClassification,
6748 ArrayRef<Expr *> Args,
6749 OverloadCandidateSet &CandidateSet,
6750 bool SuppressUserConversions,
6751 bool PartialOverloading,
6752 ConversionSequenceList EarlyConversions,
6753 OverloadCandidateParamOrder PO) {
6754 const FunctionProtoType *Proto
6755 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>());
6756 assert(Proto && "Methods without a prototype cannot be overloaded");
6757 assert(!isa<CXXConstructorDecl>(Method) &&
6758 "Use AddOverloadCandidate for constructors");
6759
6760 if (!CandidateSet.isNewCandidate(Method, PO))
6761 return;
6762
6763 // C++11 [class.copy]p23: [DR1402]
6764 // A defaulted move assignment operator that is defined as deleted is
6765 // ignored by overload resolution.
6766 if (Method->isDefaulted() && Method->isDeleted() &&
6767 Method->isMoveAssignmentOperator())
6768 return;
6769
6770 // Overload resolution is always an unevaluated context.
6771 EnterExpressionEvaluationContext Unevaluated(
6772 *this, Sema::ExpressionEvaluationContext::Unevaluated);
6773
6774 // Add this candidate
6775 OverloadCandidate &Candidate =
6776 CandidateSet.addCandidate(Args.size() + 1, EarlyConversions);
6777 Candidate.FoundDecl = FoundDecl;
6778 Candidate.Function = Method;
6779 Candidate.RewriteKind =
6780 CandidateSet.getRewriteInfo().getRewriteKind(Method, PO);
6781 Candidate.IsSurrogate = false;
6782 Candidate.IgnoreObjectArgument = false;
6783 Candidate.ExplicitCallArguments = Args.size();
6784
6785 unsigned NumParams = Proto->getNumParams();
6786
6787 // (C++ 13.3.2p2): A candidate function having fewer than m
6788 // parameters is viable only if it has an ellipsis in its parameter
6789 // list (8.3.5).
6790 if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
6791 !Proto->isVariadic()) {
6792 Candidate.Viable = false;
6793 Candidate.FailureKind = ovl_fail_too_many_arguments;
6794 return;
6795 }
6796
6797 // (C++ 13.3.2p2): A candidate function having more than m parameters
6798 // is viable only if the (m+1)st parameter has a default argument
6799 // (8.3.6). For the purposes of overload resolution, the
6800 // parameter list is truncated on the right, so that there are
6801 // exactly m parameters.
6802 unsigned MinRequiredArgs = Method->getMinRequiredArguments();
6803 if (Args.size() < MinRequiredArgs && !PartialOverloading) {
6804 // Not enough arguments.
6805 Candidate.Viable = false;
6806 Candidate.FailureKind = ovl_fail_too_few_arguments;
6807 return;
6808 }
6809
6810 Candidate.Viable = true;
6811
6812 if (Method->isStatic() || ObjectType.isNull())
6813 // The implicit object argument is ignored.
6814 Candidate.IgnoreObjectArgument = true;
6815 else {
6816 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
6817 // Determine the implicit conversion sequence for the object
6818 // parameter.
6819 Candidate.Conversions[ConvIdx] = TryObjectArgumentInitialization(
6820 *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
6821 Method, ActingContext);
6822 if (Candidate.Conversions[ConvIdx].isBad()) {
6823 Candidate.Viable = false;
6824 Candidate.FailureKind = ovl_fail_bad_conversion;
6825 return;
6826 }
6827 }
6828
6829 // (CUDA B.1): Check for invalid calls between targets.
6830 if (getLangOpts().CUDA)
6831 if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
6832 if (!IsAllowedCUDACall(Caller, Method)) {
6833 Candidate.Viable = false;
6834 Candidate.FailureKind = ovl_fail_bad_target;
6835 return;
6836 }
6837
6838 if (Method->getTrailingRequiresClause()) {
6839 ConstraintSatisfaction Satisfaction;
6840 if (CheckFunctionConstraints(Method, Satisfaction) ||
6841 !Satisfaction.IsSatisfied) {
6842 Candidate.Viable = false;
6843 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
6844 return;
6845 }
6846 }
6847
6848 // Determine the implicit conversion sequences for each of the
6849 // arguments.
6850 for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
6851 unsigned ConvIdx =
6852 PO == OverloadCandidateParamOrder::Reversed ? 0 : (ArgIdx + 1);
6853 if (Candidate.Conversions[ConvIdx].isInitialized()) {
6854 // We already formed a conversion sequence for this parameter during
6855 // template argument deduction.
6856 } else if (ArgIdx < NumParams) {
6857 // (C++ 13.3.2p3): for F to be a viable function, there shall
6858 // exist for each argument an implicit conversion sequence
6859 // (13.3.3.1) that converts that argument to the corresponding
6860 // parameter of F.
6861 QualType ParamType = Proto->getParamType(ArgIdx);
6862 Candidate.Conversions[ConvIdx]
6863 = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
6864 SuppressUserConversions,
6865 /*InOverloadResolution=*/true,
6866 /*AllowObjCWritebackConversion=*/
6867 getLangOpts().ObjCAutoRefCount);
6868 if (Candidate.Conversions[ConvIdx].isBad()) {
6869 Candidate.Viable = false;
6870 Candidate.FailureKind = ovl_fail_bad_conversion;
6871 return;
6872 }
6873 } else {
6874 // (C++ 13.3.2p2): For the purposes of overload resolution, any
6875 // argument for which there is no corresponding parameter is
6876 // considered to "match the ellipsis" (C+ 13.3.3.1.3).
6877 Candidate.Conversions[ConvIdx].setEllipsis();
6878 }
6879 }
6880
6881 if (EnableIfAttr *FailedAttr =
6882 CheckEnableIf(Method, CandidateSet.getLocation(), Args, true)) {
6883 Candidate.Viable = false;
6884 Candidate.FailureKind = ovl_fail_enable_if;
6885 Candidate.DeductionFailure.Data = FailedAttr;
6886 return;
6887 }
6888
6889 if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() &&
6890 !Method->getAttr<TargetAttr>()->isDefaultVersion()) {
6891 Candidate.Viable = false;
6892 Candidate.FailureKind = ovl_non_default_multiversion_function;
6893 }
6894 }
6895
6896 /// Add a C++ member function template as a candidate to the candidate
6897 /// set, using template argument deduction to produce an appropriate member
6898 /// 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)6899 void Sema::AddMethodTemplateCandidate(
6900 FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
6901 CXXRecordDecl *ActingContext,
6902 TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
6903 Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
6904 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
6905 bool PartialOverloading, OverloadCandidateParamOrder PO) {
6906 if (!CandidateSet.isNewCandidate(MethodTmpl, PO))
6907 return;
6908
6909 // C++ [over.match.funcs]p7:
6910 // In each case where a candidate is a function template, candidate
6911 // function template specializations are generated using template argument
6912 // deduction (14.8.3, 14.8.2). Those candidates are then handled as
6913 // candidate functions in the usual way.113) A given name can refer to one
6914 // or more function templates and also to a set of overloaded non-template
6915 // functions. In such a case, the candidate functions generated from each
6916 // function template are combined with the set of non-template candidate
6917 // functions.
6918 TemplateDeductionInfo Info(CandidateSet.getLocation());
6919 FunctionDecl *Specialization = nullptr;
6920 ConversionSequenceList Conversions;
6921 if (TemplateDeductionResult Result = DeduceTemplateArguments(
6922 MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info,
6923 PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
6924 return CheckNonDependentConversions(
6925 MethodTmpl, ParamTypes, Args, CandidateSet, Conversions,
6926 SuppressUserConversions, ActingContext, ObjectType,
6927 ObjectClassification, PO);
6928 })) {
6929 OverloadCandidate &Candidate =
6930 CandidateSet.addCandidate(Conversions.size(), Conversions);
6931 Candidate.FoundDecl = FoundDecl;
6932 Candidate.Function = MethodTmpl->getTemplatedDecl();
6933 Candidate.Viable = false;
6934 Candidate.RewriteKind =
6935 CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
6936 Candidate.IsSurrogate = false;
6937 Candidate.IgnoreObjectArgument =
6938 cast<CXXMethodDecl>(Candidate.Function)->isStatic() ||
6939 ObjectType.isNull();
6940 Candidate.ExplicitCallArguments = Args.size();
6941 if (Result == TDK_NonDependentConversionFailure)
6942 Candidate.FailureKind = ovl_fail_bad_conversion;
6943 else {
6944 Candidate.FailureKind = ovl_fail_bad_deduction;
6945 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
6946 Info);
6947 }
6948 return;
6949 }
6950
6951 // Add the function template specialization produced by template argument
6952 // deduction as a candidate.
6953 assert(Specialization && "Missing member function template specialization?");
6954 assert(isa<CXXMethodDecl>(Specialization) &&
6955 "Specialization is not a member function?");
6956 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl,
6957 ActingContext, ObjectType, ObjectClassification, Args,
6958 CandidateSet, SuppressUserConversions, PartialOverloading,
6959 Conversions, PO);
6960 }
6961
6962 /// Determine whether a given function template has a simple explicit specifier
6963 /// or a non-value-dependent explicit-specification that evaluates to true.
isNonDependentlyExplicit(FunctionTemplateDecl * FTD)6964 static bool isNonDependentlyExplicit(FunctionTemplateDecl *FTD) {
6965 return ExplicitSpecifier::getFromDecl(FTD->getTemplatedDecl()).isExplicit();
6966 }
6967
6968 /// Add a C++ function template specialization as a candidate
6969 /// in the candidate set, using template argument deduction to produce
6970 /// 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)6971 void Sema::AddTemplateOverloadCandidate(
6972 FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
6973 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
6974 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
6975 bool PartialOverloading, bool AllowExplicit, ADLCallKind IsADLCandidate,
6976 OverloadCandidateParamOrder PO) {
6977 if (!CandidateSet.isNewCandidate(FunctionTemplate, PO))
6978 return;
6979
6980 // If the function template has a non-dependent explicit specification,
6981 // exclude it now if appropriate; we are not permitted to perform deduction
6982 // and substitution in this case.
6983 if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
6984 OverloadCandidate &Candidate = CandidateSet.addCandidate();
6985 Candidate.FoundDecl = FoundDecl;
6986 Candidate.Function = FunctionTemplate->getTemplatedDecl();
6987 Candidate.Viable = false;
6988 Candidate.FailureKind = ovl_fail_explicit;
6989 return;
6990 }
6991
6992 // C++ [over.match.funcs]p7:
6993 // In each case where a candidate is a function template, candidate
6994 // function template specializations are generated using template argument
6995 // deduction (14.8.3, 14.8.2). Those candidates are then handled as
6996 // candidate functions in the usual way.113) A given name can refer to one
6997 // or more function templates and also to a set of overloaded non-template
6998 // functions. In such a case, the candidate functions generated from each
6999 // function template are combined with the set of non-template candidate
7000 // functions.
7001 TemplateDeductionInfo Info(CandidateSet.getLocation());
7002 FunctionDecl *Specialization = nullptr;
7003 ConversionSequenceList Conversions;
7004 if (TemplateDeductionResult Result = DeduceTemplateArguments(
7005 FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info,
7006 PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
7007 return CheckNonDependentConversions(
7008 FunctionTemplate, ParamTypes, Args, CandidateSet, Conversions,
7009 SuppressUserConversions, nullptr, QualType(), {}, PO);
7010 })) {
7011 OverloadCandidate &Candidate =
7012 CandidateSet.addCandidate(Conversions.size(), Conversions);
7013 Candidate.FoundDecl = FoundDecl;
7014 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7015 Candidate.Viable = false;
7016 Candidate.RewriteKind =
7017 CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
7018 Candidate.IsSurrogate = false;
7019 Candidate.IsADLCandidate = IsADLCandidate;
7020 // Ignore the object argument if there is one, since we don't have an object
7021 // type.
7022 Candidate.IgnoreObjectArgument =
7023 isa<CXXMethodDecl>(Candidate.Function) &&
7024 !isa<CXXConstructorDecl>(Candidate.Function);
7025 Candidate.ExplicitCallArguments = Args.size();
7026 if (Result == TDK_NonDependentConversionFailure)
7027 Candidate.FailureKind = ovl_fail_bad_conversion;
7028 else {
7029 Candidate.FailureKind = ovl_fail_bad_deduction;
7030 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
7031 Info);
7032 }
7033 return;
7034 }
7035
7036 // Add the function template specialization produced by template argument
7037 // deduction as a candidate.
7038 assert(Specialization && "Missing function template specialization?");
7039 AddOverloadCandidate(
7040 Specialization, FoundDecl, Args, CandidateSet, SuppressUserConversions,
7041 PartialOverloading, AllowExplicit,
7042 /*AllowExplicitConversions*/ false, IsADLCandidate, Conversions, PO);
7043 }
7044
7045 /// Check that implicit conversion sequences can be formed for each argument
7046 /// whose corresponding parameter has a non-dependent type, per DR1391's
7047 /// [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)7048 bool Sema::CheckNonDependentConversions(
7049 FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
7050 ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
7051 ConversionSequenceList &Conversions, bool SuppressUserConversions,
7052 CXXRecordDecl *ActingContext, QualType ObjectType,
7053 Expr::Classification ObjectClassification, OverloadCandidateParamOrder PO) {
7054 // FIXME: The cases in which we allow explicit conversions for constructor
7055 // arguments never consider calling a constructor template. It's not clear
7056 // that is correct.
7057 const bool AllowExplicit = false;
7058
7059 auto *FD = FunctionTemplate->getTemplatedDecl();
7060 auto *Method = dyn_cast<CXXMethodDecl>(FD);
7061 bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method);
7062 unsigned ThisConversions = HasThisConversion ? 1 : 0;
7063
7064 Conversions =
7065 CandidateSet.allocateConversionSequences(ThisConversions + Args.size());
7066
7067 // Overload resolution is always an unevaluated context.
7068 EnterExpressionEvaluationContext Unevaluated(
7069 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7070
7071 // For a method call, check the 'this' conversion here too. DR1391 doesn't
7072 // require that, but this check should never result in a hard error, and
7073 // overload resolution is permitted to sidestep instantiations.
7074 if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() &&
7075 !ObjectType.isNull()) {
7076 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
7077 Conversions[ConvIdx] = TryObjectArgumentInitialization(
7078 *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
7079 Method, ActingContext);
7080 if (Conversions[ConvIdx].isBad())
7081 return true;
7082 }
7083
7084 for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
7085 ++I) {
7086 QualType ParamType = ParamTypes[I];
7087 if (!ParamType->isDependentType()) {
7088 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed
7089 ? 0
7090 : (ThisConversions + I);
7091 Conversions[ConvIdx]
7092 = TryCopyInitialization(*this, Args[I], ParamType,
7093 SuppressUserConversions,
7094 /*InOverloadResolution=*/true,
7095 /*AllowObjCWritebackConversion=*/
7096 getLangOpts().ObjCAutoRefCount,
7097 AllowExplicit);
7098 if (Conversions[ConvIdx].isBad())
7099 return true;
7100 }
7101 }
7102
7103 return false;
7104 }
7105
7106 /// Determine whether this is an allowable conversion from the result
7107 /// of an explicit conversion operator to the expected type, per C++
7108 /// [over.match.conv]p1 and [over.match.ref]p1.
7109 ///
7110 /// \param ConvType The return type of the conversion function.
7111 ///
7112 /// \param ToType The type we are converting to.
7113 ///
7114 /// \param AllowObjCPointerConversion Allow a conversion from one
7115 /// Objective-C pointer to another.
7116 ///
7117 /// \returns true if the conversion is allowable, false otherwise.
isAllowableExplicitConversion(Sema & S,QualType ConvType,QualType ToType,bool AllowObjCPointerConversion)7118 static bool isAllowableExplicitConversion(Sema &S,
7119 QualType ConvType, QualType ToType,
7120 bool AllowObjCPointerConversion) {
7121 QualType ToNonRefType = ToType.getNonReferenceType();
7122
7123 // Easy case: the types are the same.
7124 if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType))
7125 return true;
7126
7127 // Allow qualification conversions.
7128 bool ObjCLifetimeConversion;
7129 if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false,
7130 ObjCLifetimeConversion))
7131 return true;
7132
7133 // If we're not allowed to consider Objective-C pointer conversions,
7134 // we're done.
7135 if (!AllowObjCPointerConversion)
7136 return false;
7137
7138 // Is this an Objective-C pointer conversion?
7139 bool IncompatibleObjC = false;
7140 QualType ConvertedType;
7141 return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType,
7142 IncompatibleObjC);
7143 }
7144
7145 /// AddConversionCandidate - Add a C++ conversion function as a
7146 /// candidate in the candidate set (C++ [over.match.conv],
7147 /// C++ [over.match.copy]). From is the expression we're converting from,
7148 /// and ToType is the type that we're eventually trying to convert to
7149 /// (which may or may not be the same type as the type that the
7150 /// conversion function produces).
AddConversionCandidate(CXXConversionDecl * Conversion,DeclAccessPair FoundDecl,CXXRecordDecl * ActingContext,Expr * From,QualType ToType,OverloadCandidateSet & CandidateSet,bool AllowObjCConversionOnExplicit,bool AllowExplicit,bool AllowResultConversion)7151 void Sema::AddConversionCandidate(
7152 CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
7153 CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
7154 OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
7155 bool AllowExplicit, bool AllowResultConversion) {
7156 assert(!Conversion->getDescribedFunctionTemplate() &&
7157 "Conversion function templates use AddTemplateConversionCandidate");
7158 QualType ConvType = Conversion->getConversionType().getNonReferenceType();
7159 if (!CandidateSet.isNewCandidate(Conversion))
7160 return;
7161
7162 // If the conversion function has an undeduced return type, trigger its
7163 // deduction now.
7164 if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) {
7165 if (DeduceReturnType(Conversion, From->getExprLoc()))
7166 return;
7167 ConvType = Conversion->getConversionType().getNonReferenceType();
7168 }
7169
7170 // If we don't allow any conversion of the result type, ignore conversion
7171 // functions that don't convert to exactly (possibly cv-qualified) T.
7172 if (!AllowResultConversion &&
7173 !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType))
7174 return;
7175
7176 // Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion
7177 // operator is only a candidate if its return type is the target type or
7178 // can be converted to the target type with a qualification conversion.
7179 //
7180 // FIXME: Include such functions in the candidate list and explain why we
7181 // can't select them.
7182 if (Conversion->isExplicit() &&
7183 !isAllowableExplicitConversion(*this, ConvType, ToType,
7184 AllowObjCConversionOnExplicit))
7185 return;
7186
7187 // Overload resolution is always an unevaluated context.
7188 EnterExpressionEvaluationContext Unevaluated(
7189 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7190
7191 // Add this candidate
7192 OverloadCandidate &Candidate = CandidateSet.addCandidate(1);
7193 Candidate.FoundDecl = FoundDecl;
7194 Candidate.Function = Conversion;
7195 Candidate.IsSurrogate = false;
7196 Candidate.IgnoreObjectArgument = false;
7197 Candidate.FinalConversion.setAsIdentityConversion();
7198 Candidate.FinalConversion.setFromType(ConvType);
7199 Candidate.FinalConversion.setAllToTypes(ToType);
7200 Candidate.Viable = true;
7201 Candidate.ExplicitCallArguments = 1;
7202
7203 // Explicit functions are not actually candidates at all if we're not
7204 // allowing them in this context, but keep them around so we can point
7205 // to them in diagnostics.
7206 if (!AllowExplicit && Conversion->isExplicit()) {
7207 Candidate.Viable = false;
7208 Candidate.FailureKind = ovl_fail_explicit;
7209 return;
7210 }
7211
7212 // C++ [over.match.funcs]p4:
7213 // For conversion functions, the function is considered to be a member of
7214 // the class of the implicit implied object argument for the purpose of
7215 // defining the type of the implicit object parameter.
7216 //
7217 // Determine the implicit conversion sequence for the implicit
7218 // object parameter.
7219 QualType ImplicitParamType = From->getType();
7220 if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>())
7221 ImplicitParamType = FromPtrType->getPointeeType();
7222 CXXRecordDecl *ConversionContext
7223 = cast<CXXRecordDecl>(ImplicitParamType->castAs<RecordType>()->getDecl());
7224
7225 Candidate.Conversions[0] = TryObjectArgumentInitialization(
7226 *this, CandidateSet.getLocation(), From->getType(),
7227 From->Classify(Context), Conversion, ConversionContext);
7228
7229 if (Candidate.Conversions[0].isBad()) {
7230 Candidate.Viable = false;
7231 Candidate.FailureKind = ovl_fail_bad_conversion;
7232 return;
7233 }
7234
7235 if (Conversion->getTrailingRequiresClause()) {
7236 ConstraintSatisfaction Satisfaction;
7237 if (CheckFunctionConstraints(Conversion, Satisfaction) ||
7238 !Satisfaction.IsSatisfied) {
7239 Candidate.Viable = false;
7240 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
7241 return;
7242 }
7243 }
7244
7245 // We won't go through a user-defined type conversion function to convert a
7246 // derived to base as such conversions are given Conversion Rank. They only
7247 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user]
7248 QualType FromCanon
7249 = Context.getCanonicalType(From->getType().getUnqualifiedType());
7250 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
7251 if (FromCanon == ToCanon ||
7252 IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) {
7253 Candidate.Viable = false;
7254 Candidate.FailureKind = ovl_fail_trivial_conversion;
7255 return;
7256 }
7257
7258 // To determine what the conversion from the result of calling the
7259 // conversion function to the type we're eventually trying to
7260 // convert to (ToType), we need to synthesize a call to the
7261 // conversion function and attempt copy initialization from it. This
7262 // makes sure that we get the right semantics with respect to
7263 // lvalues/rvalues and the type. Fortunately, we can allocate this
7264 // call on the stack and we don't need its arguments to be
7265 // well-formed.
7266 DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(),
7267 VK_LValue, From->getBeginLoc());
7268 ImplicitCastExpr ConversionFn(
7269 ImplicitCastExpr::OnStack, Context.getPointerType(Conversion->getType()),
7270 CK_FunctionToPointerDecay, &ConversionRef, VK_RValue, Context);
7271
7272 QualType ConversionType = Conversion->getConversionType();
7273 if (!isCompleteType(From->getBeginLoc(), ConversionType)) {
7274 Candidate.Viable = false;
7275 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7276 return;
7277 }
7278
7279 ExprValueKind VK = Expr::getValueKindForType(ConversionType);
7280
7281 // Note that it is safe to allocate CallExpr on the stack here because
7282 // there are 0 arguments (i.e., nothing is allocated using ASTContext's
7283 // allocator).
7284 QualType CallResultType = ConversionType.getNonLValueExprType(Context);
7285
7286 alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
7287 CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
7288 Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());
7289
7290 ImplicitConversionSequence ICS =
7291 TryCopyInitialization(*this, TheTemporaryCall, ToType,
7292 /*SuppressUserConversions=*/true,
7293 /*InOverloadResolution=*/false,
7294 /*AllowObjCWritebackConversion=*/false);
7295
7296 switch (ICS.getKind()) {
7297 case ImplicitConversionSequence::StandardConversion:
7298 Candidate.FinalConversion = ICS.Standard;
7299
7300 // C++ [over.ics.user]p3:
7301 // If the user-defined conversion is specified by a specialization of a
7302 // conversion function template, the second standard conversion sequence
7303 // shall have exact match rank.
7304 if (Conversion->getPrimaryTemplate() &&
7305 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
7306 Candidate.Viable = false;
7307 Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
7308 return;
7309 }
7310
7311 // C++0x [dcl.init.ref]p5:
7312 // In the second case, if the reference is an rvalue reference and
7313 // the second standard conversion sequence of the user-defined
7314 // conversion sequence includes an lvalue-to-rvalue conversion, the
7315 // program is ill-formed.
7316 if (ToType->isRValueReferenceType() &&
7317 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
7318 Candidate.Viable = false;
7319 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7320 return;
7321 }
7322 break;
7323
7324 case ImplicitConversionSequence::BadConversion:
7325 Candidate.Viable = false;
7326 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7327 return;
7328
7329 default:
7330 llvm_unreachable(
7331 "Can only end up with a standard conversion sequence or failure");
7332 }
7333
7334 if (EnableIfAttr *FailedAttr =
7335 CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
7336 Candidate.Viable = false;
7337 Candidate.FailureKind = ovl_fail_enable_if;
7338 Candidate.DeductionFailure.Data = FailedAttr;
7339 return;
7340 }
7341
7342 if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() &&
7343 !Conversion->getAttr<TargetAttr>()->isDefaultVersion()) {
7344 Candidate.Viable = false;
7345 Candidate.FailureKind = ovl_non_default_multiversion_function;
7346 }
7347 }
7348
7349 /// Adds a conversion function template specialization
7350 /// candidate to the overload set, using template argument deduction
7351 /// to deduce the template arguments of the conversion function
7352 /// template from the type that we are converting to (C++
7353 /// [temp.deduct.conv]).
AddTemplateConversionCandidate(FunctionTemplateDecl * FunctionTemplate,DeclAccessPair FoundDecl,CXXRecordDecl * ActingDC,Expr * From,QualType ToType,OverloadCandidateSet & CandidateSet,bool AllowObjCConversionOnExplicit,bool AllowExplicit,bool AllowResultConversion)7354 void Sema::AddTemplateConversionCandidate(
7355 FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
7356 CXXRecordDecl *ActingDC, Expr *From, QualType ToType,
7357 OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
7358 bool AllowExplicit, bool AllowResultConversion) {
7359 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&
7360 "Only conversion function templates permitted here");
7361
7362 if (!CandidateSet.isNewCandidate(FunctionTemplate))
7363 return;
7364
7365 // If the function template has a non-dependent explicit specification,
7366 // exclude it now if appropriate; we are not permitted to perform deduction
7367 // and substitution in this case.
7368 if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
7369 OverloadCandidate &Candidate = CandidateSet.addCandidate();
7370 Candidate.FoundDecl = FoundDecl;
7371 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7372 Candidate.Viable = false;
7373 Candidate.FailureKind = ovl_fail_explicit;
7374 return;
7375 }
7376
7377 TemplateDeductionInfo Info(CandidateSet.getLocation());
7378 CXXConversionDecl *Specialization = nullptr;
7379 if (TemplateDeductionResult Result
7380 = DeduceTemplateArguments(FunctionTemplate, ToType,
7381 Specialization, Info)) {
7382 OverloadCandidate &Candidate = CandidateSet.addCandidate();
7383 Candidate.FoundDecl = FoundDecl;
7384 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7385 Candidate.Viable = false;
7386 Candidate.FailureKind = ovl_fail_bad_deduction;
7387 Candidate.IsSurrogate = false;
7388 Candidate.IgnoreObjectArgument = false;
7389 Candidate.ExplicitCallArguments = 1;
7390 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
7391 Info);
7392 return;
7393 }
7394
7395 // Add the conversion function template specialization produced by
7396 // template argument deduction as a candidate.
7397 assert(Specialization && "Missing function template specialization?");
7398 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType,
7399 CandidateSet, AllowObjCConversionOnExplicit,
7400 AllowExplicit, AllowResultConversion);
7401 }
7402
7403 /// AddSurrogateCandidate - Adds a "surrogate" candidate function that
7404 /// converts the given @c Object to a function pointer via the
7405 /// conversion function @c Conversion, and then attempts to call it
7406 /// with the given arguments (C++ [over.call.object]p2-4). Proto is
7407 /// 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)7408 void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
7409 DeclAccessPair FoundDecl,
7410 CXXRecordDecl *ActingContext,
7411 const FunctionProtoType *Proto,
7412 Expr *Object,
7413 ArrayRef<Expr *> Args,
7414 OverloadCandidateSet& CandidateSet) {
7415 if (!CandidateSet.isNewCandidate(Conversion))
7416 return;
7417
7418 // Overload resolution is always an unevaluated context.
7419 EnterExpressionEvaluationContext Unevaluated(
7420 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7421
7422 OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1);
7423 Candidate.FoundDecl = FoundDecl;
7424 Candidate.Function = nullptr;
7425 Candidate.Surrogate = Conversion;
7426 Candidate.Viable = true;
7427 Candidate.IsSurrogate = true;
7428 Candidate.IgnoreObjectArgument = false;
7429 Candidate.ExplicitCallArguments = Args.size();
7430
7431 // Determine the implicit conversion sequence for the implicit
7432 // object parameter.
7433 ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization(
7434 *this, CandidateSet.getLocation(), Object->getType(),
7435 Object->Classify(Context), Conversion, ActingContext);
7436 if (ObjectInit.isBad()) {
7437 Candidate.Viable = false;
7438 Candidate.FailureKind = ovl_fail_bad_conversion;
7439 Candidate.Conversions[0] = ObjectInit;
7440 return;
7441 }
7442
7443 // The first conversion is actually a user-defined conversion whose
7444 // first conversion is ObjectInit's standard conversion (which is
7445 // effectively a reference binding). Record it as such.
7446 Candidate.Conversions[0].setUserDefined();
7447 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
7448 Candidate.Conversions[0].UserDefined.EllipsisConversion = false;
7449 Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false;
7450 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
7451 Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl;
7452 Candidate.Conversions[0].UserDefined.After
7453 = Candidate.Conversions[0].UserDefined.Before;
7454 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();
7455
7456 // Find the
7457 unsigned NumParams = Proto->getNumParams();
7458
7459 // (C++ 13.3.2p2): A candidate function having fewer than m
7460 // parameters is viable only if it has an ellipsis in its parameter
7461 // list (8.3.5).
7462 if (Args.size() > NumParams && !Proto->isVariadic()) {
7463 Candidate.Viable = false;
7464 Candidate.FailureKind = ovl_fail_too_many_arguments;
7465 return;
7466 }
7467
7468 // Function types don't have any default arguments, so just check if
7469 // we have enough arguments.
7470 if (Args.size() < NumParams) {
7471 // Not enough arguments.
7472 Candidate.Viable = false;
7473 Candidate.FailureKind = ovl_fail_too_few_arguments;
7474 return;
7475 }
7476
7477 // Determine the implicit conversion sequences for each of the
7478 // arguments.
7479 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
7480 if (ArgIdx < NumParams) {
7481 // (C++ 13.3.2p3): for F to be a viable function, there shall
7482 // exist for each argument an implicit conversion sequence
7483 // (13.3.3.1) that converts that argument to the corresponding
7484 // parameter of F.
7485 QualType ParamType = Proto->getParamType(ArgIdx);
7486 Candidate.Conversions[ArgIdx + 1]
7487 = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
7488 /*SuppressUserConversions=*/false,
7489 /*InOverloadResolution=*/false,
7490 /*AllowObjCWritebackConversion=*/
7491 getLangOpts().ObjCAutoRefCount);
7492 if (Candidate.Conversions[ArgIdx + 1].isBad()) {
7493 Candidate.Viable = false;
7494 Candidate.FailureKind = ovl_fail_bad_conversion;
7495 return;
7496 }
7497 } else {
7498 // (C++ 13.3.2p2): For the purposes of overload resolution, any
7499 // argument for which there is no corresponding parameter is
7500 // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
7501 Candidate.Conversions[ArgIdx + 1].setEllipsis();
7502 }
7503 }
7504
7505 if (EnableIfAttr *FailedAttr =
7506 CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
7507 Candidate.Viable = false;
7508 Candidate.FailureKind = ovl_fail_enable_if;
7509 Candidate.DeductionFailure.Data = FailedAttr;
7510 return;
7511 }
7512 }
7513
7514 /// Add all of the non-member operator function declarations in the given
7515 /// function set to the overload candidate set.
AddNonMemberOperatorCandidates(const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,TemplateArgumentListInfo * ExplicitTemplateArgs)7516 void Sema::AddNonMemberOperatorCandidates(
7517 const UnresolvedSetImpl &Fns, ArrayRef<Expr *> Args,
7518 OverloadCandidateSet &CandidateSet,
7519 TemplateArgumentListInfo *ExplicitTemplateArgs) {
7520 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
7521 NamedDecl *D = F.getDecl()->getUnderlyingDecl();
7522 ArrayRef<Expr *> FunctionArgs = Args;
7523
7524 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
7525 FunctionDecl *FD =
7526 FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
7527
7528 // Don't consider rewritten functions if we're not rewriting.
7529 if (!CandidateSet.getRewriteInfo().isAcceptableCandidate(FD))
7530 continue;
7531
7532 assert(!isa<CXXMethodDecl>(FD) &&
7533 "unqualified operator lookup found a member function");
7534
7535 if (FunTmpl) {
7536 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs,
7537 FunctionArgs, CandidateSet);
7538 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
7539 AddTemplateOverloadCandidate(
7540 FunTmpl, F.getPair(), ExplicitTemplateArgs,
7541 {FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false,
7542 true, ADLCallKind::NotADL, OverloadCandidateParamOrder::Reversed);
7543 } else {
7544 if (ExplicitTemplateArgs)
7545 continue;
7546 AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet);
7547 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
7548 AddOverloadCandidate(FD, F.getPair(),
7549 {FunctionArgs[1], FunctionArgs[0]}, CandidateSet,
7550 false, false, true, false, ADLCallKind::NotADL,
7551 None, OverloadCandidateParamOrder::Reversed);
7552 }
7553 }
7554 }
7555
7556 /// Add overload candidates for overloaded operators that are
7557 /// member functions.
7558 ///
7559 /// Add the overloaded operator candidates that are member functions
7560 /// for the operator Op that was used in an operator expression such
7561 /// as "x Op y". , Args/NumArgs provides the operator arguments, and
7562 /// CandidateSet will store the added overload candidates. (C++
7563 /// [over.match.oper]).
AddMemberOperatorCandidates(OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,OverloadCandidateParamOrder PO)7564 void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
7565 SourceLocation OpLoc,
7566 ArrayRef<Expr *> Args,
7567 OverloadCandidateSet &CandidateSet,
7568 OverloadCandidateParamOrder PO) {
7569 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
7570
7571 // C++ [over.match.oper]p3:
7572 // For a unary operator @ with an operand of a type whose
7573 // cv-unqualified version is T1, and for a binary operator @ with
7574 // a left operand of a type whose cv-unqualified version is T1 and
7575 // a right operand of a type whose cv-unqualified version is T2,
7576 // three sets of candidate functions, designated member
7577 // candidates, non-member candidates and built-in candidates, are
7578 // constructed as follows:
7579 QualType T1 = Args[0]->getType();
7580
7581 // -- If T1 is a complete class type or a class currently being
7582 // defined, the set of member candidates is the result of the
7583 // qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
7584 // the set of member candidates is empty.
7585 if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
7586 // Complete the type if it can be completed.
7587 if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined())
7588 return;
7589 // If the type is neither complete nor being defined, bail out now.
7590 if (!T1Rec->getDecl()->getDefinition())
7591 return;
7592
7593 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName);
7594 LookupQualifiedName(Operators, T1Rec->getDecl());
7595 Operators.suppressDiagnostics();
7596
7597 for (LookupResult::iterator Oper = Operators.begin(),
7598 OperEnd = Operators.end();
7599 Oper != OperEnd;
7600 ++Oper)
7601 AddMethodCandidate(Oper.getPair(), Args[0]->getType(),
7602 Args[0]->Classify(Context), Args.slice(1),
7603 CandidateSet, /*SuppressUserConversion=*/false, PO);
7604 }
7605 }
7606
7607 /// AddBuiltinCandidate - Add a candidate for a built-in
7608 /// operator. ResultTy and ParamTys are the result and parameter types
7609 /// of the built-in candidate, respectively. Args and NumArgs are the
7610 /// arguments being passed to the candidate. IsAssignmentOperator
7611 /// should be true when this built-in candidate is an assignment
7612 /// operator. NumContextualBoolArguments is the number of arguments
7613 /// (at the beginning of the argument list) that will be contextually
7614 /// converted to bool.
AddBuiltinCandidate(QualType * ParamTys,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool IsAssignmentOperator,unsigned NumContextualBoolArguments)7615 void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
7616 OverloadCandidateSet& CandidateSet,
7617 bool IsAssignmentOperator,
7618 unsigned NumContextualBoolArguments) {
7619 // Overload resolution is always an unevaluated context.
7620 EnterExpressionEvaluationContext Unevaluated(
7621 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7622
7623 // Add this candidate
7624 OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size());
7625 Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none);
7626 Candidate.Function = nullptr;
7627 Candidate.IsSurrogate = false;
7628 Candidate.IgnoreObjectArgument = false;
7629 std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes);
7630
7631 // Determine the implicit conversion sequences for each of the
7632 // arguments.
7633 Candidate.Viable = true;
7634 Candidate.ExplicitCallArguments = Args.size();
7635 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
7636 // C++ [over.match.oper]p4:
7637 // For the built-in assignment operators, conversions of the
7638 // left operand are restricted as follows:
7639 // -- no temporaries are introduced to hold the left operand, and
7640 // -- no user-defined conversions are applied to the left
7641 // operand to achieve a type match with the left-most
7642 // parameter of a built-in candidate.
7643 //
7644 // We block these conversions by turning off user-defined
7645 // conversions, since that is the only way that initialization of
7646 // a reference to a non-class type can occur from something that
7647 // is not of the same type.
7648 if (ArgIdx < NumContextualBoolArguments) {
7649 assert(ParamTys[ArgIdx] == Context.BoolTy &&
7650 "Contextual conversion to bool requires bool type");
7651 Candidate.Conversions[ArgIdx]
7652 = TryContextuallyConvertToBool(*this, Args[ArgIdx]);
7653 } else {
7654 Candidate.Conversions[ArgIdx]
7655 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx],
7656 ArgIdx == 0 && IsAssignmentOperator,
7657 /*InOverloadResolution=*/false,
7658 /*AllowObjCWritebackConversion=*/
7659 getLangOpts().ObjCAutoRefCount);
7660 }
7661 if (Candidate.Conversions[ArgIdx].isBad()) {
7662 Candidate.Viable = false;
7663 Candidate.FailureKind = ovl_fail_bad_conversion;
7664 break;
7665 }
7666 }
7667 }
7668
7669 namespace {
7670
7671 /// BuiltinCandidateTypeSet - A set of types that will be used for the
7672 /// candidate operator functions for built-in operators (C++
7673 /// [over.built]). The types are separated into pointer types and
7674 /// enumeration types.
7675 class BuiltinCandidateTypeSet {
7676 /// TypeSet - A set of types.
7677 typedef llvm::SetVector<QualType, SmallVector<QualType, 8>,
7678 llvm::SmallPtrSet<QualType, 8>> TypeSet;
7679
7680 /// PointerTypes - The set of pointer types that will be used in the
7681 /// built-in candidates.
7682 TypeSet PointerTypes;
7683
7684 /// MemberPointerTypes - The set of member pointer types that will be
7685 /// used in the built-in candidates.
7686 TypeSet MemberPointerTypes;
7687
7688 /// EnumerationTypes - The set of enumeration types that will be
7689 /// used in the built-in candidates.
7690 TypeSet EnumerationTypes;
7691
7692 /// The set of vector types that will be used in the built-in
7693 /// candidates.
7694 TypeSet VectorTypes;
7695
7696 /// The set of matrix types that will be used in the built-in
7697 /// candidates.
7698 TypeSet MatrixTypes;
7699
7700 /// A flag indicating non-record types are viable candidates
7701 bool HasNonRecordTypes;
7702
7703 /// A flag indicating whether either arithmetic or enumeration types
7704 /// were present in the candidate set.
7705 bool HasArithmeticOrEnumeralTypes;
7706
7707 /// A flag indicating whether the nullptr type was present in the
7708 /// candidate set.
7709 bool HasNullPtrType;
7710
7711 /// Sema - The semantic analysis instance where we are building the
7712 /// candidate type set.
7713 Sema &SemaRef;
7714
7715 /// Context - The AST context in which we will build the type sets.
7716 ASTContext &Context;
7717
7718 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
7719 const Qualifiers &VisibleQuals);
7720 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty);
7721
7722 public:
7723 /// iterator - Iterates through the types that are part of the set.
7724 typedef TypeSet::iterator iterator;
7725
BuiltinCandidateTypeSet(Sema & SemaRef)7726 BuiltinCandidateTypeSet(Sema &SemaRef)
7727 : HasNonRecordTypes(false),
7728 HasArithmeticOrEnumeralTypes(false),
7729 HasNullPtrType(false),
7730 SemaRef(SemaRef),
7731 Context(SemaRef.Context) { }
7732
7733 void AddTypesConvertedFrom(QualType Ty,
7734 SourceLocation Loc,
7735 bool AllowUserConversions,
7736 bool AllowExplicitConversions,
7737 const Qualifiers &VisibleTypeConversionsQuals);
7738
7739 /// pointer_begin - First pointer type found;
pointer_begin()7740 iterator pointer_begin() { return PointerTypes.begin(); }
7741
7742 /// pointer_end - Past the last pointer type found;
pointer_end()7743 iterator pointer_end() { return PointerTypes.end(); }
7744
7745 /// member_pointer_begin - First member pointer type found;
member_pointer_begin()7746 iterator member_pointer_begin() { return MemberPointerTypes.begin(); }
7747
7748 /// member_pointer_end - Past the last member pointer type found;
member_pointer_end()7749 iterator member_pointer_end() { return MemberPointerTypes.end(); }
7750
7751 /// enumeration_begin - First enumeration type found;
enumeration_begin()7752 iterator enumeration_begin() { return EnumerationTypes.begin(); }
7753
7754 /// enumeration_end - Past the last enumeration type found;
enumeration_end()7755 iterator enumeration_end() { return EnumerationTypes.end(); }
7756
vector_types()7757 llvm::iterator_range<iterator> vector_types() { return VectorTypes; }
7758
matrix_types()7759 llvm::iterator_range<iterator> matrix_types() { return MatrixTypes; }
7760
containsMatrixType(QualType Ty) const7761 bool containsMatrixType(QualType Ty) const { return MatrixTypes.count(Ty); }
hasNonRecordTypes()7762 bool hasNonRecordTypes() { return HasNonRecordTypes; }
hasArithmeticOrEnumeralTypes()7763 bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; }
hasNullPtrType() const7764 bool hasNullPtrType() const { return HasNullPtrType; }
7765 };
7766
7767 } // end anonymous namespace
7768
7769 /// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to
7770 /// the set of pointer types along with any more-qualified variants of
7771 /// that type. For example, if @p Ty is "int const *", this routine
7772 /// will add "int const *", "int const volatile *", "int const
7773 /// restrict *", and "int const volatile restrict *" to the set of
7774 /// pointer types. Returns true if the add of @p Ty itself succeeded,
7775 /// false otherwise.
7776 ///
7777 /// FIXME: what to do about extended qualifiers?
7778 bool
AddPointerWithMoreQualifiedTypeVariants(QualType Ty,const Qualifiers & VisibleQuals)7779 BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
7780 const Qualifiers &VisibleQuals) {
7781
7782 // Insert this type.
7783 if (!PointerTypes.insert(Ty))
7784 return false;
7785
7786 QualType PointeeTy;
7787 const PointerType *PointerTy = Ty->getAs<PointerType>();
7788 bool buildObjCPtr = false;
7789 if (!PointerTy) {
7790 const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>();
7791 PointeeTy = PTy->getPointeeType();
7792 buildObjCPtr = true;
7793 } else {
7794 PointeeTy = PointerTy->getPointeeType();
7795 }
7796
7797 // Don't add qualified variants of arrays. For one, they're not allowed
7798 // (the qualifier would sink to the element type), and for another, the
7799 // only overload situation where it matters is subscript or pointer +- int,
7800 // and those shouldn't have qualifier variants anyway.
7801 if (PointeeTy->isArrayType())
7802 return true;
7803
7804 unsigned BaseCVR = PointeeTy.getCVRQualifiers();
7805 bool hasVolatile = VisibleQuals.hasVolatile();
7806 bool hasRestrict = VisibleQuals.hasRestrict();
7807
7808 // Iterate through all strict supersets of BaseCVR.
7809 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
7810 if ((CVR | BaseCVR) != CVR) continue;
7811 // Skip over volatile if no volatile found anywhere in the types.
7812 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue;
7813
7814 // Skip over restrict if no restrict found anywhere in the types, or if
7815 // the type cannot be restrict-qualified.
7816 if ((CVR & Qualifiers::Restrict) &&
7817 (!hasRestrict ||
7818 (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType()))))
7819 continue;
7820
7821 // Build qualified pointee type.
7822 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
7823
7824 // Build qualified pointer type.
7825 QualType QPointerTy;
7826 if (!buildObjCPtr)
7827 QPointerTy = Context.getPointerType(QPointeeTy);
7828 else
7829 QPointerTy = Context.getObjCObjectPointerType(QPointeeTy);
7830
7831 // Insert qualified pointer type.
7832 PointerTypes.insert(QPointerTy);
7833 }
7834
7835 return true;
7836 }
7837
7838 /// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty
7839 /// to the set of pointer types along with any more-qualified variants of
7840 /// that type. For example, if @p Ty is "int const *", this routine
7841 /// will add "int const *", "int const volatile *", "int const
7842 /// restrict *", and "int const volatile restrict *" to the set of
7843 /// pointer types. Returns true if the add of @p Ty itself succeeded,
7844 /// false otherwise.
7845 ///
7846 /// FIXME: what to do about extended qualifiers?
7847 bool
AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty)7848 BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants(
7849 QualType Ty) {
7850 // Insert this type.
7851 if (!MemberPointerTypes.insert(Ty))
7852 return false;
7853
7854 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>();
7855 assert(PointerTy && "type was not a member pointer type!");
7856
7857 QualType PointeeTy = PointerTy->getPointeeType();
7858 // Don't add qualified variants of arrays. For one, they're not allowed
7859 // (the qualifier would sink to the element type), and for another, the
7860 // only overload situation where it matters is subscript or pointer +- int,
7861 // and those shouldn't have qualifier variants anyway.
7862 if (PointeeTy->isArrayType())
7863 return true;
7864 const Type *ClassTy = PointerTy->getClass();
7865
7866 // Iterate through all strict supersets of the pointee type's CVR
7867 // qualifiers.
7868 unsigned BaseCVR = PointeeTy.getCVRQualifiers();
7869 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
7870 if ((CVR | BaseCVR) != CVR) continue;
7871
7872 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
7873 MemberPointerTypes.insert(
7874 Context.getMemberPointerType(QPointeeTy, ClassTy));
7875 }
7876
7877 return true;
7878 }
7879
7880 /// AddTypesConvertedFrom - Add each of the types to which the type @p
7881 /// Ty can be implicit converted to the given set of @p Types. We're
7882 /// primarily interested in pointer types and enumeration types. We also
7883 /// take member pointer types, for the conditional operator.
7884 /// AllowUserConversions is true if we should look at the conversion
7885 /// functions of a class type, and AllowExplicitConversions if we
7886 /// should also include the explicit conversion functions of a class
7887 /// type.
7888 void
AddTypesConvertedFrom(QualType Ty,SourceLocation Loc,bool AllowUserConversions,bool AllowExplicitConversions,const Qualifiers & VisibleQuals)7889 BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty,
7890 SourceLocation Loc,
7891 bool AllowUserConversions,
7892 bool AllowExplicitConversions,
7893 const Qualifiers &VisibleQuals) {
7894 // Only deal with canonical types.
7895 Ty = Context.getCanonicalType(Ty);
7896
7897 // Look through reference types; they aren't part of the type of an
7898 // expression for the purposes of conversions.
7899 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>())
7900 Ty = RefTy->getPointeeType();
7901
7902 // If we're dealing with an array type, decay to the pointer.
7903 if (Ty->isArrayType())
7904 Ty = SemaRef.Context.getArrayDecayedType(Ty);
7905
7906 // Otherwise, we don't care about qualifiers on the type.
7907 Ty = Ty.getLocalUnqualifiedType();
7908
7909 // Flag if we ever add a non-record type.
7910 const RecordType *TyRec = Ty->getAs<RecordType>();
7911 HasNonRecordTypes = HasNonRecordTypes || !TyRec;
7912
7913 // Flag if we encounter an arithmetic type.
7914 HasArithmeticOrEnumeralTypes =
7915 HasArithmeticOrEnumeralTypes || Ty->isArithmeticType();
7916
7917 if (Ty->isObjCIdType() || Ty->isObjCClassType())
7918 PointerTypes.insert(Ty);
7919 else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) {
7920 // Insert our type, and its more-qualified variants, into the set
7921 // of types.
7922 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals))
7923 return;
7924 } else if (Ty->isMemberPointerType()) {
7925 // Member pointers are far easier, since the pointee can't be converted.
7926 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty))
7927 return;
7928 } else if (Ty->isEnumeralType()) {
7929 HasArithmeticOrEnumeralTypes = true;
7930 EnumerationTypes.insert(Ty);
7931 } else if (Ty->isVectorType()) {
7932 // We treat vector types as arithmetic types in many contexts as an
7933 // extension.
7934 HasArithmeticOrEnumeralTypes = true;
7935 VectorTypes.insert(Ty);
7936 } else if (Ty->isMatrixType()) {
7937 // Similar to vector types, we treat vector types as arithmetic types in
7938 // many contexts as an extension.
7939 HasArithmeticOrEnumeralTypes = true;
7940 MatrixTypes.insert(Ty);
7941 } else if (Ty->isNullPtrType()) {
7942 HasNullPtrType = true;
7943 } else if (AllowUserConversions && TyRec) {
7944 // No conversion functions in incomplete types.
7945 if (!SemaRef.isCompleteType(Loc, Ty))
7946 return;
7947
7948 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
7949 for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
7950 if (isa<UsingShadowDecl>(D))
7951 D = cast<UsingShadowDecl>(D)->getTargetDecl();
7952
7953 // Skip conversion function templates; they don't tell us anything
7954 // about which builtin types we can convert to.
7955 if (isa<FunctionTemplateDecl>(D))
7956 continue;
7957
7958 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
7959 if (AllowExplicitConversions || !Conv->isExplicit()) {
7960 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false,
7961 VisibleQuals);
7962 }
7963 }
7964 }
7965 }
7966 /// Helper function for adjusting address spaces for the pointer or reference
7967 /// operands of builtin operators depending on the argument.
AdjustAddressSpaceForBuiltinOperandType(Sema & S,QualType T,Expr * Arg)7968 static QualType AdjustAddressSpaceForBuiltinOperandType(Sema &S, QualType T,
7969 Expr *Arg) {
7970 return S.Context.getAddrSpaceQualType(T, Arg->getType().getAddressSpace());
7971 }
7972
7973 /// Helper function for AddBuiltinOperatorCandidates() that adds
7974 /// the volatile- and non-volatile-qualified assignment operators for the
7975 /// given type to the candidate set.
AddBuiltinAssignmentOperatorCandidates(Sema & S,QualType T,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)7976 static void AddBuiltinAssignmentOperatorCandidates(Sema &S,
7977 QualType T,
7978 ArrayRef<Expr *> Args,
7979 OverloadCandidateSet &CandidateSet) {
7980 QualType ParamTypes[2];
7981
7982 // T& operator=(T&, T)
7983 ParamTypes[0] = S.Context.getLValueReferenceType(
7984 AdjustAddressSpaceForBuiltinOperandType(S, T, Args[0]));
7985 ParamTypes[1] = T;
7986 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
7987 /*IsAssignmentOperator=*/true);
7988
7989 if (!S.Context.getCanonicalType(T).isVolatileQualified()) {
7990 // volatile T& operator=(volatile T&, T)
7991 ParamTypes[0] = S.Context.getLValueReferenceType(
7992 AdjustAddressSpaceForBuiltinOperandType(S, S.Context.getVolatileType(T),
7993 Args[0]));
7994 ParamTypes[1] = T;
7995 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
7996 /*IsAssignmentOperator=*/true);
7997 }
7998 }
7999
8000 /// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers,
8001 /// if any, found in visible type conversion functions found in ArgExpr's type.
CollectVRQualifiers(ASTContext & Context,Expr * ArgExpr)8002 static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) {
8003 Qualifiers VRQuals;
8004 const RecordType *TyRec;
8005 if (const MemberPointerType *RHSMPType =
8006 ArgExpr->getType()->getAs<MemberPointerType>())
8007 TyRec = RHSMPType->getClass()->getAs<RecordType>();
8008 else
8009 TyRec = ArgExpr->getType()->getAs<RecordType>();
8010 if (!TyRec) {
8011 // Just to be safe, assume the worst case.
8012 VRQuals.addVolatile();
8013 VRQuals.addRestrict();
8014 return VRQuals;
8015 }
8016
8017 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
8018 if (!ClassDecl->hasDefinition())
8019 return VRQuals;
8020
8021 for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
8022 if (isa<UsingShadowDecl>(D))
8023 D = cast<UsingShadowDecl>(D)->getTargetDecl();
8024 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) {
8025 QualType CanTy = Context.getCanonicalType(Conv->getConversionType());
8026 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>())
8027 CanTy = ResTypeRef->getPointeeType();
8028 // Need to go down the pointer/mempointer chain and add qualifiers
8029 // as see them.
8030 bool done = false;
8031 while (!done) {
8032 if (CanTy.isRestrictQualified())
8033 VRQuals.addRestrict();
8034 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>())
8035 CanTy = ResTypePtr->getPointeeType();
8036 else if (const MemberPointerType *ResTypeMPtr =
8037 CanTy->getAs<MemberPointerType>())
8038 CanTy = ResTypeMPtr->getPointeeType();
8039 else
8040 done = true;
8041 if (CanTy.isVolatileQualified())
8042 VRQuals.addVolatile();
8043 if (VRQuals.hasRestrict() && VRQuals.hasVolatile())
8044 return VRQuals;
8045 }
8046 }
8047 }
8048 return VRQuals;
8049 }
8050
8051 namespace {
8052
8053 /// Helper class to manage the addition of builtin operator overload
8054 /// candidates. It provides shared state and utility methods used throughout
8055 /// the process, as well as a helper method to add each group of builtin
8056 /// operator overloads from the standard to a candidate set.
8057 class BuiltinOperatorOverloadBuilder {
8058 // Common instance state available to all overload candidate addition methods.
8059 Sema &S;
8060 ArrayRef<Expr *> Args;
8061 Qualifiers VisibleTypeConversionsQuals;
8062 bool HasArithmeticOrEnumeralCandidateType;
8063 SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes;
8064 OverloadCandidateSet &CandidateSet;
8065
8066 static constexpr int ArithmeticTypesCap = 24;
8067 SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes;
8068
8069 // Define some indices used to iterate over the arithmetic types in
8070 // ArithmeticTypes. The "promoted arithmetic types" are the arithmetic
8071 // types are that preserved by promotion (C++ [over.built]p2).
8072 unsigned FirstIntegralType,
8073 LastIntegralType;
8074 unsigned FirstPromotedIntegralType,
8075 LastPromotedIntegralType;
8076 unsigned FirstPromotedArithmeticType,
8077 LastPromotedArithmeticType;
8078 unsigned FirstCapabilityType,
8079 LastCapabilityType;
8080 unsigned NumArithmeticTypes;
8081
InitArithmeticTypes()8082 void InitArithmeticTypes() {
8083 // Start of promoted types.
8084 FirstPromotedArithmeticType = 0;
8085 ArithmeticTypes.push_back(S.Context.FloatTy);
8086 ArithmeticTypes.push_back(S.Context.DoubleTy);
8087 ArithmeticTypes.push_back(S.Context.LongDoubleTy);
8088 if (S.Context.getTargetInfo().hasFloat128Type())
8089 ArithmeticTypes.push_back(S.Context.Float128Ty);
8090
8091 // Start of integral types.
8092 FirstIntegralType = ArithmeticTypes.size();
8093 FirstPromotedIntegralType = ArithmeticTypes.size();
8094 ArithmeticTypes.push_back(S.Context.IntTy);
8095 ArithmeticTypes.push_back(S.Context.LongTy);
8096 ArithmeticTypes.push_back(S.Context.LongLongTy);
8097 if (S.Context.getTargetInfo().hasInt128Type())
8098 ArithmeticTypes.push_back(S.Context.Int128Ty);
8099 ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
8100 ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
8101 ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
8102 if (S.Context.getTargetInfo().hasInt128Type())
8103 ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
8104
8105 // Capability types
8106 FirstCapabilityType = ArithmeticTypes.size();
8107 if (S.Context.getTargetInfo().SupportsCapabilities()) {
8108 ArithmeticTypes.push_back(S.Context.IntCapTy);
8109 ArithmeticTypes.push_back(S.Context.UnsignedIntCapTy);
8110 }
8111 LastCapabilityType = ArithmeticTypes.size();
8112
8113 LastPromotedIntegralType = ArithmeticTypes.size();
8114 LastPromotedArithmeticType = ArithmeticTypes.size();
8115 // End of promoted types.
8116
8117 ArithmeticTypes.push_back(S.Context.BoolTy);
8118 ArithmeticTypes.push_back(S.Context.CharTy);
8119 ArithmeticTypes.push_back(S.Context.WCharTy);
8120 if (S.Context.getLangOpts().Char8)
8121 ArithmeticTypes.push_back(S.Context.Char8Ty);
8122 ArithmeticTypes.push_back(S.Context.Char16Ty);
8123 ArithmeticTypes.push_back(S.Context.Char32Ty);
8124 ArithmeticTypes.push_back(S.Context.SignedCharTy);
8125 ArithmeticTypes.push_back(S.Context.ShortTy);
8126 ArithmeticTypes.push_back(S.Context.UnsignedCharTy);
8127 ArithmeticTypes.push_back(S.Context.UnsignedShortTy);
8128 LastIntegralType = ArithmeticTypes.size();
8129 NumArithmeticTypes = ArithmeticTypes.size();
8130 // End of integral types.
8131 // FIXME: What about complex? What about half?
8132
8133 assert(ArithmeticTypes.size() <= ArithmeticTypesCap &&
8134 "Enough inline storage for all arithmetic types.");
8135 }
8136
8137 /// Helper method to factor out the common pattern of adding overloads
8138 /// for '++' and '--' builtin operators.
addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,bool HasVolatile,bool HasRestrict)8139 void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,
8140 bool HasVolatile,
8141 bool HasRestrict) {
8142 QualType ParamTypes[2] = {
8143 S.Context.getLValueReferenceType(CandidateTy),
8144 S.Context.IntTy
8145 };
8146
8147 // Non-volatile version.
8148 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8149
8150 // Use a heuristic to reduce number of builtin candidates in the set:
8151 // add volatile version only if there are conversions to a volatile type.
8152 if (HasVolatile) {
8153 ParamTypes[0] =
8154 S.Context.getLValueReferenceType(
8155 S.Context.getVolatileType(CandidateTy));
8156 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8157 }
8158
8159 // Add restrict version only if there are conversions to a restrict type
8160 // and our candidate type is a non-restrict-qualified pointer.
8161 if (HasRestrict && CandidateTy->isAnyPointerType() &&
8162 !CandidateTy.isRestrictQualified()) {
8163 ParamTypes[0]
8164 = S.Context.getLValueReferenceType(
8165 S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict));
8166 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8167
8168 if (HasVolatile) {
8169 ParamTypes[0]
8170 = S.Context.getLValueReferenceType(
8171 S.Context.getCVRQualifiedType(CandidateTy,
8172 (Qualifiers::Volatile |
8173 Qualifiers::Restrict)));
8174 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8175 }
8176 }
8177
8178 }
8179
8180 /// Helper to add an overload candidate for a binary builtin with types \p L
8181 /// and \p R.
AddCandidate(QualType L,QualType R)8182 void AddCandidate(QualType L, QualType R) {
8183 QualType LandR[2] = {L, R};
8184 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8185 }
8186
8187 public:
BuiltinOperatorOverloadBuilder(Sema & S,ArrayRef<Expr * > Args,Qualifiers VisibleTypeConversionsQuals,bool HasArithmeticOrEnumeralCandidateType,SmallVectorImpl<BuiltinCandidateTypeSet> & CandidateTypes,OverloadCandidateSet & CandidateSet)8188 BuiltinOperatorOverloadBuilder(
8189 Sema &S, ArrayRef<Expr *> Args,
8190 Qualifiers VisibleTypeConversionsQuals,
8191 bool HasArithmeticOrEnumeralCandidateType,
8192 SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes,
8193 OverloadCandidateSet &CandidateSet)
8194 : S(S), Args(Args),
8195 VisibleTypeConversionsQuals(VisibleTypeConversionsQuals),
8196 HasArithmeticOrEnumeralCandidateType(
8197 HasArithmeticOrEnumeralCandidateType),
8198 CandidateTypes(CandidateTypes),
8199 CandidateSet(CandidateSet) {
8200
8201 InitArithmeticTypes();
8202 }
8203
8204 // Increment is deprecated for bool since C++17.
8205 //
8206 // C++ [over.built]p3:
8207 //
8208 // For every pair (T, VQ), where T is an arithmetic type other
8209 // than bool, and VQ is either volatile or empty, there exist
8210 // candidate operator functions of the form
8211 //
8212 // VQ T& operator++(VQ T&);
8213 // T operator++(VQ T&, int);
8214 //
8215 // C++ [over.built]p4:
8216 //
8217 // For every pair (T, VQ), where T is an arithmetic type other
8218 // than bool, and VQ is either volatile or empty, there exist
8219 // candidate operator functions of the form
8220 //
8221 // VQ T& operator--(VQ T&);
8222 // T operator--(VQ T&, int);
addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op)8223 void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) {
8224 if (!HasArithmeticOrEnumeralCandidateType)
8225 return;
8226
8227 for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
8228 const auto TypeOfT = ArithmeticTypes[Arith];
8229 if (TypeOfT == S.Context.BoolTy) {
8230 if (Op == OO_MinusMinus)
8231 continue;
8232 if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17)
8233 continue;
8234 }
8235 addPlusPlusMinusMinusStyleOverloads(
8236 TypeOfT,
8237 VisibleTypeConversionsQuals.hasVolatile(),
8238 VisibleTypeConversionsQuals.hasRestrict());
8239 }
8240 }
8241
8242 // C++ [over.built]p5:
8243 //
8244 // For every pair (T, VQ), where T is a cv-qualified or
8245 // cv-unqualified object type, and VQ is either volatile or
8246 // empty, there exist candidate operator functions of the form
8247 //
8248 // T*VQ& operator++(T*VQ&);
8249 // T*VQ& operator--(T*VQ&);
8250 // T* operator++(T*VQ&, int);
8251 // T* operator--(T*VQ&, int);
addPlusPlusMinusMinusPointerOverloads()8252 void addPlusPlusMinusMinusPointerOverloads() {
8253 for (BuiltinCandidateTypeSet::iterator
8254 Ptr = CandidateTypes[0].pointer_begin(),
8255 PtrEnd = CandidateTypes[0].pointer_end();
8256 Ptr != PtrEnd; ++Ptr) {
8257 // Skip pointer types that aren't pointers to object types.
8258 if (!(*Ptr)->getPointeeType()->isObjectType())
8259 continue;
8260
8261 addPlusPlusMinusMinusStyleOverloads(*Ptr,
8262 (!(*Ptr).isVolatileQualified() &&
8263 VisibleTypeConversionsQuals.hasVolatile()),
8264 (!(*Ptr).isRestrictQualified() &&
8265 VisibleTypeConversionsQuals.hasRestrict()));
8266 }
8267 }
8268
8269 // C++ [over.built]p6:
8270 // For every cv-qualified or cv-unqualified object type T, there
8271 // exist candidate operator functions of the form
8272 //
8273 // T& operator*(T*);
8274 //
8275 // C++ [over.built]p7:
8276 // For every function type T that does not have cv-qualifiers or a
8277 // ref-qualifier, there exist candidate operator functions of the form
8278 // T& operator*(T*);
addUnaryStarPointerOverloads()8279 void addUnaryStarPointerOverloads() {
8280 for (BuiltinCandidateTypeSet::iterator
8281 Ptr = CandidateTypes[0].pointer_begin(),
8282 PtrEnd = CandidateTypes[0].pointer_end();
8283 Ptr != PtrEnd; ++Ptr) {
8284 QualType ParamTy = *Ptr;
8285 QualType PointeeTy = ParamTy->getPointeeType();
8286 if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType())
8287 continue;
8288
8289 if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>())
8290 if (Proto->getMethodQuals() || Proto->getRefQualifier())
8291 continue;
8292
8293 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
8294 }
8295 }
8296
8297 // C++ [over.built]p9:
8298 // For every promoted arithmetic type T, there exist candidate
8299 // operator functions of the form
8300 //
8301 // T operator+(T);
8302 // T operator-(T);
addUnaryPlusOrMinusArithmeticOverloads()8303 void addUnaryPlusOrMinusArithmeticOverloads() {
8304 if (!HasArithmeticOrEnumeralCandidateType)
8305 return;
8306
8307 for (unsigned Arith = FirstPromotedArithmeticType;
8308 Arith < LastPromotedArithmeticType; ++Arith) {
8309 QualType ArithTy = ArithmeticTypes[Arith];
8310 S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet);
8311 }
8312
8313 // Extension: We also add these operators for vector types.
8314 for (QualType VecTy : CandidateTypes[0].vector_types())
8315 S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
8316 }
8317
8318 // C++ [over.built]p8:
8319 // For every type T, there exist candidate operator functions of
8320 // the form
8321 //
8322 // T* operator+(T*);
addUnaryPlusPointerOverloads()8323 void addUnaryPlusPointerOverloads() {
8324 for (BuiltinCandidateTypeSet::iterator
8325 Ptr = CandidateTypes[0].pointer_begin(),
8326 PtrEnd = CandidateTypes[0].pointer_end();
8327 Ptr != PtrEnd; ++Ptr) {
8328 QualType ParamTy = *Ptr;
8329 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
8330 }
8331 }
8332
8333 // C++ [over.built]p10:
8334 // For every promoted integral type T, there exist candidate
8335 // operator functions of the form
8336 //
8337 // T operator~(T);
addUnaryTildePromotedIntegralOverloads()8338 void addUnaryTildePromotedIntegralOverloads() {
8339 if (!HasArithmeticOrEnumeralCandidateType)
8340 return;
8341
8342 for (unsigned Int = FirstPromotedIntegralType;
8343 Int < LastPromotedIntegralType; ++Int) {
8344 QualType IntTy = ArithmeticTypes[Int];
8345 S.AddBuiltinCandidate(&IntTy, Args, CandidateSet);
8346 }
8347
8348 // Extension: We also add this operator for vector types.
8349 for (QualType VecTy : CandidateTypes[0].vector_types())
8350 S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
8351 }
8352
8353 // C++ [over.match.oper]p16:
8354 // For every pointer to member type T or type std::nullptr_t, there
8355 // exist candidate operator functions of the form
8356 //
8357 // bool operator==(T,T);
8358 // bool operator!=(T,T);
addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads()8359 void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() {
8360 /// Set of (canonical) types that we've already handled.
8361 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8362
8363 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8364 for (BuiltinCandidateTypeSet::iterator
8365 MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
8366 MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
8367 MemPtr != MemPtrEnd;
8368 ++MemPtr) {
8369 // Don't add the same builtin candidate twice.
8370 if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
8371 continue;
8372
8373 QualType ParamTypes[2] = { *MemPtr, *MemPtr };
8374 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8375 }
8376
8377 if (CandidateTypes[ArgIdx].hasNullPtrType()) {
8378 CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy);
8379 if (AddedTypes.insert(NullPtrTy).second) {
8380 QualType ParamTypes[2] = { NullPtrTy, NullPtrTy };
8381 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8382 }
8383 }
8384 }
8385 }
8386
8387 // C++ [over.built]p15:
8388 //
8389 // For every T, where T is an enumeration type or a pointer type,
8390 // there exist candidate operator functions of the form
8391 //
8392 // bool operator<(T, T);
8393 // bool operator>(T, T);
8394 // bool operator<=(T, T);
8395 // bool operator>=(T, T);
8396 // bool operator==(T, T);
8397 // bool operator!=(T, T);
8398 // R operator<=>(T, T)
addGenericBinaryPointerOrEnumeralOverloads()8399 void addGenericBinaryPointerOrEnumeralOverloads() {
8400 // C++ [over.match.oper]p3:
8401 // [...]the built-in candidates include all of the candidate operator
8402 // functions defined in 13.6 that, compared to the given operator, [...]
8403 // do not have the same parameter-type-list as any non-template non-member
8404 // candidate.
8405 //
8406 // Note that in practice, this only affects enumeration types because there
8407 // aren't any built-in candidates of record type, and a user-defined operator
8408 // must have an operand of record or enumeration type. Also, the only other
8409 // overloaded operator with enumeration arguments, operator=,
8410 // cannot be overloaded for enumeration types, so this is the only place
8411 // where we must suppress candidates like this.
8412 llvm::DenseSet<std::pair<CanQualType, CanQualType> >
8413 UserDefinedBinaryOperators;
8414
8415 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8416 if (CandidateTypes[ArgIdx].enumeration_begin() !=
8417 CandidateTypes[ArgIdx].enumeration_end()) {
8418 for (OverloadCandidateSet::iterator C = CandidateSet.begin(),
8419 CEnd = CandidateSet.end();
8420 C != CEnd; ++C) {
8421 if (!C->Viable || !C->Function || C->Function->getNumParams() != 2)
8422 continue;
8423
8424 if (C->Function->isFunctionTemplateSpecialization())
8425 continue;
8426
8427 // We interpret "same parameter-type-list" as applying to the
8428 // "synthesized candidate, with the order of the two parameters
8429 // reversed", not to the original function.
8430 bool Reversed = C->isReversed();
8431 QualType FirstParamType = C->Function->getParamDecl(Reversed ? 1 : 0)
8432 ->getType()
8433 .getUnqualifiedType();
8434 QualType SecondParamType = C->Function->getParamDecl(Reversed ? 0 : 1)
8435 ->getType()
8436 .getUnqualifiedType();
8437
8438 // Skip if either parameter isn't of enumeral type.
8439 if (!FirstParamType->isEnumeralType() ||
8440 !SecondParamType->isEnumeralType())
8441 continue;
8442
8443 // Add this operator to the set of known user-defined operators.
8444 UserDefinedBinaryOperators.insert(
8445 std::make_pair(S.Context.getCanonicalType(FirstParamType),
8446 S.Context.getCanonicalType(SecondParamType)));
8447 }
8448 }
8449 }
8450
8451 /// Set of (canonical) types that we've already handled.
8452 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8453
8454 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8455 for (BuiltinCandidateTypeSet::iterator
8456 Ptr = CandidateTypes[ArgIdx].pointer_begin(),
8457 PtrEnd = CandidateTypes[ArgIdx].pointer_end();
8458 Ptr != PtrEnd; ++Ptr) {
8459 // Don't add the same builtin candidate twice.
8460 if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
8461 continue;
8462
8463 QualType ParamTypes[2] = { *Ptr, *Ptr };
8464 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8465 }
8466 for (BuiltinCandidateTypeSet::iterator
8467 Enum = CandidateTypes[ArgIdx].enumeration_begin(),
8468 EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
8469 Enum != EnumEnd; ++Enum) {
8470 CanQualType CanonType = S.Context.getCanonicalType(*Enum);
8471
8472 // Don't add the same builtin candidate twice, or if a user defined
8473 // candidate exists.
8474 if (!AddedTypes.insert(CanonType).second ||
8475 UserDefinedBinaryOperators.count(std::make_pair(CanonType,
8476 CanonType)))
8477 continue;
8478 QualType ParamTypes[2] = { *Enum, *Enum };
8479 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8480 }
8481 }
8482 }
8483
8484 // C++ [over.built]p13:
8485 //
8486 // For every cv-qualified or cv-unqualified object type T
8487 // there exist candidate operator functions of the form
8488 //
8489 // T* operator+(T*, ptrdiff_t);
8490 // T& operator[](T*, ptrdiff_t); [BELOW]
8491 // T* operator-(T*, ptrdiff_t);
8492 // T* operator+(ptrdiff_t, T*);
8493 // T& operator[](ptrdiff_t, T*); [BELOW]
8494 //
8495 // C++ [over.built]p14:
8496 //
8497 // For every T, where T is a pointer to object type, there
8498 // exist candidate operator functions of the form
8499 //
8500 // ptrdiff_t operator-(T, T);
addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op)8501 void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) {
8502 /// Set of (canonical) types that we've already handled.
8503 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8504
8505 for (int Arg = 0; Arg < 2; ++Arg) {
8506 QualType AsymmetricParamTypes[2] = {
8507 S.Context.getPointerDiffType(),
8508 S.Context.getPointerDiffType(),
8509 };
8510 for (BuiltinCandidateTypeSet::iterator
8511 Ptr = CandidateTypes[Arg].pointer_begin(),
8512 PtrEnd = CandidateTypes[Arg].pointer_end();
8513 Ptr != PtrEnd; ++Ptr) {
8514 QualType PointeeTy = (*Ptr)->getPointeeType();
8515 if (!PointeeTy->isObjectType())
8516 continue;
8517
8518 AsymmetricParamTypes[Arg] = *Ptr;
8519 if (Arg == 0 || Op == OO_Plus) {
8520 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t)
8521 // T* operator+(ptrdiff_t, T*);
8522 S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet);
8523 }
8524 if (Op == OO_Minus) {
8525 // ptrdiff_t operator-(T, T);
8526 if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
8527 continue;
8528
8529 QualType ParamTypes[2] = { *Ptr, *Ptr };
8530 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8531 }
8532 }
8533 }
8534 }
8535
8536 // C++ [over.built]p12:
8537 //
8538 // For every pair of promoted arithmetic types L and R, there
8539 // exist candidate operator functions of the form
8540 //
8541 // LR operator*(L, R);
8542 // LR operator/(L, R);
8543 // LR operator+(L, R);
8544 // LR operator-(L, R);
8545 // bool operator<(L, R);
8546 // bool operator>(L, R);
8547 // bool operator<=(L, R);
8548 // bool operator>=(L, R);
8549 // bool operator==(L, R);
8550 // bool operator!=(L, R);
8551 //
8552 // where LR is the result of the usual arithmetic conversions
8553 // between types L and R.
8554 //
8555 // C++ [over.built]p24:
8556 //
8557 // For every pair of promoted arithmetic types L and R, there exist
8558 // candidate operator functions of the form
8559 //
8560 // LR operator?(bool, L, R);
8561 //
8562 // where LR is the result of the usual arithmetic conversions
8563 // between types L and R.
8564 // Our candidates ignore the first parameter.
addGenericBinaryArithmeticOverloads()8565 void addGenericBinaryArithmeticOverloads() {
8566 if (!HasArithmeticOrEnumeralCandidateType)
8567 return;
8568 for (unsigned Left = FirstPromotedArithmeticType;
8569 Left < LastPromotedArithmeticType; ++Left) {
8570 for (unsigned Right = FirstPromotedArithmeticType;
8571 Right < LastPromotedArithmeticType; ++Right) {
8572 QualType LandR[2] = { ArithmeticTypes[Left],
8573 ArithmeticTypes[Right] };
8574 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8575 }
8576 }
8577
8578 // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the
8579 // conditional operator for vector types.
8580 for (QualType Vec1Ty : CandidateTypes[0].vector_types())
8581 for (QualType Vec2Ty : CandidateTypes[1].vector_types()) {
8582 QualType LandR[2] = {Vec1Ty, Vec2Ty};
8583 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8584 }
8585 }
8586
8587 /// Add binary operator overloads for each candidate matrix type M1, M2:
8588 /// * (M1, M1) -> M1
8589 /// * (M1, M1.getElementType()) -> M1
8590 /// * (M2.getElementType(), M2) -> M2
8591 /// * (M2, M2) -> M2 // Only if M2 is not part of CandidateTypes[0].
addMatrixBinaryArithmeticOverloads()8592 void addMatrixBinaryArithmeticOverloads() {
8593 if (!HasArithmeticOrEnumeralCandidateType)
8594 return;
8595
8596 for (QualType M1 : CandidateTypes[0].matrix_types()) {
8597 AddCandidate(M1, cast<MatrixType>(M1)->getElementType());
8598 AddCandidate(M1, M1);
8599 }
8600
8601 for (QualType M2 : CandidateTypes[1].matrix_types()) {
8602 AddCandidate(cast<MatrixType>(M2)->getElementType(), M2);
8603 if (!CandidateTypes[0].containsMatrixType(M2))
8604 AddCandidate(M2, M2);
8605 }
8606 }
8607
8608 // C++2a [over.built]p14:
8609 //
8610 // For every integral type T there exists a candidate operator function
8611 // of the form
8612 //
8613 // std::strong_ordering operator<=>(T, T)
8614 //
8615 // C++2a [over.built]p15:
8616 //
8617 // For every pair of floating-point types L and R, there exists a candidate
8618 // operator function of the form
8619 //
8620 // std::partial_ordering operator<=>(L, R);
8621 //
8622 // FIXME: The current specification for integral types doesn't play nice with
8623 // the direction of p0946r0, which allows mixed integral and unscoped-enum
8624 // comparisons. Under the current spec this can lead to ambiguity during
8625 // overload resolution. For example:
8626 //
8627 // enum A : int {a};
8628 // auto x = (a <=> (long)42);
8629 //
8630 // error: call is ambiguous for arguments 'A' and 'long'.
8631 // note: candidate operator<=>(int, int)
8632 // note: candidate operator<=>(long, long)
8633 //
8634 // To avoid this error, this function deviates from the specification and adds
8635 // the mixed overloads `operator<=>(L, R)` where L and R are promoted
8636 // arithmetic types (the same as the generic relational overloads).
8637 //
8638 // For now this function acts as a placeholder.
addThreeWayArithmeticOverloads()8639 void addThreeWayArithmeticOverloads() {
8640 addGenericBinaryArithmeticOverloads();
8641 }
8642
8643 // C++ [over.built]p17:
8644 //
8645 // For every pair of promoted integral types L and R, there
8646 // exist candidate operator functions of the form
8647 //
8648 // LR operator%(L, R);
8649 // LR operator&(L, R);
8650 // LR operator^(L, R);
8651 // LR operator|(L, R);
8652 // L operator<<(L, R);
8653 // L operator>>(L, R);
8654 //
8655 // where LR is the result of the usual arithmetic conversions
8656 // between types L and R.
addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op)8657 void addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op) {
8658 if (!HasArithmeticOrEnumeralCandidateType)
8659 return;
8660
8661 unsigned LastType = S.Context.getTargetInfo().SupportsCapabilities()
8662 ? LastCapabilityType : LastPromotedIntegralType;
8663 // XXXAR: allow any type as the RHS operand for a bitwise op with capabilities
8664 for (unsigned Left = FirstPromotedIntegralType;
8665 Left < LastType; ++Left) {
8666 for (unsigned Right = FirstPromotedIntegralType;
8667 Right < LastPromotedIntegralType; ++Right) {
8668 QualType LandR[2] = { ArithmeticTypes[Left],
8669 ArithmeticTypes[Right] };
8670 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8671 }
8672 }
8673
8674 }
8675
8676 // C++ [over.built]p20:
8677 //
8678 // For every pair (T, VQ), where T is an enumeration or
8679 // pointer to member type and VQ is either volatile or
8680 // empty, there exist candidate operator functions of the form
8681 //
8682 // VQ T& operator=(VQ T&, T);
addAssignmentMemberPointerOrEnumeralOverloads()8683 void addAssignmentMemberPointerOrEnumeralOverloads() {
8684 /// Set of (canonical) types that we've already handled.
8685 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8686
8687 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
8688 for (BuiltinCandidateTypeSet::iterator
8689 Enum = CandidateTypes[ArgIdx].enumeration_begin(),
8690 EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
8691 Enum != EnumEnd; ++Enum) {
8692 if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second)
8693 continue;
8694
8695 AddBuiltinAssignmentOperatorCandidates(S, *Enum, Args, CandidateSet);
8696 }
8697
8698 for (BuiltinCandidateTypeSet::iterator
8699 MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
8700 MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
8701 MemPtr != MemPtrEnd; ++MemPtr) {
8702 if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
8703 continue;
8704
8705 AddBuiltinAssignmentOperatorCandidates(S, *MemPtr, Args, CandidateSet);
8706 }
8707 }
8708 }
8709
8710 // C++ [over.built]p19:
8711 //
8712 // For every pair (T, VQ), where T is any type and VQ is either
8713 // volatile or empty, there exist candidate operator functions
8714 // of the form
8715 //
8716 // T*VQ& operator=(T*VQ&, T*);
8717 //
8718 // C++ [over.built]p21:
8719 //
8720 // For every pair (T, VQ), where T is a cv-qualified or
8721 // cv-unqualified object type and VQ is either volatile or
8722 // empty, there exist candidate operator functions of the form
8723 //
8724 // T*VQ& operator+=(T*VQ&, ptrdiff_t);
8725 // T*VQ& operator-=(T*VQ&, ptrdiff_t);
addAssignmentPointerOverloads(bool isEqualOp)8726 void addAssignmentPointerOverloads(bool isEqualOp) {
8727 /// Set of (canonical) types that we've already handled.
8728 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8729
8730 for (BuiltinCandidateTypeSet::iterator
8731 Ptr = CandidateTypes[0].pointer_begin(),
8732 PtrEnd = CandidateTypes[0].pointer_end();
8733 Ptr != PtrEnd; ++Ptr) {
8734 // If this is operator=, keep track of the builtin candidates we added.
8735 if (isEqualOp)
8736 AddedTypes.insert(S.Context.getCanonicalType(*Ptr));
8737 else if (!(*Ptr)->getPointeeType()->isObjectType())
8738 continue;
8739
8740 // non-volatile version
8741 QualType ParamTypes[2] = {
8742 S.Context.getLValueReferenceType(*Ptr),
8743 isEqualOp ? *Ptr : S.Context.getPointerDiffType(),
8744 };
8745 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8746 /*IsAssignmentOperator=*/ isEqualOp);
8747
8748 bool NeedVolatile = !(*Ptr).isVolatileQualified() &&
8749 VisibleTypeConversionsQuals.hasVolatile();
8750 if (NeedVolatile) {
8751 // volatile version
8752 ParamTypes[0] =
8753 S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr));
8754 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8755 /*IsAssignmentOperator=*/isEqualOp);
8756 }
8757
8758 if (!(*Ptr).isRestrictQualified() &&
8759 VisibleTypeConversionsQuals.hasRestrict()) {
8760 // restrict version
8761 ParamTypes[0]
8762 = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr));
8763 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8764 /*IsAssignmentOperator=*/isEqualOp);
8765
8766 if (NeedVolatile) {
8767 // volatile restrict version
8768 ParamTypes[0]
8769 = S.Context.getLValueReferenceType(
8770 S.Context.getCVRQualifiedType(*Ptr,
8771 (Qualifiers::Volatile |
8772 Qualifiers::Restrict)));
8773 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8774 /*IsAssignmentOperator=*/isEqualOp);
8775 }
8776 }
8777 }
8778
8779 if (isEqualOp) {
8780 for (BuiltinCandidateTypeSet::iterator
8781 Ptr = CandidateTypes[1].pointer_begin(),
8782 PtrEnd = CandidateTypes[1].pointer_end();
8783 Ptr != PtrEnd; ++Ptr) {
8784 // Make sure we don't add the same candidate twice.
8785 if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
8786 continue;
8787
8788 QualType ParamTypes[2] = {
8789 S.Context.getLValueReferenceType(*Ptr),
8790 *Ptr,
8791 };
8792
8793 // non-volatile version
8794 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8795 /*IsAssignmentOperator=*/true);
8796
8797 bool NeedVolatile = !(*Ptr).isVolatileQualified() &&
8798 VisibleTypeConversionsQuals.hasVolatile();
8799 if (NeedVolatile) {
8800 // volatile version
8801 ParamTypes[0] =
8802 S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr));
8803 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8804 /*IsAssignmentOperator=*/true);
8805 }
8806
8807 if (!(*Ptr).isRestrictQualified() &&
8808 VisibleTypeConversionsQuals.hasRestrict()) {
8809 // restrict version
8810 ParamTypes[0]
8811 = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr));
8812 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8813 /*IsAssignmentOperator=*/true);
8814
8815 if (NeedVolatile) {
8816 // volatile restrict version
8817 ParamTypes[0]
8818 = S.Context.getLValueReferenceType(
8819 S.Context.getCVRQualifiedType(*Ptr,
8820 (Qualifiers::Volatile |
8821 Qualifiers::Restrict)));
8822 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8823 /*IsAssignmentOperator=*/true);
8824 }
8825 }
8826 }
8827 }
8828 }
8829
8830 // C++ [over.built]p18:
8831 //
8832 // For every triple (L, VQ, R), where L is an arithmetic type,
8833 // VQ is either volatile or empty, and R is a promoted
8834 // arithmetic type, there exist candidate operator functions of
8835 // the form
8836 //
8837 // VQ L& operator=(VQ L&, R);
8838 // VQ L& operator*=(VQ L&, R);
8839 // VQ L& operator/=(VQ L&, R);
8840 // VQ L& operator+=(VQ L&, R);
8841 // VQ L& operator-=(VQ L&, R);
addAssignmentArithmeticOverloads(bool isEqualOp)8842 void addAssignmentArithmeticOverloads(bool isEqualOp) {
8843 if (!HasArithmeticOrEnumeralCandidateType)
8844 return;
8845
8846 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) {
8847 for (unsigned Right = FirstPromotedArithmeticType;
8848 Right < LastPromotedArithmeticType; ++Right) {
8849 QualType ParamTypes[2];
8850 ParamTypes[1] = ArithmeticTypes[Right];
8851 auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
8852 S, ArithmeticTypes[Left], Args[0]);
8853 // Add this built-in operator as a candidate (VQ is empty).
8854 ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
8855 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8856 /*IsAssignmentOperator=*/isEqualOp);
8857
8858 // Add this built-in operator as a candidate (VQ is 'volatile').
8859 if (VisibleTypeConversionsQuals.hasVolatile()) {
8860 ParamTypes[0] = S.Context.getVolatileType(LeftBaseTy);
8861 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
8862 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8863 /*IsAssignmentOperator=*/isEqualOp);
8864 }
8865 }
8866 }
8867
8868 // Extension: Add the binary operators =, +=, -=, *=, /= for vector types.
8869 for (QualType Vec1Ty : CandidateTypes[0].vector_types())
8870 for (QualType Vec2Ty : CandidateTypes[0].vector_types()) {
8871 QualType ParamTypes[2];
8872 ParamTypes[1] = Vec2Ty;
8873 // Add this built-in operator as a candidate (VQ is empty).
8874 ParamTypes[0] = S.Context.getLValueReferenceType(Vec1Ty);
8875 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8876 /*IsAssignmentOperator=*/isEqualOp);
8877
8878 // Add this built-in operator as a candidate (VQ is 'volatile').
8879 if (VisibleTypeConversionsQuals.hasVolatile()) {
8880 ParamTypes[0] = S.Context.getVolatileType(Vec1Ty);
8881 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
8882 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8883 /*IsAssignmentOperator=*/isEqualOp);
8884 }
8885 }
8886 }
8887
8888 // C++ [over.built]p22:
8889 //
8890 // For every triple (L, VQ, R), where L is an integral type, VQ
8891 // is either volatile or empty, and R is a promoted integral
8892 // type, there exist candidate operator functions of the form
8893 //
8894 // VQ L& operator%=(VQ L&, R);
8895 // VQ L& operator<<=(VQ L&, R);
8896 // VQ L& operator>>=(VQ L&, R);
8897 // VQ L& operator&=(VQ L&, R);
8898 // VQ L& operator^=(VQ L&, R);
8899 // VQ L& operator|=(VQ L&, R);
addAssignmentIntegralOverloads()8900 void addAssignmentIntegralOverloads() {
8901 if (!HasArithmeticOrEnumeralCandidateType)
8902 return;
8903
8904 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) {
8905 for (unsigned Right = FirstPromotedIntegralType;
8906 Right < LastPromotedIntegralType; ++Right) {
8907 QualType ParamTypes[2];
8908 ParamTypes[1] = ArithmeticTypes[Right];
8909 auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
8910 S, ArithmeticTypes[Left], Args[0]);
8911 // Add this built-in operator as a candidate (VQ is empty).
8912 ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
8913 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8914 if (VisibleTypeConversionsQuals.hasVolatile()) {
8915 // Add this built-in operator as a candidate (VQ is 'volatile').
8916 ParamTypes[0] = LeftBaseTy;
8917 ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]);
8918 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
8919 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8920 }
8921 }
8922 }
8923 }
8924
8925 // C++ [over.operator]p23:
8926 //
8927 // There also exist candidate operator functions of the form
8928 //
8929 // bool operator!(bool);
8930 // bool operator&&(bool, bool);
8931 // bool operator||(bool, bool);
addExclaimOverload()8932 void addExclaimOverload() {
8933 QualType ParamTy = S.Context.BoolTy;
8934 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet,
8935 /*IsAssignmentOperator=*/false,
8936 /*NumContextualBoolArguments=*/1);
8937 }
addAmpAmpOrPipePipeOverload()8938 void addAmpAmpOrPipePipeOverload() {
8939 QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy };
8940 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8941 /*IsAssignmentOperator=*/false,
8942 /*NumContextualBoolArguments=*/2);
8943 }
8944
8945 // C++ [over.built]p13:
8946 //
8947 // For every cv-qualified or cv-unqualified object type T there
8948 // exist candidate operator functions of the form
8949 //
8950 // T* operator+(T*, ptrdiff_t); [ABOVE]
8951 // T& operator[](T*, ptrdiff_t);
8952 // T* operator-(T*, ptrdiff_t); [ABOVE]
8953 // T* operator+(ptrdiff_t, T*); [ABOVE]
8954 // T& operator[](ptrdiff_t, T*);
addSubscriptOverloads()8955 void addSubscriptOverloads() {
8956 for (BuiltinCandidateTypeSet::iterator
8957 Ptr = CandidateTypes[0].pointer_begin(),
8958 PtrEnd = CandidateTypes[0].pointer_end();
8959 Ptr != PtrEnd; ++Ptr) {
8960 QualType ParamTypes[2] = { *Ptr, S.Context.getPointerDiffType() };
8961 QualType PointeeType = (*Ptr)->getPointeeType();
8962 if (!PointeeType->isObjectType())
8963 continue;
8964
8965 // T& operator[](T*, ptrdiff_t)
8966 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8967 }
8968
8969 for (BuiltinCandidateTypeSet::iterator
8970 Ptr = CandidateTypes[1].pointer_begin(),
8971 PtrEnd = CandidateTypes[1].pointer_end();
8972 Ptr != PtrEnd; ++Ptr) {
8973 QualType ParamTypes[2] = { S.Context.getPointerDiffType(), *Ptr };
8974 QualType PointeeType = (*Ptr)->getPointeeType();
8975 if (!PointeeType->isObjectType())
8976 continue;
8977
8978 // T& operator[](ptrdiff_t, T*)
8979 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8980 }
8981 }
8982
8983 // C++ [over.built]p11:
8984 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type,
8985 // C1 is the same type as C2 or is a derived class of C2, T is an object
8986 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
8987 // there exist candidate operator functions of the form
8988 //
8989 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
8990 //
8991 // where CV12 is the union of CV1 and CV2.
addArrowStarOverloads()8992 void addArrowStarOverloads() {
8993 for (BuiltinCandidateTypeSet::iterator
8994 Ptr = CandidateTypes[0].pointer_begin(),
8995 PtrEnd = CandidateTypes[0].pointer_end();
8996 Ptr != PtrEnd; ++Ptr) {
8997 QualType C1Ty = (*Ptr);
8998 QualType C1;
8999 QualifierCollector Q1;
9000 C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0);
9001 if (!isa<RecordType>(C1))
9002 continue;
9003 // heuristic to reduce number of builtin candidates in the set.
9004 // Add volatile/restrict version only if there are conversions to a
9005 // volatile/restrict type.
9006 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile())
9007 continue;
9008 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict())
9009 continue;
9010 for (BuiltinCandidateTypeSet::iterator
9011 MemPtr = CandidateTypes[1].member_pointer_begin(),
9012 MemPtrEnd = CandidateTypes[1].member_pointer_end();
9013 MemPtr != MemPtrEnd; ++MemPtr) {
9014 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr);
9015 QualType C2 = QualType(mptr->getClass(), 0);
9016 C2 = C2.getUnqualifiedType();
9017 if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2))
9018 break;
9019 QualType ParamTypes[2] = { *Ptr, *MemPtr };
9020 // build CV12 T&
9021 QualType T = mptr->getPointeeType();
9022 if (!VisibleTypeConversionsQuals.hasVolatile() &&
9023 T.isVolatileQualified())
9024 continue;
9025 if (!VisibleTypeConversionsQuals.hasRestrict() &&
9026 T.isRestrictQualified())
9027 continue;
9028 T = Q1.apply(S.Context, T);
9029 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9030 }
9031 }
9032 }
9033
9034 // Note that we don't consider the first argument, since it has been
9035 // contextually converted to bool long ago. The candidates below are
9036 // therefore added as binary.
9037 //
9038 // C++ [over.built]p25:
9039 // For every type T, where T is a pointer, pointer-to-member, or scoped
9040 // enumeration type, there exist candidate operator functions of the form
9041 //
9042 // T operator?(bool, T, T);
9043 //
addConditionalOperatorOverloads()9044 void addConditionalOperatorOverloads() {
9045 /// Set of (canonical) types that we've already handled.
9046 llvm::SmallPtrSet<QualType, 8> AddedTypes;
9047
9048 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
9049 for (BuiltinCandidateTypeSet::iterator
9050 Ptr = CandidateTypes[ArgIdx].pointer_begin(),
9051 PtrEnd = CandidateTypes[ArgIdx].pointer_end();
9052 Ptr != PtrEnd; ++Ptr) {
9053 if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
9054 continue;
9055
9056 QualType ParamTypes[2] = { *Ptr, *Ptr };
9057 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9058 }
9059
9060 for (BuiltinCandidateTypeSet::iterator
9061 MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
9062 MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
9063 MemPtr != MemPtrEnd; ++MemPtr) {
9064 if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
9065 continue;
9066
9067 QualType ParamTypes[2] = { *MemPtr, *MemPtr };
9068 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9069 }
9070
9071 if (S.getLangOpts().CPlusPlus11) {
9072 for (BuiltinCandidateTypeSet::iterator
9073 Enum = CandidateTypes[ArgIdx].enumeration_begin(),
9074 EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
9075 Enum != EnumEnd; ++Enum) {
9076 if (!(*Enum)->castAs<EnumType>()->getDecl()->isScoped())
9077 continue;
9078
9079 if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second)
9080 continue;
9081
9082 QualType ParamTypes[2] = { *Enum, *Enum };
9083 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9084 }
9085 }
9086 }
9087 }
9088 };
9089
9090 } // end anonymous namespace
9091
9092 /// AddBuiltinOperatorCandidates - Add the appropriate built-in
9093 /// operator overloads to the candidate set (C++ [over.built]), based
9094 /// on the operator @p Op and the arguments given. For example, if the
9095 /// operator is a binary '+', this routine might add "int
9096 /// operator+(int, int)" to cover integer addition.
AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)9097 void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
9098 SourceLocation OpLoc,
9099 ArrayRef<Expr *> Args,
9100 OverloadCandidateSet &CandidateSet) {
9101 // Find all of the types that the arguments can convert to, but only
9102 // if the operator we're looking at has built-in operator candidates
9103 // that make use of these types. Also record whether we encounter non-record
9104 // candidate types or either arithmetic or enumeral candidate types.
9105 Qualifiers VisibleTypeConversionsQuals;
9106 VisibleTypeConversionsQuals.addConst();
9107 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx)
9108 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]);
9109
9110 bool HasNonRecordCandidateType = false;
9111 bool HasArithmeticOrEnumeralCandidateType = false;
9112 SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes;
9113 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
9114 CandidateTypes.emplace_back(*this);
9115 CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(),
9116 OpLoc,
9117 true,
9118 (Op == OO_Exclaim ||
9119 Op == OO_AmpAmp ||
9120 Op == OO_PipePipe),
9121 VisibleTypeConversionsQuals);
9122 HasNonRecordCandidateType = HasNonRecordCandidateType ||
9123 CandidateTypes[ArgIdx].hasNonRecordTypes();
9124 HasArithmeticOrEnumeralCandidateType =
9125 HasArithmeticOrEnumeralCandidateType ||
9126 CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes();
9127 }
9128
9129 // Exit early when no non-record types have been added to the candidate set
9130 // for any of the arguments to the operator.
9131 //
9132 // We can't exit early for !, ||, or &&, since there we have always have
9133 // 'bool' overloads.
9134 if (!HasNonRecordCandidateType &&
9135 !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe))
9136 return;
9137
9138 // Setup an object to manage the common state for building overloads.
9139 BuiltinOperatorOverloadBuilder OpBuilder(*this, Args,
9140 VisibleTypeConversionsQuals,
9141 HasArithmeticOrEnumeralCandidateType,
9142 CandidateTypes, CandidateSet);
9143
9144 // Dispatch over the operation to add in only those overloads which apply.
9145 switch (Op) {
9146 case OO_None:
9147 case NUM_OVERLOADED_OPERATORS:
9148 llvm_unreachable("Expected an overloaded operator");
9149
9150 case OO_New:
9151 case OO_Delete:
9152 case OO_Array_New:
9153 case OO_Array_Delete:
9154 case OO_Call:
9155 llvm_unreachable(
9156 "Special operators don't use AddBuiltinOperatorCandidates");
9157
9158 case OO_Comma:
9159 case OO_Arrow:
9160 case OO_Coawait:
9161 // C++ [over.match.oper]p3:
9162 // -- For the operator ',', the unary operator '&', the
9163 // operator '->', or the operator 'co_await', the
9164 // built-in candidates set is empty.
9165 break;
9166
9167 case OO_Plus: // '+' is either unary or binary
9168 if (Args.size() == 1)
9169 OpBuilder.addUnaryPlusPointerOverloads();
9170 LLVM_FALLTHROUGH;
9171
9172 case OO_Minus: // '-' is either unary or binary
9173 if (Args.size() == 1) {
9174 OpBuilder.addUnaryPlusOrMinusArithmeticOverloads();
9175 } else {
9176 OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op);
9177 OpBuilder.addGenericBinaryArithmeticOverloads();
9178 OpBuilder.addMatrixBinaryArithmeticOverloads();
9179 }
9180 break;
9181
9182 case OO_Star: // '*' is either unary or binary
9183 if (Args.size() == 1)
9184 OpBuilder.addUnaryStarPointerOverloads();
9185 else {
9186 OpBuilder.addGenericBinaryArithmeticOverloads();
9187 OpBuilder.addMatrixBinaryArithmeticOverloads();
9188 }
9189 break;
9190
9191 case OO_Slash:
9192 OpBuilder.addGenericBinaryArithmeticOverloads();
9193 break;
9194
9195 case OO_PlusPlus:
9196 case OO_MinusMinus:
9197 OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op);
9198 OpBuilder.addPlusPlusMinusMinusPointerOverloads();
9199 break;
9200
9201 case OO_EqualEqual:
9202 case OO_ExclaimEqual:
9203 OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
9204 LLVM_FALLTHROUGH;
9205
9206 case OO_Less:
9207 case OO_Greater:
9208 case OO_LessEqual:
9209 case OO_GreaterEqual:
9210 OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
9211 OpBuilder.addGenericBinaryArithmeticOverloads();
9212 break;
9213
9214 case OO_Spaceship:
9215 OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
9216 OpBuilder.addThreeWayArithmeticOverloads();
9217 break;
9218
9219 case OO_Percent:
9220 case OO_Caret:
9221 case OO_Pipe:
9222 case OO_LessLess:
9223 case OO_GreaterGreater:
9224 OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
9225 break;
9226
9227 case OO_Amp: // '&' is either unary or binary
9228 if (Args.size() == 1)
9229 // C++ [over.match.oper]p3:
9230 // -- For the operator ',', the unary operator '&', or the
9231 // operator '->', the built-in candidates set is empty.
9232 break;
9233
9234 OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
9235 break;
9236
9237 case OO_Tilde:
9238 OpBuilder.addUnaryTildePromotedIntegralOverloads();
9239 break;
9240
9241 case OO_Equal:
9242 OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads();
9243 LLVM_FALLTHROUGH;
9244
9245 case OO_PlusEqual:
9246 case OO_MinusEqual:
9247 OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal);
9248 LLVM_FALLTHROUGH;
9249
9250 case OO_StarEqual:
9251 case OO_SlashEqual:
9252 OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal);
9253 break;
9254
9255 case OO_PercentEqual:
9256 case OO_LessLessEqual:
9257 case OO_GreaterGreaterEqual:
9258 case OO_AmpEqual:
9259 case OO_CaretEqual:
9260 case OO_PipeEqual:
9261 OpBuilder.addAssignmentIntegralOverloads();
9262 break;
9263
9264 case OO_Exclaim:
9265 OpBuilder.addExclaimOverload();
9266 break;
9267
9268 case OO_AmpAmp:
9269 case OO_PipePipe:
9270 OpBuilder.addAmpAmpOrPipePipeOverload();
9271 break;
9272
9273 case OO_Subscript:
9274 OpBuilder.addSubscriptOverloads();
9275 break;
9276
9277 case OO_ArrowStar:
9278 OpBuilder.addArrowStarOverloads();
9279 break;
9280
9281 case OO_Conditional:
9282 OpBuilder.addConditionalOperatorOverloads();
9283 OpBuilder.addGenericBinaryArithmeticOverloads();
9284 break;
9285 }
9286 }
9287
9288 /// Add function candidates found via argument-dependent lookup
9289 /// to the set of overloading candidates.
9290 ///
9291 /// This routine performs argument-dependent name lookup based on the
9292 /// given function name (which may also be an operator name) and adds
9293 /// all of the overload candidates found by ADL to the overload
9294 /// candidate set (C++ [basic.lookup.argdep]).
9295 void
AddArgumentDependentLookupCandidates(DeclarationName Name,SourceLocation Loc,ArrayRef<Expr * > Args,TemplateArgumentListInfo * ExplicitTemplateArgs,OverloadCandidateSet & CandidateSet,bool PartialOverloading)9296 Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
9297 SourceLocation Loc,
9298 ArrayRef<Expr *> Args,
9299 TemplateArgumentListInfo *ExplicitTemplateArgs,
9300 OverloadCandidateSet& CandidateSet,
9301 bool PartialOverloading) {
9302 ADLResult Fns;
9303
9304 // FIXME: This approach for uniquing ADL results (and removing
9305 // redundant candidates from the set) relies on pointer-equality,
9306 // which means we need to key off the canonical decl. However,
9307 // always going back to the canonical decl might not get us the
9308 // right set of default arguments. What default arguments are
9309 // we supposed to consider on ADL candidates, anyway?
9310
9311 // FIXME: Pass in the explicit template arguments?
9312 ArgumentDependentLookup(Name, Loc, Args, Fns);
9313
9314 // Erase all of the candidates we already knew about.
9315 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
9316 CandEnd = CandidateSet.end();
9317 Cand != CandEnd; ++Cand)
9318 if (Cand->Function) {
9319 Fns.erase(Cand->Function);
9320 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
9321 Fns.erase(FunTmpl);
9322 }
9323
9324 // For each of the ADL candidates we found, add it to the overload
9325 // set.
9326 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
9327 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none);
9328
9329 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
9330 if (ExplicitTemplateArgs)
9331 continue;
9332
9333 AddOverloadCandidate(
9334 FD, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false,
9335 PartialOverloading, /*AllowExplicit=*/true,
9336 /*AllowExplicitConversions=*/false, ADLCallKind::UsesADL);
9337 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) {
9338 AddOverloadCandidate(
9339 FD, FoundDecl, {Args[1], Args[0]}, CandidateSet,
9340 /*SuppressUserConversions=*/false, PartialOverloading,
9341 /*AllowExplicit=*/true, /*AllowExplicitConversions=*/false,
9342 ADLCallKind::UsesADL, None, OverloadCandidateParamOrder::Reversed);
9343 }
9344 } else {
9345 auto *FTD = cast<FunctionTemplateDecl>(*I);
9346 AddTemplateOverloadCandidate(
9347 FTD, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet,
9348 /*SuppressUserConversions=*/false, PartialOverloading,
9349 /*AllowExplicit=*/true, ADLCallKind::UsesADL);
9350 if (CandidateSet.getRewriteInfo().shouldAddReversed(
9351 Context, FTD->getTemplatedDecl())) {
9352 AddTemplateOverloadCandidate(
9353 FTD, FoundDecl, ExplicitTemplateArgs, {Args[1], Args[0]},
9354 CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading,
9355 /*AllowExplicit=*/true, ADLCallKind::UsesADL,
9356 OverloadCandidateParamOrder::Reversed);
9357 }
9358 }
9359 }
9360 }
9361
9362 namespace {
9363 enum class Comparison { Equal, Better, Worse };
9364 }
9365
9366 /// Compares the enable_if attributes of two FunctionDecls, for the purposes of
9367 /// overload resolution.
9368 ///
9369 /// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff
9370 /// Cand1's first N enable_if attributes have precisely the same conditions as
9371 /// Cand2's first N enable_if attributes (where N = the number of enable_if
9372 /// attributes on Cand2), and Cand1 has more than N enable_if attributes.
9373 ///
9374 /// Note that you can have a pair of candidates such that Cand1's enable_if
9375 /// attributes are worse than Cand2's, and Cand2's enable_if attributes are
9376 /// worse than Cand1's.
compareEnableIfAttrs(const Sema & S,const FunctionDecl * Cand1,const FunctionDecl * Cand2)9377 static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1,
9378 const FunctionDecl *Cand2) {
9379 // Common case: One (or both) decls don't have enable_if attrs.
9380 bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>();
9381 bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>();
9382 if (!Cand1Attr || !Cand2Attr) {
9383 if (Cand1Attr == Cand2Attr)
9384 return Comparison::Equal;
9385 return Cand1Attr ? Comparison::Better : Comparison::Worse;
9386 }
9387
9388 auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>();
9389 auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>();
9390
9391 llvm::FoldingSetNodeID Cand1ID, Cand2ID;
9392 for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) {
9393 Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
9394 Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);
9395
9396 // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1
9397 // has fewer enable_if attributes than Cand2, and vice versa.
9398 if (!Cand1A)
9399 return Comparison::Worse;
9400 if (!Cand2A)
9401 return Comparison::Better;
9402
9403 Cand1ID.clear();
9404 Cand2ID.clear();
9405
9406 (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true);
9407 (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true);
9408 if (Cand1ID != Cand2ID)
9409 return Comparison::Worse;
9410 }
9411
9412 return Comparison::Equal;
9413 }
9414
9415 static Comparison
isBetterMultiversionCandidate(const OverloadCandidate & Cand1,const OverloadCandidate & Cand2)9416 isBetterMultiversionCandidate(const OverloadCandidate &Cand1,
9417 const OverloadCandidate &Cand2) {
9418 if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function ||
9419 !Cand2.Function->isMultiVersion())
9420 return Comparison::Equal;
9421
9422 // If both are invalid, they are equal. If one of them is invalid, the other
9423 // is better.
9424 if (Cand1.Function->isInvalidDecl()) {
9425 if (Cand2.Function->isInvalidDecl())
9426 return Comparison::Equal;
9427 return Comparison::Worse;
9428 }
9429 if (Cand2.Function->isInvalidDecl())
9430 return Comparison::Better;
9431
9432 // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
9433 // cpu_dispatch, else arbitrarily based on the identifiers.
9434 bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();
9435 bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>();
9436 const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>();
9437 const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>();
9438
9439 if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec)
9440 return Comparison::Equal;
9441
9442 if (Cand1CPUDisp && !Cand2CPUDisp)
9443 return Comparison::Better;
9444 if (Cand2CPUDisp && !Cand1CPUDisp)
9445 return Comparison::Worse;
9446
9447 if (Cand1CPUSpec && Cand2CPUSpec) {
9448 if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size())
9449 return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size()
9450 ? Comparison::Better
9451 : Comparison::Worse;
9452
9453 std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator>
9454 FirstDiff = std::mismatch(
9455 Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(),
9456 Cand2CPUSpec->cpus_begin(),
9457 [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) {
9458 return LHS->getName() == RHS->getName();
9459 });
9460
9461 assert(FirstDiff.first != Cand1CPUSpec->cpus_end() &&
9462 "Two different cpu-specific versions should not have the same "
9463 "identifier list, otherwise they'd be the same decl!");
9464 return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName()
9465 ? Comparison::Better
9466 : Comparison::Worse;
9467 }
9468 llvm_unreachable("No way to get here unless both had cpu_dispatch");
9469 }
9470
9471 /// Compute the type of the implicit object parameter for the given function,
9472 /// if any. Returns None if there is no implicit object parameter, and a null
9473 /// QualType if there is a 'matches anything' implicit object parameter.
getImplicitObjectParamType(ASTContext & Context,const FunctionDecl * F)9474 static Optional<QualType> getImplicitObjectParamType(ASTContext &Context,
9475 const FunctionDecl *F) {
9476 if (!isa<CXXMethodDecl>(F) || isa<CXXConstructorDecl>(F))
9477 return llvm::None;
9478
9479 auto *M = cast<CXXMethodDecl>(F);
9480 // Static member functions' object parameters match all types.
9481 if (M->isStatic())
9482 return QualType();
9483
9484 QualType T = M->getThisObjectType();
9485 if (M->getRefQualifier() == RQ_RValue)
9486 return Context.getRValueReferenceType(T);
9487 return Context.getLValueReferenceType(T);
9488 }
9489
haveSameParameterTypes(ASTContext & Context,const FunctionDecl * F1,const FunctionDecl * F2,unsigned NumParams)9490 static bool haveSameParameterTypes(ASTContext &Context, const FunctionDecl *F1,
9491 const FunctionDecl *F2, unsigned NumParams) {
9492 if (declaresSameEntity(F1, F2))
9493 return true;
9494
9495 auto NextParam = [&](const FunctionDecl *F, unsigned &I, bool First) {
9496 if (First) {
9497 if (Optional<QualType> T = getImplicitObjectParamType(Context, F))
9498 return *T;
9499 }
9500 assert(I < F->getNumParams());
9501 return F->getParamDecl(I++)->getType();
9502 };
9503
9504 unsigned I1 = 0, I2 = 0;
9505 for (unsigned I = 0; I != NumParams; ++I) {
9506 QualType T1 = NextParam(F1, I1, I == 0);
9507 QualType T2 = NextParam(F2, I2, I == 0);
9508 if (!T1.isNull() && !T1.isNull() && !Context.hasSameUnqualifiedType(T1, T2))
9509 return false;
9510 }
9511 return true;
9512 }
9513
9514 /// isBetterOverloadCandidate - Determines whether the first overload
9515 /// 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)9516 bool clang::isBetterOverloadCandidate(
9517 Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2,
9518 SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) {
9519 // Define viable functions to be better candidates than non-viable
9520 // functions.
9521 if (!Cand2.Viable)
9522 return Cand1.Viable;
9523 else if (!Cand1.Viable)
9524 return false;
9525
9526 // C++ [over.match.best]p1:
9527 //
9528 // -- if F is a static member function, ICS1(F) is defined such
9529 // that ICS1(F) is neither better nor worse than ICS1(G) for
9530 // any function G, and, symmetrically, ICS1(G) is neither
9531 // better nor worse than ICS1(F).
9532 unsigned StartArg = 0;
9533 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument)
9534 StartArg = 1;
9535
9536 auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) {
9537 // We don't allow incompatible pointer conversions in C++.
9538 if (!S.getLangOpts().CPlusPlus)
9539 return ICS.isStandard() &&
9540 ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion;
9541
9542 // The only ill-formed conversion we allow in C++ is the string literal to
9543 // char* conversion, which is only considered ill-formed after C++11.
9544 return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
9545 hasDeprecatedStringLiteralToCharPtrConversion(ICS);
9546 };
9547
9548 // Define functions that don't require ill-formed conversions for a given
9549 // argument to be better candidates than functions that do.
9550 unsigned NumArgs = Cand1.Conversions.size();
9551 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch");
9552 bool HasBetterConversion = false;
9553 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
9554 bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]);
9555 bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]);
9556 if (Cand1Bad != Cand2Bad) {
9557 if (Cand1Bad)
9558 return false;
9559 HasBetterConversion = true;
9560 }
9561 }
9562
9563 if (HasBetterConversion)
9564 return true;
9565
9566 // C++ [over.match.best]p1:
9567 // A viable function F1 is defined to be a better function than another
9568 // viable function F2 if for all arguments i, ICSi(F1) is not a worse
9569 // conversion sequence than ICSi(F2), and then...
9570 bool HasWorseConversion = false;
9571 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
9572 switch (CompareImplicitConversionSequences(S, Loc,
9573 Cand1.Conversions[ArgIdx],
9574 Cand2.Conversions[ArgIdx])) {
9575 case ImplicitConversionSequence::Better:
9576 // Cand1 has a better conversion sequence.
9577 HasBetterConversion = true;
9578 break;
9579
9580 case ImplicitConversionSequence::Worse:
9581 if (Cand1.Function && Cand2.Function &&
9582 Cand1.isReversed() != Cand2.isReversed() &&
9583 haveSameParameterTypes(S.Context, Cand1.Function, Cand2.Function,
9584 NumArgs)) {
9585 // Work around large-scale breakage caused by considering reversed
9586 // forms of operator== in C++20:
9587 //
9588 // When comparing a function against a reversed function with the same
9589 // parameter types, if we have a better conversion for one argument and
9590 // a worse conversion for the other, the implicit conversion sequences
9591 // are treated as being equally good.
9592 //
9593 // This prevents a comparison function from being considered ambiguous
9594 // with a reversed form that is written in the same way.
9595 //
9596 // We diagnose this as an extension from CreateOverloadedBinOp.
9597 HasWorseConversion = true;
9598 break;
9599 }
9600
9601 // Cand1 can't be better than Cand2.
9602 return false;
9603
9604 case ImplicitConversionSequence::Indistinguishable:
9605 // Do nothing.
9606 break;
9607 }
9608 }
9609
9610 // -- for some argument j, ICSj(F1) is a better conversion sequence than
9611 // ICSj(F2), or, if not that,
9612 if (HasBetterConversion && !HasWorseConversion)
9613 return true;
9614
9615 // -- the context is an initialization by user-defined conversion
9616 // (see 8.5, 13.3.1.5) and the standard conversion sequence
9617 // from the return type of F1 to the destination type (i.e.,
9618 // the type of the entity being initialized) is a better
9619 // conversion sequence than the standard conversion sequence
9620 // from the return type of F2 to the destination type.
9621 if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion &&
9622 Cand1.Function && Cand2.Function &&
9623 isa<CXXConversionDecl>(Cand1.Function) &&
9624 isa<CXXConversionDecl>(Cand2.Function)) {
9625 // First check whether we prefer one of the conversion functions over the
9626 // other. This only distinguishes the results in non-standard, extension
9627 // cases such as the conversion from a lambda closure type to a function
9628 // pointer or block.
9629 ImplicitConversionSequence::CompareKind Result =
9630 compareConversionFunctions(S, Cand1.Function, Cand2.Function);
9631 if (Result == ImplicitConversionSequence::Indistinguishable)
9632 Result = CompareStandardConversionSequences(S, Loc,
9633 Cand1.FinalConversion,
9634 Cand2.FinalConversion);
9635
9636 if (Result != ImplicitConversionSequence::Indistinguishable)
9637 return Result == ImplicitConversionSequence::Better;
9638
9639 // FIXME: Compare kind of reference binding if conversion functions
9640 // convert to a reference type used in direct reference binding, per
9641 // C++14 [over.match.best]p1 section 2 bullet 3.
9642 }
9643
9644 // FIXME: Work around a defect in the C++17 guaranteed copy elision wording,
9645 // as combined with the resolution to CWG issue 243.
9646 //
9647 // When the context is initialization by constructor ([over.match.ctor] or
9648 // either phase of [over.match.list]), a constructor is preferred over
9649 // a conversion function.
9650 if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 &&
9651 Cand1.Function && Cand2.Function &&
9652 isa<CXXConstructorDecl>(Cand1.Function) !=
9653 isa<CXXConstructorDecl>(Cand2.Function))
9654 return isa<CXXConstructorDecl>(Cand1.Function);
9655
9656 // -- F1 is a non-template function and F2 is a function template
9657 // specialization, or, if not that,
9658 bool Cand1IsSpecialization = Cand1.Function &&
9659 Cand1.Function->getPrimaryTemplate();
9660 bool Cand2IsSpecialization = Cand2.Function &&
9661 Cand2.Function->getPrimaryTemplate();
9662 if (Cand1IsSpecialization != Cand2IsSpecialization)
9663 return Cand2IsSpecialization;
9664
9665 // -- F1 and F2 are function template specializations, and the function
9666 // template for F1 is more specialized than the template for F2
9667 // according to the partial ordering rules described in 14.5.5.2, or,
9668 // if not that,
9669 if (Cand1IsSpecialization && Cand2IsSpecialization) {
9670 if (FunctionTemplateDecl *BetterTemplate = S.getMoreSpecializedTemplate(
9671 Cand1.Function->getPrimaryTemplate(),
9672 Cand2.Function->getPrimaryTemplate(), Loc,
9673 isa<CXXConversionDecl>(Cand1.Function) ? TPOC_Conversion
9674 : TPOC_Call,
9675 Cand1.ExplicitCallArguments, Cand2.ExplicitCallArguments,
9676 Cand1.isReversed() ^ Cand2.isReversed()))
9677 return BetterTemplate == Cand1.Function->getPrimaryTemplate();
9678 }
9679
9680 // -— F1 and F2 are non-template functions with the same
9681 // parameter-type-lists, and F1 is more constrained than F2 [...],
9682 if (Cand1.Function && Cand2.Function && !Cand1IsSpecialization &&
9683 !Cand2IsSpecialization && Cand1.Function->hasPrototype() &&
9684 Cand2.Function->hasPrototype()) {
9685 auto *PT1 = cast<FunctionProtoType>(Cand1.Function->getFunctionType());
9686 auto *PT2 = cast<FunctionProtoType>(Cand2.Function->getFunctionType());
9687 if (PT1->getNumParams() == PT2->getNumParams() &&
9688 PT1->isVariadic() == PT2->isVariadic() &&
9689 S.FunctionParamTypesAreEqual(PT1, PT2)) {
9690 Expr *RC1 = Cand1.Function->getTrailingRequiresClause();
9691 Expr *RC2 = Cand2.Function->getTrailingRequiresClause();
9692 if (RC1 && RC2) {
9693 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
9694 if (S.IsAtLeastAsConstrained(Cand1.Function, {RC1}, Cand2.Function,
9695 {RC2}, AtLeastAsConstrained1) ||
9696 S.IsAtLeastAsConstrained(Cand2.Function, {RC2}, Cand1.Function,
9697 {RC1}, AtLeastAsConstrained2))
9698 return false;
9699 if (AtLeastAsConstrained1 != AtLeastAsConstrained2)
9700 return AtLeastAsConstrained1;
9701 } else if (RC1 || RC2) {
9702 return RC1 != nullptr;
9703 }
9704 }
9705 }
9706
9707 // -- F1 is a constructor for a class D, F2 is a constructor for a base
9708 // class B of D, and for all arguments the corresponding parameters of
9709 // F1 and F2 have the same type.
9710 // FIXME: Implement the "all parameters have the same type" check.
9711 bool Cand1IsInherited =
9712 dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
9713 bool Cand2IsInherited =
9714 dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
9715 if (Cand1IsInherited != Cand2IsInherited)
9716 return Cand2IsInherited;
9717 else if (Cand1IsInherited) {
9718 assert(Cand2IsInherited);
9719 auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
9720 auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
9721 if (Cand1Class->isDerivedFrom(Cand2Class))
9722 return true;
9723 if (Cand2Class->isDerivedFrom(Cand1Class))
9724 return false;
9725 // Inherited from sibling base classes: still ambiguous.
9726 }
9727
9728 // -- F2 is a rewritten candidate (12.4.1.2) and F1 is not
9729 // -- F1 and F2 are rewritten candidates, and F2 is a synthesized candidate
9730 // with reversed order of parameters and F1 is not
9731 //
9732 // We rank reversed + different operator as worse than just reversed, but
9733 // that comparison can never happen, because we only consider reversing for
9734 // the maximally-rewritten operator (== or <=>).
9735 if (Cand1.RewriteKind != Cand2.RewriteKind)
9736 return Cand1.RewriteKind < Cand2.RewriteKind;
9737
9738 // Check C++17 tie-breakers for deduction guides.
9739 {
9740 auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function);
9741 auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function);
9742 if (Guide1 && Guide2) {
9743 // -- F1 is generated from a deduction-guide and F2 is not
9744 if (Guide1->isImplicit() != Guide2->isImplicit())
9745 return Guide2->isImplicit();
9746
9747 // -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not
9748 if (Guide1->isCopyDeductionCandidate())
9749 return true;
9750 }
9751 }
9752
9753 // Check for enable_if value-based overload resolution.
9754 if (Cand1.Function && Cand2.Function) {
9755 Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function);
9756 if (Cmp != Comparison::Equal)
9757 return Cmp == Comparison::Better;
9758 }
9759
9760 if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
9761 FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
9762 return S.IdentifyCUDAPreference(Caller, Cand1.Function) >
9763 S.IdentifyCUDAPreference(Caller, Cand2.Function);
9764 }
9765
9766 bool HasPS1 = Cand1.Function != nullptr &&
9767 functionHasPassObjectSizeParams(Cand1.Function);
9768 bool HasPS2 = Cand2.Function != nullptr &&
9769 functionHasPassObjectSizeParams(Cand2.Function);
9770 if (HasPS1 != HasPS2 && HasPS1)
9771 return true;
9772
9773 Comparison MV = isBetterMultiversionCandidate(Cand1, Cand2);
9774 return MV == Comparison::Better;
9775 }
9776
9777 /// Determine whether two declarations are "equivalent" for the purposes of
9778 /// name lookup and overload resolution. This applies when the same internal/no
9779 /// linkage entity is defined by two modules (probably by textually including
9780 /// the same header). In such a case, we don't consider the declarations to
9781 /// declare the same entity, but we also don't want lookups with both
9782 /// declarations visible to be ambiguous in some cases (this happens when using
9783 /// a modularized libstdc++).
isEquivalentInternalLinkageDeclaration(const NamedDecl * A,const NamedDecl * B)9784 bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
9785 const NamedDecl *B) {
9786 auto *VA = dyn_cast_or_null<ValueDecl>(A);
9787 auto *VB = dyn_cast_or_null<ValueDecl>(B);
9788 if (!VA || !VB)
9789 return false;
9790
9791 // The declarations must be declaring the same name as an internal linkage
9792 // entity in different modules.
9793 if (!VA->getDeclContext()->getRedeclContext()->Equals(
9794 VB->getDeclContext()->getRedeclContext()) ||
9795 getOwningModule(VA) == getOwningModule(VB) ||
9796 VA->isExternallyVisible() || VB->isExternallyVisible())
9797 return false;
9798
9799 // Check that the declarations appear to be equivalent.
9800 //
9801 // FIXME: Checking the type isn't really enough to resolve the ambiguity.
9802 // For constants and functions, we should check the initializer or body is
9803 // the same. For non-constant variables, we shouldn't allow it at all.
9804 if (Context.hasSameType(VA->getType(), VB->getType()))
9805 return true;
9806
9807 // Enum constants within unnamed enumerations will have different types, but
9808 // may still be similar enough to be interchangeable for our purposes.
9809 if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) {
9810 if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) {
9811 // Only handle anonymous enums. If the enumerations were named and
9812 // equivalent, they would have been merged to the same type.
9813 auto *EnumA = cast<EnumDecl>(EA->getDeclContext());
9814 auto *EnumB = cast<EnumDecl>(EB->getDeclContext());
9815 if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() ||
9816 !Context.hasSameType(EnumA->getIntegerType(),
9817 EnumB->getIntegerType()))
9818 return false;
9819 // Allow this only if the value is the same for both enumerators.
9820 return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal());
9821 }
9822 }
9823
9824 // Nothing else is sufficiently similar.
9825 return false;
9826 }
9827
diagnoseEquivalentInternalLinkageDeclarations(SourceLocation Loc,const NamedDecl * D,ArrayRef<const NamedDecl * > Equiv)9828 void Sema::diagnoseEquivalentInternalLinkageDeclarations(
9829 SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
9830 Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;
9831
9832 Module *M = getOwningModule(D);
9833 Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
9834 << !M << (M ? M->getFullModuleName() : "");
9835
9836 for (auto *E : Equiv) {
9837 Module *M = getOwningModule(E);
9838 Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
9839 << !M << (M ? M->getFullModuleName() : "");
9840 }
9841 }
9842
9843 /// Computes the best viable function (C++ 13.3.3)
9844 /// within an overload candidate set.
9845 ///
9846 /// \param Loc The location of the function name (or operator symbol) for
9847 /// which overload resolution occurs.
9848 ///
9849 /// \param Best If overload resolution was successful or found a deleted
9850 /// function, \p Best points to the candidate function found.
9851 ///
9852 /// \returns The result of overload resolution.
9853 OverloadingResult
BestViableFunction(Sema & S,SourceLocation Loc,iterator & Best)9854 OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
9855 iterator &Best) {
9856 llvm::SmallVector<OverloadCandidate *, 16> Candidates;
9857 std::transform(begin(), end(), std::back_inserter(Candidates),
9858 [](OverloadCandidate &Cand) { return &Cand; });
9859
9860 // [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but
9861 // are accepted by both clang and NVCC. However, during a particular
9862 // compilation mode only one call variant is viable. We need to
9863 // exclude non-viable overload candidates from consideration based
9864 // only on their host/device attributes. Specifically, if one
9865 // candidate call is WrongSide and the other is SameSide, we ignore
9866 // the WrongSide candidate.
9867 if (S.getLangOpts().CUDA) {
9868 const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
9869 bool ContainsSameSideCandidate =
9870 llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
9871 // Check viable function only.
9872 return Cand->Viable && Cand->Function &&
9873 S.IdentifyCUDAPreference(Caller, Cand->Function) ==
9874 Sema::CFP_SameSide;
9875 });
9876 if (ContainsSameSideCandidate) {
9877 auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
9878 // Check viable function only to avoid unnecessary data copying/moving.
9879 return Cand->Viable && Cand->Function &&
9880 S.IdentifyCUDAPreference(Caller, Cand->Function) ==
9881 Sema::CFP_WrongSide;
9882 };
9883 llvm::erase_if(Candidates, IsWrongSideCandidate);
9884 }
9885 }
9886
9887 // Find the best viable function.
9888 Best = end();
9889 for (auto *Cand : Candidates) {
9890 Cand->Best = false;
9891 if (Cand->Viable)
9892 if (Best == end() ||
9893 isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind))
9894 Best = Cand;
9895 }
9896
9897 // If we didn't find any viable functions, abort.
9898 if (Best == end())
9899 return OR_No_Viable_Function;
9900
9901 llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;
9902
9903 llvm::SmallVector<OverloadCandidate*, 4> PendingBest;
9904 PendingBest.push_back(&*Best);
9905 Best->Best = true;
9906
9907 // Make sure that this function is better than every other viable
9908 // function. If not, we have an ambiguity.
9909 while (!PendingBest.empty()) {
9910 auto *Curr = PendingBest.pop_back_val();
9911 for (auto *Cand : Candidates) {
9912 if (Cand->Viable && !Cand->Best &&
9913 !isBetterOverloadCandidate(S, *Curr, *Cand, Loc, Kind)) {
9914 PendingBest.push_back(Cand);
9915 Cand->Best = true;
9916
9917 if (S.isEquivalentInternalLinkageDeclaration(Cand->Function,
9918 Curr->Function))
9919 EquivalentCands.push_back(Cand->Function);
9920 else
9921 Best = end();
9922 }
9923 }
9924 }
9925
9926 // If we found more than one best candidate, this is ambiguous.
9927 if (Best == end())
9928 return OR_Ambiguous;
9929
9930 // Best is the best viable function.
9931 if (Best->Function && Best->Function->isDeleted())
9932 return OR_Deleted;
9933
9934 if (!EquivalentCands.empty())
9935 S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
9936 EquivalentCands);
9937
9938 return OR_Success;
9939 }
9940
9941 namespace {
9942
9943 enum OverloadCandidateKind {
9944 oc_function,
9945 oc_method,
9946 oc_reversed_binary_operator,
9947 oc_constructor,
9948 oc_implicit_default_constructor,
9949 oc_implicit_copy_constructor,
9950 oc_implicit_move_constructor,
9951 oc_implicit_copy_assignment,
9952 oc_implicit_move_assignment,
9953 oc_implicit_equality_comparison,
9954 oc_inherited_constructor
9955 };
9956
9957 enum OverloadCandidateSelect {
9958 ocs_non_template,
9959 ocs_template,
9960 ocs_described_template,
9961 };
9962
9963 static std::pair<OverloadCandidateKind, OverloadCandidateSelect>
ClassifyOverloadCandidate(Sema & S,NamedDecl * Found,FunctionDecl * Fn,OverloadCandidateRewriteKind CRK,std::string & Description)9964 ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn,
9965 OverloadCandidateRewriteKind CRK,
9966 std::string &Description) {
9967
9968 bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl();
9969 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) {
9970 isTemplate = true;
9971 Description = S.getTemplateArgumentBindingsText(
9972 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs());
9973 }
9974
9975 OverloadCandidateSelect Select = [&]() {
9976 if (!Description.empty())
9977 return ocs_described_template;
9978 return isTemplate ? ocs_template : ocs_non_template;
9979 }();
9980
9981 OverloadCandidateKind Kind = [&]() {
9982 if (Fn->isImplicit() && Fn->getOverloadedOperator() == OO_EqualEqual)
9983 return oc_implicit_equality_comparison;
9984
9985 if (CRK & CRK_Reversed)
9986 return oc_reversed_binary_operator;
9987
9988 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) {
9989 if (!Ctor->isImplicit()) {
9990 if (isa<ConstructorUsingShadowDecl>(Found))
9991 return oc_inherited_constructor;
9992 else
9993 return oc_constructor;
9994 }
9995
9996 if (Ctor->isDefaultConstructor())
9997 return oc_implicit_default_constructor;
9998
9999 if (Ctor->isMoveConstructor())
10000 return oc_implicit_move_constructor;
10001
10002 assert(Ctor->isCopyConstructor() &&
10003 "unexpected sort of implicit constructor");
10004 return oc_implicit_copy_constructor;
10005 }
10006
10007 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) {
10008 // This actually gets spelled 'candidate function' for now, but
10009 // it doesn't hurt to split it out.
10010 if (!Meth->isImplicit())
10011 return oc_method;
10012
10013 if (Meth->isMoveAssignmentOperator())
10014 return oc_implicit_move_assignment;
10015
10016 if (Meth->isCopyAssignmentOperator())
10017 return oc_implicit_copy_assignment;
10018
10019 assert(isa<CXXConversionDecl>(Meth) && "expected conversion");
10020 return oc_method;
10021 }
10022
10023 return oc_function;
10024 }();
10025
10026 return std::make_pair(Kind, Select);
10027 }
10028
MaybeEmitInheritedConstructorNote(Sema & S,Decl * FoundDecl)10029 void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) {
10030 // FIXME: It'd be nice to only emit a note once per using-decl per overload
10031 // set.
10032 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl))
10033 S.Diag(FoundDecl->getLocation(),
10034 diag::note_ovl_candidate_inherited_constructor)
10035 << Shadow->getNominatedBaseClass();
10036 }
10037
10038 } // end anonymous namespace
10039
isFunctionAlwaysEnabled(const ASTContext & Ctx,const FunctionDecl * FD)10040 static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
10041 const FunctionDecl *FD) {
10042 for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
10043 bool AlwaysTrue;
10044 if (EnableIf->getCond()->isValueDependent() ||
10045 !EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
10046 return false;
10047 if (!AlwaysTrue)
10048 return false;
10049 }
10050 return true;
10051 }
10052
10053 /// Returns true if we can take the address of the function.
10054 ///
10055 /// \param Complain - If true, we'll emit a diagnostic
10056 /// \param InOverloadResolution - For the purposes of emitting a diagnostic, are
10057 /// we in overload resolution?
10058 /// \param Loc - The location of the statement we're complaining about. Ignored
10059 /// if we're not complaining, or if we're in overload resolution.
checkAddressOfFunctionIsAvailable(Sema & S,const FunctionDecl * FD,bool Complain,bool InOverloadResolution,SourceLocation Loc)10060 static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD,
10061 bool Complain,
10062 bool InOverloadResolution,
10063 SourceLocation Loc) {
10064 if (!isFunctionAlwaysEnabled(S.Context, FD)) {
10065 if (Complain) {
10066 if (InOverloadResolution)
10067 S.Diag(FD->getBeginLoc(),
10068 diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr);
10069 else
10070 S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD;
10071 }
10072 return false;
10073 }
10074
10075 if (FD->getTrailingRequiresClause()) {
10076 ConstraintSatisfaction Satisfaction;
10077 if (S.CheckFunctionConstraints(FD, Satisfaction, Loc))
10078 return false;
10079 if (!Satisfaction.IsSatisfied) {
10080 if (Complain) {
10081 if (InOverloadResolution)
10082 S.Diag(FD->getBeginLoc(),
10083 diag::note_ovl_candidate_unsatisfied_constraints);
10084 else
10085 S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied)
10086 << FD;
10087 S.DiagnoseUnsatisfiedConstraint(Satisfaction);
10088 }
10089 return false;
10090 }
10091 }
10092
10093 auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) {
10094 return P->hasAttr<PassObjectSizeAttr>();
10095 });
10096 if (I == FD->param_end())
10097 return true;
10098
10099 if (Complain) {
10100 // Add one to ParamNo because it's user-facing
10101 unsigned ParamNo = std::distance(FD->param_begin(), I) + 1;
10102 if (InOverloadResolution)
10103 S.Diag(FD->getLocation(),
10104 diag::note_ovl_candidate_has_pass_object_size_params)
10105 << ParamNo;
10106 else
10107 S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params)
10108 << FD << ParamNo;
10109 }
10110 return false;
10111 }
10112
checkAddressOfCandidateIsAvailable(Sema & S,const FunctionDecl * FD)10113 static bool checkAddressOfCandidateIsAvailable(Sema &S,
10114 const FunctionDecl *FD) {
10115 return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true,
10116 /*InOverloadResolution=*/true,
10117 /*Loc=*/SourceLocation());
10118 }
10119
checkAddressOfFunctionIsAvailable(const FunctionDecl * Function,bool Complain,SourceLocation Loc)10120 bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
10121 bool Complain,
10122 SourceLocation Loc) {
10123 return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain,
10124 /*InOverloadResolution=*/false,
10125 Loc);
10126 }
10127
10128 // Notes the location of an overload candidate.
NoteOverloadCandidate(NamedDecl * Found,FunctionDecl * Fn,OverloadCandidateRewriteKind RewriteKind,QualType DestType,bool TakingAddress)10129 void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
10130 OverloadCandidateRewriteKind RewriteKind,
10131 QualType DestType, bool TakingAddress) {
10132 if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn))
10133 return;
10134 if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() &&
10135 !Fn->getAttr<TargetAttr>()->isDefaultVersion())
10136 return;
10137
10138 std::string FnDesc;
10139 std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair =
10140 ClassifyOverloadCandidate(*this, Found, Fn, RewriteKind, FnDesc);
10141 PartialDiagnostic PD = PDiag(diag::note_ovl_candidate)
10142 << (unsigned)KSPair.first << (unsigned)KSPair.second
10143 << Fn << FnDesc;
10144
10145 HandleFunctionTypeMismatch(PD, Fn->getType(), DestType);
10146 Diag(Fn->getLocation(), PD);
10147 MaybeEmitInheritedConstructorNote(*this, Found);
10148 }
10149
10150 static void
MaybeDiagnoseAmbiguousConstraints(Sema & S,ArrayRef<OverloadCandidate> Cands)10151 MaybeDiagnoseAmbiguousConstraints(Sema &S, ArrayRef<OverloadCandidate> Cands) {
10152 // Perhaps the ambiguity was caused by two atomic constraints that are
10153 // 'identical' but not equivalent:
10154 //
10155 // void foo() requires (sizeof(T) > 4) { } // #1
10156 // void foo() requires (sizeof(T) > 4) && T::value { } // #2
10157 //
10158 // The 'sizeof(T) > 4' constraints are seemingly equivalent and should cause
10159 // #2 to subsume #1, but these constraint are not considered equivalent
10160 // according to the subsumption rules because they are not the same
10161 // source-level construct. This behavior is quite confusing and we should try
10162 // to help the user figure out what happened.
10163
10164 SmallVector<const Expr *, 3> FirstAC, SecondAC;
10165 FunctionDecl *FirstCand = nullptr, *SecondCand = nullptr;
10166 for (auto I = Cands.begin(), E = Cands.end(); I != E; ++I) {
10167 if (!I->Function)
10168 continue;
10169 SmallVector<const Expr *, 3> AC;
10170 if (auto *Template = I->Function->getPrimaryTemplate())
10171 Template->getAssociatedConstraints(AC);
10172 else
10173 I->Function->getAssociatedConstraints(AC);
10174 if (AC.empty())
10175 continue;
10176 if (FirstCand == nullptr) {
10177 FirstCand = I->Function;
10178 FirstAC = AC;
10179 } else if (SecondCand == nullptr) {
10180 SecondCand = I->Function;
10181 SecondAC = AC;
10182 } else {
10183 // We have more than one pair of constrained functions - this check is
10184 // expensive and we'd rather not try to diagnose it.
10185 return;
10186 }
10187 }
10188 if (!SecondCand)
10189 return;
10190 // The diagnostic can only happen if there are associated constraints on
10191 // both sides (there needs to be some identical atomic constraint).
10192 if (S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(FirstCand, FirstAC,
10193 SecondCand, SecondAC))
10194 // Just show the user one diagnostic, they'll probably figure it out
10195 // from here.
10196 return;
10197 }
10198
10199 // Notes the location of all overload candidates designated through
10200 // OverloadedExpr
NoteAllOverloadCandidates(Expr * OverloadedExpr,QualType DestType,bool TakingAddress)10201 void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType,
10202 bool TakingAddress) {
10203 assert(OverloadedExpr->getType() == Context.OverloadTy);
10204
10205 OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr);
10206 OverloadExpr *OvlExpr = Ovl.Expression;
10207
10208 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
10209 IEnd = OvlExpr->decls_end();
10210 I != IEnd; ++I) {
10211 if (FunctionTemplateDecl *FunTmpl =
10212 dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) {
10213 NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), CRK_None, DestType,
10214 TakingAddress);
10215 } else if (FunctionDecl *Fun
10216 = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) {
10217 NoteOverloadCandidate(*I, Fun, CRK_None, DestType, TakingAddress);
10218 }
10219 }
10220 }
10221
10222 /// Diagnoses an ambiguous conversion. The partial diagnostic is the
10223 /// "lead" diagnostic; it will be given two arguments, the source and
10224 /// target types of the conversion.
DiagnoseAmbiguousConversion(Sema & S,SourceLocation CaretLoc,const PartialDiagnostic & PDiag) const10225 void ImplicitConversionSequence::DiagnoseAmbiguousConversion(
10226 Sema &S,
10227 SourceLocation CaretLoc,
10228 const PartialDiagnostic &PDiag) const {
10229 S.Diag(CaretLoc, PDiag)
10230 << Ambiguous.getFromType() << Ambiguous.getToType();
10231 // FIXME: The note limiting machinery is borrowed from
10232 // OverloadCandidateSet::NoteCandidates; there's an opportunity for
10233 // refactoring here.
10234 const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
10235 unsigned CandsShown = 0;
10236 AmbiguousConversionSequence::const_iterator I, E;
10237 for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) {
10238 if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
10239 break;
10240 ++CandsShown;
10241 S.NoteOverloadCandidate(I->first, I->second);
10242 }
10243 if (I != E)
10244 S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I);
10245 }
10246
DiagnoseBadConversion(Sema & S,OverloadCandidate * Cand,unsigned I,bool TakingCandidateAddress)10247 static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
10248 unsigned I, bool TakingCandidateAddress) {
10249 const ImplicitConversionSequence &Conv = Cand->Conversions[I];
10250 assert(Conv.isBad());
10251 assert(Cand->Function && "for now, candidate must be a function");
10252 FunctionDecl *Fn = Cand->Function;
10253
10254 // There's a conversion slot for the object argument if this is a
10255 // non-constructor method. Note that 'I' corresponds the
10256 // conversion-slot index.
10257 bool isObjectArgument = false;
10258 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) {
10259 if (I == 0)
10260 isObjectArgument = true;
10261 else
10262 I--;
10263 }
10264
10265 std::string FnDesc;
10266 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
10267 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(),
10268 FnDesc);
10269
10270 Expr *FromExpr = Conv.Bad.FromExpr;
10271 QualType FromTy = Conv.Bad.getFromType();
10272 QualType ToTy = Conv.Bad.getToType();
10273
10274 if (FromTy == S.Context.OverloadTy) {
10275 assert(FromExpr && "overload set argument came from implicit argument?");
10276 Expr *E = FromExpr->IgnoreParens();
10277 if (isa<UnaryOperator>(E))
10278 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
10279 DeclarationName Name = cast<OverloadExpr>(E)->getName();
10280
10281 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload)
10282 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10283 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy
10284 << Name << I + 1;
10285 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10286 return;
10287 }
10288
10289 // Do some hand-waving analysis to see if the non-viability is due
10290 // to a qualifier mismatch.
10291 CanQualType CFromTy = S.Context.getCanonicalType(FromTy);
10292 CanQualType CToTy = S.Context.getCanonicalType(ToTy);
10293 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>())
10294 CToTy = RT->getPointeeType();
10295 else {
10296 // TODO: detect and diagnose the full richness of const mismatches.
10297 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>())
10298 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) {
10299 CFromTy = FromPT->getPointeeType();
10300 CToTy = ToPT->getPointeeType();
10301 }
10302 }
10303
10304 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() &&
10305 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) {
10306 Qualifiers FromQs = CFromTy.getQualifiers();
10307 Qualifiers ToQs = CToTy.getQualifiers();
10308
10309 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) {
10310 if (isObjectArgument)
10311 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace_this)
10312 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10313 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10314 << FromQs.getAddressSpace() << ToQs.getAddressSpace();
10315 else
10316 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace)
10317 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10318 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10319 << FromQs.getAddressSpace() << ToQs.getAddressSpace()
10320 << ToTy->isReferenceType() << I + 1;
10321 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10322 return;
10323 }
10324
10325 if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
10326 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership)
10327 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10328 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10329 << FromQs.getObjCLifetime() << ToQs.getObjCLifetime()
10330 << (unsigned)isObjectArgument << I + 1;
10331 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10332 return;
10333 }
10334
10335 if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
10336 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc)
10337 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10338 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10339 << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
10340 << (unsigned)isObjectArgument << I + 1;
10341 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10342 return;
10343 }
10344
10345 if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
10346 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
10347 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10348 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10349 << FromQs.hasUnaligned() << I + 1;
10350 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10351 return;
10352 }
10353
10354 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
10355 assert(CVR && "unexpected qualifiers mismatch");
10356
10357 if (isObjectArgument) {
10358 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
10359 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10360 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10361 << (CVR - 1);
10362 } else {
10363 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr)
10364 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10365 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10366 << (CVR - 1) << I + 1;
10367 }
10368 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10369 return;
10370 }
10371
10372 // Special diagnostic for failure to convert an initializer list, since
10373 // telling the user that it has type void is not useful.
10374 if (FromExpr && isa<InitListExpr>(FromExpr)) {
10375 // XXXAR: it would be nice if we could somehow diagnose capability -> pointer
10376 // narrowing conversions here instead of just printing candidate not viable
10377 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument)
10378 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10379 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10380 << ToTy << (unsigned)isObjectArgument << I + 1;
10381 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10382 return;
10383 }
10384
10385 // Diagnose references or pointers to incomplete types differently,
10386 // since it's far from impossible that the incompleteness triggered
10387 // the failure.
10388 QualType TempFromTy = FromTy.getNonReferenceType();
10389 if (const PointerType *PTy = TempFromTy->getAs<PointerType>())
10390 TempFromTy = PTy->getPointeeType();
10391 if (TempFromTy->isIncompleteType()) {
10392 // Emit the generic diagnostic and, optionally, add the hints to it.
10393 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete)
10394 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10395 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10396 << ToTy << (unsigned)isObjectArgument << I + 1
10397 << (unsigned)(Cand->Fix.Kind);
10398
10399 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10400 return;
10401 }
10402
10403 // Diagnose base -> derived pointer conversions.
10404 unsigned BaseToDerivedConversion = 0;
10405 if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) {
10406 if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) {
10407 if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
10408 FromPtrTy->getPointeeType()) &&
10409 !FromPtrTy->getPointeeType()->isIncompleteType() &&
10410 !ToPtrTy->getPointeeType()->isIncompleteType() &&
10411 S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(),
10412 FromPtrTy->getPointeeType()))
10413 BaseToDerivedConversion = 1;
10414 }
10415 } else if (const ObjCObjectPointerType *FromPtrTy
10416 = FromTy->getAs<ObjCObjectPointerType>()) {
10417 if (const ObjCObjectPointerType *ToPtrTy
10418 = ToTy->getAs<ObjCObjectPointerType>())
10419 if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl())
10420 if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl())
10421 if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
10422 FromPtrTy->getPointeeType()) &&
10423 FromIface->isSuperClassOf(ToIface))
10424 BaseToDerivedConversion = 2;
10425 } else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) {
10426 if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) &&
10427 !FromTy->isIncompleteType() &&
10428 !ToRefTy->getPointeeType()->isIncompleteType() &&
10429 S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) {
10430 BaseToDerivedConversion = 3;
10431 } else if (ToTy->isLValueReferenceType() && !FromExpr->isLValue() &&
10432 ToTy.getNonReferenceType().getCanonicalType() ==
10433 FromTy.getNonReferenceType().getCanonicalType()) {
10434 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_lvalue)
10435 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10436 << (unsigned)isObjectArgument << I + 1
10437 << (FromExpr ? FromExpr->getSourceRange() : SourceRange());
10438 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10439 return;
10440 }
10441 }
10442
10443 if (BaseToDerivedConversion) {
10444 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv)
10445 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10446 << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10447 << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1;
10448 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10449 return;
10450 }
10451
10452 if (isa<ObjCObjectPointerType>(CFromTy) &&
10453 isa<PointerType>(CToTy)) {
10454 Qualifiers FromQs = CFromTy.getQualifiers();
10455 Qualifiers ToQs = CToTy.getQualifiers();
10456 if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
10457 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv)
10458 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10459 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10460 << FromTy << ToTy << (unsigned)isObjectArgument << I + 1;
10461 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10462 return;
10463 }
10464 }
10465
10466 if (TakingCandidateAddress &&
10467 !checkAddressOfCandidateIsAvailable(S, Cand->Function))
10468 return;
10469
10470 // Emit the generic diagnostic and, optionally, add the hints to it.
10471 PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv);
10472 FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10473 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10474 << ToTy << (unsigned)isObjectArgument << I + 1
10475 << (unsigned)(Cand->Fix.Kind);
10476
10477 // If we can fix the conversion, suggest the FixIts.
10478 for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(),
10479 HE = Cand->Fix.Hints.end(); HI != HE; ++HI)
10480 FDiag << *HI;
10481 S.Diag(Fn->getLocation(), FDiag);
10482
10483 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10484 }
10485
10486 /// Additional arity mismatch diagnosis specific to a function overload
10487 /// candidates. This is not covered by the more general DiagnoseArityMismatch()
10488 /// over a candidate in any candidate set.
CheckArityMismatch(Sema & S,OverloadCandidate * Cand,unsigned NumArgs)10489 static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand,
10490 unsigned NumArgs) {
10491 FunctionDecl *Fn = Cand->Function;
10492 unsigned MinParams = Fn->getMinRequiredArguments();
10493
10494 // With invalid overloaded operators, it's possible that we think we
10495 // have an arity mismatch when in fact it looks like we have the
10496 // right number of arguments, because only overloaded operators have
10497 // the weird behavior of overloading member and non-member functions.
10498 // Just don't report anything.
10499 if (Fn->isInvalidDecl() &&
10500 Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
10501 return true;
10502
10503 if (NumArgs < MinParams) {
10504 assert((Cand->FailureKind == ovl_fail_too_few_arguments) ||
10505 (Cand->FailureKind == ovl_fail_bad_deduction &&
10506 Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments));
10507 } else {
10508 assert((Cand->FailureKind == ovl_fail_too_many_arguments) ||
10509 (Cand->FailureKind == ovl_fail_bad_deduction &&
10510 Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments));
10511 }
10512
10513 return false;
10514 }
10515
10516 /// General arity mismatch diagnosis over a candidate in a candidate set.
DiagnoseArityMismatch(Sema & S,NamedDecl * Found,Decl * D,unsigned NumFormalArgs)10517 static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D,
10518 unsigned NumFormalArgs) {
10519 assert(isa<FunctionDecl>(D) &&
10520 "The templated declaration should at least be a function"
10521 " when diagnosing bad template argument deduction due to too many"
10522 " or too few arguments");
10523
10524 FunctionDecl *Fn = cast<FunctionDecl>(D);
10525
10526 // TODO: treat calls to a missing default constructor as a special case
10527 const auto *FnTy = Fn->getType()->castAs<FunctionProtoType>();
10528 unsigned MinParams = Fn->getMinRequiredArguments();
10529
10530 // at least / at most / exactly
10531 unsigned mode, modeCount;
10532 if (NumFormalArgs < MinParams) {
10533 if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() ||
10534 FnTy->isTemplateVariadic())
10535 mode = 0; // "at least"
10536 else
10537 mode = 2; // "exactly"
10538 modeCount = MinParams;
10539 } else {
10540 if (MinParams != FnTy->getNumParams())
10541 mode = 1; // "at most"
10542 else
10543 mode = 2; // "exactly"
10544 modeCount = FnTy->getNumParams();
10545 }
10546
10547 std::string Description;
10548 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
10549 ClassifyOverloadCandidate(S, Found, Fn, CRK_None, Description);
10550
10551 if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName())
10552 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one)
10553 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10554 << Description << mode << Fn->getParamDecl(0) << NumFormalArgs;
10555 else
10556 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity)
10557 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10558 << Description << mode << modeCount << NumFormalArgs;
10559
10560 MaybeEmitInheritedConstructorNote(S, Found);
10561 }
10562
10563 /// Arity mismatch diagnosis specific to a function overload candidate.
DiagnoseArityMismatch(Sema & S,OverloadCandidate * Cand,unsigned NumFormalArgs)10564 static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
10565 unsigned NumFormalArgs) {
10566 if (!CheckArityMismatch(S, Cand, NumFormalArgs))
10567 DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs);
10568 }
10569
getDescribedTemplate(Decl * Templated)10570 static TemplateDecl *getDescribedTemplate(Decl *Templated) {
10571 if (TemplateDecl *TD = Templated->getDescribedTemplate())
10572 return TD;
10573 llvm_unreachable("Unsupported: Getting the described template declaration"
10574 " for bad deduction diagnosis");
10575 }
10576
10577 /// Diagnose a failed template-argument deduction.
DiagnoseBadDeduction(Sema & S,NamedDecl * Found,Decl * Templated,DeductionFailureInfo & DeductionFailure,unsigned NumArgs,bool TakingCandidateAddress)10578 static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated,
10579 DeductionFailureInfo &DeductionFailure,
10580 unsigned NumArgs,
10581 bool TakingCandidateAddress) {
10582 TemplateParameter Param = DeductionFailure.getTemplateParameter();
10583 NamedDecl *ParamD;
10584 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) ||
10585 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) ||
10586 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>());
10587 switch (DeductionFailure.Result) {
10588 case Sema::TDK_Success:
10589 llvm_unreachable("TDK_success while diagnosing bad deduction");
10590
10591 case Sema::TDK_Incomplete: {
10592 assert(ParamD && "no parameter found for incomplete deduction result");
10593 S.Diag(Templated->getLocation(),
10594 diag::note_ovl_candidate_incomplete_deduction)
10595 << ParamD->getDeclName();
10596 MaybeEmitInheritedConstructorNote(S, Found);
10597 return;
10598 }
10599
10600 case Sema::TDK_IncompletePack: {
10601 assert(ParamD && "no parameter found for incomplete deduction result");
10602 S.Diag(Templated->getLocation(),
10603 diag::note_ovl_candidate_incomplete_deduction_pack)
10604 << ParamD->getDeclName()
10605 << (DeductionFailure.getFirstArg()->pack_size() + 1)
10606 << *DeductionFailure.getFirstArg();
10607 MaybeEmitInheritedConstructorNote(S, Found);
10608 return;
10609 }
10610
10611 case Sema::TDK_Underqualified: {
10612 assert(ParamD && "no parameter found for bad qualifiers deduction result");
10613 TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD);
10614
10615 QualType Param = DeductionFailure.getFirstArg()->getAsType();
10616
10617 // Param will have been canonicalized, but it should just be a
10618 // qualified version of ParamD, so move the qualifiers to that.
10619 QualifierCollector Qs;
10620 Qs.strip(Param);
10621 QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl());
10622 assert(S.Context.hasSameType(Param, NonCanonParam));
10623
10624 // Arg has also been canonicalized, but there's nothing we can do
10625 // about that. It also doesn't matter as much, because it won't
10626 // have any template parameters in it (because deduction isn't
10627 // done on dependent types).
10628 QualType Arg = DeductionFailure.getSecondArg()->getAsType();
10629
10630 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified)
10631 << ParamD->getDeclName() << Arg << NonCanonParam;
10632 MaybeEmitInheritedConstructorNote(S, Found);
10633 return;
10634 }
10635
10636 case Sema::TDK_Inconsistent: {
10637 assert(ParamD && "no parameter found for inconsistent deduction result");
10638 int which = 0;
10639 if (isa<TemplateTypeParmDecl>(ParamD))
10640 which = 0;
10641 else if (isa<NonTypeTemplateParmDecl>(ParamD)) {
10642 // Deduction might have failed because we deduced arguments of two
10643 // different types for a non-type template parameter.
10644 // FIXME: Use a different TDK value for this.
10645 QualType T1 =
10646 DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType();
10647 QualType T2 =
10648 DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType();
10649 if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) {
10650 S.Diag(Templated->getLocation(),
10651 diag::note_ovl_candidate_inconsistent_deduction_types)
10652 << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1
10653 << *DeductionFailure.getSecondArg() << T2;
10654 MaybeEmitInheritedConstructorNote(S, Found);
10655 return;
10656 }
10657
10658 which = 1;
10659 } else {
10660 which = 2;
10661 }
10662
10663 // Tweak the diagnostic if the problem is that we deduced packs of
10664 // different arities. We'll print the actual packs anyway in case that
10665 // includes additional useful information.
10666 if (DeductionFailure.getFirstArg()->getKind() == TemplateArgument::Pack &&
10667 DeductionFailure.getSecondArg()->getKind() == TemplateArgument::Pack &&
10668 DeductionFailure.getFirstArg()->pack_size() !=
10669 DeductionFailure.getSecondArg()->pack_size()) {
10670 which = 3;
10671 }
10672
10673 S.Diag(Templated->getLocation(),
10674 diag::note_ovl_candidate_inconsistent_deduction)
10675 << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg()
10676 << *DeductionFailure.getSecondArg();
10677 MaybeEmitInheritedConstructorNote(S, Found);
10678 return;
10679 }
10680
10681 case Sema::TDK_InvalidExplicitArguments:
10682 assert(ParamD && "no parameter found for invalid explicit arguments");
10683 if (ParamD->getDeclName())
10684 S.Diag(Templated->getLocation(),
10685 diag::note_ovl_candidate_explicit_arg_mismatch_named)
10686 << ParamD->getDeclName();
10687 else {
10688 int index = 0;
10689 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD))
10690 index = TTP->getIndex();
10691 else if (NonTypeTemplateParmDecl *NTTP
10692 = dyn_cast<NonTypeTemplateParmDecl>(ParamD))
10693 index = NTTP->getIndex();
10694 else
10695 index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex();
10696 S.Diag(Templated->getLocation(),
10697 diag::note_ovl_candidate_explicit_arg_mismatch_unnamed)
10698 << (index + 1);
10699 }
10700 MaybeEmitInheritedConstructorNote(S, Found);
10701 return;
10702
10703 case Sema::TDK_ConstraintsNotSatisfied: {
10704 // Format the template argument list into the argument string.
10705 SmallString<128> TemplateArgString;
10706 TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList();
10707 TemplateArgString = " ";
10708 TemplateArgString += S.getTemplateArgumentBindingsText(
10709 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10710 if (TemplateArgString.size() == 1)
10711 TemplateArgString.clear();
10712 S.Diag(Templated->getLocation(),
10713 diag::note_ovl_candidate_unsatisfied_constraints)
10714 << TemplateArgString;
10715
10716 S.DiagnoseUnsatisfiedConstraint(
10717 static_cast<CNSInfo*>(DeductionFailure.Data)->Satisfaction);
10718 return;
10719 }
10720 case Sema::TDK_TooManyArguments:
10721 case Sema::TDK_TooFewArguments:
10722 DiagnoseArityMismatch(S, Found, Templated, NumArgs);
10723 return;
10724
10725 case Sema::TDK_InstantiationDepth:
10726 S.Diag(Templated->getLocation(),
10727 diag::note_ovl_candidate_instantiation_depth);
10728 MaybeEmitInheritedConstructorNote(S, Found);
10729 return;
10730
10731 case Sema::TDK_SubstitutionFailure: {
10732 // Format the template argument list into the argument string.
10733 SmallString<128> TemplateArgString;
10734 if (TemplateArgumentList *Args =
10735 DeductionFailure.getTemplateArgumentList()) {
10736 TemplateArgString = " ";
10737 TemplateArgString += S.getTemplateArgumentBindingsText(
10738 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10739 if (TemplateArgString.size() == 1)
10740 TemplateArgString.clear();
10741 }
10742
10743 // If this candidate was disabled by enable_if, say so.
10744 PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic();
10745 if (PDiag && PDiag->second.getDiagID() ==
10746 diag::err_typename_nested_not_found_enable_if) {
10747 // FIXME: Use the source range of the condition, and the fully-qualified
10748 // name of the enable_if template. These are both present in PDiag.
10749 S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if)
10750 << "'enable_if'" << TemplateArgString;
10751 return;
10752 }
10753
10754 // We found a specific requirement that disabled the enable_if.
10755 if (PDiag && PDiag->second.getDiagID() ==
10756 diag::err_typename_nested_not_found_requirement) {
10757 S.Diag(Templated->getLocation(),
10758 diag::note_ovl_candidate_disabled_by_requirement)
10759 << PDiag->second.getStringArg(0) << TemplateArgString;
10760 return;
10761 }
10762
10763 // Format the SFINAE diagnostic into the argument string.
10764 // FIXME: Add a general mechanism to include a PartialDiagnostic *'s
10765 // formatted message in another diagnostic.
10766 SmallString<128> SFINAEArgString;
10767 SourceRange R;
10768 if (PDiag) {
10769 SFINAEArgString = ": ";
10770 R = SourceRange(PDiag->first, PDiag->first);
10771 PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
10772 }
10773
10774 S.Diag(Templated->getLocation(),
10775 diag::note_ovl_candidate_substitution_failure)
10776 << TemplateArgString << SFINAEArgString << R;
10777 MaybeEmitInheritedConstructorNote(S, Found);
10778 return;
10779 }
10780
10781 case Sema::TDK_DeducedMismatch:
10782 case Sema::TDK_DeducedMismatchNested: {
10783 // Format the template argument list into the argument string.
10784 SmallString<128> TemplateArgString;
10785 if (TemplateArgumentList *Args =
10786 DeductionFailure.getTemplateArgumentList()) {
10787 TemplateArgString = " ";
10788 TemplateArgString += S.getTemplateArgumentBindingsText(
10789 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10790 if (TemplateArgString.size() == 1)
10791 TemplateArgString.clear();
10792 }
10793
10794 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch)
10795 << (*DeductionFailure.getCallArgIndex() + 1)
10796 << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg()
10797 << TemplateArgString
10798 << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested);
10799 break;
10800 }
10801
10802 case Sema::TDK_NonDeducedMismatch: {
10803 // FIXME: Provide a source location to indicate what we couldn't match.
10804 TemplateArgument FirstTA = *DeductionFailure.getFirstArg();
10805 TemplateArgument SecondTA = *DeductionFailure.getSecondArg();
10806 if (FirstTA.getKind() == TemplateArgument::Template &&
10807 SecondTA.getKind() == TemplateArgument::Template) {
10808 TemplateName FirstTN = FirstTA.getAsTemplate();
10809 TemplateName SecondTN = SecondTA.getAsTemplate();
10810 if (FirstTN.getKind() == TemplateName::Template &&
10811 SecondTN.getKind() == TemplateName::Template) {
10812 if (FirstTN.getAsTemplateDecl()->getName() ==
10813 SecondTN.getAsTemplateDecl()->getName()) {
10814 // FIXME: This fixes a bad diagnostic where both templates are named
10815 // the same. This particular case is a bit difficult since:
10816 // 1) It is passed as a string to the diagnostic printer.
10817 // 2) The diagnostic printer only attempts to find a better
10818 // name for types, not decls.
10819 // Ideally, this should folded into the diagnostic printer.
10820 S.Diag(Templated->getLocation(),
10821 diag::note_ovl_candidate_non_deduced_mismatch_qualified)
10822 << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl();
10823 return;
10824 }
10825 }
10826 }
10827
10828 if (TakingCandidateAddress && isa<FunctionDecl>(Templated) &&
10829 !checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated)))
10830 return;
10831
10832 // FIXME: For generic lambda parameters, check if the function is a lambda
10833 // call operator, and if so, emit a prettier and more informative
10834 // diagnostic that mentions 'auto' and lambda in addition to
10835 // (or instead of?) the canonical template type parameters.
10836 S.Diag(Templated->getLocation(),
10837 diag::note_ovl_candidate_non_deduced_mismatch)
10838 << FirstTA << SecondTA;
10839 return;
10840 }
10841 // TODO: diagnose these individually, then kill off
10842 // note_ovl_candidate_bad_deduction, which is uselessly vague.
10843 case Sema::TDK_MiscellaneousDeductionFailure:
10844 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction);
10845 MaybeEmitInheritedConstructorNote(S, Found);
10846 return;
10847 case Sema::TDK_CUDATargetMismatch:
10848 S.Diag(Templated->getLocation(),
10849 diag::note_cuda_ovl_candidate_target_mismatch);
10850 return;
10851 }
10852 }
10853
10854 /// Diagnose a failed template-argument deduction, for function calls.
DiagnoseBadDeduction(Sema & S,OverloadCandidate * Cand,unsigned NumArgs,bool TakingCandidateAddress)10855 static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand,
10856 unsigned NumArgs,
10857 bool TakingCandidateAddress) {
10858 unsigned TDK = Cand->DeductionFailure.Result;
10859 if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) {
10860 if (CheckArityMismatch(S, Cand, NumArgs))
10861 return;
10862 }
10863 DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern
10864 Cand->DeductionFailure, NumArgs, TakingCandidateAddress);
10865 }
10866
10867 /// CUDA: diagnose an invalid call across targets.
DiagnoseBadTarget(Sema & S,OverloadCandidate * Cand)10868 static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) {
10869 FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext);
10870 FunctionDecl *Callee = Cand->Function;
10871
10872 Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller),
10873 CalleeTarget = S.IdentifyCUDATarget(Callee);
10874
10875 std::string FnDesc;
10876 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
10877 ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee,
10878 Cand->getRewriteKind(), FnDesc);
10879
10880 S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target)
10881 << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
10882 << FnDesc /* Ignored */
10883 << CalleeTarget << CallerTarget;
10884
10885 // This could be an implicit constructor for which we could not infer the
10886 // target due to a collsion. Diagnose that case.
10887 CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee);
10888 if (Meth != nullptr && Meth->isImplicit()) {
10889 CXXRecordDecl *ParentClass = Meth->getParent();
10890 Sema::CXXSpecialMember CSM;
10891
10892 switch (FnKindPair.first) {
10893 default:
10894 return;
10895 case oc_implicit_default_constructor:
10896 CSM = Sema::CXXDefaultConstructor;
10897 break;
10898 case oc_implicit_copy_constructor:
10899 CSM = Sema::CXXCopyConstructor;
10900 break;
10901 case oc_implicit_move_constructor:
10902 CSM = Sema::CXXMoveConstructor;
10903 break;
10904 case oc_implicit_copy_assignment:
10905 CSM = Sema::CXXCopyAssignment;
10906 break;
10907 case oc_implicit_move_assignment:
10908 CSM = Sema::CXXMoveAssignment;
10909 break;
10910 };
10911
10912 bool ConstRHS = false;
10913 if (Meth->getNumParams()) {
10914 if (const ReferenceType *RT =
10915 Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) {
10916 ConstRHS = RT->getPointeeType().isConstQualified();
10917 }
10918 }
10919
10920 S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth,
10921 /* ConstRHS */ ConstRHS,
10922 /* Diagnose */ true);
10923 }
10924 }
10925
DiagnoseFailedEnableIfAttr(Sema & S,OverloadCandidate * Cand)10926 static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) {
10927 FunctionDecl *Callee = Cand->Function;
10928 EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data);
10929
10930 S.Diag(Callee->getLocation(),
10931 diag::note_ovl_candidate_disabled_by_function_cond_attr)
10932 << Attr->getCond()->getSourceRange() << Attr->getMessage();
10933 }
10934
DiagnoseFailedExplicitSpec(Sema & S,OverloadCandidate * Cand)10935 static void DiagnoseFailedExplicitSpec(Sema &S, OverloadCandidate *Cand) {
10936 ExplicitSpecifier ES = ExplicitSpecifier::getFromDecl(Cand->Function);
10937 assert(ES.isExplicit() && "not an explicit candidate");
10938
10939 unsigned Kind;
10940 switch (Cand->Function->getDeclKind()) {
10941 case Decl::Kind::CXXConstructor:
10942 Kind = 0;
10943 break;
10944 case Decl::Kind::CXXConversion:
10945 Kind = 1;
10946 break;
10947 case Decl::Kind::CXXDeductionGuide:
10948 Kind = Cand->Function->isImplicit() ? 0 : 2;
10949 break;
10950 default:
10951 llvm_unreachable("invalid Decl");
10952 }
10953
10954 // Note the location of the first (in-class) declaration; a redeclaration
10955 // (particularly an out-of-class definition) will typically lack the
10956 // 'explicit' specifier.
10957 // FIXME: This is probably a good thing to do for all 'candidate' notes.
10958 FunctionDecl *First = Cand->Function->getFirstDecl();
10959 if (FunctionDecl *Pattern = First->getTemplateInstantiationPattern())
10960 First = Pattern->getFirstDecl();
10961
10962 S.Diag(First->getLocation(),
10963 diag::note_ovl_candidate_explicit)
10964 << Kind << (ES.getExpr() ? 1 : 0)
10965 << (ES.getExpr() ? ES.getExpr()->getSourceRange() : SourceRange());
10966 }
10967
DiagnoseOpenCLExtensionDisabled(Sema & S,OverloadCandidate * Cand)10968 static void DiagnoseOpenCLExtensionDisabled(Sema &S, OverloadCandidate *Cand) {
10969 FunctionDecl *Callee = Cand->Function;
10970
10971 S.Diag(Callee->getLocation(),
10972 diag::note_ovl_candidate_disabled_by_extension)
10973 << S.getOpenCLExtensionsFromDeclExtMap(Callee);
10974 }
10975
10976 /// Generates a 'note' diagnostic for an overload candidate. We've
10977 /// already generated a primary error at the call site.
10978 ///
10979 /// It really does need to be a single diagnostic with its caret
10980 /// pointed at the candidate declaration. Yes, this creates some
10981 /// major challenges of technical writing. Yes, this makes pointing
10982 /// out problems with specific arguments quite awkward. It's still
10983 /// better than generating twenty screens of text for every failed
10984 /// overload.
10985 ///
10986 /// It would be great to be able to express per-candidate problems
10987 /// more richly for those diagnostic clients that cared, but we'd
10988 /// still have to be just as careful with the default diagnostics.
10989 /// \param CtorDestAS Addr space of object being constructed (for ctor
10990 /// candidates only).
NoteFunctionCandidate(Sema & S,OverloadCandidate * Cand,unsigned NumArgs,bool TakingCandidateAddress,LangAS CtorDestAS=LangAS::Default)10991 static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
10992 unsigned NumArgs,
10993 bool TakingCandidateAddress,
10994 LangAS CtorDestAS = LangAS::Default) {
10995 FunctionDecl *Fn = Cand->Function;
10996
10997 // Note deleted candidates, but only if they're viable.
10998 if (Cand->Viable) {
10999 if (Fn->isDeleted()) {
11000 std::string FnDesc;
11001 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
11002 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
11003 Cand->getRewriteKind(), FnDesc);
11004
11005 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted)
11006 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
11007 << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0);
11008 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11009 return;
11010 }
11011
11012 // We don't really have anything else to say about viable candidates.
11013 S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11014 return;
11015 }
11016
11017 switch (Cand->FailureKind) {
11018 case ovl_fail_too_many_arguments:
11019 case ovl_fail_too_few_arguments:
11020 return DiagnoseArityMismatch(S, Cand, NumArgs);
11021
11022 case ovl_fail_bad_deduction:
11023 return DiagnoseBadDeduction(S, Cand, NumArgs,
11024 TakingCandidateAddress);
11025
11026 case ovl_fail_illegal_constructor: {
11027 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor)
11028 << (Fn->getPrimaryTemplate() ? 1 : 0);
11029 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11030 return;
11031 }
11032
11033 case ovl_fail_object_addrspace_mismatch: {
11034 Qualifiers QualsForPrinting;
11035 QualsForPrinting.setAddressSpace(CtorDestAS);
11036 S.Diag(Fn->getLocation(),
11037 diag::note_ovl_candidate_illegal_constructor_adrspace_mismatch)
11038 << QualsForPrinting;
11039 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11040 return;
11041 }
11042
11043 case ovl_fail_trivial_conversion:
11044 case ovl_fail_bad_final_conversion:
11045 case ovl_fail_final_conversion_not_exact:
11046 return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11047
11048 case ovl_fail_bad_conversion: {
11049 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0);
11050 for (unsigned N = Cand->Conversions.size(); I != N; ++I)
11051 if (Cand->Conversions[I].isBad())
11052 return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress);
11053
11054 // FIXME: this currently happens when we're called from SemaInit
11055 // when user-conversion overload fails. Figure out how to handle
11056 // those conditions and diagnose them well.
11057 return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11058 }
11059
11060 case ovl_fail_bad_target:
11061 return DiagnoseBadTarget(S, Cand);
11062
11063 case ovl_fail_enable_if:
11064 return DiagnoseFailedEnableIfAttr(S, Cand);
11065
11066 case ovl_fail_explicit:
11067 return DiagnoseFailedExplicitSpec(S, Cand);
11068
11069 case ovl_fail_ext_disabled:
11070 return DiagnoseOpenCLExtensionDisabled(S, Cand);
11071
11072 case ovl_fail_inhctor_slice:
11073 // It's generally not interesting to note copy/move constructors here.
11074 if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor())
11075 return;
11076 S.Diag(Fn->getLocation(),
11077 diag::note_ovl_candidate_inherited_constructor_slice)
11078 << (Fn->getPrimaryTemplate() ? 1 : 0)
11079 << Fn->getParamDecl(0)->getType()->isRValueReferenceType();
11080 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11081 return;
11082
11083 case ovl_fail_addr_not_available: {
11084 bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function);
11085 (void)Available;
11086 assert(!Available);
11087 break;
11088 }
11089 case ovl_non_default_multiversion_function:
11090 // Do nothing, these should simply be ignored.
11091 break;
11092
11093 case ovl_fail_constraints_not_satisfied: {
11094 std::string FnDesc;
11095 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
11096 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
11097 Cand->getRewriteKind(), FnDesc);
11098
11099 S.Diag(Fn->getLocation(),
11100 diag::note_ovl_candidate_constraints_not_satisfied)
11101 << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
11102 << FnDesc /* Ignored */;
11103 ConstraintSatisfaction Satisfaction;
11104 if (S.CheckFunctionConstraints(Fn, Satisfaction))
11105 break;
11106 S.DiagnoseUnsatisfiedConstraint(Satisfaction);
11107 }
11108 }
11109 }
11110
NoteSurrogateCandidate(Sema & S,OverloadCandidate * Cand)11111 static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) {
11112 // Desugar the type of the surrogate down to a function type,
11113 // retaining as many typedefs as possible while still showing
11114 // the function type (and, therefore, its parameter types).
11115 QualType FnType = Cand->Surrogate->getConversionType();
11116 bool isLValueReference = false;
11117 bool isRValueReference = false;
11118 bool isPointer = false;
11119 if (const LValueReferenceType *FnTypeRef =
11120 FnType->getAs<LValueReferenceType>()) {
11121 FnType = FnTypeRef->getPointeeType();
11122 isLValueReference = true;
11123 } else if (const RValueReferenceType *FnTypeRef =
11124 FnType->getAs<RValueReferenceType>()) {
11125 FnType = FnTypeRef->getPointeeType();
11126 isRValueReference = true;
11127 }
11128 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) {
11129 FnType = FnTypePtr->getPointeeType();
11130 isPointer = true;
11131 }
11132 // Desugar down to a function type.
11133 FnType = QualType(FnType->getAs<FunctionType>(), 0);
11134 // Reconstruct the pointer/reference as appropriate.
11135 if (isPointer) FnType = S.Context.getPointerType(FnType);
11136 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType);
11137 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType);
11138
11139 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand)
11140 << FnType;
11141 }
11142
NoteBuiltinOperatorCandidate(Sema & S,StringRef Opc,SourceLocation OpLoc,OverloadCandidate * Cand)11143 static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc,
11144 SourceLocation OpLoc,
11145 OverloadCandidate *Cand) {
11146 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary");
11147 std::string TypeStr("operator");
11148 TypeStr += Opc;
11149 TypeStr += "(";
11150 TypeStr += Cand->BuiltinParamTypes[0].getAsString();
11151 if (Cand->Conversions.size() == 1) {
11152 TypeStr += ")";
11153 S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
11154 } else {
11155 TypeStr += ", ";
11156 TypeStr += Cand->BuiltinParamTypes[1].getAsString();
11157 TypeStr += ")";
11158 S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
11159 }
11160 }
11161
NoteAmbiguousUserConversions(Sema & S,SourceLocation OpLoc,OverloadCandidate * Cand)11162 static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc,
11163 OverloadCandidate *Cand) {
11164 for (const ImplicitConversionSequence &ICS : Cand->Conversions) {
11165 if (ICS.isBad()) break; // all meaningless after first invalid
11166 if (!ICS.isAmbiguous()) continue;
11167
11168 ICS.DiagnoseAmbiguousConversion(
11169 S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion));
11170 }
11171 }
11172
GetLocationForCandidate(const OverloadCandidate * Cand)11173 static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) {
11174 if (Cand->Function)
11175 return Cand->Function->getLocation();
11176 if (Cand->IsSurrogate)
11177 return Cand->Surrogate->getLocation();
11178 return SourceLocation();
11179 }
11180
RankDeductionFailure(const DeductionFailureInfo & DFI)11181 static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) {
11182 switch ((Sema::TemplateDeductionResult)DFI.Result) {
11183 case Sema::TDK_Success:
11184 case Sema::TDK_NonDependentConversionFailure:
11185 llvm_unreachable("non-deduction failure while diagnosing bad deduction");
11186
11187 case Sema::TDK_Invalid:
11188 case Sema::TDK_Incomplete:
11189 case Sema::TDK_IncompletePack:
11190 return 1;
11191
11192 case Sema::TDK_Underqualified:
11193 case Sema::TDK_Inconsistent:
11194 return 2;
11195
11196 case Sema::TDK_SubstitutionFailure:
11197 case Sema::TDK_DeducedMismatch:
11198 case Sema::TDK_ConstraintsNotSatisfied:
11199 case Sema::TDK_DeducedMismatchNested:
11200 case Sema::TDK_NonDeducedMismatch:
11201 case Sema::TDK_MiscellaneousDeductionFailure:
11202 case Sema::TDK_CUDATargetMismatch:
11203 return 3;
11204
11205 case Sema::TDK_InstantiationDepth:
11206 return 4;
11207
11208 case Sema::TDK_InvalidExplicitArguments:
11209 return 5;
11210
11211 case Sema::TDK_TooManyArguments:
11212 case Sema::TDK_TooFewArguments:
11213 return 6;
11214 }
11215 llvm_unreachable("Unhandled deduction result");
11216 }
11217
11218 namespace {
11219 struct CompareOverloadCandidatesForDisplay {
11220 Sema &S;
11221 SourceLocation Loc;
11222 size_t NumArgs;
11223 OverloadCandidateSet::CandidateSetKind CSK;
11224
CompareOverloadCandidatesForDisplay__anon5fe2f31f1811::CompareOverloadCandidatesForDisplay11225 CompareOverloadCandidatesForDisplay(
11226 Sema &S, SourceLocation Loc, size_t NArgs,
11227 OverloadCandidateSet::CandidateSetKind CSK)
11228 : S(S), NumArgs(NArgs), CSK(CSK) {}
11229
EffectiveFailureKind__anon5fe2f31f1811::CompareOverloadCandidatesForDisplay11230 OverloadFailureKind EffectiveFailureKind(const OverloadCandidate *C) const {
11231 // If there are too many or too few arguments, that's the high-order bit we
11232 // want to sort by, even if the immediate failure kind was something else.
11233 if (C->FailureKind == ovl_fail_too_many_arguments ||
11234 C->FailureKind == ovl_fail_too_few_arguments)
11235 return static_cast<OverloadFailureKind>(C->FailureKind);
11236
11237 if (C->Function) {
11238 if (NumArgs > C->Function->getNumParams() && !C->Function->isVariadic())
11239 return ovl_fail_too_many_arguments;
11240 if (NumArgs < C->Function->getMinRequiredArguments())
11241 return ovl_fail_too_few_arguments;
11242 }
11243
11244 return static_cast<OverloadFailureKind>(C->FailureKind);
11245 }
11246
operator ()__anon5fe2f31f1811::CompareOverloadCandidatesForDisplay11247 bool operator()(const OverloadCandidate *L,
11248 const OverloadCandidate *R) {
11249 // Fast-path this check.
11250 if (L == R) return false;
11251
11252 // Order first by viability.
11253 if (L->Viable) {
11254 if (!R->Viable) return true;
11255
11256 // TODO: introduce a tri-valued comparison for overload
11257 // candidates. Would be more worthwhile if we had a sort
11258 // that could exploit it.
11259 if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK))
11260 return true;
11261 if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK))
11262 return false;
11263 } else if (R->Viable)
11264 return false;
11265
11266 assert(L->Viable == R->Viable);
11267
11268 // Criteria by which we can sort non-viable candidates:
11269 if (!L->Viable) {
11270 OverloadFailureKind LFailureKind = EffectiveFailureKind(L);
11271 OverloadFailureKind RFailureKind = EffectiveFailureKind(R);
11272
11273 // 1. Arity mismatches come after other candidates.
11274 if (LFailureKind == ovl_fail_too_many_arguments ||
11275 LFailureKind == ovl_fail_too_few_arguments) {
11276 if (RFailureKind == ovl_fail_too_many_arguments ||
11277 RFailureKind == ovl_fail_too_few_arguments) {
11278 int LDist = std::abs((int)L->getNumParams() - (int)NumArgs);
11279 int RDist = std::abs((int)R->getNumParams() - (int)NumArgs);
11280 if (LDist == RDist) {
11281 if (LFailureKind == RFailureKind)
11282 // Sort non-surrogates before surrogates.
11283 return !L->IsSurrogate && R->IsSurrogate;
11284 // Sort candidates requiring fewer parameters than there were
11285 // arguments given after candidates requiring more parameters
11286 // than there were arguments given.
11287 return LFailureKind == ovl_fail_too_many_arguments;
11288 }
11289 return LDist < RDist;
11290 }
11291 return false;
11292 }
11293 if (RFailureKind == ovl_fail_too_many_arguments ||
11294 RFailureKind == ovl_fail_too_few_arguments)
11295 return true;
11296
11297 // 2. Bad conversions come first and are ordered by the number
11298 // of bad conversions and quality of good conversions.
11299 if (LFailureKind == ovl_fail_bad_conversion) {
11300 if (RFailureKind != ovl_fail_bad_conversion)
11301 return true;
11302
11303 // The conversion that can be fixed with a smaller number of changes,
11304 // comes first.
11305 unsigned numLFixes = L->Fix.NumConversionsFixed;
11306 unsigned numRFixes = R->Fix.NumConversionsFixed;
11307 numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes;
11308 numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes;
11309 if (numLFixes != numRFixes) {
11310 return numLFixes < numRFixes;
11311 }
11312
11313 // If there's any ordering between the defined conversions...
11314 // FIXME: this might not be transitive.
11315 assert(L->Conversions.size() == R->Conversions.size());
11316
11317 int leftBetter = 0;
11318 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument);
11319 for (unsigned E = L->Conversions.size(); I != E; ++I) {
11320 switch (CompareImplicitConversionSequences(S, Loc,
11321 L->Conversions[I],
11322 R->Conversions[I])) {
11323 case ImplicitConversionSequence::Better:
11324 leftBetter++;
11325 break;
11326
11327 case ImplicitConversionSequence::Worse:
11328 leftBetter--;
11329 break;
11330
11331 case ImplicitConversionSequence::Indistinguishable:
11332 break;
11333 }
11334 }
11335 if (leftBetter > 0) return true;
11336 if (leftBetter < 0) return false;
11337
11338 } else if (RFailureKind == ovl_fail_bad_conversion)
11339 return false;
11340
11341 if (LFailureKind == ovl_fail_bad_deduction) {
11342 if (RFailureKind != ovl_fail_bad_deduction)
11343 return true;
11344
11345 if (L->DeductionFailure.Result != R->DeductionFailure.Result)
11346 return RankDeductionFailure(L->DeductionFailure)
11347 < RankDeductionFailure(R->DeductionFailure);
11348 } else if (RFailureKind == ovl_fail_bad_deduction)
11349 return false;
11350
11351 // TODO: others?
11352 }
11353
11354 // Sort everything else by location.
11355 SourceLocation LLoc = GetLocationForCandidate(L);
11356 SourceLocation RLoc = GetLocationForCandidate(R);
11357
11358 // Put candidates without locations (e.g. builtins) at the end.
11359 if (LLoc.isInvalid()) return false;
11360 if (RLoc.isInvalid()) return true;
11361
11362 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
11363 }
11364 };
11365 }
11366
11367 /// CompleteNonViableCandidate - Normally, overload resolution only
11368 /// computes up to the first bad conversion. Produces the FixIt set if
11369 /// possible.
11370 static void
CompleteNonViableCandidate(Sema & S,OverloadCandidate * Cand,ArrayRef<Expr * > Args,OverloadCandidateSet::CandidateSetKind CSK)11371 CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand,
11372 ArrayRef<Expr *> Args,
11373 OverloadCandidateSet::CandidateSetKind CSK) {
11374 assert(!Cand->Viable);
11375
11376 // Don't do anything on failures other than bad conversion.
11377 if (Cand->FailureKind != ovl_fail_bad_conversion)
11378 return;
11379
11380 // We only want the FixIts if all the arguments can be corrected.
11381 bool Unfixable = false;
11382 // Use a implicit copy initialization to check conversion fixes.
11383 Cand->Fix.setConversionChecker(TryCopyInitialization);
11384
11385 // Attempt to fix the bad conversion.
11386 unsigned ConvCount = Cand->Conversions.size();
11387 for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/;
11388 ++ConvIdx) {
11389 assert(ConvIdx != ConvCount && "no bad conversion in candidate");
11390 if (Cand->Conversions[ConvIdx].isInitialized() &&
11391 Cand->Conversions[ConvIdx].isBad()) {
11392 Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
11393 break;
11394 }
11395 }
11396
11397 // FIXME: this should probably be preserved from the overload
11398 // operation somehow.
11399 bool SuppressUserConversions = false;
11400
11401 unsigned ConvIdx = 0;
11402 unsigned ArgIdx = 0;
11403 ArrayRef<QualType> ParamTypes;
11404 bool Reversed = Cand->isReversed();
11405
11406 if (Cand->IsSurrogate) {
11407 QualType ConvType
11408 = Cand->Surrogate->getConversionType().getNonReferenceType();
11409 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
11410 ConvType = ConvPtrType->getPointeeType();
11411 ParamTypes = ConvType->castAs<FunctionProtoType>()->getParamTypes();
11412 // Conversion 0 is 'this', which doesn't have a corresponding parameter.
11413 ConvIdx = 1;
11414 } else if (Cand->Function) {
11415 ParamTypes =
11416 Cand->Function->getType()->castAs<FunctionProtoType>()->getParamTypes();
11417 if (isa<CXXMethodDecl>(Cand->Function) &&
11418 !isa<CXXConstructorDecl>(Cand->Function) && !Reversed) {
11419 // Conversion 0 is 'this', which doesn't have a corresponding parameter.
11420 ConvIdx = 1;
11421 if (CSK == OverloadCandidateSet::CSK_Operator &&
11422 Cand->Function->getDeclName().getCXXOverloadedOperator() != OO_Call)
11423 // Argument 0 is 'this', which doesn't have a corresponding parameter.
11424 ArgIdx = 1;
11425 }
11426 } else {
11427 // Builtin operator.
11428 assert(ConvCount <= 3);
11429 ParamTypes = Cand->BuiltinParamTypes;
11430 }
11431
11432 // Fill in the rest of the conversions.
11433 for (unsigned ParamIdx = Reversed ? ParamTypes.size() - 1 : 0;
11434 ConvIdx != ConvCount;
11435 ++ConvIdx, ++ArgIdx, ParamIdx += (Reversed ? -1 : 1)) {
11436 assert(ArgIdx < Args.size() && "no argument for this arg conversion");
11437 if (Cand->Conversions[ConvIdx].isInitialized()) {
11438 // We've already checked this conversion.
11439 } else if (ParamIdx < ParamTypes.size()) {
11440 if (ParamTypes[ParamIdx]->isDependentType())
11441 Cand->Conversions[ConvIdx].setAsIdentityConversion(
11442 Args[ArgIdx]->getType());
11443 else {
11444 Cand->Conversions[ConvIdx] =
11445 TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ParamIdx],
11446 SuppressUserConversions,
11447 /*InOverloadResolution=*/true,
11448 /*AllowObjCWritebackConversion=*/
11449 S.getLangOpts().ObjCAutoRefCount);
11450 // Store the FixIt in the candidate if it exists.
11451 if (!Unfixable && Cand->Conversions[ConvIdx].isBad())
11452 Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
11453 }
11454 } else
11455 Cand->Conversions[ConvIdx].setEllipsis();
11456 }
11457 }
11458
CompleteCandidates(Sema & S,OverloadCandidateDisplayKind OCD,ArrayRef<Expr * > Args,SourceLocation OpLoc,llvm::function_ref<bool (OverloadCandidate &)> Filter)11459 SmallVector<OverloadCandidate *, 32> OverloadCandidateSet::CompleteCandidates(
11460 Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
11461 SourceLocation OpLoc,
11462 llvm::function_ref<bool(OverloadCandidate &)> Filter) {
11463 // Sort the candidates by viability and position. Sorting directly would
11464 // be prohibitive, so we make a set of pointers and sort those.
11465 SmallVector<OverloadCandidate*, 32> Cands;
11466 if (OCD == OCD_AllCandidates) Cands.reserve(size());
11467 for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
11468 if (!Filter(*Cand))
11469 continue;
11470 switch (OCD) {
11471 case OCD_AllCandidates:
11472 if (!Cand->Viable) {
11473 if (!Cand->Function && !Cand->IsSurrogate) {
11474 // This a non-viable builtin candidate. We do not, in general,
11475 // want to list every possible builtin candidate.
11476 continue;
11477 }
11478 CompleteNonViableCandidate(S, Cand, Args, Kind);
11479 }
11480 break;
11481
11482 case OCD_ViableCandidates:
11483 if (!Cand->Viable)
11484 continue;
11485 break;
11486
11487 case OCD_AmbiguousCandidates:
11488 if (!Cand->Best)
11489 continue;
11490 break;
11491 }
11492
11493 Cands.push_back(Cand);
11494 }
11495
11496 llvm::stable_sort(
11497 Cands, CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind));
11498
11499 return Cands;
11500 }
11501
11502 /// When overload resolution fails, prints diagnostic messages containing the
11503 /// 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)11504 void OverloadCandidateSet::NoteCandidates(PartialDiagnosticAt PD,
11505 Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
11506 StringRef Opc, SourceLocation OpLoc,
11507 llvm::function_ref<bool(OverloadCandidate &)> Filter) {
11508
11509 auto Cands = CompleteCandidates(S, OCD, Args, OpLoc, Filter);
11510
11511 S.Diag(PD.first, PD.second);
11512
11513 NoteCandidates(S, Args, Cands, Opc, OpLoc);
11514
11515 if (OCD == OCD_AmbiguousCandidates)
11516 MaybeDiagnoseAmbiguousConstraints(S, {begin(), end()});
11517 }
11518
NoteCandidates(Sema & S,ArrayRef<Expr * > Args,ArrayRef<OverloadCandidate * > Cands,StringRef Opc,SourceLocation OpLoc)11519 void OverloadCandidateSet::NoteCandidates(Sema &S, ArrayRef<Expr *> Args,
11520 ArrayRef<OverloadCandidate *> Cands,
11521 StringRef Opc, SourceLocation OpLoc) {
11522 bool ReportedAmbiguousConversions = false;
11523
11524 const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
11525 unsigned CandsShown = 0;
11526 auto I = Cands.begin(), E = Cands.end();
11527 for (; I != E; ++I) {
11528 OverloadCandidate *Cand = *I;
11529
11530 // Set an arbitrary limit on the number of candidate functions we'll spam
11531 // the user with. FIXME: This limit should depend on details of the
11532 // candidate list.
11533 if (CandsShown >= 4 && ShowOverloads == Ovl_Best) {
11534 break;
11535 }
11536 ++CandsShown;
11537
11538 if (Cand->Function)
11539 NoteFunctionCandidate(S, Cand, Args.size(),
11540 /*TakingCandidateAddress=*/false, DestAS);
11541 else if (Cand->IsSurrogate)
11542 NoteSurrogateCandidate(S, Cand);
11543 else {
11544 assert(Cand->Viable &&
11545 "Non-viable built-in candidates are not added to Cands.");
11546 // Generally we only see ambiguities including viable builtin
11547 // operators if overload resolution got screwed up by an
11548 // ambiguous user-defined conversion.
11549 //
11550 // FIXME: It's quite possible for different conversions to see
11551 // different ambiguities, though.
11552 if (!ReportedAmbiguousConversions) {
11553 NoteAmbiguousUserConversions(S, OpLoc, Cand);
11554 ReportedAmbiguousConversions = true;
11555 }
11556
11557 // If this is a viable builtin, print it.
11558 NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand);
11559 }
11560 }
11561
11562 if (I != E)
11563 S.Diag(OpLoc, diag::note_ovl_too_many_candidates) << int(E - I);
11564 }
11565
11566 static SourceLocation
GetLocationForCandidate(const TemplateSpecCandidate * Cand)11567 GetLocationForCandidate(const TemplateSpecCandidate *Cand) {
11568 return Cand->Specialization ? Cand->Specialization->getLocation()
11569 : SourceLocation();
11570 }
11571
11572 namespace {
11573 struct CompareTemplateSpecCandidatesForDisplay {
11574 Sema &S;
CompareTemplateSpecCandidatesForDisplay__anon5fe2f31f1911::CompareTemplateSpecCandidatesForDisplay11575 CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {}
11576
operator ()__anon5fe2f31f1911::CompareTemplateSpecCandidatesForDisplay11577 bool operator()(const TemplateSpecCandidate *L,
11578 const TemplateSpecCandidate *R) {
11579 // Fast-path this check.
11580 if (L == R)
11581 return false;
11582
11583 // Assuming that both candidates are not matches...
11584
11585 // Sort by the ranking of deduction failures.
11586 if (L->DeductionFailure.Result != R->DeductionFailure.Result)
11587 return RankDeductionFailure(L->DeductionFailure) <
11588 RankDeductionFailure(R->DeductionFailure);
11589
11590 // Sort everything else by location.
11591 SourceLocation LLoc = GetLocationForCandidate(L);
11592 SourceLocation RLoc = GetLocationForCandidate(R);
11593
11594 // Put candidates without locations (e.g. builtins) at the end.
11595 if (LLoc.isInvalid())
11596 return false;
11597 if (RLoc.isInvalid())
11598 return true;
11599
11600 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
11601 }
11602 };
11603 }
11604
11605 /// Diagnose a template argument deduction failure.
11606 /// We are treating these failures as overload failures due to bad
11607 /// deductions.
NoteDeductionFailure(Sema & S,bool ForTakingAddress)11608 void TemplateSpecCandidate::NoteDeductionFailure(Sema &S,
11609 bool ForTakingAddress) {
11610 DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern
11611 DeductionFailure, /*NumArgs=*/0, ForTakingAddress);
11612 }
11613
destroyCandidates()11614 void TemplateSpecCandidateSet::destroyCandidates() {
11615 for (iterator i = begin(), e = end(); i != e; ++i) {
11616 i->DeductionFailure.Destroy();
11617 }
11618 }
11619
clear()11620 void TemplateSpecCandidateSet::clear() {
11621 destroyCandidates();
11622 Candidates.clear();
11623 }
11624
11625 /// NoteCandidates - When no template specialization match is found, prints
11626 /// diagnostic messages containing the non-matching specializations that form
11627 /// the candidate set.
11628 /// This is analoguous to OverloadCandidateSet::NoteCandidates() with
11629 /// OCD == OCD_AllCandidates and Cand->Viable == false.
NoteCandidates(Sema & S,SourceLocation Loc)11630 void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) {
11631 // Sort the candidates by position (assuming no candidate is a match).
11632 // Sorting directly would be prohibitive, so we make a set of pointers
11633 // and sort those.
11634 SmallVector<TemplateSpecCandidate *, 32> Cands;
11635 Cands.reserve(size());
11636 for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
11637 if (Cand->Specialization)
11638 Cands.push_back(Cand);
11639 // Otherwise, this is a non-matching builtin candidate. We do not,
11640 // in general, want to list every possible builtin candidate.
11641 }
11642
11643 llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S));
11644
11645 // FIXME: Perhaps rename OverloadsShown and getShowOverloads()
11646 // for generalization purposes (?).
11647 const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
11648
11649 SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E;
11650 unsigned CandsShown = 0;
11651 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
11652 TemplateSpecCandidate *Cand = *I;
11653
11654 // Set an arbitrary limit on the number of candidates we'll spam
11655 // the user with. FIXME: This limit should depend on details of the
11656 // candidate list.
11657 if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
11658 break;
11659 ++CandsShown;
11660
11661 assert(Cand->Specialization &&
11662 "Non-matching built-in candidates are not added to Cands.");
11663 Cand->NoteDeductionFailure(S, ForTakingAddress);
11664 }
11665
11666 if (I != E)
11667 S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I);
11668 }
11669
11670 // [PossiblyAFunctionType] --> [Return]
11671 // NonFunctionType --> NonFunctionType
11672 // R (A) --> R(A)
11673 // R (*)(A) --> R (A)
11674 // R (&)(A) --> R (A)
11675 // R (S::*)(A) --> R (A)
ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType)11676 QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) {
11677 QualType Ret = PossiblyAFunctionType;
11678 if (const PointerType *ToTypePtr =
11679 PossiblyAFunctionType->getAs<PointerType>())
11680 Ret = ToTypePtr->getPointeeType();
11681 else if (const ReferenceType *ToTypeRef =
11682 PossiblyAFunctionType->getAs<ReferenceType>())
11683 Ret = ToTypeRef->getPointeeType();
11684 else if (const MemberPointerType *MemTypePtr =
11685 PossiblyAFunctionType->getAs<MemberPointerType>())
11686 Ret = MemTypePtr->getPointeeType();
11687 Ret =
11688 Context.getCanonicalType(Ret).getUnqualifiedType();
11689 return Ret;
11690 }
11691
completeFunctionType(Sema & S,FunctionDecl * FD,SourceLocation Loc,bool Complain=true)11692 static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc,
11693 bool Complain = true) {
11694 if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
11695 S.DeduceReturnType(FD, Loc, Complain))
11696 return true;
11697
11698 auto *FPT = FD->getType()->castAs<FunctionProtoType>();
11699 if (S.getLangOpts().CPlusPlus17 &&
11700 isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
11701 !S.ResolveExceptionSpec(Loc, FPT))
11702 return true;
11703
11704 return false;
11705 }
11706
11707 namespace {
11708 // A helper class to help with address of function resolution
11709 // - allows us to avoid passing around all those ugly parameters
11710 class AddressOfFunctionResolver {
11711 Sema& S;
11712 Expr* SourceExpr;
11713 const QualType& TargetType;
11714 QualType TargetFunctionType; // Extracted function type from target type
11715
11716 bool Complain;
11717 //DeclAccessPair& ResultFunctionAccessPair;
11718 ASTContext& Context;
11719
11720 bool TargetTypeIsNonStaticMemberFunction;
11721 bool FoundNonTemplateFunction;
11722 bool StaticMemberFunctionFromBoundPointer;
11723 bool HasComplained;
11724
11725 OverloadExpr::FindResult OvlExprInfo;
11726 OverloadExpr *OvlExpr;
11727 TemplateArgumentListInfo OvlExplicitTemplateArgs;
11728 SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches;
11729 TemplateSpecCandidateSet FailedCandidates;
11730
11731 public:
AddressOfFunctionResolver(Sema & S,Expr * SourceExpr,const QualType & TargetType,bool Complain)11732 AddressOfFunctionResolver(Sema &S, Expr *SourceExpr,
11733 const QualType &TargetType, bool Complain)
11734 : S(S), SourceExpr(SourceExpr), TargetType(TargetType),
11735 Complain(Complain), Context(S.getASTContext()),
11736 TargetTypeIsNonStaticMemberFunction(
11737 !!TargetType->getAs<MemberPointerType>()),
11738 FoundNonTemplateFunction(false),
11739 StaticMemberFunctionFromBoundPointer(false),
11740 HasComplained(false),
11741 OvlExprInfo(OverloadExpr::find(SourceExpr)),
11742 OvlExpr(OvlExprInfo.Expression),
11743 FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) {
11744 ExtractUnqualifiedFunctionTypeFromTargetType();
11745
11746 if (TargetFunctionType->isFunctionType()) {
11747 if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr))
11748 if (!UME->isImplicitAccess() &&
11749 !S.ResolveSingleFunctionTemplateSpecialization(UME))
11750 StaticMemberFunctionFromBoundPointer = true;
11751 } else if (OvlExpr->hasExplicitTemplateArgs()) {
11752 DeclAccessPair dap;
11753 if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization(
11754 OvlExpr, false, &dap)) {
11755 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
11756 if (!Method->isStatic()) {
11757 // If the target type is a non-function type and the function found
11758 // is a non-static member function, pretend as if that was the
11759 // target, it's the only possible type to end up with.
11760 TargetTypeIsNonStaticMemberFunction = true;
11761
11762 // And skip adding the function if its not in the proper form.
11763 // We'll diagnose this due to an empty set of functions.
11764 if (!OvlExprInfo.HasFormOfMemberPointer)
11765 return;
11766 }
11767
11768 Matches.push_back(std::make_pair(dap, Fn));
11769 }
11770 return;
11771 }
11772
11773 if (OvlExpr->hasExplicitTemplateArgs())
11774 OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs);
11775
11776 if (FindAllFunctionsThatMatchTargetTypeExactly()) {
11777 // C++ [over.over]p4:
11778 // If more than one function is selected, [...]
11779 if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) {
11780 if (FoundNonTemplateFunction)
11781 EliminateAllTemplateMatches();
11782 else
11783 EliminateAllExceptMostSpecializedTemplate();
11784 }
11785 }
11786
11787 if (S.getLangOpts().CUDA && Matches.size() > 1)
11788 EliminateSuboptimalCudaMatches();
11789 }
11790
hasComplained() const11791 bool hasComplained() const { return HasComplained; }
11792
11793 private:
candidateHasExactlyCorrectType(const FunctionDecl * FD)11794 bool candidateHasExactlyCorrectType(const FunctionDecl *FD) {
11795 QualType Discard;
11796 return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) ||
11797 S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard);
11798 }
11799
11800 /// \return true if A is considered a better overload candidate for the
11801 /// desired type than B.
isBetterCandidate(const FunctionDecl * A,const FunctionDecl * B)11802 bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) {
11803 // If A doesn't have exactly the correct type, we don't want to classify it
11804 // as "better" than anything else. This way, the user is required to
11805 // disambiguate for us if there are multiple candidates and no exact match.
11806 return candidateHasExactlyCorrectType(A) &&
11807 (!candidateHasExactlyCorrectType(B) ||
11808 compareEnableIfAttrs(S, A, B) == Comparison::Better);
11809 }
11810
11811 /// \return true if we were able to eliminate all but one overload candidate,
11812 /// false otherwise.
eliminiateSuboptimalOverloadCandidates()11813 bool eliminiateSuboptimalOverloadCandidates() {
11814 // Same algorithm as overload resolution -- one pass to pick the "best",
11815 // another pass to be sure that nothing is better than the best.
11816 auto Best = Matches.begin();
11817 for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I)
11818 if (isBetterCandidate(I->second, Best->second))
11819 Best = I;
11820
11821 const FunctionDecl *BestFn = Best->second;
11822 auto IsBestOrInferiorToBest = [this, BestFn](
11823 const std::pair<DeclAccessPair, FunctionDecl *> &Pair) {
11824 return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second);
11825 };
11826
11827 // Note: We explicitly leave Matches unmodified if there isn't a clear best
11828 // option, so we can potentially give the user a better error
11829 if (!llvm::all_of(Matches, IsBestOrInferiorToBest))
11830 return false;
11831 Matches[0] = *Best;
11832 Matches.resize(1);
11833 return true;
11834 }
11835
isTargetTypeAFunction() const11836 bool isTargetTypeAFunction() const {
11837 return TargetFunctionType->isFunctionType();
11838 }
11839
11840 // [ToType] [Return]
11841
11842 // R (*)(A) --> R (A), IsNonStaticMemberFunction = false
11843 // R (&)(A) --> R (A), IsNonStaticMemberFunction = false
11844 // R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true
ExtractUnqualifiedFunctionTypeFromTargetType()11845 void inline ExtractUnqualifiedFunctionTypeFromTargetType() {
11846 TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType);
11847 }
11848
11849 // return true if any matching specializations were found
AddMatchingTemplateFunction(FunctionTemplateDecl * FunctionTemplate,const DeclAccessPair & CurAccessFunPair)11850 bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate,
11851 const DeclAccessPair& CurAccessFunPair) {
11852 if (CXXMethodDecl *Method
11853 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) {
11854 // Skip non-static function templates when converting to pointer, and
11855 // static when converting to member pointer.
11856 if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
11857 return false;
11858 }
11859 else if (TargetTypeIsNonStaticMemberFunction)
11860 return false;
11861
11862 // C++ [over.over]p2:
11863 // If the name is a function template, template argument deduction is
11864 // done (14.8.2.2), and if the argument deduction succeeds, the
11865 // resulting template argument list is used to generate a single
11866 // function template specialization, which is added to the set of
11867 // overloaded functions considered.
11868 FunctionDecl *Specialization = nullptr;
11869 TemplateDeductionInfo Info(FailedCandidates.getLocation());
11870 if (Sema::TemplateDeductionResult Result
11871 = S.DeduceTemplateArguments(FunctionTemplate,
11872 &OvlExplicitTemplateArgs,
11873 TargetFunctionType, Specialization,
11874 Info, /*IsAddressOfFunction*/true)) {
11875 // Make a note of the failed deduction for diagnostics.
11876 FailedCandidates.addCandidate()
11877 .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(),
11878 MakeDeductionFailureInfo(Context, Result, Info));
11879 return false;
11880 }
11881
11882 // Template argument deduction ensures that we have an exact match or
11883 // compatible pointer-to-function arguments that would be adjusted by ICS.
11884 // This function template specicalization works.
11885 assert(S.isSameOrCompatibleFunctionType(
11886 Context.getCanonicalType(Specialization->getType()),
11887 Context.getCanonicalType(TargetFunctionType)));
11888
11889 if (!S.checkAddressOfFunctionIsAvailable(Specialization))
11890 return false;
11891
11892 Matches.push_back(std::make_pair(CurAccessFunPair, Specialization));
11893 return true;
11894 }
11895
AddMatchingNonTemplateFunction(NamedDecl * Fn,const DeclAccessPair & CurAccessFunPair)11896 bool AddMatchingNonTemplateFunction(NamedDecl* Fn,
11897 const DeclAccessPair& CurAccessFunPair) {
11898 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
11899 // Skip non-static functions when converting to pointer, and static
11900 // when converting to member pointer.
11901 if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
11902 return false;
11903 }
11904 else if (TargetTypeIsNonStaticMemberFunction)
11905 return false;
11906
11907 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) {
11908 if (S.getLangOpts().CUDA)
11909 if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext))
11910 if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl))
11911 return false;
11912 if (FunDecl->isMultiVersion()) {
11913 const auto *TA = FunDecl->getAttr<TargetAttr>();
11914 if (TA && !TA->isDefaultVersion())
11915 return false;
11916 }
11917
11918 // If any candidate has a placeholder return type, trigger its deduction
11919 // now.
11920 if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(),
11921 Complain)) {
11922 HasComplained |= Complain;
11923 return false;
11924 }
11925
11926 if (!S.checkAddressOfFunctionIsAvailable(FunDecl))
11927 return false;
11928
11929 // If we're in C, we need to support types that aren't exactly identical.
11930 if (!S.getLangOpts().CPlusPlus ||
11931 candidateHasExactlyCorrectType(FunDecl)) {
11932 Matches.push_back(std::make_pair(
11933 CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl())));
11934 FoundNonTemplateFunction = true;
11935 return true;
11936 }
11937 }
11938
11939 return false;
11940 }
11941
FindAllFunctionsThatMatchTargetTypeExactly()11942 bool FindAllFunctionsThatMatchTargetTypeExactly() {
11943 bool Ret = false;
11944
11945 // If the overload expression doesn't have the form of a pointer to
11946 // member, don't try to convert it to a pointer-to-member type.
11947 if (IsInvalidFormOfPointerToMemberFunction())
11948 return false;
11949
11950 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
11951 E = OvlExpr->decls_end();
11952 I != E; ++I) {
11953 // Look through any using declarations to find the underlying function.
11954 NamedDecl *Fn = (*I)->getUnderlyingDecl();
11955
11956 // C++ [over.over]p3:
11957 // Non-member functions and static member functions match
11958 // targets of type "pointer-to-function" or "reference-to-function."
11959 // Nonstatic member functions match targets of
11960 // type "pointer-to-member-function."
11961 // Note that according to DR 247, the containing class does not matter.
11962 if (FunctionTemplateDecl *FunctionTemplate
11963 = dyn_cast<FunctionTemplateDecl>(Fn)) {
11964 if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair()))
11965 Ret = true;
11966 }
11967 // If we have explicit template arguments supplied, skip non-templates.
11968 else if (!OvlExpr->hasExplicitTemplateArgs() &&
11969 AddMatchingNonTemplateFunction(Fn, I.getPair()))
11970 Ret = true;
11971 }
11972 assert(Ret || Matches.empty());
11973 return Ret;
11974 }
11975
EliminateAllExceptMostSpecializedTemplate()11976 void EliminateAllExceptMostSpecializedTemplate() {
11977 // [...] and any given function template specialization F1 is
11978 // eliminated if the set contains a second function template
11979 // specialization whose function template is more specialized
11980 // than the function template of F1 according to the partial
11981 // ordering rules of 14.5.5.2.
11982
11983 // The algorithm specified above is quadratic. We instead use a
11984 // two-pass algorithm (similar to the one used to identify the
11985 // best viable function in an overload set) that identifies the
11986 // best function template (if it exists).
11987
11988 UnresolvedSet<4> MatchesCopy; // TODO: avoid!
11989 for (unsigned I = 0, E = Matches.size(); I != E; ++I)
11990 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess());
11991
11992 // TODO: It looks like FailedCandidates does not serve much purpose
11993 // here, since the no_viable diagnostic has index 0.
11994 UnresolvedSetIterator Result = S.getMostSpecialized(
11995 MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates,
11996 SourceExpr->getBeginLoc(), S.PDiag(),
11997 S.PDiag(diag::err_addr_ovl_ambiguous)
11998 << Matches[0].second->getDeclName(),
11999 S.PDiag(diag::note_ovl_candidate)
12000 << (unsigned)oc_function << (unsigned)ocs_described_template,
12001 Complain, TargetFunctionType);
12002
12003 if (Result != MatchesCopy.end()) {
12004 // Make it the first and only element
12005 Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
12006 Matches[0].second = cast<FunctionDecl>(*Result);
12007 Matches.resize(1);
12008 } else
12009 HasComplained |= Complain;
12010 }
12011
EliminateAllTemplateMatches()12012 void EliminateAllTemplateMatches() {
12013 // [...] any function template specializations in the set are
12014 // eliminated if the set also contains a non-template function, [...]
12015 for (unsigned I = 0, N = Matches.size(); I != N; ) {
12016 if (Matches[I].second->getPrimaryTemplate() == nullptr)
12017 ++I;
12018 else {
12019 Matches[I] = Matches[--N];
12020 Matches.resize(N);
12021 }
12022 }
12023 }
12024
EliminateSuboptimalCudaMatches()12025 void EliminateSuboptimalCudaMatches() {
12026 S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches);
12027 }
12028
12029 public:
ComplainNoMatchesFound() const12030 void ComplainNoMatchesFound() const {
12031 assert(Matches.empty());
12032 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable)
12033 << OvlExpr->getName() << TargetFunctionType
12034 << OvlExpr->getSourceRange();
12035 if (FailedCandidates.empty())
12036 S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
12037 /*TakingAddress=*/true);
12038 else {
12039 // We have some deduction failure messages. Use them to diagnose
12040 // the function templates, and diagnose the non-template candidates
12041 // normally.
12042 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
12043 IEnd = OvlExpr->decls_end();
12044 I != IEnd; ++I)
12045 if (FunctionDecl *Fun =
12046 dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()))
12047 if (!functionHasPassObjectSizeParams(Fun))
12048 S.NoteOverloadCandidate(*I, Fun, CRK_None, TargetFunctionType,
12049 /*TakingAddress=*/true);
12050 FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc());
12051 }
12052 }
12053
IsInvalidFormOfPointerToMemberFunction() const12054 bool IsInvalidFormOfPointerToMemberFunction() const {
12055 return TargetTypeIsNonStaticMemberFunction &&
12056 !OvlExprInfo.HasFormOfMemberPointer;
12057 }
12058
ComplainIsInvalidFormOfPointerToMemberFunction() const12059 void ComplainIsInvalidFormOfPointerToMemberFunction() const {
12060 // TODO: Should we condition this on whether any functions might
12061 // have matched, or is it more appropriate to do that in callers?
12062 // TODO: a fixit wouldn't hurt.
12063 S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier)
12064 << TargetType << OvlExpr->getSourceRange();
12065 }
12066
IsStaticMemberFunctionFromBoundPointer() const12067 bool IsStaticMemberFunctionFromBoundPointer() const {
12068 return StaticMemberFunctionFromBoundPointer;
12069 }
12070
ComplainIsStaticMemberFunctionFromBoundPointer() const12071 void ComplainIsStaticMemberFunctionFromBoundPointer() const {
12072 S.Diag(OvlExpr->getBeginLoc(),
12073 diag::err_invalid_form_pointer_member_function)
12074 << OvlExpr->getSourceRange();
12075 }
12076
ComplainOfInvalidConversion() const12077 void ComplainOfInvalidConversion() const {
12078 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref)
12079 << OvlExpr->getName() << TargetType;
12080 }
12081
ComplainMultipleMatchesFound() const12082 void ComplainMultipleMatchesFound() const {
12083 assert(Matches.size() > 1);
12084 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous)
12085 << OvlExpr->getName() << OvlExpr->getSourceRange();
12086 S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
12087 /*TakingAddress=*/true);
12088 }
12089
hadMultipleCandidates() const12090 bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); }
12091
getNumMatches() const12092 int getNumMatches() const { return Matches.size(); }
12093
getMatchingFunctionDecl() const12094 FunctionDecl* getMatchingFunctionDecl() const {
12095 if (Matches.size() != 1) return nullptr;
12096 return Matches[0].second;
12097 }
12098
getMatchingFunctionAccessPair() const12099 const DeclAccessPair* getMatchingFunctionAccessPair() const {
12100 if (Matches.size() != 1) return nullptr;
12101 return &Matches[0].first;
12102 }
12103 };
12104 }
12105
12106 /// ResolveAddressOfOverloadedFunction - Try to resolve the address of
12107 /// an overloaded function (C++ [over.over]), where @p From is an
12108 /// expression with overloaded function type and @p ToType is the type
12109 /// we're trying to resolve to. For example:
12110 ///
12111 /// @code
12112 /// int f(double);
12113 /// int f(int);
12114 ///
12115 /// int (*pfd)(double) = f; // selects f(double)
12116 /// @endcode
12117 ///
12118 /// This routine returns the resulting FunctionDecl if it could be
12119 /// resolved, and NULL otherwise. When @p Complain is true, this
12120 /// routine will emit diagnostics if there is an error.
12121 FunctionDecl *
ResolveAddressOfOverloadedFunction(Expr * AddressOfExpr,QualType TargetType,bool Complain,DeclAccessPair & FoundResult,bool * pHadMultipleCandidates)12122 Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
12123 QualType TargetType,
12124 bool Complain,
12125 DeclAccessPair &FoundResult,
12126 bool *pHadMultipleCandidates) {
12127 assert(AddressOfExpr->getType() == Context.OverloadTy);
12128
12129 AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType,
12130 Complain);
12131 int NumMatches = Resolver.getNumMatches();
12132 FunctionDecl *Fn = nullptr;
12133 bool ShouldComplain = Complain && !Resolver.hasComplained();
12134 if (NumMatches == 0 && ShouldComplain) {
12135 if (Resolver.IsInvalidFormOfPointerToMemberFunction())
12136 Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
12137 else
12138 Resolver.ComplainNoMatchesFound();
12139 }
12140 else if (NumMatches > 1 && ShouldComplain)
12141 Resolver.ComplainMultipleMatchesFound();
12142 else if (NumMatches == 1) {
12143 Fn = Resolver.getMatchingFunctionDecl();
12144 assert(Fn);
12145 if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
12146 ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT);
12147 FoundResult = *Resolver.getMatchingFunctionAccessPair();
12148 if (Complain) {
12149 if (Resolver.IsStaticMemberFunctionFromBoundPointer())
12150 Resolver.ComplainIsStaticMemberFunctionFromBoundPointer();
12151 else
12152 CheckAddressOfMemberAccess(AddressOfExpr, FoundResult);
12153 }
12154 }
12155
12156 if (pHadMultipleCandidates)
12157 *pHadMultipleCandidates = Resolver.hadMultipleCandidates();
12158 return Fn;
12159 }
12160
12161 /// Given an expression that refers to an overloaded function, try to
12162 /// resolve that function to a single function that can have its address taken.
12163 /// This will modify `Pair` iff it returns non-null.
12164 ///
12165 /// This routine can only succeed if from all of the candidates in the overload
12166 /// set for SrcExpr that can have their addresses taken, there is one candidate
12167 /// that is more constrained than the rest.
12168 FunctionDecl *
resolveAddressOfSingleOverloadCandidate(Expr * E,DeclAccessPair & Pair)12169 Sema::resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &Pair) {
12170 OverloadExpr::FindResult R = OverloadExpr::find(E);
12171 OverloadExpr *Ovl = R.Expression;
12172 bool IsResultAmbiguous = false;
12173 FunctionDecl *Result = nullptr;
12174 DeclAccessPair DAP;
12175 SmallVector<FunctionDecl *, 2> AmbiguousDecls;
12176
12177 auto CheckMoreConstrained =
12178 [&] (FunctionDecl *FD1, FunctionDecl *FD2) -> Optional<bool> {
12179 SmallVector<const Expr *, 1> AC1, AC2;
12180 FD1->getAssociatedConstraints(AC1);
12181 FD2->getAssociatedConstraints(AC2);
12182 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
12183 if (IsAtLeastAsConstrained(FD1, AC1, FD2, AC2, AtLeastAsConstrained1))
12184 return None;
12185 if (IsAtLeastAsConstrained(FD2, AC2, FD1, AC1, AtLeastAsConstrained2))
12186 return None;
12187 if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
12188 return None;
12189 return AtLeastAsConstrained1;
12190 };
12191
12192 // Don't use the AddressOfResolver because we're specifically looking for
12193 // cases where we have one overload candidate that lacks
12194 // enable_if/pass_object_size/...
12195 for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
12196 auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
12197 if (!FD)
12198 return nullptr;
12199
12200 if (!checkAddressOfFunctionIsAvailable(FD))
12201 continue;
12202
12203 // We have more than one result - see if it is more constrained than the
12204 // previous one.
12205 if (Result) {
12206 Optional<bool> MoreConstrainedThanPrevious = CheckMoreConstrained(FD,
12207 Result);
12208 if (!MoreConstrainedThanPrevious) {
12209 IsResultAmbiguous = true;
12210 AmbiguousDecls.push_back(FD);
12211 continue;
12212 }
12213 if (!*MoreConstrainedThanPrevious)
12214 continue;
12215 // FD is more constrained - replace Result with it.
12216 }
12217 IsResultAmbiguous = false;
12218 DAP = I.getPair();
12219 Result = FD;
12220 }
12221
12222 if (IsResultAmbiguous)
12223 return nullptr;
12224
12225 if (Result) {
12226 SmallVector<const Expr *, 1> ResultAC;
12227 // We skipped over some ambiguous declarations which might be ambiguous with
12228 // the selected result.
12229 for (FunctionDecl *Skipped : AmbiguousDecls)
12230 if (!CheckMoreConstrained(Skipped, Result).hasValue())
12231 return nullptr;
12232 Pair = DAP;
12233 }
12234 return Result;
12235 }
12236
12237 /// Given an overloaded function, tries to turn it into a non-overloaded
12238 /// function reference using resolveAddressOfSingleOverloadCandidate. This
12239 /// will perform access checks, diagnose the use of the resultant decl, and, if
12240 /// requested, potentially perform a function-to-pointer decay.
12241 ///
12242 /// Returns false if resolveAddressOfSingleOverloadCandidate fails.
12243 /// Otherwise, returns true. This may emit diagnostics and return true.
resolveAndFixAddressOfSingleOverloadCandidate(ExprResult & SrcExpr,bool DoFunctionPointerConverion)12244 bool Sema::resolveAndFixAddressOfSingleOverloadCandidate(
12245 ExprResult &SrcExpr, bool DoFunctionPointerConverion) {
12246 Expr *E = SrcExpr.get();
12247 assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload");
12248
12249 DeclAccessPair DAP;
12250 FunctionDecl *Found = resolveAddressOfSingleOverloadCandidate(E, DAP);
12251 if (!Found || Found->isCPUDispatchMultiVersion() ||
12252 Found->isCPUSpecificMultiVersion())
12253 return false;
12254
12255 // Emitting multiple diagnostics for a function that is both inaccessible and
12256 // unavailable is consistent with our behavior elsewhere. So, always check
12257 // for both.
12258 DiagnoseUseOfDecl(Found, E->getExprLoc());
12259 CheckAddressOfMemberAccess(E, DAP);
12260 Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found);
12261 if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType())
12262 SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
12263 else
12264 SrcExpr = Fixed;
12265 return true;
12266 }
12267
12268 /// Given an expression that refers to an overloaded function, try to
12269 /// resolve that overloaded function expression down to a single function.
12270 ///
12271 /// This routine can only resolve template-ids that refer to a single function
12272 /// template, where that template-id refers to a single template whose template
12273 /// arguments are either provided by the template-id or have defaults,
12274 /// as described in C++0x [temp.arg.explicit]p3.
12275 ///
12276 /// If no template-ids are found, no diagnostics are emitted and NULL is
12277 /// returned.
12278 FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr * ovl,bool Complain,DeclAccessPair * FoundResult)12279 Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
12280 bool Complain,
12281 DeclAccessPair *FoundResult) {
12282 // C++ [over.over]p1:
12283 // [...] [Note: any redundant set of parentheses surrounding the
12284 // overloaded function name is ignored (5.1). ]
12285 // C++ [over.over]p1:
12286 // [...] The overloaded function name can be preceded by the &
12287 // operator.
12288
12289 // If we didn't actually find any template-ids, we're done.
12290 if (!ovl->hasExplicitTemplateArgs())
12291 return nullptr;
12292
12293 TemplateArgumentListInfo ExplicitTemplateArgs;
12294 ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
12295 TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc());
12296
12297 // Look through all of the overloaded functions, searching for one
12298 // whose type matches exactly.
12299 FunctionDecl *Matched = nullptr;
12300 for (UnresolvedSetIterator I = ovl->decls_begin(),
12301 E = ovl->decls_end(); I != E; ++I) {
12302 // C++0x [temp.arg.explicit]p3:
12303 // [...] In contexts where deduction is done and fails, or in contexts
12304 // where deduction is not done, if a template argument list is
12305 // specified and it, along with any default template arguments,
12306 // identifies a single function template specialization, then the
12307 // template-id is an lvalue for the function template specialization.
12308 FunctionTemplateDecl *FunctionTemplate
12309 = cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl());
12310
12311 // C++ [over.over]p2:
12312 // If the name is a function template, template argument deduction is
12313 // done (14.8.2.2), and if the argument deduction succeeds, the
12314 // resulting template argument list is used to generate a single
12315 // function template specialization, which is added to the set of
12316 // overloaded functions considered.
12317 FunctionDecl *Specialization = nullptr;
12318 TemplateDeductionInfo Info(FailedCandidates.getLocation());
12319 if (TemplateDeductionResult Result
12320 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs,
12321 Specialization, Info,
12322 /*IsAddressOfFunction*/true)) {
12323 // Make a note of the failed deduction for diagnostics.
12324 // TODO: Actually use the failed-deduction info?
12325 FailedCandidates.addCandidate()
12326 .set(I.getPair(), FunctionTemplate->getTemplatedDecl(),
12327 MakeDeductionFailureInfo(Context, Result, Info));
12328 continue;
12329 }
12330
12331 assert(Specialization && "no specialization and no error?");
12332
12333 // Multiple matches; we can't resolve to a single declaration.
12334 if (Matched) {
12335 if (Complain) {
12336 Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous)
12337 << ovl->getName();
12338 NoteAllOverloadCandidates(ovl);
12339 }
12340 return nullptr;
12341 }
12342
12343 Matched = Specialization;
12344 if (FoundResult) *FoundResult = I.getPair();
12345 }
12346
12347 if (Matched &&
12348 completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain))
12349 return nullptr;
12350
12351 return Matched;
12352 }
12353
12354 // Resolve and fix an overloaded expression that can be resolved
12355 // because it identifies a single function template specialization.
12356 //
12357 // Last three arguments should only be supplied if Complain = true
12358 //
12359 // Return true if it was logically possible to so resolve the
12360 // expression, regardless of whether or not it succeeded. Always
12361 // returns true if 'complain' is set.
ResolveAndFixSingleFunctionTemplateSpecialization(ExprResult & SrcExpr,bool doFunctionPointerConverion,bool complain,SourceRange OpRangeForComplaining,QualType DestTypeForComplaining,unsigned DiagIDForComplaining)12362 bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization(
12363 ExprResult &SrcExpr, bool doFunctionPointerConverion,
12364 bool complain, SourceRange OpRangeForComplaining,
12365 QualType DestTypeForComplaining,
12366 unsigned DiagIDForComplaining) {
12367 assert(SrcExpr.get()->getType() == Context.OverloadTy);
12368
12369 OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get());
12370
12371 DeclAccessPair found;
12372 ExprResult SingleFunctionExpression;
12373 if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization(
12374 ovl.Expression, /*complain*/ false, &found)) {
12375 if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) {
12376 SrcExpr = ExprError();
12377 return true;
12378 }
12379
12380 // It is only correct to resolve to an instance method if we're
12381 // resolving a form that's permitted to be a pointer to member.
12382 // Otherwise we'll end up making a bound member expression, which
12383 // is illegal in all the contexts we resolve like this.
12384 if (!ovl.HasFormOfMemberPointer &&
12385 isa<CXXMethodDecl>(fn) &&
12386 cast<CXXMethodDecl>(fn)->isInstance()) {
12387 if (!complain) return false;
12388
12389 Diag(ovl.Expression->getExprLoc(),
12390 diag::err_bound_member_function)
12391 << 0 << ovl.Expression->getSourceRange();
12392
12393 // TODO: I believe we only end up here if there's a mix of
12394 // static and non-static candidates (otherwise the expression
12395 // would have 'bound member' type, not 'overload' type).
12396 // Ideally we would note which candidate was chosen and why
12397 // the static candidates were rejected.
12398 SrcExpr = ExprError();
12399 return true;
12400 }
12401
12402 // Fix the expression to refer to 'fn'.
12403 SingleFunctionExpression =
12404 FixOverloadedFunctionReference(SrcExpr.get(), found, fn);
12405
12406 // If desired, do function-to-pointer decay.
12407 if (doFunctionPointerConverion) {
12408 SingleFunctionExpression =
12409 DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get());
12410 if (SingleFunctionExpression.isInvalid()) {
12411 SrcExpr = ExprError();
12412 return true;
12413 }
12414 }
12415 }
12416
12417 if (!SingleFunctionExpression.isUsable()) {
12418 if (complain) {
12419 Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining)
12420 << ovl.Expression->getName()
12421 << DestTypeForComplaining
12422 << OpRangeForComplaining
12423 << ovl.Expression->getQualifierLoc().getSourceRange();
12424 NoteAllOverloadCandidates(SrcExpr.get());
12425
12426 SrcExpr = ExprError();
12427 return true;
12428 }
12429
12430 return false;
12431 }
12432
12433 SrcExpr = SingleFunctionExpression;
12434 return true;
12435 }
12436
12437 /// Add a single candidate to the overload set.
AddOverloadedCallCandidate(Sema & S,DeclAccessPair FoundDecl,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool PartialOverloading,bool KnownValid)12438 static void AddOverloadedCallCandidate(Sema &S,
12439 DeclAccessPair FoundDecl,
12440 TemplateArgumentListInfo *ExplicitTemplateArgs,
12441 ArrayRef<Expr *> Args,
12442 OverloadCandidateSet &CandidateSet,
12443 bool PartialOverloading,
12444 bool KnownValid) {
12445 NamedDecl *Callee = FoundDecl.getDecl();
12446 if (isa<UsingShadowDecl>(Callee))
12447 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl();
12448
12449 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) {
12450 if (ExplicitTemplateArgs) {
12451 assert(!KnownValid && "Explicit template arguments?");
12452 return;
12453 }
12454 // Prevent ill-formed function decls to be added as overload candidates.
12455 if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>()))
12456 return;
12457
12458 S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet,
12459 /*SuppressUserConversions=*/false,
12460 PartialOverloading);
12461 return;
12462 }
12463
12464 if (FunctionTemplateDecl *FuncTemplate
12465 = dyn_cast<FunctionTemplateDecl>(Callee)) {
12466 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl,
12467 ExplicitTemplateArgs, Args, CandidateSet,
12468 /*SuppressUserConversions=*/false,
12469 PartialOverloading);
12470 return;
12471 }
12472
12473 assert(!KnownValid && "unhandled case in overloaded call candidate");
12474 }
12475
12476 /// Add the overload candidates named by callee and/or found by argument
12477 /// dependent lookup to the given overload set.
AddOverloadedCallCandidates(UnresolvedLookupExpr * ULE,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool PartialOverloading)12478 void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
12479 ArrayRef<Expr *> Args,
12480 OverloadCandidateSet &CandidateSet,
12481 bool PartialOverloading) {
12482
12483 #ifndef NDEBUG
12484 // Verify that ArgumentDependentLookup is consistent with the rules
12485 // in C++0x [basic.lookup.argdep]p3:
12486 //
12487 // Let X be the lookup set produced by unqualified lookup (3.4.1)
12488 // and let Y be the lookup set produced by argument dependent
12489 // lookup (defined as follows). If X contains
12490 //
12491 // -- a declaration of a class member, or
12492 //
12493 // -- a block-scope function declaration that is not a
12494 // using-declaration, or
12495 //
12496 // -- a declaration that is neither a function or a function
12497 // template
12498 //
12499 // then Y is empty.
12500
12501 if (ULE->requiresADL()) {
12502 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
12503 E = ULE->decls_end(); I != E; ++I) {
12504 assert(!(*I)->getDeclContext()->isRecord());
12505 assert(isa<UsingShadowDecl>(*I) ||
12506 !(*I)->getDeclContext()->isFunctionOrMethod());
12507 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate());
12508 }
12509 }
12510 #endif
12511
12512 // It would be nice to avoid this copy.
12513 TemplateArgumentListInfo TABuffer;
12514 TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
12515 if (ULE->hasExplicitTemplateArgs()) {
12516 ULE->copyTemplateArgumentsInto(TABuffer);
12517 ExplicitTemplateArgs = &TABuffer;
12518 }
12519
12520 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
12521 E = ULE->decls_end(); I != E; ++I)
12522 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
12523 CandidateSet, PartialOverloading,
12524 /*KnownValid*/ true);
12525
12526 if (ULE->requiresADL())
12527 AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(),
12528 Args, ExplicitTemplateArgs,
12529 CandidateSet, PartialOverloading);
12530 }
12531
12532 /// Determine whether a declaration with the specified name could be moved into
12533 /// a different namespace.
canBeDeclaredInNamespace(const DeclarationName & Name)12534 static bool canBeDeclaredInNamespace(const DeclarationName &Name) {
12535 switch (Name.getCXXOverloadedOperator()) {
12536 case OO_New: case OO_Array_New:
12537 case OO_Delete: case OO_Array_Delete:
12538 return false;
12539
12540 default:
12541 return true;
12542 }
12543 }
12544
12545 /// Attempt to recover from an ill-formed use of a non-dependent name in a
12546 /// template, where the non-dependent name was declared after the template
12547 /// was defined. This is common in code written for a compilers which do not
12548 /// correctly implement two-stage name lookup.
12549 ///
12550 /// Returns true if a viable candidate was found and a diagnostic was issued.
12551 static bool
DiagnoseTwoPhaseLookup(Sema & SemaRef,SourceLocation FnLoc,const CXXScopeSpec & SS,LookupResult & R,OverloadCandidateSet::CandidateSetKind CSK,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,bool * DoDiagnoseEmptyLookup=nullptr)12552 DiagnoseTwoPhaseLookup(Sema &SemaRef, SourceLocation FnLoc,
12553 const CXXScopeSpec &SS, LookupResult &R,
12554 OverloadCandidateSet::CandidateSetKind CSK,
12555 TemplateArgumentListInfo *ExplicitTemplateArgs,
12556 ArrayRef<Expr *> Args,
12557 bool *DoDiagnoseEmptyLookup = nullptr) {
12558 if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty())
12559 return false;
12560
12561 for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) {
12562 if (DC->isTransparentContext())
12563 continue;
12564
12565 SemaRef.LookupQualifiedName(R, DC);
12566
12567 if (!R.empty()) {
12568 R.suppressDiagnostics();
12569
12570 if (isa<CXXRecordDecl>(DC)) {
12571 // Don't diagnose names we find in classes; we get much better
12572 // diagnostics for these from DiagnoseEmptyLookup.
12573 R.clear();
12574 if (DoDiagnoseEmptyLookup)
12575 *DoDiagnoseEmptyLookup = true;
12576 return false;
12577 }
12578
12579 OverloadCandidateSet Candidates(FnLoc, CSK);
12580 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
12581 AddOverloadedCallCandidate(SemaRef, I.getPair(),
12582 ExplicitTemplateArgs, Args,
12583 Candidates, false, /*KnownValid*/ false);
12584
12585 OverloadCandidateSet::iterator Best;
12586 if (Candidates.BestViableFunction(SemaRef, FnLoc, Best) != OR_Success) {
12587 // No viable functions. Don't bother the user with notes for functions
12588 // which don't work and shouldn't be found anyway.
12589 R.clear();
12590 return false;
12591 }
12592
12593 // Find the namespaces where ADL would have looked, and suggest
12594 // declaring the function there instead.
12595 Sema::AssociatedNamespaceSet AssociatedNamespaces;
12596 Sema::AssociatedClassSet AssociatedClasses;
12597 SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args,
12598 AssociatedNamespaces,
12599 AssociatedClasses);
12600 Sema::AssociatedNamespaceSet SuggestedNamespaces;
12601 if (canBeDeclaredInNamespace(R.getLookupName())) {
12602 DeclContext *Std = SemaRef.getStdNamespace();
12603 for (Sema::AssociatedNamespaceSet::iterator
12604 it = AssociatedNamespaces.begin(),
12605 end = AssociatedNamespaces.end(); it != end; ++it) {
12606 // Never suggest declaring a function within namespace 'std'.
12607 if (Std && Std->Encloses(*it))
12608 continue;
12609
12610 // Never suggest declaring a function within a namespace with a
12611 // reserved name, like __gnu_cxx.
12612 NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it);
12613 if (NS &&
12614 NS->getQualifiedNameAsString().find("__") != std::string::npos)
12615 continue;
12616
12617 SuggestedNamespaces.insert(*it);
12618 }
12619 }
12620
12621 SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup)
12622 << R.getLookupName();
12623 if (SuggestedNamespaces.empty()) {
12624 SemaRef.Diag(Best->Function->getLocation(),
12625 diag::note_not_found_by_two_phase_lookup)
12626 << R.getLookupName() << 0;
12627 } else if (SuggestedNamespaces.size() == 1) {
12628 SemaRef.Diag(Best->Function->getLocation(),
12629 diag::note_not_found_by_two_phase_lookup)
12630 << R.getLookupName() << 1 << *SuggestedNamespaces.begin();
12631 } else {
12632 // FIXME: It would be useful to list the associated namespaces here,
12633 // but the diagnostics infrastructure doesn't provide a way to produce
12634 // a localized representation of a list of items.
12635 SemaRef.Diag(Best->Function->getLocation(),
12636 diag::note_not_found_by_two_phase_lookup)
12637 << R.getLookupName() << 2;
12638 }
12639
12640 // Try to recover by calling this function.
12641 return true;
12642 }
12643
12644 R.clear();
12645 }
12646
12647 return false;
12648 }
12649
12650 /// Attempt to recover from ill-formed use of a non-dependent operator in a
12651 /// template, where the non-dependent operator was declared after the template
12652 /// was defined.
12653 ///
12654 /// Returns true if a viable candidate was found and a diagnostic was issued.
12655 static bool
DiagnoseTwoPhaseOperatorLookup(Sema & SemaRef,OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args)12656 DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op,
12657 SourceLocation OpLoc,
12658 ArrayRef<Expr *> Args) {
12659 DeclarationName OpName =
12660 SemaRef.Context.DeclarationNames.getCXXOperatorName(Op);
12661 LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName);
12662 return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R,
12663 OverloadCandidateSet::CSK_Operator,
12664 /*ExplicitTemplateArgs=*/nullptr, Args);
12665 }
12666
12667 namespace {
12668 class BuildRecoveryCallExprRAII {
12669 Sema &SemaRef;
12670 public:
BuildRecoveryCallExprRAII(Sema & S)12671 BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) {
12672 assert(SemaRef.IsBuildingRecoveryCallExpr == false);
12673 SemaRef.IsBuildingRecoveryCallExpr = true;
12674 }
12675
~BuildRecoveryCallExprRAII()12676 ~BuildRecoveryCallExprRAII() {
12677 SemaRef.IsBuildingRecoveryCallExpr = false;
12678 }
12679 };
12680
12681 }
12682
12683 /// Attempts to recover from a call where no functions were found.
12684 ///
12685 /// Returns true if new candidates were found.
12686 static ExprResult
BuildRecoveryCallExpr(Sema & SemaRef,Scope * S,Expr * Fn,UnresolvedLookupExpr * ULE,SourceLocation LParenLoc,MutableArrayRef<Expr * > Args,SourceLocation RParenLoc,bool EmptyLookup,bool AllowTypoCorrection)12687 BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
12688 UnresolvedLookupExpr *ULE,
12689 SourceLocation LParenLoc,
12690 MutableArrayRef<Expr *> Args,
12691 SourceLocation RParenLoc,
12692 bool EmptyLookup, bool AllowTypoCorrection) {
12693 // Do not try to recover if it is already building a recovery call.
12694 // This stops infinite loops for template instantiations like
12695 //
12696 // template <typename T> auto foo(T t) -> decltype(foo(t)) {}
12697 // template <typename T> auto foo(T t) -> decltype(foo(&t)) {}
12698 //
12699 if (SemaRef.IsBuildingRecoveryCallExpr)
12700 return ExprError();
12701 BuildRecoveryCallExprRAII RCE(SemaRef);
12702
12703 CXXScopeSpec SS;
12704 SS.Adopt(ULE->getQualifierLoc());
12705 SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc();
12706
12707 TemplateArgumentListInfo TABuffer;
12708 TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
12709 if (ULE->hasExplicitTemplateArgs()) {
12710 ULE->copyTemplateArgumentsInto(TABuffer);
12711 ExplicitTemplateArgs = &TABuffer;
12712 }
12713
12714 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(),
12715 Sema::LookupOrdinaryName);
12716 bool DoDiagnoseEmptyLookup = EmptyLookup;
12717 if (!DiagnoseTwoPhaseLookup(
12718 SemaRef, Fn->getExprLoc(), SS, R, OverloadCandidateSet::CSK_Normal,
12719 ExplicitTemplateArgs, Args, &DoDiagnoseEmptyLookup)) {
12720 NoTypoCorrectionCCC NoTypoValidator{};
12721 FunctionCallFilterCCC FunctionCallValidator(SemaRef, Args.size(),
12722 ExplicitTemplateArgs != nullptr,
12723 dyn_cast<MemberExpr>(Fn));
12724 CorrectionCandidateCallback &Validator =
12725 AllowTypoCorrection
12726 ? static_cast<CorrectionCandidateCallback &>(FunctionCallValidator)
12727 : static_cast<CorrectionCandidateCallback &>(NoTypoValidator);
12728 if (!DoDiagnoseEmptyLookup ||
12729 SemaRef.DiagnoseEmptyLookup(S, SS, R, Validator, ExplicitTemplateArgs,
12730 Args))
12731 return ExprError();
12732 }
12733
12734 assert(!R.empty() && "lookup results empty despite recovery");
12735
12736 // If recovery created an ambiguity, just bail out.
12737 if (R.isAmbiguous()) {
12738 R.suppressDiagnostics();
12739 return ExprError();
12740 }
12741
12742 // Build an implicit member call if appropriate. Just drop the
12743 // casts and such from the call, we don't really care.
12744 ExprResult NewFn = ExprError();
12745 if ((*R.begin())->isCXXClassMember())
12746 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R,
12747 ExplicitTemplateArgs, S);
12748 else if (ExplicitTemplateArgs || TemplateKWLoc.isValid())
12749 NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false,
12750 ExplicitTemplateArgs);
12751 else
12752 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false);
12753
12754 if (NewFn.isInvalid())
12755 return ExprError();
12756
12757 // This shouldn't cause an infinite loop because we're giving it
12758 // an expression with viable lookup results, which should never
12759 // end up here.
12760 return SemaRef.BuildCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc,
12761 MultiExprArg(Args.data(), Args.size()),
12762 RParenLoc);
12763 }
12764
12765 /// Constructs and populates an OverloadedCandidateSet from
12766 /// the given function.
12767 /// \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)12768 bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn,
12769 UnresolvedLookupExpr *ULE,
12770 MultiExprArg Args,
12771 SourceLocation RParenLoc,
12772 OverloadCandidateSet *CandidateSet,
12773 ExprResult *Result) {
12774 #ifndef NDEBUG
12775 if (ULE->requiresADL()) {
12776 // To do ADL, we must have found an unqualified name.
12777 assert(!ULE->getQualifier() && "qualified name with ADL");
12778
12779 // We don't perform ADL for implicit declarations of builtins.
12780 // Verify that this was correctly set up.
12781 FunctionDecl *F;
12782 if (ULE->decls_begin() != ULE->decls_end() &&
12783 ULE->decls_begin() + 1 == ULE->decls_end() &&
12784 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) &&
12785 F->getBuiltinID() && F->isImplicit())
12786 llvm_unreachable("performing ADL for builtin");
12787
12788 // We don't perform ADL in C.
12789 assert(getLangOpts().CPlusPlus && "ADL enabled in C");
12790 }
12791 #endif
12792
12793 UnbridgedCastsSet UnbridgedCasts;
12794 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) {
12795 *Result = ExprError();
12796 return true;
12797 }
12798
12799 // Add the functions denoted by the callee to the set of candidate
12800 // functions, including those from argument-dependent lookup.
12801 AddOverloadedCallCandidates(ULE, Args, *CandidateSet);
12802
12803 if (getLangOpts().MSVCCompat &&
12804 CurContext->isDependentContext() && !isSFINAEContext() &&
12805 (isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) {
12806
12807 OverloadCandidateSet::iterator Best;
12808 if (CandidateSet->empty() ||
12809 CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) ==
12810 OR_No_Viable_Function) {
12811 // In Microsoft mode, if we are inside a template class member function
12812 // then create a type dependent CallExpr. The goal is to postpone name
12813 // lookup to instantiation time to be able to search into type dependent
12814 // base classes.
12815 CallExpr *CE = CallExpr::Create(Context, Fn, Args, Context.DependentTy,
12816 VK_RValue, RParenLoc);
12817 CE->markDependentForPostponedNameLookup();
12818 *Result = CE;
12819 return true;
12820 }
12821 }
12822
12823 if (CandidateSet->empty())
12824 return false;
12825
12826 UnbridgedCasts.restore();
12827 return false;
12828 }
12829
12830 // Guess at what the return type for an unresolvable overload should be.
chooseRecoveryType(OverloadCandidateSet & CS,OverloadCandidateSet::iterator * Best)12831 static QualType chooseRecoveryType(OverloadCandidateSet &CS,
12832 OverloadCandidateSet::iterator *Best) {
12833 llvm::Optional<QualType> Result;
12834 // Adjust Type after seeing a candidate.
12835 auto ConsiderCandidate = [&](const OverloadCandidate &Candidate) {
12836 if (!Candidate.Function)
12837 return;
12838 QualType T = Candidate.Function->getReturnType();
12839 if (T.isNull())
12840 return;
12841 if (!Result)
12842 Result = T;
12843 else if (Result != T)
12844 Result = QualType();
12845 };
12846
12847 // Look for an unambiguous type from a progressively larger subset.
12848 // e.g. if types disagree, but all *viable* overloads return int, choose int.
12849 //
12850 // First, consider only the best candidate.
12851 if (Best && *Best != CS.end())
12852 ConsiderCandidate(**Best);
12853 // Next, consider only viable candidates.
12854 if (!Result)
12855 for (const auto &C : CS)
12856 if (C.Viable)
12857 ConsiderCandidate(C);
12858 // Finally, consider all candidates.
12859 if (!Result)
12860 for (const auto &C : CS)
12861 ConsiderCandidate(C);
12862
12863 return Result.getValueOr(QualType());
12864 }
12865
12866 /// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns
12867 /// the completed call expression. If overload resolution fails, emits
12868 /// 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)12869 static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
12870 UnresolvedLookupExpr *ULE,
12871 SourceLocation LParenLoc,
12872 MultiExprArg Args,
12873 SourceLocation RParenLoc,
12874 Expr *ExecConfig,
12875 OverloadCandidateSet *CandidateSet,
12876 OverloadCandidateSet::iterator *Best,
12877 OverloadingResult OverloadResult,
12878 bool AllowTypoCorrection) {
12879 if (CandidateSet->empty())
12880 return BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc, Args,
12881 RParenLoc, /*EmptyLookup=*/true,
12882 AllowTypoCorrection);
12883
12884 switch (OverloadResult) {
12885 case OR_Success: {
12886 FunctionDecl *FDecl = (*Best)->Function;
12887 SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl);
12888 if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc()))
12889 return ExprError();
12890 Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
12891 return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
12892 ExecConfig, /*IsExecConfig=*/false,
12893 (*Best)->IsADLCandidate);
12894 }
12895
12896 case OR_No_Viable_Function: {
12897 // Try to recover by looking for viable functions which the user might
12898 // have meant to call.
12899 ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc,
12900 Args, RParenLoc,
12901 /*EmptyLookup=*/false,
12902 AllowTypoCorrection);
12903 if (!Recovery.isInvalid())
12904 return Recovery;
12905
12906 // If the user passes in a function that we can't take the address of, we
12907 // generally end up emitting really bad error messages. Here, we attempt to
12908 // emit better ones.
12909 for (const Expr *Arg : Args) {
12910 if (!Arg->getType()->isFunctionType())
12911 continue;
12912 if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) {
12913 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
12914 if (FD &&
12915 !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
12916 Arg->getExprLoc()))
12917 return ExprError();
12918 }
12919 }
12920
12921 CandidateSet->NoteCandidates(
12922 PartialDiagnosticAt(
12923 Fn->getBeginLoc(),
12924 SemaRef.PDiag(diag::err_ovl_no_viable_function_in_call)
12925 << ULE->getName() << Fn->getSourceRange()),
12926 SemaRef, OCD_AllCandidates, Args);
12927 break;
12928 }
12929
12930 case OR_Ambiguous:
12931 CandidateSet->NoteCandidates(
12932 PartialDiagnosticAt(Fn->getBeginLoc(),
12933 SemaRef.PDiag(diag::err_ovl_ambiguous_call)
12934 << ULE->getName() << Fn->getSourceRange()),
12935 SemaRef, OCD_AmbiguousCandidates, Args);
12936 break;
12937
12938 case OR_Deleted: {
12939 CandidateSet->NoteCandidates(
12940 PartialDiagnosticAt(Fn->getBeginLoc(),
12941 SemaRef.PDiag(diag::err_ovl_deleted_call)
12942 << ULE->getName() << Fn->getSourceRange()),
12943 SemaRef, OCD_AllCandidates, Args);
12944
12945 // We emitted an error for the unavailable/deleted function call but keep
12946 // the call in the AST.
12947 FunctionDecl *FDecl = (*Best)->Function;
12948 Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
12949 return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
12950 ExecConfig, /*IsExecConfig=*/false,
12951 (*Best)->IsADLCandidate);
12952 }
12953 }
12954
12955 // Overload resolution failed, try to recover.
12956 SmallVector<Expr *, 8> SubExprs = {Fn};
12957 SubExprs.append(Args.begin(), Args.end());
12958 return SemaRef.CreateRecoveryExpr(Fn->getBeginLoc(), RParenLoc, SubExprs,
12959 chooseRecoveryType(*CandidateSet, Best));
12960 }
12961
markUnaddressableCandidatesUnviable(Sema & S,OverloadCandidateSet & CS)12962 static void markUnaddressableCandidatesUnviable(Sema &S,
12963 OverloadCandidateSet &CS) {
12964 for (auto I = CS.begin(), E = CS.end(); I != E; ++I) {
12965 if (I->Viable &&
12966 !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) {
12967 I->Viable = false;
12968 I->FailureKind = ovl_fail_addr_not_available;
12969 }
12970 }
12971 }
12972
12973 /// BuildOverloadedCallExpr - Given the call expression that calls Fn
12974 /// (which eventually refers to the declaration Func) and the call
12975 /// arguments Args/NumArgs, attempt to resolve the function call down
12976 /// to a specific function. If overload resolution succeeds, returns
12977 /// the call expression produced by overload resolution.
12978 /// 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)12979 ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn,
12980 UnresolvedLookupExpr *ULE,
12981 SourceLocation LParenLoc,
12982 MultiExprArg Args,
12983 SourceLocation RParenLoc,
12984 Expr *ExecConfig,
12985 bool AllowTypoCorrection,
12986 bool CalleesAddressIsTaken) {
12987 OverloadCandidateSet CandidateSet(Fn->getExprLoc(),
12988 OverloadCandidateSet::CSK_Normal);
12989 ExprResult result;
12990
12991 if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet,
12992 &result))
12993 return result;
12994
12995 // If the user handed us something like `(&Foo)(Bar)`, we need to ensure that
12996 // functions that aren't addressible are considered unviable.
12997 if (CalleesAddressIsTaken)
12998 markUnaddressableCandidatesUnviable(*this, CandidateSet);
12999
13000 OverloadCandidateSet::iterator Best;
13001 OverloadingResult OverloadResult =
13002 CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best);
13003
13004 return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, RParenLoc,
13005 ExecConfig, &CandidateSet, &Best,
13006 OverloadResult, AllowTypoCorrection);
13007 }
13008
IsOverloaded(const UnresolvedSetImpl & Functions)13009 static bool IsOverloaded(const UnresolvedSetImpl &Functions) {
13010 return Functions.size() > 1 ||
13011 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin()));
13012 }
13013
13014 /// Create a unary operation that may resolve to an overloaded
13015 /// operator.
13016 ///
13017 /// \param OpLoc The location of the operator itself (e.g., '*').
13018 ///
13019 /// \param Opc The UnaryOperatorKind that describes this operator.
13020 ///
13021 /// \param Fns The set of non-member functions that will be
13022 /// considered by overload resolution. The caller needs to build this
13023 /// set based on the context using, e.g.,
13024 /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13025 /// set should not contain any member functions; those will be added
13026 /// by CreateOverloadedUnaryOp().
13027 ///
13028 /// \param Input The input argument.
13029 ExprResult
CreateOverloadedUnaryOp(SourceLocation OpLoc,UnaryOperatorKind Opc,const UnresolvedSetImpl & Fns,Expr * Input,bool PerformADL)13030 Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
13031 const UnresolvedSetImpl &Fns,
13032 Expr *Input, bool PerformADL) {
13033 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc);
13034 assert(Op != OO_None && "Invalid opcode for overloaded unary operator");
13035 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13036 // TODO: provide better source location info.
13037 DeclarationNameInfo OpNameInfo(OpName, OpLoc);
13038
13039 if (checkPlaceholderForOverload(*this, Input))
13040 return ExprError();
13041
13042 Expr *Args[2] = { Input, nullptr };
13043 unsigned NumArgs = 1;
13044
13045 // For post-increment and post-decrement, add the implicit '0' as
13046 // the second argument, so that we know this is a post-increment or
13047 // post-decrement.
13048 if (Opc == UO_PostInc || Opc == UO_PostDec) {
13049 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
13050 Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy,
13051 SourceLocation());
13052 NumArgs = 2;
13053 }
13054
13055 ArrayRef<Expr *> ArgsArray(Args, NumArgs);
13056
13057 if (Input->isTypeDependent()) {
13058 if (Fns.empty())
13059 return UnaryOperator::Create(Context, Input, Opc, Context.DependentTy,
13060 VK_RValue, OK_Ordinary, OpLoc, false,
13061 CurFPFeatureOverrides());
13062
13063 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
13064 UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create(
13065 Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo,
13066 /*ADL*/ true, IsOverloaded(Fns), Fns.begin(), Fns.end());
13067 return CXXOperatorCallExpr::Create(Context, Op, Fn, ArgsArray,
13068 Context.DependentTy, VK_RValue, OpLoc,
13069 CurFPFeatureOverrides());
13070 }
13071
13072 // Build an empty overload set.
13073 OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);
13074
13075 // Add the candidates from the given function set.
13076 AddNonMemberOperatorCandidates(Fns, ArgsArray, CandidateSet);
13077
13078 // Add operator candidates that are member functions.
13079 AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
13080
13081 // Add candidates from ADL.
13082 if (PerformADL) {
13083 AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray,
13084 /*ExplicitTemplateArgs*/nullptr,
13085 CandidateSet);
13086 }
13087
13088 // Add builtin operator candidates.
13089 AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
13090
13091 bool HadMultipleCandidates = (CandidateSet.size() > 1);
13092
13093 // Perform overload resolution.
13094 OverloadCandidateSet::iterator Best;
13095 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
13096 case OR_Success: {
13097 // We found a built-in operator or an overloaded operator.
13098 FunctionDecl *FnDecl = Best->Function;
13099
13100 if (FnDecl) {
13101 Expr *Base = nullptr;
13102 // We matched an overloaded operator. Build a call to that
13103 // operator.
13104
13105 // Convert the arguments.
13106 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
13107 CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl);
13108
13109 ExprResult InputRes =
13110 PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr,
13111 Best->FoundDecl, Method);
13112 if (InputRes.isInvalid())
13113 return ExprError();
13114 Base = Input = InputRes.get();
13115 } else {
13116 // Convert the arguments.
13117 ExprResult InputInit
13118 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
13119 Context,
13120 FnDecl->getParamDecl(0)),
13121 SourceLocation(),
13122 Input);
13123 if (InputInit.isInvalid())
13124 return ExprError();
13125 Input = InputInit.get();
13126 }
13127
13128 // Build the actual expression node.
13129 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl,
13130 Base, HadMultipleCandidates,
13131 OpLoc);
13132 if (FnExpr.isInvalid())
13133 return ExprError();
13134
13135 // Determine the result type.
13136 QualType ResultTy = FnDecl->getReturnType();
13137 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
13138 ResultTy = ResultTy.getNonLValueExprType(Context);
13139
13140 Args[0] = Input;
13141 CallExpr *TheCall = CXXOperatorCallExpr::Create(
13142 Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc,
13143 CurFPFeatureOverrides(), Best->IsADLCandidate);
13144
13145 if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl))
13146 return ExprError();
13147
13148 if (CheckFunctionCall(FnDecl, TheCall,
13149 FnDecl->getType()->castAs<FunctionProtoType>()))
13150 return ExprError();
13151 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), FnDecl);
13152 } else {
13153 // We matched a built-in operator. Convert the arguments, then
13154 // break out so that we will build the appropriate built-in
13155 // operator node.
13156 ExprResult InputRes = PerformImplicitConversion(
13157 Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing,
13158 CCK_ForBuiltinOverloadedOp);
13159 if (InputRes.isInvalid())
13160 return ExprError();
13161 Input = InputRes.get();
13162 break;
13163 }
13164 }
13165
13166 case OR_No_Viable_Function:
13167 // This is an erroneous use of an operator which can be overloaded by
13168 // a non-member function. Check for non-member operators which were
13169 // defined too late to be candidates.
13170 if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray))
13171 // FIXME: Recover by calling the found function.
13172 return ExprError();
13173
13174 // No viable function; fall through to handling this as a
13175 // built-in operator, which will produce an error message for us.
13176 break;
13177
13178 case OR_Ambiguous:
13179 CandidateSet.NoteCandidates(
13180 PartialDiagnosticAt(OpLoc,
13181 PDiag(diag::err_ovl_ambiguous_oper_unary)
13182 << UnaryOperator::getOpcodeStr(Opc)
13183 << Input->getType() << Input->getSourceRange()),
13184 *this, OCD_AmbiguousCandidates, ArgsArray,
13185 UnaryOperator::getOpcodeStr(Opc), OpLoc);
13186 return ExprError();
13187
13188 case OR_Deleted:
13189 CandidateSet.NoteCandidates(
13190 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
13191 << UnaryOperator::getOpcodeStr(Opc)
13192 << Input->getSourceRange()),
13193 *this, OCD_AllCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc),
13194 OpLoc);
13195 return ExprError();
13196 }
13197
13198 // Either we found no viable overloaded operator or we matched a
13199 // built-in operator. In either case, fall through to trying to
13200 // build a built-in operation.
13201 return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
13202 }
13203
13204 /// Perform lookup for an overloaded binary operator.
LookupOverloadedBinOp(OverloadCandidateSet & CandidateSet,OverloadedOperatorKind Op,const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,bool PerformADL)13205 void Sema::LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
13206 OverloadedOperatorKind Op,
13207 const UnresolvedSetImpl &Fns,
13208 ArrayRef<Expr *> Args, bool PerformADL) {
13209 SourceLocation OpLoc = CandidateSet.getLocation();
13210
13211 OverloadedOperatorKind ExtraOp =
13212 CandidateSet.getRewriteInfo().AllowRewrittenCandidates
13213 ? getRewrittenOverloadedOperator(Op)
13214 : OO_None;
13215
13216 // Add the candidates from the given function set. This also adds the
13217 // rewritten candidates using these functions if necessary.
13218 AddNonMemberOperatorCandidates(Fns, Args, CandidateSet);
13219
13220 // Add operator candidates that are member functions.
13221 AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet);
13222 if (CandidateSet.getRewriteInfo().shouldAddReversed(Op))
13223 AddMemberOperatorCandidates(Op, OpLoc, {Args[1], Args[0]}, CandidateSet,
13224 OverloadCandidateParamOrder::Reversed);
13225
13226 // In C++20, also add any rewritten member candidates.
13227 if (ExtraOp) {
13228 AddMemberOperatorCandidates(ExtraOp, OpLoc, Args, CandidateSet);
13229 if (CandidateSet.getRewriteInfo().shouldAddReversed(ExtraOp))
13230 AddMemberOperatorCandidates(ExtraOp, OpLoc, {Args[1], Args[0]},
13231 CandidateSet,
13232 OverloadCandidateParamOrder::Reversed);
13233 }
13234
13235 // Add candidates from ADL. Per [over.match.oper]p2, this lookup is not
13236 // performed for an assignment operator (nor for operator[] nor operator->,
13237 // which don't get here).
13238 if (Op != OO_Equal && PerformADL) {
13239 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13240 AddArgumentDependentLookupCandidates(OpName, OpLoc, Args,
13241 /*ExplicitTemplateArgs*/ nullptr,
13242 CandidateSet);
13243 if (ExtraOp) {
13244 DeclarationName ExtraOpName =
13245 Context.DeclarationNames.getCXXOperatorName(ExtraOp);
13246 AddArgumentDependentLookupCandidates(ExtraOpName, OpLoc, Args,
13247 /*ExplicitTemplateArgs*/ nullptr,
13248 CandidateSet);
13249 }
13250 }
13251
13252 // Add builtin operator candidates.
13253 //
13254 // FIXME: We don't add any rewritten candidates here. This is strictly
13255 // incorrect; a builtin candidate could be hidden by a non-viable candidate,
13256 // resulting in our selecting a rewritten builtin candidate. For example:
13257 //
13258 // enum class E { e };
13259 // bool operator!=(E, E) requires false;
13260 // bool k = E::e != E::e;
13261 //
13262 // ... should select the rewritten builtin candidate 'operator==(E, E)'. But
13263 // it seems unreasonable to consider rewritten builtin candidates. A core
13264 // issue has been filed proposing to removed this requirement.
13265 AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet);
13266 }
13267
13268 /// Create a binary operation that may resolve to an overloaded
13269 /// operator.
13270 ///
13271 /// \param OpLoc The location of the operator itself (e.g., '+').
13272 ///
13273 /// \param Opc The BinaryOperatorKind that describes this operator.
13274 ///
13275 /// \param Fns The set of non-member functions that will be
13276 /// considered by overload resolution. The caller needs to build this
13277 /// set based on the context using, e.g.,
13278 /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13279 /// set should not contain any member functions; those will be added
13280 /// by CreateOverloadedBinOp().
13281 ///
13282 /// \param LHS Left-hand argument.
13283 /// \param RHS Right-hand argument.
13284 /// \param PerformADL Whether to consider operator candidates found by ADL.
13285 /// \param AllowRewrittenCandidates Whether to consider candidates found by
13286 /// C++20 operator rewrites.
13287 /// \param DefaultedFn If we are synthesizing a defaulted operator function,
13288 /// the function in question. Such a function is never a candidate in
13289 /// our overload resolution. This also enables synthesizing a three-way
13290 /// 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)13291 ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
13292 BinaryOperatorKind Opc,
13293 const UnresolvedSetImpl &Fns, Expr *LHS,
13294 Expr *RHS, bool PerformADL,
13295 bool AllowRewrittenCandidates,
13296 FunctionDecl *DefaultedFn) {
13297 Expr *Args[2] = { LHS, RHS };
13298 LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple
13299
13300 if (!getLangOpts().CPlusPlus20)
13301 AllowRewrittenCandidates = false;
13302
13303 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc);
13304
13305 // If either side is type-dependent, create an appropriate dependent
13306 // expression.
13307 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
13308 if (Fns.empty()) {
13309 // If there are no functions to store, just build a dependent
13310 // BinaryOperator or CompoundAssignment.
13311 if (Opc <= BO_Assign || Opc > BO_OrAssign)
13312 return BinaryOperator::Create(
13313 Context, Args[0], Args[1], Opc, Context.DependentTy, VK_RValue,
13314 OK_Ordinary, OpLoc, CurFPFeatureOverrides());
13315 return CompoundAssignOperator::Create(
13316 Context, Args[0], Args[1], Opc, Context.DependentTy, VK_LValue,
13317 OK_Ordinary, OpLoc, CurFPFeatureOverrides(), Context.DependentTy,
13318 Context.DependentTy);
13319 }
13320
13321 // FIXME: save results of ADL from here?
13322 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
13323 // TODO: provide better source location info in DNLoc component.
13324 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13325 DeclarationNameInfo OpNameInfo(OpName, OpLoc);
13326 UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create(
13327 Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo,
13328 /*ADL*/ PerformADL, IsOverloaded(Fns), Fns.begin(), Fns.end());
13329 return CXXOperatorCallExpr::Create(Context, Op, Fn, Args,
13330 Context.DependentTy, VK_RValue, OpLoc,
13331 CurFPFeatureOverrides());
13332 }
13333
13334 // Always do placeholder-like conversions on the RHS.
13335 if (checkPlaceholderForOverload(*this, Args[1]))
13336 return ExprError();
13337
13338 // Do placeholder-like conversion on the LHS; note that we should
13339 // not get here with a PseudoObject LHS.
13340 assert(Args[0]->getObjectKind() != OK_ObjCProperty);
13341 if (checkPlaceholderForOverload(*this, Args[0]))
13342 return ExprError();
13343
13344 // If this is the assignment operator, we only perform overload resolution
13345 // if the left-hand side is a class or enumeration type. This is actually
13346 // a hack. The standard requires that we do overload resolution between the
13347 // various built-in candidates, but as DR507 points out, this can lead to
13348 // problems. So we do it this way, which pretty much follows what GCC does.
13349 // Note that we go the traditional code path for compound assignment forms.
13350 if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
13351 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13352
13353 // If this is the .* operator, which is not overloadable, just
13354 // create a built-in binary operator.
13355 if (Opc == BO_PtrMemD)
13356 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13357
13358 // Build the overload set.
13359 OverloadCandidateSet CandidateSet(
13360 OpLoc, OverloadCandidateSet::CSK_Operator,
13361 OverloadCandidateSet::OperatorRewriteInfo(Op, AllowRewrittenCandidates));
13362 if (DefaultedFn)
13363 CandidateSet.exclude(DefaultedFn);
13364 LookupOverloadedBinOp(CandidateSet, Op, Fns, Args, PerformADL);
13365
13366 bool HadMultipleCandidates = (CandidateSet.size() > 1);
13367
13368 // Perform overload resolution.
13369 OverloadCandidateSet::iterator Best;
13370 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
13371 case OR_Success: {
13372 // We found a built-in operator or an overloaded operator.
13373 FunctionDecl *FnDecl = Best->Function;
13374
13375 bool IsReversed = Best->isReversed();
13376 if (IsReversed)
13377 std::swap(Args[0], Args[1]);
13378
13379 if (FnDecl) {
13380 Expr *Base = nullptr;
13381 // We matched an overloaded operator. Build a call to that
13382 // operator.
13383
13384 OverloadedOperatorKind ChosenOp =
13385 FnDecl->getDeclName().getCXXOverloadedOperator();
13386
13387 // C++2a [over.match.oper]p9:
13388 // If a rewritten operator== candidate is selected by overload
13389 // resolution for an operator@, its return type shall be cv bool
13390 if (Best->RewriteKind && ChosenOp == OO_EqualEqual &&
13391 !FnDecl->getReturnType()->isBooleanType()) {
13392 bool IsExtension =
13393 FnDecl->getReturnType()->isIntegralOrUnscopedEnumerationType();
13394 Diag(OpLoc, IsExtension ? diag::ext_ovl_rewrite_equalequal_not_bool
13395 : diag::err_ovl_rewrite_equalequal_not_bool)
13396 << FnDecl->getReturnType() << BinaryOperator::getOpcodeStr(Opc)
13397 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13398 Diag(FnDecl->getLocation(), diag::note_declared_at);
13399 if (!IsExtension)
13400 return ExprError();
13401 }
13402
13403 if (AllowRewrittenCandidates && !IsReversed &&
13404 CandidateSet.getRewriteInfo().isReversible()) {
13405 // We could have reversed this operator, but didn't. Check if some
13406 // reversed form was a viable candidate, and if so, if it had a
13407 // better conversion for either parameter. If so, this call is
13408 // formally ambiguous, and allowing it is an extension.
13409 llvm::SmallVector<FunctionDecl*, 4> AmbiguousWith;
13410 for (OverloadCandidate &Cand : CandidateSet) {
13411 if (Cand.Viable && Cand.Function && Cand.isReversed() &&
13412 haveSameParameterTypes(Context, Cand.Function, FnDecl, 2)) {
13413 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
13414 if (CompareImplicitConversionSequences(
13415 *this, OpLoc, Cand.Conversions[ArgIdx],
13416 Best->Conversions[ArgIdx]) ==
13417 ImplicitConversionSequence::Better) {
13418 AmbiguousWith.push_back(Cand.Function);
13419 break;
13420 }
13421 }
13422 }
13423 }
13424
13425 if (!AmbiguousWith.empty()) {
13426 bool AmbiguousWithSelf =
13427 AmbiguousWith.size() == 1 &&
13428 declaresSameEntity(AmbiguousWith.front(), FnDecl);
13429 Diag(OpLoc, diag::ext_ovl_ambiguous_oper_binary_reversed)
13430 << BinaryOperator::getOpcodeStr(Opc)
13431 << Args[0]->getType() << Args[1]->getType() << AmbiguousWithSelf
13432 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13433 if (AmbiguousWithSelf) {
13434 Diag(FnDecl->getLocation(),
13435 diag::note_ovl_ambiguous_oper_binary_reversed_self);
13436 } else {
13437 Diag(FnDecl->getLocation(),
13438 diag::note_ovl_ambiguous_oper_binary_selected_candidate);
13439 for (auto *F : AmbiguousWith)
13440 Diag(F->getLocation(),
13441 diag::note_ovl_ambiguous_oper_binary_reversed_candidate);
13442 }
13443 }
13444 }
13445
13446 // Convert the arguments.
13447 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
13448 // Best->Access is only meaningful for class members.
13449 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl);
13450
13451 ExprResult Arg1 =
13452 PerformCopyInitialization(
13453 InitializedEntity::InitializeParameter(Context,
13454 FnDecl->getParamDecl(0)),
13455 SourceLocation(), Args[1]);
13456 if (Arg1.isInvalid())
13457 return ExprError();
13458
13459 ExprResult Arg0 =
13460 PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
13461 Best->FoundDecl, Method);
13462 if (Arg0.isInvalid())
13463 return ExprError();
13464 Base = Args[0] = Arg0.getAs<Expr>();
13465 Args[1] = RHS = Arg1.getAs<Expr>();
13466 } else {
13467 // Convert the arguments.
13468 ExprResult Arg0 = PerformCopyInitialization(
13469 InitializedEntity::InitializeParameter(Context,
13470 FnDecl->getParamDecl(0)),
13471 SourceLocation(), Args[0]);
13472 if (Arg0.isInvalid())
13473 return ExprError();
13474
13475 ExprResult Arg1 =
13476 PerformCopyInitialization(
13477 InitializedEntity::InitializeParameter(Context,
13478 FnDecl->getParamDecl(1)),
13479 SourceLocation(), Args[1]);
13480 if (Arg1.isInvalid())
13481 return ExprError();
13482 Args[0] = LHS = Arg0.getAs<Expr>();
13483 Args[1] = RHS = Arg1.getAs<Expr>();
13484 }
13485
13486 // Build the actual expression node.
13487 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
13488 Best->FoundDecl, Base,
13489 HadMultipleCandidates, OpLoc);
13490 if (FnExpr.isInvalid())
13491 return ExprError();
13492
13493 // Determine the result type.
13494 QualType ResultTy = FnDecl->getReturnType();
13495 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
13496 ResultTy = ResultTy.getNonLValueExprType(Context);
13497
13498 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
13499 Context, ChosenOp, FnExpr.get(), Args, ResultTy, VK, OpLoc,
13500 CurFPFeatureOverrides(), Best->IsADLCandidate);
13501
13502 if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall,
13503 FnDecl))
13504 return ExprError();
13505
13506 ArrayRef<const Expr *> ArgsArray(Args, 2);
13507 const Expr *ImplicitThis = nullptr;
13508 // Cut off the implicit 'this'.
13509 if (isa<CXXMethodDecl>(FnDecl)) {
13510 ImplicitThis = ArgsArray[0];
13511 ArgsArray = ArgsArray.slice(1);
13512 }
13513
13514 // Check for a self move.
13515 if (Op == OO_Equal)
13516 DiagnoseSelfMove(Args[0], Args[1], OpLoc);
13517
13518 checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray,
13519 isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(),
13520 VariadicDoesNotApply);
13521
13522 ExprResult R = MaybeBindToTemporary(TheCall);
13523 if (R.isInvalid())
13524 return ExprError();
13525
13526 R = CheckForImmediateInvocation(R, FnDecl);
13527 if (R.isInvalid())
13528 return ExprError();
13529
13530 // For a rewritten candidate, we've already reversed the arguments
13531 // if needed. Perform the rest of the rewrite now.
13532 if ((Best->RewriteKind & CRK_DifferentOperator) ||
13533 (Op == OO_Spaceship && IsReversed)) {
13534 if (Op == OO_ExclaimEqual) {
13535 assert(ChosenOp == OO_EqualEqual && "unexpected operator name");
13536 R = CreateBuiltinUnaryOp(OpLoc, UO_LNot, R.get());
13537 } else {
13538 assert(ChosenOp == OO_Spaceship && "unexpected operator name");
13539 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
13540 Expr *ZeroLiteral =
13541 IntegerLiteral::Create(Context, Zero, Context.IntTy, OpLoc);
13542
13543 Sema::CodeSynthesisContext Ctx;
13544 Ctx.Kind = Sema::CodeSynthesisContext::RewritingOperatorAsSpaceship;
13545 Ctx.Entity = FnDecl;
13546 pushCodeSynthesisContext(Ctx);
13547
13548 R = CreateOverloadedBinOp(
13549 OpLoc, Opc, Fns, IsReversed ? ZeroLiteral : R.get(),
13550 IsReversed ? R.get() : ZeroLiteral, PerformADL,
13551 /*AllowRewrittenCandidates=*/false);
13552
13553 popCodeSynthesisContext();
13554 }
13555 if (R.isInvalid())
13556 return ExprError();
13557 } else {
13558 assert(ChosenOp == Op && "unexpected operator name");
13559 }
13560
13561 // Make a note in the AST if we did any rewriting.
13562 if (Best->RewriteKind != CRK_None)
13563 R = new (Context) CXXRewrittenBinaryOperator(R.get(), IsReversed);
13564
13565 return R;
13566 } else {
13567 // We matched a built-in operator. Convert the arguments, then
13568 // break out so that we will build the appropriate built-in
13569 // operator node.
13570 ExprResult ArgsRes0 = PerformImplicitConversion(
13571 Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
13572 AA_Passing, CCK_ForBuiltinOverloadedOp);
13573 if (ArgsRes0.isInvalid())
13574 return ExprError();
13575 Args[0] = ArgsRes0.get();
13576
13577 ExprResult ArgsRes1 = PerformImplicitConversion(
13578 Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
13579 AA_Passing, CCK_ForBuiltinOverloadedOp);
13580 if (ArgsRes1.isInvalid())
13581 return ExprError();
13582 Args[1] = ArgsRes1.get();
13583 break;
13584 }
13585 }
13586
13587 case OR_No_Viable_Function: {
13588 // C++ [over.match.oper]p9:
13589 // If the operator is the operator , [...] and there are no
13590 // viable functions, then the operator is assumed to be the
13591 // built-in operator and interpreted according to clause 5.
13592 if (Opc == BO_Comma)
13593 break;
13594
13595 // When defaulting an 'operator<=>', we can try to synthesize a three-way
13596 // compare result using '==' and '<'.
13597 if (DefaultedFn && Opc == BO_Cmp) {
13598 ExprResult E = BuildSynthesizedThreeWayComparison(OpLoc, Fns, Args[0],
13599 Args[1], DefaultedFn);
13600 if (E.isInvalid() || E.isUsable())
13601 return E;
13602 }
13603
13604 // For class as left operand for assignment or compound assignment
13605 // operator do not fall through to handling in built-in, but report that
13606 // no overloaded assignment operator found
13607 ExprResult Result = ExprError();
13608 StringRef OpcStr = BinaryOperator::getOpcodeStr(Opc);
13609 auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates,
13610 Args, OpLoc);
13611 if (Args[0]->getType()->isRecordType() &&
13612 Opc >= BO_Assign && Opc <= BO_OrAssign) {
13613 Diag(OpLoc, diag::err_ovl_no_viable_oper)
13614 << BinaryOperator::getOpcodeStr(Opc)
13615 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13616 if (Args[0]->getType()->isIncompleteType()) {
13617 Diag(OpLoc, diag::note_assign_lhs_incomplete)
13618 << Args[0]->getType()
13619 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13620 }
13621 } else {
13622 // This is an erroneous use of an operator which can be overloaded by
13623 // a non-member function. Check for non-member operators which were
13624 // defined too late to be candidates.
13625 if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args))
13626 // FIXME: Recover by calling the found function.
13627 return ExprError();
13628
13629 // No viable function; try to create a built-in operation, which will
13630 // produce an error. Then, show the non-viable candidates.
13631 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13632 }
13633 assert(Result.isInvalid() &&
13634 "C++ binary operator overloading is missing candidates!");
13635 CandidateSet.NoteCandidates(*this, Args, Cands, OpcStr, OpLoc);
13636 return Result;
13637 }
13638
13639 case OR_Ambiguous:
13640 CandidateSet.NoteCandidates(
13641 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
13642 << BinaryOperator::getOpcodeStr(Opc)
13643 << Args[0]->getType()
13644 << Args[1]->getType()
13645 << Args[0]->getSourceRange()
13646 << Args[1]->getSourceRange()),
13647 *this, OCD_AmbiguousCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
13648 OpLoc);
13649 return ExprError();
13650
13651 case OR_Deleted:
13652 if (isImplicitlyDeleted(Best->Function)) {
13653 FunctionDecl *DeletedFD = Best->Function;
13654 DefaultedFunctionKind DFK = getDefaultedFunctionKind(DeletedFD);
13655 if (DFK.isSpecialMember()) {
13656 Diag(OpLoc, diag::err_ovl_deleted_special_oper)
13657 << Args[0]->getType() << DFK.asSpecialMember();
13658 } else {
13659 assert(DFK.isComparison());
13660 Diag(OpLoc, diag::err_ovl_deleted_comparison)
13661 << Args[0]->getType() << DeletedFD;
13662 }
13663
13664 // The user probably meant to call this special member. Just
13665 // explain why it's deleted.
13666 NoteDeletedFunction(DeletedFD);
13667 return ExprError();
13668 }
13669 CandidateSet.NoteCandidates(
13670 PartialDiagnosticAt(
13671 OpLoc, PDiag(diag::err_ovl_deleted_oper)
13672 << getOperatorSpelling(Best->Function->getDeclName()
13673 .getCXXOverloadedOperator())
13674 << Args[0]->getSourceRange()
13675 << Args[1]->getSourceRange()),
13676 *this, OCD_AllCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
13677 OpLoc);
13678 return ExprError();
13679 }
13680
13681 // We matched a built-in operator; build it.
13682 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13683 }
13684
BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,const UnresolvedSetImpl & Fns,Expr * LHS,Expr * RHS,FunctionDecl * DefaultedFn)13685 ExprResult Sema::BuildSynthesizedThreeWayComparison(
13686 SourceLocation OpLoc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS,
13687 FunctionDecl *DefaultedFn) {
13688 const ComparisonCategoryInfo *Info =
13689 Context.CompCategories.lookupInfoForType(DefaultedFn->getReturnType());
13690 // If we're not producing a known comparison category type, we can't
13691 // synthesize a three-way comparison. Let the caller diagnose this.
13692 if (!Info)
13693 return ExprResult((Expr*)nullptr);
13694
13695 // If we ever want to perform this synthesis more generally, we will need to
13696 // apply the temporary materialization conversion to the operands.
13697 assert(LHS->isGLValue() && RHS->isGLValue() &&
13698 "cannot use prvalue expressions more than once");
13699 Expr *OrigLHS = LHS;
13700 Expr *OrigRHS = RHS;
13701
13702 // Replace the LHS and RHS with OpaqueValueExprs; we're going to refer to
13703 // each of them multiple times below.
13704 LHS = new (Context)
13705 OpaqueValueExpr(LHS->getExprLoc(), LHS->getType(), LHS->getValueKind(),
13706 LHS->getObjectKind(), LHS);
13707 RHS = new (Context)
13708 OpaqueValueExpr(RHS->getExprLoc(), RHS->getType(), RHS->getValueKind(),
13709 RHS->getObjectKind(), RHS);
13710
13711 ExprResult Eq = CreateOverloadedBinOp(OpLoc, BO_EQ, Fns, LHS, RHS, true, true,
13712 DefaultedFn);
13713 if (Eq.isInvalid())
13714 return ExprError();
13715
13716 ExprResult Less = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, LHS, RHS, true,
13717 true, DefaultedFn);
13718 if (Less.isInvalid())
13719 return ExprError();
13720
13721 ExprResult Greater;
13722 if (Info->isPartial()) {
13723 Greater = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, RHS, LHS, true, true,
13724 DefaultedFn);
13725 if (Greater.isInvalid())
13726 return ExprError();
13727 }
13728
13729 // Form the list of comparisons we're going to perform.
13730 struct Comparison {
13731 ExprResult Cmp;
13732 ComparisonCategoryResult Result;
13733 } Comparisons[4] =
13734 { {Eq, Info->isStrong() ? ComparisonCategoryResult::Equal
13735 : ComparisonCategoryResult::Equivalent},
13736 {Less, ComparisonCategoryResult::Less},
13737 {Greater, ComparisonCategoryResult::Greater},
13738 {ExprResult(), ComparisonCategoryResult::Unordered},
13739 };
13740
13741 int I = Info->isPartial() ? 3 : 2;
13742
13743 // Combine the comparisons with suitable conditional expressions.
13744 ExprResult Result;
13745 for (; I >= 0; --I) {
13746 // Build a reference to the comparison category constant.
13747 auto *VI = Info->lookupValueInfo(Comparisons[I].Result);
13748 // FIXME: Missing a constant for a comparison category. Diagnose this?
13749 if (!VI)
13750 return ExprResult((Expr*)nullptr);
13751 ExprResult ThisResult =
13752 BuildDeclarationNameExpr(CXXScopeSpec(), DeclarationNameInfo(), VI->VD);
13753 if (ThisResult.isInvalid())
13754 return ExprError();
13755
13756 // Build a conditional unless this is the final case.
13757 if (Result.get()) {
13758 Result = ActOnConditionalOp(OpLoc, OpLoc, Comparisons[I].Cmp.get(),
13759 ThisResult.get(), Result.get());
13760 if (Result.isInvalid())
13761 return ExprError();
13762 } else {
13763 Result = ThisResult;
13764 }
13765 }
13766
13767 // Build a PseudoObjectExpr to model the rewriting of an <=> operator, and to
13768 // bind the OpaqueValueExprs before they're (repeatedly) used.
13769 Expr *SyntacticForm = BinaryOperator::Create(
13770 Context, OrigLHS, OrigRHS, BO_Cmp, Result.get()->getType(),
13771 Result.get()->getValueKind(), Result.get()->getObjectKind(), OpLoc,
13772 CurFPFeatureOverrides());
13773 Expr *SemanticForm[] = {LHS, RHS, Result.get()};
13774 return PseudoObjectExpr::Create(Context, SyntacticForm, SemanticForm, 2);
13775 }
13776
13777 ExprResult
CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,SourceLocation RLoc,Expr * Base,Expr * Idx)13778 Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
13779 SourceLocation RLoc,
13780 Expr *Base, Expr *Idx) {
13781 Expr *Args[2] = { Base, Idx };
13782 DeclarationName OpName =
13783 Context.DeclarationNames.getCXXOperatorName(OO_Subscript);
13784
13785 // If either side is type-dependent, create an appropriate dependent
13786 // expression.
13787 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
13788
13789 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
13790 // CHECKME: no 'operator' keyword?
13791 DeclarationNameInfo OpNameInfo(OpName, LLoc);
13792 OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
13793 UnresolvedLookupExpr *Fn
13794 = UnresolvedLookupExpr::Create(Context, NamingClass,
13795 NestedNameSpecifierLoc(), OpNameInfo,
13796 /*ADL*/ true, /*Overloaded*/ false,
13797 UnresolvedSetIterator(),
13798 UnresolvedSetIterator());
13799 // Can't add any actual overloads yet
13800
13801 return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn, Args,
13802 Context.DependentTy, VK_RValue, RLoc,
13803 CurFPFeatureOverrides());
13804 }
13805
13806 // Handle placeholders on both operands.
13807 if (checkPlaceholderForOverload(*this, Args[0]))
13808 return ExprError();
13809 if (checkPlaceholderForOverload(*this, Args[1]))
13810 return ExprError();
13811
13812 // Build an empty overload set.
13813 OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator);
13814
13815 // Subscript can only be overloaded as a member function.
13816
13817 // Add operator candidates that are member functions.
13818 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
13819
13820 // Add builtin operator candidates.
13821 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
13822
13823 bool HadMultipleCandidates = (CandidateSet.size() > 1);
13824
13825 // Perform overload resolution.
13826 OverloadCandidateSet::iterator Best;
13827 switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) {
13828 case OR_Success: {
13829 // We found a built-in operator or an overloaded operator.
13830 FunctionDecl *FnDecl = Best->Function;
13831
13832 if (FnDecl) {
13833 // We matched an overloaded operator. Build a call to that
13834 // operator.
13835
13836 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl);
13837
13838 // Convert the arguments.
13839 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
13840 ExprResult Arg0 =
13841 PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
13842 Best->FoundDecl, Method);
13843 if (Arg0.isInvalid())
13844 return ExprError();
13845 Args[0] = Arg0.get();
13846
13847 // Convert the arguments.
13848 ExprResult InputInit
13849 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
13850 Context,
13851 FnDecl->getParamDecl(0)),
13852 SourceLocation(),
13853 Args[1]);
13854 if (InputInit.isInvalid())
13855 return ExprError();
13856
13857 Args[1] = InputInit.getAs<Expr>();
13858
13859 // Build the actual expression node.
13860 DeclarationNameInfo OpLocInfo(OpName, LLoc);
13861 OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
13862 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
13863 Best->FoundDecl,
13864 Base,
13865 HadMultipleCandidates,
13866 OpLocInfo.getLoc(),
13867 OpLocInfo.getInfo());
13868 if (FnExpr.isInvalid())
13869 return ExprError();
13870
13871 // Determine the result type
13872 QualType ResultTy = FnDecl->getReturnType();
13873 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
13874 ResultTy = ResultTy.getNonLValueExprType(Context);
13875
13876 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
13877 Context, OO_Subscript, FnExpr.get(), Args, ResultTy, VK, RLoc,
13878 CurFPFeatureOverrides());
13879 if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl))
13880 return ExprError();
13881
13882 if (CheckFunctionCall(Method, TheCall,
13883 Method->getType()->castAs<FunctionProtoType>()))
13884 return ExprError();
13885
13886 return MaybeBindToTemporary(TheCall);
13887 } else {
13888 // We matched a built-in operator. Convert the arguments, then
13889 // break out so that we will build the appropriate built-in
13890 // operator node.
13891 ExprResult ArgsRes0 = PerformImplicitConversion(
13892 Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
13893 AA_Passing, CCK_ForBuiltinOverloadedOp);
13894 if (ArgsRes0.isInvalid())
13895 return ExprError();
13896 Args[0] = ArgsRes0.get();
13897
13898 ExprResult ArgsRes1 = PerformImplicitConversion(
13899 Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
13900 AA_Passing, CCK_ForBuiltinOverloadedOp);
13901 if (ArgsRes1.isInvalid())
13902 return ExprError();
13903 Args[1] = ArgsRes1.get();
13904
13905 break;
13906 }
13907 }
13908
13909 case OR_No_Viable_Function: {
13910 PartialDiagnostic PD = CandidateSet.empty()
13911 ? (PDiag(diag::err_ovl_no_oper)
13912 << Args[0]->getType() << /*subscript*/ 0
13913 << Args[0]->getSourceRange() << Args[1]->getSourceRange())
13914 : (PDiag(diag::err_ovl_no_viable_subscript)
13915 << Args[0]->getType() << Args[0]->getSourceRange()
13916 << Args[1]->getSourceRange());
13917 CandidateSet.NoteCandidates(PartialDiagnosticAt(LLoc, PD), *this,
13918 OCD_AllCandidates, Args, "[]", LLoc);
13919 return ExprError();
13920 }
13921
13922 case OR_Ambiguous:
13923 CandidateSet.NoteCandidates(
13924 PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
13925 << "[]" << Args[0]->getType()
13926 << Args[1]->getType()
13927 << Args[0]->getSourceRange()
13928 << Args[1]->getSourceRange()),
13929 *this, OCD_AmbiguousCandidates, Args, "[]", LLoc);
13930 return ExprError();
13931
13932 case OR_Deleted:
13933 CandidateSet.NoteCandidates(
13934 PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_deleted_oper)
13935 << "[]" << Args[0]->getSourceRange()
13936 << Args[1]->getSourceRange()),
13937 *this, OCD_AllCandidates, Args, "[]", LLoc);
13938 return ExprError();
13939 }
13940
13941 // We matched a built-in operator; build it.
13942 return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc);
13943 }
13944
13945 /// BuildCallToMemberFunction - Build a call to a member
13946 /// function. MemExpr is the expression that refers to the member
13947 /// function (and includes the object parameter), Args/NumArgs are the
13948 /// arguments to the function call (not including the object
13949 /// parameter). The caller needs to validate that the member
13950 /// expression refers to a non-static member function or an overloaded
13951 /// member function.
13952 ExprResult
BuildCallToMemberFunction(Scope * S,Expr * MemExprE,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc)13953 Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
13954 SourceLocation LParenLoc,
13955 MultiExprArg Args,
13956 SourceLocation RParenLoc) {
13957 assert(MemExprE->getType() == Context.BoundMemberTy ||
13958 MemExprE->getType() == Context.OverloadTy);
13959
13960 // Dig out the member expression. This holds both the object
13961 // argument and the member function we're referring to.
13962 Expr *NakedMemExpr = MemExprE->IgnoreParens();
13963
13964 // Determine whether this is a call to a pointer-to-member function.
13965 if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) {
13966 assert(op->getType() == Context.BoundMemberTy);
13967 assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI);
13968
13969 QualType fnType =
13970 op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType();
13971
13972 const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>();
13973 QualType resultType = proto->getCallResultType(Context);
13974 ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType());
13975
13976 // Check that the object type isn't more qualified than the
13977 // member function we're calling.
13978 Qualifiers funcQuals = proto->getMethodQuals();
13979
13980 QualType objectType = op->getLHS()->getType();
13981 if (op->getOpcode() == BO_PtrMemI)
13982 objectType = objectType->castAs<PointerType>()->getPointeeType();
13983 Qualifiers objectQuals = objectType.getQualifiers();
13984
13985 Qualifiers difference = objectQuals - funcQuals;
13986 difference.removeObjCGCAttr();
13987 difference.removeAddressSpace();
13988 if (difference) {
13989 std::string qualsString = difference.getAsString();
13990 Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
13991 << fnType.getUnqualifiedType()
13992 << qualsString
13993 << (qualsString.find(' ') == std::string::npos ? 1 : 2);
13994 }
13995
13996 CXXMemberCallExpr *call =
13997 CXXMemberCallExpr::Create(Context, MemExprE, Args, resultType,
13998 valueKind, RParenLoc, proto->getNumParams());
13999
14000 if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(),
14001 call, nullptr))
14002 return ExprError();
14003
14004 if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc))
14005 return ExprError();
14006
14007 if (CheckOtherCall(call, proto))
14008 return ExprError();
14009
14010 return MaybeBindToTemporary(call);
14011 }
14012
14013 if (isa<CXXPseudoDestructorExpr>(NakedMemExpr))
14014 return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_RValue,
14015 RParenLoc);
14016
14017 UnbridgedCastsSet UnbridgedCasts;
14018 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
14019 return ExprError();
14020
14021 MemberExpr *MemExpr;
14022 CXXMethodDecl *Method = nullptr;
14023 DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public);
14024 NestedNameSpecifier *Qualifier = nullptr;
14025 if (isa<MemberExpr>(NakedMemExpr)) {
14026 MemExpr = cast<MemberExpr>(NakedMemExpr);
14027 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl());
14028 FoundDecl = MemExpr->getFoundDecl();
14029 Qualifier = MemExpr->getQualifier();
14030 UnbridgedCasts.restore();
14031 } else {
14032 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr);
14033 Qualifier = UnresExpr->getQualifier();
14034
14035 QualType ObjectType = UnresExpr->getBaseType();
14036 Expr::Classification ObjectClassification
14037 = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue()
14038 : UnresExpr->getBase()->Classify(Context);
14039
14040 // Add overload candidates
14041 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(),
14042 OverloadCandidateSet::CSK_Normal);
14043
14044 // FIXME: avoid copy.
14045 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
14046 if (UnresExpr->hasExplicitTemplateArgs()) {
14047 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
14048 TemplateArgs = &TemplateArgsBuffer;
14049 }
14050
14051 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(),
14052 E = UnresExpr->decls_end(); I != E; ++I) {
14053
14054 NamedDecl *Func = *I;
14055 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext());
14056 if (isa<UsingShadowDecl>(Func))
14057 Func = cast<UsingShadowDecl>(Func)->getTargetDecl();
14058
14059
14060 // Microsoft supports direct constructor calls.
14061 if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) {
14062 AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), Args,
14063 CandidateSet,
14064 /*SuppressUserConversions*/ false);
14065 } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
14066 // If explicit template arguments were provided, we can't call a
14067 // non-template member function.
14068 if (TemplateArgs)
14069 continue;
14070
14071 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType,
14072 ObjectClassification, Args, CandidateSet,
14073 /*SuppressUserConversions=*/false);
14074 } else {
14075 AddMethodTemplateCandidate(
14076 cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC,
14077 TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet,
14078 /*SuppressUserConversions=*/false);
14079 }
14080 }
14081
14082 DeclarationName DeclName = UnresExpr->getMemberName();
14083
14084 UnbridgedCasts.restore();
14085
14086 OverloadCandidateSet::iterator Best;
14087 switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(),
14088 Best)) {
14089 case OR_Success:
14090 Method = cast<CXXMethodDecl>(Best->Function);
14091 FoundDecl = Best->FoundDecl;
14092 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
14093 if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
14094 return ExprError();
14095 // If FoundDecl is different from Method (such as if one is a template
14096 // and the other a specialization), make sure DiagnoseUseOfDecl is
14097 // called on both.
14098 // FIXME: This would be more comprehensively addressed by modifying
14099 // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
14100 // being used.
14101 if (Method != FoundDecl.getDecl() &&
14102 DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
14103 return ExprError();
14104 break;
14105
14106 case OR_No_Viable_Function:
14107 CandidateSet.NoteCandidates(
14108 PartialDiagnosticAt(
14109 UnresExpr->getMemberLoc(),
14110 PDiag(diag::err_ovl_no_viable_member_function_in_call)
14111 << DeclName << MemExprE->getSourceRange()),
14112 *this, OCD_AllCandidates, Args);
14113 // FIXME: Leaking incoming expressions!
14114 return ExprError();
14115
14116 case OR_Ambiguous:
14117 CandidateSet.NoteCandidates(
14118 PartialDiagnosticAt(UnresExpr->getMemberLoc(),
14119 PDiag(diag::err_ovl_ambiguous_member_call)
14120 << DeclName << MemExprE->getSourceRange()),
14121 *this, OCD_AmbiguousCandidates, Args);
14122 // FIXME: Leaking incoming expressions!
14123 return ExprError();
14124
14125 case OR_Deleted:
14126 CandidateSet.NoteCandidates(
14127 PartialDiagnosticAt(UnresExpr->getMemberLoc(),
14128 PDiag(diag::err_ovl_deleted_member_call)
14129 << DeclName << MemExprE->getSourceRange()),
14130 *this, OCD_AllCandidates, Args);
14131 // FIXME: Leaking incoming expressions!
14132 return ExprError();
14133 }
14134
14135 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method);
14136
14137 // If overload resolution picked a static member, build a
14138 // non-member call based on that function.
14139 if (Method->isStatic()) {
14140 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args,
14141 RParenLoc);
14142 }
14143
14144 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens());
14145 }
14146
14147 QualType ResultType = Method->getReturnType();
14148 ExprValueKind VK = Expr::getValueKindForType(ResultType);
14149 ResultType = ResultType.getNonLValueExprType(Context);
14150
14151 assert(Method && "Member call to something that isn't a method?");
14152 const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
14153 CXXMemberCallExpr *TheCall =
14154 CXXMemberCallExpr::Create(Context, MemExprE, Args, ResultType, VK,
14155 RParenLoc, Proto->getNumParams());
14156
14157 // Check for a valid return type.
14158 if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(),
14159 TheCall, Method))
14160 return ExprError();
14161
14162 // Convert the object argument (for a non-static member function call).
14163 // We only need to do this if there was actually an overload; otherwise
14164 // it was done at lookup.
14165 if (!Method->isStatic()) {
14166 ExprResult ObjectArg =
14167 PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier,
14168 FoundDecl, Method);
14169 if (ObjectArg.isInvalid())
14170 return ExprError();
14171 MemExpr->setBase(ObjectArg.get());
14172 }
14173
14174 // Convert the rest of the arguments
14175 if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args,
14176 RParenLoc))
14177 return ExprError();
14178
14179 DiagnoseSentinelCalls(Method, LParenLoc, Args);
14180
14181 if (CheckFunctionCall(Method, TheCall, Proto))
14182 return ExprError();
14183
14184 // In the case the method to call was not selected by the overloading
14185 // resolution process, we still need to handle the enable_if attribute. Do
14186 // that here, so it will not hide previous -- and more relevant -- errors.
14187 if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) {
14188 if (const EnableIfAttr *Attr =
14189 CheckEnableIf(Method, LParenLoc, Args, true)) {
14190 Diag(MemE->getMemberLoc(),
14191 diag::err_ovl_no_viable_member_function_in_call)
14192 << Method << Method->getSourceRange();
14193 Diag(Method->getLocation(),
14194 diag::note_ovl_candidate_disabled_by_function_cond_attr)
14195 << Attr->getCond()->getSourceRange() << Attr->getMessage();
14196 return ExprError();
14197 }
14198 }
14199
14200 if ((isa<CXXConstructorDecl>(CurContext) ||
14201 isa<CXXDestructorDecl>(CurContext)) &&
14202 TheCall->getMethodDecl()->isPure()) {
14203 const CXXMethodDecl *MD = TheCall->getMethodDecl();
14204
14205 if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) &&
14206 MemExpr->performsVirtualDispatch(getLangOpts())) {
14207 Diag(MemExpr->getBeginLoc(),
14208 diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor)
14209 << MD->getDeclName() << isa<CXXDestructorDecl>(CurContext)
14210 << MD->getParent()->getDeclName();
14211
14212 Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName();
14213 if (getLangOpts().AppleKext)
14214 Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext)
14215 << MD->getParent()->getDeclName() << MD->getDeclName();
14216 }
14217 }
14218
14219 if (CXXDestructorDecl *DD =
14220 dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) {
14221 // a->A::f() doesn't go through the vtable, except in AppleKext mode.
14222 bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext;
14223 CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false,
14224 CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true,
14225 MemExpr->getMemberLoc());
14226 }
14227
14228 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall),
14229 TheCall->getMethodDecl());
14230 }
14231
14232 /// BuildCallToObjectOfClassType - Build a call to an object of class
14233 /// type (C++ [over.call.object]), which can end up invoking an
14234 /// overloaded function call operator (@c operator()) or performing a
14235 /// user-defined conversion on the object argument.
14236 ExprResult
BuildCallToObjectOfClassType(Scope * S,Expr * Obj,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc)14237 Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
14238 SourceLocation LParenLoc,
14239 MultiExprArg Args,
14240 SourceLocation RParenLoc) {
14241 if (checkPlaceholderForOverload(*this, Obj))
14242 return ExprError();
14243 ExprResult Object = Obj;
14244
14245 UnbridgedCastsSet UnbridgedCasts;
14246 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
14247 return ExprError();
14248
14249 assert(Object.get()->getType()->isRecordType() &&
14250 "Requires object type argument");
14251
14252 // C++ [over.call.object]p1:
14253 // If the primary-expression E in the function call syntax
14254 // evaluates to a class object of type "cv T", then the set of
14255 // candidate functions includes at least the function call
14256 // operators of T. The function call operators of T are obtained by
14257 // ordinary lookup of the name operator() in the context of
14258 // (E).operator().
14259 OverloadCandidateSet CandidateSet(LParenLoc,
14260 OverloadCandidateSet::CSK_Operator);
14261 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call);
14262
14263 if (RequireCompleteType(LParenLoc, Object.get()->getType(),
14264 diag::err_incomplete_object_call, Object.get()))
14265 return true;
14266
14267 const auto *Record = Object.get()->getType()->castAs<RecordType>();
14268 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName);
14269 LookupQualifiedName(R, Record->getDecl());
14270 R.suppressDiagnostics();
14271
14272 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
14273 Oper != OperEnd; ++Oper) {
14274 AddMethodCandidate(Oper.getPair(), Object.get()->getType(),
14275 Object.get()->Classify(Context), Args, CandidateSet,
14276 /*SuppressUserConversion=*/false);
14277 }
14278
14279 // C++ [over.call.object]p2:
14280 // In addition, for each (non-explicit in C++0x) conversion function
14281 // declared in T of the form
14282 //
14283 // operator conversion-type-id () cv-qualifier;
14284 //
14285 // where cv-qualifier is the same cv-qualification as, or a
14286 // greater cv-qualification than, cv, and where conversion-type-id
14287 // denotes the type "pointer to function of (P1,...,Pn) returning
14288 // R", or the type "reference to pointer to function of
14289 // (P1,...,Pn) returning R", or the type "reference to function
14290 // of (P1,...,Pn) returning R", a surrogate call function [...]
14291 // is also considered as a candidate function. Similarly,
14292 // surrogate call functions are added to the set of candidate
14293 // functions for each conversion function declared in an
14294 // accessible base class provided the function is not hidden
14295 // within T by another intervening declaration.
14296 const auto &Conversions =
14297 cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions();
14298 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
14299 NamedDecl *D = *I;
14300 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
14301 if (isa<UsingShadowDecl>(D))
14302 D = cast<UsingShadowDecl>(D)->getTargetDecl();
14303
14304 // Skip over templated conversion functions; they aren't
14305 // surrogates.
14306 if (isa<FunctionTemplateDecl>(D))
14307 continue;
14308
14309 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
14310 if (!Conv->isExplicit()) {
14311 // Strip the reference type (if any) and then the pointer type (if
14312 // any) to get down to what might be a function type.
14313 QualType ConvType = Conv->getConversionType().getNonReferenceType();
14314 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
14315 ConvType = ConvPtrType->getPointeeType();
14316
14317 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>())
14318 {
14319 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto,
14320 Object.get(), Args, CandidateSet);
14321 }
14322 }
14323 }
14324
14325 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14326
14327 // Perform overload resolution.
14328 OverloadCandidateSet::iterator Best;
14329 switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(),
14330 Best)) {
14331 case OR_Success:
14332 // Overload resolution succeeded; we'll build the appropriate call
14333 // below.
14334 break;
14335
14336 case OR_No_Viable_Function: {
14337 PartialDiagnostic PD =
14338 CandidateSet.empty()
14339 ? (PDiag(diag::err_ovl_no_oper)
14340 << Object.get()->getType() << /*call*/ 1
14341 << Object.get()->getSourceRange())
14342 : (PDiag(diag::err_ovl_no_viable_object_call)
14343 << Object.get()->getType() << Object.get()->getSourceRange());
14344 CandidateSet.NoteCandidates(
14345 PartialDiagnosticAt(Object.get()->getBeginLoc(), PD), *this,
14346 OCD_AllCandidates, Args);
14347 break;
14348 }
14349 case OR_Ambiguous:
14350 CandidateSet.NoteCandidates(
14351 PartialDiagnosticAt(Object.get()->getBeginLoc(),
14352 PDiag(diag::err_ovl_ambiguous_object_call)
14353 << Object.get()->getType()
14354 << Object.get()->getSourceRange()),
14355 *this, OCD_AmbiguousCandidates, Args);
14356 break;
14357
14358 case OR_Deleted:
14359 CandidateSet.NoteCandidates(
14360 PartialDiagnosticAt(Object.get()->getBeginLoc(),
14361 PDiag(diag::err_ovl_deleted_object_call)
14362 << Object.get()->getType()
14363 << Object.get()->getSourceRange()),
14364 *this, OCD_AllCandidates, Args);
14365 break;
14366 }
14367
14368 if (Best == CandidateSet.end())
14369 return true;
14370
14371 UnbridgedCasts.restore();
14372
14373 if (Best->Function == nullptr) {
14374 // Since there is no function declaration, this is one of the
14375 // surrogate candidates. Dig out the conversion function.
14376 CXXConversionDecl *Conv
14377 = cast<CXXConversionDecl>(
14378 Best->Conversions[0].UserDefined.ConversionFunction);
14379
14380 CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr,
14381 Best->FoundDecl);
14382 if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
14383 return ExprError();
14384 assert(Conv == Best->FoundDecl.getDecl() &&
14385 "Found Decl & conversion-to-functionptr should be same, right?!");
14386 // We selected one of the surrogate functions that converts the
14387 // object parameter to a function pointer. Perform the conversion
14388 // on the object argument, then let BuildCallExpr finish the job.
14389
14390 // Create an implicit member expr to refer to the conversion operator.
14391 // and then call it.
14392 ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl,
14393 Conv, HadMultipleCandidates);
14394 if (Call.isInvalid())
14395 return ExprError();
14396 // Record usage of conversion in an implicit cast.
14397 Call = ImplicitCastExpr::Create(Context, Call.get()->getType(),
14398 CK_UserDefinedConversion, Call.get(),
14399 nullptr, VK_RValue);
14400
14401 return BuildCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc);
14402 }
14403
14404 CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl);
14405
14406 // We found an overloaded operator(). Build a CXXOperatorCallExpr
14407 // that calls this method, using Object for the implicit object
14408 // parameter and passing along the remaining arguments.
14409 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
14410
14411 // An error diagnostic has already been printed when parsing the declaration.
14412 if (Method->isInvalidDecl())
14413 return ExprError();
14414
14415 const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
14416 unsigned NumParams = Proto->getNumParams();
14417
14418 DeclarationNameInfo OpLocInfo(
14419 Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc);
14420 OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc));
14421 ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
14422 Obj, HadMultipleCandidates,
14423 OpLocInfo.getLoc(),
14424 OpLocInfo.getInfo());
14425 if (NewFn.isInvalid())
14426 return true;
14427
14428 // The number of argument slots to allocate in the call. If we have default
14429 // arguments we need to allocate space for them as well. We additionally
14430 // need one more slot for the object parameter.
14431 unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams);
14432
14433 // Build the full argument list for the method call (the implicit object
14434 // parameter is placed at the beginning of the list).
14435 SmallVector<Expr *, 8> MethodArgs(NumArgsSlots);
14436
14437 bool IsError = false;
14438
14439 // Initialize the implicit object parameter.
14440 ExprResult ObjRes =
14441 PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr,
14442 Best->FoundDecl, Method);
14443 if (ObjRes.isInvalid())
14444 IsError = true;
14445 else
14446 Object = ObjRes;
14447 MethodArgs[0] = Object.get();
14448
14449 // Check the argument types.
14450 for (unsigned i = 0; i != NumParams; i++) {
14451 Expr *Arg;
14452 if (i < Args.size()) {
14453 Arg = Args[i];
14454
14455 // Pass the argument.
14456
14457 ExprResult InputInit
14458 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
14459 Context,
14460 Method->getParamDecl(i)),
14461 SourceLocation(), Arg);
14462
14463 IsError |= InputInit.isInvalid();
14464 Arg = InputInit.getAs<Expr>();
14465 } else {
14466 ExprResult DefArg
14467 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i));
14468 if (DefArg.isInvalid()) {
14469 IsError = true;
14470 break;
14471 }
14472
14473 Arg = DefArg.getAs<Expr>();
14474 }
14475
14476 MethodArgs[i + 1] = Arg;
14477 }
14478
14479 // If this is a variadic call, handle args passed through "...".
14480 if (Proto->isVariadic()) {
14481 // Promote the arguments (C99 6.5.2.2p7).
14482 for (unsigned i = NumParams, e = Args.size(); i < e; i++) {
14483 ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
14484 nullptr);
14485 IsError |= Arg.isInvalid();
14486 MethodArgs[i + 1] = Arg.get();
14487 }
14488 }
14489
14490 if (IsError)
14491 return true;
14492
14493 DiagnoseSentinelCalls(Method, LParenLoc, Args);
14494
14495 // Once we've built TheCall, all of the expressions are properly owned.
14496 QualType ResultTy = Method->getReturnType();
14497 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14498 ResultTy = ResultTy.getNonLValueExprType(Context);
14499
14500 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
14501 Context, OO_Call, NewFn.get(), MethodArgs, ResultTy, VK, RParenLoc,
14502 CurFPFeatureOverrides());
14503
14504 if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method))
14505 return true;
14506
14507 if (CheckFunctionCall(Method, TheCall, Proto))
14508 return true;
14509
14510 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
14511 }
14512
14513 /// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
14514 /// (if one exists), where @c Base is an expression of class type and
14515 /// @c Member is the name of the member we're trying to find.
14516 ExprResult
BuildOverloadedArrowExpr(Scope * S,Expr * Base,SourceLocation OpLoc,bool * NoArrowOperatorFound)14517 Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
14518 bool *NoArrowOperatorFound) {
14519 assert(Base->getType()->isRecordType() &&
14520 "left-hand side must have class type");
14521
14522 if (checkPlaceholderForOverload(*this, Base))
14523 return ExprError();
14524
14525 SourceLocation Loc = Base->getExprLoc();
14526
14527 // C++ [over.ref]p1:
14528 //
14529 // [...] An expression x->m is interpreted as (x.operator->())->m
14530 // for a class object x of type T if T::operator->() exists and if
14531 // the operator is selected as the best match function by the
14532 // overload resolution mechanism (13.3).
14533 DeclarationName OpName =
14534 Context.DeclarationNames.getCXXOperatorName(OO_Arrow);
14535 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator);
14536
14537 if (RequireCompleteType(Loc, Base->getType(),
14538 diag::err_typecheck_incomplete_tag, Base))
14539 return ExprError();
14540
14541 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
14542 LookupQualifiedName(R, Base->getType()->castAs<RecordType>()->getDecl());
14543 R.suppressDiagnostics();
14544
14545 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
14546 Oper != OperEnd; ++Oper) {
14547 AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context),
14548 None, CandidateSet, /*SuppressUserConversion=*/false);
14549 }
14550
14551 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14552
14553 // Perform overload resolution.
14554 OverloadCandidateSet::iterator Best;
14555 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
14556 case OR_Success:
14557 // Overload resolution succeeded; we'll build the call below.
14558 break;
14559
14560 case OR_No_Viable_Function: {
14561 auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Base);
14562 if (CandidateSet.empty()) {
14563 QualType BaseType = Base->getType();
14564 if (NoArrowOperatorFound) {
14565 // Report this specific error to the caller instead of emitting a
14566 // diagnostic, as requested.
14567 *NoArrowOperatorFound = true;
14568 return ExprError();
14569 }
14570 Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
14571 << BaseType << Base->getSourceRange();
14572 if (BaseType->isRecordType() && !BaseType->isPointerType()) {
14573 Diag(OpLoc, diag::note_typecheck_member_reference_suggestion)
14574 << FixItHint::CreateReplacement(OpLoc, ".");
14575 }
14576 } else
14577 Diag(OpLoc, diag::err_ovl_no_viable_oper)
14578 << "operator->" << Base->getSourceRange();
14579 CandidateSet.NoteCandidates(*this, Base, Cands);
14580 return ExprError();
14581 }
14582 case OR_Ambiguous:
14583 CandidateSet.NoteCandidates(
14584 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary)
14585 << "->" << Base->getType()
14586 << Base->getSourceRange()),
14587 *this, OCD_AmbiguousCandidates, Base);
14588 return ExprError();
14589
14590 case OR_Deleted:
14591 CandidateSet.NoteCandidates(
14592 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
14593 << "->" << Base->getSourceRange()),
14594 *this, OCD_AllCandidates, Base);
14595 return ExprError();
14596 }
14597
14598 CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl);
14599
14600 // Convert the object parameter.
14601 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
14602 ExprResult BaseResult =
14603 PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr,
14604 Best->FoundDecl, Method);
14605 if (BaseResult.isInvalid())
14606 return ExprError();
14607 Base = BaseResult.get();
14608
14609 // Build the operator call.
14610 ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
14611 Base, HadMultipleCandidates, OpLoc);
14612 if (FnExpr.isInvalid())
14613 return ExprError();
14614
14615 QualType ResultTy = Method->getReturnType();
14616 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14617 ResultTy = ResultTy.getNonLValueExprType(Context);
14618 CXXOperatorCallExpr *TheCall =
14619 CXXOperatorCallExpr::Create(Context, OO_Arrow, FnExpr.get(), Base,
14620 ResultTy, VK, OpLoc, CurFPFeatureOverrides());
14621
14622 if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method))
14623 return ExprError();
14624
14625 if (CheckFunctionCall(Method, TheCall,
14626 Method->getType()->castAs<FunctionProtoType>()))
14627 return ExprError();
14628
14629 return MaybeBindToTemporary(TheCall);
14630 }
14631
14632 /// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to
14633 /// a literal operator described by the provided lookup results.
BuildLiteralOperatorCall(LookupResult & R,DeclarationNameInfo & SuffixInfo,ArrayRef<Expr * > Args,SourceLocation LitEndLoc,TemplateArgumentListInfo * TemplateArgs)14634 ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R,
14635 DeclarationNameInfo &SuffixInfo,
14636 ArrayRef<Expr*> Args,
14637 SourceLocation LitEndLoc,
14638 TemplateArgumentListInfo *TemplateArgs) {
14639 SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc();
14640
14641 OverloadCandidateSet CandidateSet(UDSuffixLoc,
14642 OverloadCandidateSet::CSK_Normal);
14643 AddNonMemberOperatorCandidates(R.asUnresolvedSet(), Args, CandidateSet,
14644 TemplateArgs);
14645
14646 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14647
14648 // Perform overload resolution. This will usually be trivial, but might need
14649 // to perform substitutions for a literal operator template.
14650 OverloadCandidateSet::iterator Best;
14651 switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) {
14652 case OR_Success:
14653 case OR_Deleted:
14654 break;
14655
14656 case OR_No_Viable_Function:
14657 CandidateSet.NoteCandidates(
14658 PartialDiagnosticAt(UDSuffixLoc,
14659 PDiag(diag::err_ovl_no_viable_function_in_call)
14660 << R.getLookupName()),
14661 *this, OCD_AllCandidates, Args);
14662 return ExprError();
14663
14664 case OR_Ambiguous:
14665 CandidateSet.NoteCandidates(
14666 PartialDiagnosticAt(R.getNameLoc(), PDiag(diag::err_ovl_ambiguous_call)
14667 << R.getLookupName()),
14668 *this, OCD_AmbiguousCandidates, Args);
14669 return ExprError();
14670 }
14671
14672 FunctionDecl *FD = Best->Function;
14673 ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl,
14674 nullptr, HadMultipleCandidates,
14675 SuffixInfo.getLoc(),
14676 SuffixInfo.getInfo());
14677 if (Fn.isInvalid())
14678 return true;
14679
14680 // Check the argument types. This should almost always be a no-op, except
14681 // that array-to-pointer decay is applied to string literals.
14682 Expr *ConvArgs[2];
14683 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
14684 ExprResult InputInit = PerformCopyInitialization(
14685 InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)),
14686 SourceLocation(), Args[ArgIdx]);
14687 if (InputInit.isInvalid())
14688 return true;
14689 ConvArgs[ArgIdx] = InputInit.get();
14690 }
14691
14692 QualType ResultTy = FD->getReturnType();
14693 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14694 ResultTy = ResultTy.getNonLValueExprType(Context);
14695
14696 UserDefinedLiteral *UDL = UserDefinedLiteral::Create(
14697 Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy,
14698 VK, LitEndLoc, UDSuffixLoc);
14699
14700 if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD))
14701 return ExprError();
14702
14703 if (CheckFunctionCall(FD, UDL, nullptr))
14704 return ExprError();
14705
14706 return CheckForImmediateInvocation(MaybeBindToTemporary(UDL), FD);
14707 }
14708
14709 /// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
14710 /// given LookupResult is non-empty, it is assumed to describe a member which
14711 /// will be invoked. Otherwise, the function will be found via argument
14712 /// dependent lookup.
14713 /// CallExpr is set to a valid expression and FRS_Success returned on success,
14714 /// otherwise CallExpr is set to ExprError() and some non-success value
14715 /// is returned.
14716 Sema::ForRangeStatus
BuildForRangeBeginEndCall(SourceLocation Loc,SourceLocation RangeLoc,const DeclarationNameInfo & NameInfo,LookupResult & MemberLookup,OverloadCandidateSet * CandidateSet,Expr * Range,ExprResult * CallExpr)14717 Sema::BuildForRangeBeginEndCall(SourceLocation Loc,
14718 SourceLocation RangeLoc,
14719 const DeclarationNameInfo &NameInfo,
14720 LookupResult &MemberLookup,
14721 OverloadCandidateSet *CandidateSet,
14722 Expr *Range, ExprResult *CallExpr) {
14723 Scope *S = nullptr;
14724
14725 CandidateSet->clear(OverloadCandidateSet::CSK_Normal);
14726 if (!MemberLookup.empty()) {
14727 ExprResult MemberRef =
14728 BuildMemberReferenceExpr(Range, Range->getType(), Loc,
14729 /*IsPtr=*/false, CXXScopeSpec(),
14730 /*TemplateKWLoc=*/SourceLocation(),
14731 /*FirstQualifierInScope=*/nullptr,
14732 MemberLookup,
14733 /*TemplateArgs=*/nullptr, S);
14734 if (MemberRef.isInvalid()) {
14735 *CallExpr = ExprError();
14736 return FRS_DiagnosticIssued;
14737 }
14738 *CallExpr = BuildCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr);
14739 if (CallExpr->isInvalid()) {
14740 *CallExpr = ExprError();
14741 return FRS_DiagnosticIssued;
14742 }
14743 } else {
14744 UnresolvedSet<0> FoundNames;
14745 UnresolvedLookupExpr *Fn =
14746 UnresolvedLookupExpr::Create(Context, /*NamingClass=*/nullptr,
14747 NestedNameSpecifierLoc(), NameInfo,
14748 /*NeedsADL=*/true, /*Overloaded=*/false,
14749 FoundNames.begin(), FoundNames.end());
14750
14751 bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc,
14752 CandidateSet, CallExpr);
14753 if (CandidateSet->empty() || CandidateSetError) {
14754 *CallExpr = ExprError();
14755 return FRS_NoViableFunction;
14756 }
14757 OverloadCandidateSet::iterator Best;
14758 OverloadingResult OverloadResult =
14759 CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best);
14760
14761 if (OverloadResult == OR_No_Viable_Function) {
14762 *CallExpr = ExprError();
14763 return FRS_NoViableFunction;
14764 }
14765 *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range,
14766 Loc, nullptr, CandidateSet, &Best,
14767 OverloadResult,
14768 /*AllowTypoCorrection=*/false);
14769 if (CallExpr->isInvalid() || OverloadResult != OR_Success) {
14770 *CallExpr = ExprError();
14771 return FRS_DiagnosticIssued;
14772 }
14773 }
14774 return FRS_Success;
14775 }
14776
14777
14778 /// FixOverloadedFunctionReference - E is an expression that refers to
14779 /// a C++ overloaded function (possibly with some parentheses and
14780 /// perhaps a '&' around it). We have resolved the overloaded function
14781 /// to the function declaration Fn, so patch up the expression E to
14782 /// refer (possibly indirectly) to Fn. Returns the new expr.
FixOverloadedFunctionReference(Expr * E,DeclAccessPair Found,FunctionDecl * Fn)14783 Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found,
14784 FunctionDecl *Fn) {
14785 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
14786 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(),
14787 Found, Fn);
14788 if (SubExpr == PE->getSubExpr())
14789 return PE;
14790
14791 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr);
14792 }
14793
14794 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
14795 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(),
14796 Found, Fn);
14797 assert(Context.hasSameType(ICE->getSubExpr()->getType(),
14798 SubExpr->getType()) &&
14799 "Implicit cast type cannot be determined from overload");
14800 assert(ICE->path_empty() && "fixing up hierarchy conversion?");
14801 if (SubExpr == ICE->getSubExpr())
14802 return ICE;
14803
14804 return ImplicitCastExpr::Create(Context, ICE->getType(),
14805 ICE->getCastKind(),
14806 SubExpr, nullptr,
14807 ICE->getValueKind());
14808 }
14809
14810 if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
14811 if (!GSE->isResultDependent()) {
14812 Expr *SubExpr =
14813 FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn);
14814 if (SubExpr == GSE->getResultExpr())
14815 return GSE;
14816
14817 // Replace the resulting type information before rebuilding the generic
14818 // selection expression.
14819 ArrayRef<Expr *> A = GSE->getAssocExprs();
14820 SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end());
14821 unsigned ResultIdx = GSE->getResultIndex();
14822 AssocExprs[ResultIdx] = SubExpr;
14823
14824 return GenericSelectionExpr::Create(
14825 Context, GSE->getGenericLoc(), GSE->getControllingExpr(),
14826 GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(),
14827 GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(),
14828 ResultIdx);
14829 }
14830 // Rather than fall through to the unreachable, return the original generic
14831 // selection expression.
14832 return GSE;
14833 }
14834
14835 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) {
14836 assert(UnOp->getOpcode() == UO_AddrOf &&
14837 "Can only take the address of an overloaded function");
14838 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
14839 if (Method->isStatic()) {
14840 // Do nothing: static member functions aren't any different
14841 // from non-member functions.
14842 } else {
14843 // Fix the subexpression, which really has to be an
14844 // UnresolvedLookupExpr holding an overloaded member function
14845 // or template.
14846 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
14847 Found, Fn);
14848 if (SubExpr == UnOp->getSubExpr())
14849 return UnOp;
14850
14851 assert(isa<DeclRefExpr>(SubExpr)
14852 && "fixed to something other than a decl ref");
14853 assert(cast<DeclRefExpr>(SubExpr)->getQualifier()
14854 && "fixed to a member ref with no nested name qualifier");
14855
14856 // We have taken the address of a pointer to member
14857 // function. Perform the computation here so that we get the
14858 // appropriate pointer to member type.
14859 QualType ClassType
14860 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
14861 QualType MemPtrType
14862 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr());
14863 // Under the MS ABI, lock down the inheritance model now.
14864 if (Context.getTargetInfo().getCXXABI().isMicrosoft())
14865 (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType);
14866
14867 return UnaryOperator::Create(
14868 Context, SubExpr, UO_AddrOf, MemPtrType, VK_RValue, OK_Ordinary,
14869 UnOp->getOperatorLoc(), false, CurFPFeatureOverrides());
14870 }
14871 }
14872 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
14873 Found, Fn);
14874 if (SubExpr == UnOp->getSubExpr())
14875 return UnOp;
14876
14877 return UnaryOperator::Create(Context, SubExpr, UO_AddrOf,
14878 Context.getPointerType(SubExpr->getType()),
14879 VK_RValue, OK_Ordinary, UnOp->getOperatorLoc(),
14880 false, CurFPFeatureOverrides());
14881 }
14882
14883 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
14884 // FIXME: avoid copy.
14885 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
14886 if (ULE->hasExplicitTemplateArgs()) {
14887 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer);
14888 TemplateArgs = &TemplateArgsBuffer;
14889 }
14890
14891 DeclRefExpr *DRE =
14892 BuildDeclRefExpr(Fn, Fn->getType(), VK_LValue, ULE->getNameInfo(),
14893 ULE->getQualifierLoc(), Found.getDecl(),
14894 ULE->getTemplateKeywordLoc(), TemplateArgs);
14895 DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1);
14896 return DRE;
14897 }
14898
14899 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) {
14900 // FIXME: avoid copy.
14901 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
14902 if (MemExpr->hasExplicitTemplateArgs()) {
14903 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
14904 TemplateArgs = &TemplateArgsBuffer;
14905 }
14906
14907 Expr *Base;
14908
14909 // If we're filling in a static method where we used to have an
14910 // implicit member access, rewrite to a simple decl ref.
14911 if (MemExpr->isImplicitAccess()) {
14912 if (cast<CXXMethodDecl>(Fn)->isStatic()) {
14913 DeclRefExpr *DRE = BuildDeclRefExpr(
14914 Fn, Fn->getType(), VK_LValue, MemExpr->getNameInfo(),
14915 MemExpr->getQualifierLoc(), Found.getDecl(),
14916 MemExpr->getTemplateKeywordLoc(), TemplateArgs);
14917 DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1);
14918 return DRE;
14919 } else {
14920 SourceLocation Loc = MemExpr->getMemberLoc();
14921 if (MemExpr->getQualifier())
14922 Loc = MemExpr->getQualifierLoc().getBeginLoc();
14923 Base =
14924 BuildCXXThisExpr(Loc, MemExpr->getBaseType(), /*IsImplicit=*/true);
14925 }
14926 } else
14927 Base = MemExpr->getBase();
14928
14929 ExprValueKind valueKind;
14930 QualType type;
14931 if (cast<CXXMethodDecl>(Fn)->isStatic()) {
14932 valueKind = VK_LValue;
14933 type = Fn->getType();
14934 } else {
14935 valueKind = VK_RValue;
14936 type = Context.BoundMemberTy;
14937 }
14938
14939 return BuildMemberExpr(
14940 Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(),
14941 MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found,
14942 /*HadMultipleCandidates=*/true, MemExpr->getMemberNameInfo(),
14943 type, valueKind, OK_Ordinary, TemplateArgs);
14944 }
14945
14946 llvm_unreachable("Invalid reference to overloaded function");
14947 }
14948
FixOverloadedFunctionReference(ExprResult E,DeclAccessPair Found,FunctionDecl * Fn)14949 ExprResult Sema::FixOverloadedFunctionReference(ExprResult E,
14950 DeclAccessPair Found,
14951 FunctionDecl *Fn) {
14952 return FixOverloadedFunctionReference(E.get(), Found, Fn);
14953 }
14954