Bug Summary

File:clang/lib/Sema/SemaOverload.cpp
Warning:line 13735, column 21
Although the value stored to 'RHS' is used in the enclosing expression, the value is never actually read from 'RHS'

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name SemaOverload.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/include -I tools/clang/include -I include -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-01-16-232930-107970-1 -x c++ /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/clang/lib/Sema/SemaOverload.cpp
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
40using namespace clang;
41using namespace sema;
42
43using AllowedExplicit = Sema::AllowedExplicit;
44
45static 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.
52static ExprResult
53CreateFunctionRefExpr(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
83static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
84 bool InOverloadResolution,
85 StandardConversionSequence &SCS,
86 bool CStyle,
87 bool AllowObjCWritebackConversion);
88
89static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From,
90 QualType &ToType,
91 bool InOverloadResolution,
92 StandardConversionSequence &SCS,
93 bool CStyle);
94static OverloadingResult
95IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
96 UserDefinedConversionSequence& User,
97 OverloadCandidateSet& Conversions,
98 AllowedExplicit AllowExplicit,
99 bool AllowObjCConversionOnExplicit);
100
101static ImplicitConversionSequence::CompareKind
102CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
103 const StandardConversionSequence& SCS1,
104 const StandardConversionSequence& SCS2);
105
106static ImplicitConversionSequence::CompareKind
107CompareQualificationConversions(Sema &S,
108 const StandardConversionSequence& SCS1,
109 const StandardConversionSequence& SCS2);
110
111static ImplicitConversionSequence::CompareKind
112CompareDerivedToBaseConversions(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.
118ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) {
119 static const ImplicitConversionRank
120 Rank[(int)ICK_Num_Conversion_Kinds] = {
121 ICR_Exact_Match,
122 ICR_Exact_Match,
123 ICR_Exact_Match,
124 ICR_Exact_Match,
125 ICR_Exact_Match,
126 ICR_Exact_Match,
127 ICR_Promotion,
128 ICR_Promotion,
129 ICR_Promotion,
130 ICR_Conversion,
131 ICR_Conversion,
132 ICR_Conversion,
133 ICR_Conversion,
134 ICR_Conversion,
135 ICR_Conversion,
136 ICR_Conversion,
137 ICR_Conversion,
138 ICR_Conversion,
139 ICR_Conversion,
140 ICR_Conversion,
141 ICR_OCL_Scalar_Widening,
142 ICR_Complex_Real_Conversion,
143 ICR_Conversion,
144 ICR_Conversion,
145 ICR_Writeback_Conversion,
146 ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
147 // it was omitted by the patch that added
148 // ICK_Zero_Event_Conversion
149 ICR_C_Conversion,
150 ICR_C_Conversion_Extension
151 };
152 return Rank[(int)Kind];
153}
154
155/// GetImplicitConversionName - Return the name of this kind of
156/// implicit conversion.
157static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
158 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
159 "No conversion",
160 "Lvalue-to-rvalue",
161 "Array-to-pointer",
162 "Function-to-pointer",
163 "Function pointer conversion",
164 "Qualification",
165 "Integral promotion",
166 "Floating point promotion",
167 "Complex promotion",
168 "Integral conversion",
169 "Floating conversion",
170 "Complex conversion",
171 "Floating-integral conversion",
172 "Pointer conversion",
173 "Pointer-to-member conversion",
174 "Boolean conversion",
175 "Compatible-types conversion",
176 "Derived-to-base conversion",
177 "Vector conversion",
178 "SVE Vector conversion",
179 "Vector splat",
180 "Complex-real conversion",
181 "Block Pointer conversion",
182 "Transparent Union Conversion",
183 "Writeback conversion",
184 "OpenCL Zero Event Conversion",
185 "C specific type conversion",
186 "Incompatible pointer conversion"
187 };
188 return Name[Kind];
189}
190
191/// StandardConversionSequence - Set the standard conversion
192/// sequence to the identity conversion.
193void StandardConversionSequence::setAsIdentityConversion() {
194 First = ICK_Identity;
195 Second = ICK_Identity;
196 Third = ICK_Identity;
197 DeprecatedStringLiteralToCharPtr = false;
198 QualificationIncludesObjCLifetime = false;
199 ReferenceBinding = false;
200 DirectBinding = false;
201 IsLvalueReference = true;
202 BindsToFunctionLvalue = false;
203 BindsToRvalue = false;
204 BindsImplicitObjectArgumentWithoutRefQualifier = false;
205 ObjCLifetimeConversionBinding = false;
206 CopyConstructor = nullptr;
207}
208
209/// getRank - Retrieve the rank of this standard conversion sequence
210/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
211/// implicit conversions.
212ImplicitConversionRank StandardConversionSequence::getRank() const {
213 ImplicitConversionRank Rank = ICR_Exact_Match;
214 if (GetConversionRank(First) > Rank)
215 Rank = GetConversionRank(First);
216 if (GetConversionRank(Second) > Rank)
217 Rank = GetConversionRank(Second);
218 if (GetConversionRank(Third) > Rank)
219 Rank = GetConversionRank(Third);
220 return Rank;
221}
222
223/// isPointerConversionToBool - Determines whether this conversion is
224/// a conversion of a pointer or pointer-to-member to bool. This is
225/// used as part of the ranking of standard conversion sequences
226/// (C++ 13.3.3.2p4).
227bool StandardConversionSequence::isPointerConversionToBool() const {
228 // Note that FromType has not necessarily been transformed by the
229 // array-to-pointer or function-to-pointer implicit conversions, so
230 // check for their presence as well as checking whether FromType is
231 // a pointer.
232 if (getToType(1)->isBooleanType() &&
233 (getFromType()->isPointerType() ||
234 getFromType()->isMemberPointerType() ||
235 getFromType()->isObjCObjectPointerType() ||
236 getFromType()->isBlockPointerType() ||
237 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
238 return true;
239
240 return false;
241}
242
243/// isPointerConversionToVoidPointer - Determines whether this
244/// conversion is a conversion of a pointer to a void pointer. This is
245/// used as part of the ranking of standard conversion sequences (C++
246/// 13.3.3.2p4).
247bool
248StandardConversionSequence::
249isPointerConversionToVoidPointer(ASTContext& Context) const {
250 QualType FromType = getFromType();
251 QualType ToType = getToType(1);
252
253 // Note that FromType has not necessarily been transformed by the
254 // array-to-pointer implicit conversion, so check for its presence
255 // and redo the conversion to get a pointer.
256 if (First == ICK_Array_To_Pointer)
257 FromType = Context.getArrayDecayedType(FromType);
258
259 if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
260 if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
261 return ToPtrType->getPointeeType()->isVoidType();
262
263 return false;
264}
265
266/// Skip any implicit casts which could be either part of a narrowing conversion
267/// or after one in an implicit conversion.
268static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx,
269 const Expr *Converted) {
270 // We can have cleanups wrapping the converted expression; these need to be
271 // preserved so that destructors run if necessary.
272 if (auto *EWC = dyn_cast<ExprWithCleanups>(Converted)) {
273 Expr *Inner =
274 const_cast<Expr *>(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr()));
275 return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(),
276 EWC->getObjects());
277 }
278
279 while (auto *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
280 switch (ICE->getCastKind()) {
281 case CK_NoOp:
282 case CK_IntegralCast:
283 case CK_IntegralToBoolean:
284 case CK_IntegralToFloating:
285 case CK_BooleanToSignedIntegral:
286 case CK_FloatingToIntegral:
287 case CK_FloatingToBoolean:
288 case CK_FloatingCast:
289 Converted = ICE->getSubExpr();
290 continue;
291
292 default:
293 return Converted;
294 }
295 }
296
297 return Converted;
298}
299
300/// Check if this standard conversion sequence represents a narrowing
301/// conversion, according to C++11 [dcl.init.list]p7.
302///
303/// \param Ctx The AST context.
304/// \param Converted The result of applying this standard conversion sequence.
305/// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the
306/// value of the expression prior to the narrowing conversion.
307/// \param ConstantType If this is an NK_Constant_Narrowing conversion, the
308/// type of the expression prior to the narrowing conversion.
309/// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
310/// from floating point types to integral types should be ignored.
311NarrowingKind StandardConversionSequence::getNarrowingKind(
312 ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
313 QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
314 assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++")(static_cast <bool> (Ctx.getLangOpts().CPlusPlus &&
"narrowing check outside C++") ? void (0) : __assert_fail ("Ctx.getLangOpts().CPlusPlus && \"narrowing check outside C++\""
, "clang/lib/Sema/SemaOverload.cpp", 314, __extension__ __PRETTY_FUNCTION__
))
;
315
316 // C++11 [dcl.init.list]p7:
317 // A narrowing conversion is an implicit conversion ...
318 QualType FromType = getToType(0);
319 QualType ToType = getToType(1);
320
321 // A conversion to an enumeration type is narrowing if the conversion to
322 // the underlying type is narrowing. This only arises for expressions of
323 // the form 'Enum{init}'.
324 if (auto *ET = ToType->getAs<EnumType>())
325 ToType = ET->getDecl()->getIntegerType();
326
327 switch (Second) {
328 // 'bool' is an integral type; dispatch to the right place to handle it.
329 case ICK_Boolean_Conversion:
330 if (FromType->isRealFloatingType())
331 goto FloatingIntegralConversion;
332 if (FromType->isIntegralOrUnscopedEnumerationType())
333 goto IntegralConversion;
334 // -- from a pointer type or pointer-to-member type to bool, or
335 return NK_Type_Narrowing;
336
337 // -- from a floating-point type to an integer type, or
338 //
339 // -- from an integer type or unscoped enumeration type to a floating-point
340 // type, except where the source is a constant expression and the actual
341 // value after conversion will fit into the target type and will produce
342 // the original value when converted back to the original type, or
343 case ICK_Floating_Integral:
344 FloatingIntegralConversion:
345 if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
346 return NK_Type_Narrowing;
347 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
348 ToType->isRealFloatingType()) {
349 if (IgnoreFloatToIntegralConversion)
350 return NK_Not_Narrowing;
351 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
352 assert(Initializer && "Unknown conversion expression")(static_cast <bool> (Initializer && "Unknown conversion expression"
) ? void (0) : __assert_fail ("Initializer && \"Unknown conversion expression\""
, "clang/lib/Sema/SemaOverload.cpp", 352, __extension__ __PRETTY_FUNCTION__
))
;
353
354 // If it's value-dependent, we can't tell whether it's narrowing.
355 if (Initializer->isValueDependent())
356 return NK_Dependent_Narrowing;
357
358 if (Optional<llvm::APSInt> IntConstantValue =
359 Initializer->getIntegerConstantExpr(Ctx)) {
360 // Convert the integer to the floating type.
361 llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
362 Result.convertFromAPInt(*IntConstantValue, IntConstantValue->isSigned(),
363 llvm::APFloat::rmNearestTiesToEven);
364 // And back.
365 llvm::APSInt ConvertedValue = *IntConstantValue;
366 bool ignored;
367 Result.convertToInteger(ConvertedValue,
368 llvm::APFloat::rmTowardZero, &ignored);
369 // If the resulting value is different, this was a narrowing conversion.
370 if (*IntConstantValue != ConvertedValue) {
371 ConstantValue = APValue(*IntConstantValue);
372 ConstantType = Initializer->getType();
373 return NK_Constant_Narrowing;
374 }
375 } else {
376 // Variables are always narrowings.
377 return NK_Variable_Narrowing;
378 }
379 }
380 return NK_Not_Narrowing;
381
382 // -- from long double to double or float, or from double to float, except
383 // where the source is a constant expression and the actual value after
384 // conversion is within the range of values that can be represented (even
385 // if it cannot be represented exactly), or
386 case ICK_Floating_Conversion:
387 if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
388 Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
389 // FromType is larger than ToType.
390 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
391
392 // If it's value-dependent, we can't tell whether it's narrowing.
393 if (Initializer->isValueDependent())
394 return NK_Dependent_Narrowing;
395
396 if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
397 // Constant!
398 assert(ConstantValue.isFloat())(static_cast <bool> (ConstantValue.isFloat()) ? void (0
) : __assert_fail ("ConstantValue.isFloat()", "clang/lib/Sema/SemaOverload.cpp"
, 398, __extension__ __PRETTY_FUNCTION__))
;
399 llvm::APFloat FloatVal = ConstantValue.getFloat();
400 // Convert the source value into the target type.
401 bool ignored;
402 llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
403 Ctx.getFloatTypeSemantics(ToType),
404 llvm::APFloat::rmNearestTiesToEven, &ignored);
405 // If there was no overflow, the source value is within the range of
406 // values that can be represented.
407 if (ConvertStatus & llvm::APFloat::opOverflow) {
408 ConstantType = Initializer->getType();
409 return NK_Constant_Narrowing;
410 }
411 } else {
412 return NK_Variable_Narrowing;
413 }
414 }
415 return NK_Not_Narrowing;
416
417 // -- from an integer type or unscoped enumeration type to an integer type
418 // that cannot represent all the values of the original type, except where
419 // the source is a constant expression and the actual value after
420 // conversion will fit into the target type and will produce the original
421 // value when converted back to the original type.
422 case ICK_Integral_Conversion:
423 IntegralConversion: {
424 assert(FromType->isIntegralOrUnscopedEnumerationType())(static_cast <bool> (FromType->isIntegralOrUnscopedEnumerationType
()) ? void (0) : __assert_fail ("FromType->isIntegralOrUnscopedEnumerationType()"
, "clang/lib/Sema/SemaOverload.cpp", 424, __extension__ __PRETTY_FUNCTION__
))
;
425 assert(ToType->isIntegralOrUnscopedEnumerationType())(static_cast <bool> (ToType->isIntegralOrUnscopedEnumerationType
()) ? void (0) : __assert_fail ("ToType->isIntegralOrUnscopedEnumerationType()"
, "clang/lib/Sema/SemaOverload.cpp", 425, __extension__ __PRETTY_FUNCTION__
))
;
426 const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
427 const unsigned FromWidth = Ctx.getIntWidth(FromType);
428 const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
429 const unsigned ToWidth = Ctx.getIntWidth(ToType);
430
431 if (FromWidth > ToWidth ||
432 (FromWidth == ToWidth && FromSigned != ToSigned) ||
433 (FromSigned && !ToSigned)) {
434 // Not all values of FromType can be represented in ToType.
435 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
436
437 // If it's value-dependent, we can't tell whether it's narrowing.
438 if (Initializer->isValueDependent())
439 return NK_Dependent_Narrowing;
440
441 Optional<llvm::APSInt> OptInitializerValue;
442 if (!(OptInitializerValue = Initializer->getIntegerConstantExpr(Ctx))) {
443 // Such conversions on variables are always narrowing.
444 return NK_Variable_Narrowing;
445 }
446 llvm::APSInt &InitializerValue = *OptInitializerValue;
447 bool Narrowing = false;
448 if (FromWidth < ToWidth) {
449 // Negative -> unsigned is narrowing. Otherwise, more bits is never
450 // narrowing.
451 if (InitializerValue.isSigned() && InitializerValue.isNegative())
452 Narrowing = true;
453 } else {
454 // Add a bit to the InitializerValue so we don't have to worry about
455 // signed vs. unsigned comparisons.
456 InitializerValue = InitializerValue.extend(
457 InitializerValue.getBitWidth() + 1);
458 // Convert the initializer to and from the target width and signed-ness.
459 llvm::APSInt ConvertedValue = InitializerValue;
460 ConvertedValue = ConvertedValue.trunc(ToWidth);
461 ConvertedValue.setIsSigned(ToSigned);
462 ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
463 ConvertedValue.setIsSigned(InitializerValue.isSigned());
464 // If the result is different, this was a narrowing conversion.
465 if (ConvertedValue != InitializerValue)
466 Narrowing = true;
467 }
468 if (Narrowing) {
469 ConstantType = Initializer->getType();
470 ConstantValue = APValue(InitializerValue);
471 return NK_Constant_Narrowing;
472 }
473 }
474 return NK_Not_Narrowing;
475 }
476
477 default:
478 // Other kinds of conversions are not narrowings.
479 return NK_Not_Narrowing;
480 }
481}
482
483/// dump - Print this standard conversion sequence to standard
484/// error. Useful for debugging overloading issues.
485LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void StandardConversionSequence::dump() const {
486 raw_ostream &OS = llvm::errs();
487 bool PrintedSomething = false;
488 if (First != ICK_Identity) {
489 OS << GetImplicitConversionName(First);
490 PrintedSomething = true;
491 }
492
493 if (Second != ICK_Identity) {
494 if (PrintedSomething) {
495 OS << " -> ";
496 }
497 OS << GetImplicitConversionName(Second);
498
499 if (CopyConstructor) {
500 OS << " (by copy constructor)";
501 } else if (DirectBinding) {
502 OS << " (direct reference binding)";
503 } else if (ReferenceBinding) {
504 OS << " (reference binding)";
505 }
506 PrintedSomething = true;
507 }
508
509 if (Third != ICK_Identity) {
510 if (PrintedSomething) {
511 OS << " -> ";
512 }
513 OS << GetImplicitConversionName(Third);
514 PrintedSomething = true;
515 }
516
517 if (!PrintedSomething) {
518 OS << "No conversions required";
519 }
520}
521
522/// dump - Print this user-defined conversion sequence to standard
523/// error. Useful for debugging overloading issues.
524void UserDefinedConversionSequence::dump() const {
525 raw_ostream &OS = llvm::errs();
526 if (Before.First || Before.Second || Before.Third) {
527 Before.dump();
528 OS << " -> ";
529 }
530 if (ConversionFunction)
531 OS << '\'' << *ConversionFunction << '\'';
532 else
533 OS << "aggregate initialization";
534 if (After.First || After.Second || After.Third) {
535 OS << " -> ";
536 After.dump();
537 }
538}
539
540/// dump - Print this implicit conversion sequence to standard
541/// error. Useful for debugging overloading issues.
542void ImplicitConversionSequence::dump() const {
543 raw_ostream &OS = llvm::errs();
544 if (hasInitializerListContainerType())
545 OS << "Worst list element conversion: ";
546 switch (ConversionKind) {
547 case StandardConversion:
548 OS << "Standard conversion: ";
549 Standard.dump();
550 break;
551 case UserDefinedConversion:
552 OS << "User-defined conversion: ";
553 UserDefined.dump();
554 break;
555 case EllipsisConversion:
556 OS << "Ellipsis conversion";
557 break;
558 case AmbiguousConversion:
559 OS << "Ambiguous conversion";
560 break;
561 case BadConversion:
562 OS << "Bad conversion";
563 break;
564 }
565
566 OS << "\n";
567}
568
569void AmbiguousConversionSequence::construct() {
570 new (&conversions()) ConversionSet();
571}
572
573void AmbiguousConversionSequence::destruct() {
574 conversions().~ConversionSet();
575}
576
577void
578AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
579 FromTypePtr = O.FromTypePtr;
580 ToTypePtr = O.ToTypePtr;
581 new (&conversions()) ConversionSet(O.conversions());
582}
583
584namespace {
585 // Structure used by DeductionFailureInfo to store
586 // template argument information.
587 struct DFIArguments {
588 TemplateArgument FirstArg;
589 TemplateArgument SecondArg;
590 };
591 // Structure used by DeductionFailureInfo to store
592 // template parameter and template argument information.
593 struct DFIParamWithArguments : DFIArguments {
594 TemplateParameter Param;
595 };
596 // Structure used by DeductionFailureInfo to store template argument
597 // information and the index of the problematic call argument.
598 struct DFIDeducedMismatchArgs : DFIArguments {
599 TemplateArgumentList *TemplateArgs;
600 unsigned CallArgIndex;
601 };
602 // Structure used by DeductionFailureInfo to store information about
603 // unsatisfied constraints.
604 struct CNSInfo {
605 TemplateArgumentList *TemplateArgs;
606 ConstraintSatisfaction Satisfaction;
607 };
608}
609
610/// Convert from Sema's representation of template deduction information
611/// to the form used in overload-candidate information.
612DeductionFailureInfo
613clang::MakeDeductionFailureInfo(ASTContext &Context,
614 Sema::TemplateDeductionResult TDK,
615 TemplateDeductionInfo &Info) {
616 DeductionFailureInfo Result;
617 Result.Result = static_cast<unsigned>(TDK);
618 Result.HasDiagnostic = false;
619 switch (TDK) {
620 case Sema::TDK_Invalid:
621 case Sema::TDK_InstantiationDepth:
622 case Sema::TDK_TooManyArguments:
623 case Sema::TDK_TooFewArguments:
624 case Sema::TDK_MiscellaneousDeductionFailure:
625 case Sema::TDK_CUDATargetMismatch:
626 Result.Data = nullptr;
627 break;
628
629 case Sema::TDK_Incomplete:
630 case Sema::TDK_InvalidExplicitArguments:
631 Result.Data = Info.Param.getOpaqueValue();
632 break;
633
634 case Sema::TDK_DeducedMismatch:
635 case Sema::TDK_DeducedMismatchNested: {
636 // FIXME: Should allocate from normal heap so that we can free this later.
637 auto *Saved = new (Context) DFIDeducedMismatchArgs;
638 Saved->FirstArg = Info.FirstArg;
639 Saved->SecondArg = Info.SecondArg;
640 Saved->TemplateArgs = Info.take();
641 Saved->CallArgIndex = Info.CallArgIndex;
642 Result.Data = Saved;
643 break;
644 }
645
646 case Sema::TDK_NonDeducedMismatch: {
647 // FIXME: Should allocate from normal heap so that we can free this later.
648 DFIArguments *Saved = new (Context) DFIArguments;
649 Saved->FirstArg = Info.FirstArg;
650 Saved->SecondArg = Info.SecondArg;
651 Result.Data = Saved;
652 break;
653 }
654
655 case Sema::TDK_IncompletePack:
656 // FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
657 case Sema::TDK_Inconsistent:
658 case Sema::TDK_Underqualified: {
659 // FIXME: Should allocate from normal heap so that we can free this later.
660 DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
661 Saved->Param = Info.Param;
662 Saved->FirstArg = Info.FirstArg;
663 Saved->SecondArg = Info.SecondArg;
664 Result.Data = Saved;
665 break;
666 }
667
668 case Sema::TDK_SubstitutionFailure:
669 Result.Data = Info.take();
670 if (Info.hasSFINAEDiagnostic()) {
671 PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
672 SourceLocation(), PartialDiagnostic::NullDiagnostic());
673 Info.takeSFINAEDiagnostic(*Diag);
674 Result.HasDiagnostic = true;
675 }
676 break;
677
678 case Sema::TDK_ConstraintsNotSatisfied: {
679 CNSInfo *Saved = new (Context) CNSInfo;
680 Saved->TemplateArgs = Info.take();
681 Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
682 Result.Data = Saved;
683 break;
684 }
685
686 case Sema::TDK_Success:
687 case Sema::TDK_NonDependentConversionFailure:
688 llvm_unreachable("not a deduction failure")::llvm::llvm_unreachable_internal("not a deduction failure", "clang/lib/Sema/SemaOverload.cpp"
, 688)
;
689 }
690
691 return Result;
692}
693
694void DeductionFailureInfo::Destroy() {
695 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
696 case Sema::TDK_Success:
697 case Sema::TDK_Invalid:
698 case Sema::TDK_InstantiationDepth:
699 case Sema::TDK_Incomplete:
700 case Sema::TDK_TooManyArguments:
701 case Sema::TDK_TooFewArguments:
702 case Sema::TDK_InvalidExplicitArguments:
703 case Sema::TDK_CUDATargetMismatch:
704 case Sema::TDK_NonDependentConversionFailure:
705 break;
706
707 case Sema::TDK_IncompletePack:
708 case Sema::TDK_Inconsistent:
709 case Sema::TDK_Underqualified:
710 case Sema::TDK_DeducedMismatch:
711 case Sema::TDK_DeducedMismatchNested:
712 case Sema::TDK_NonDeducedMismatch:
713 // FIXME: Destroy the data?
714 Data = nullptr;
715 break;
716
717 case Sema::TDK_SubstitutionFailure:
718 // FIXME: Destroy the template argument list?
719 Data = nullptr;
720 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
721 Diag->~PartialDiagnosticAt();
722 HasDiagnostic = false;
723 }
724 break;
725
726 case Sema::TDK_ConstraintsNotSatisfied:
727 // FIXME: Destroy the template argument list?
728 Data = nullptr;
729 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
730 Diag->~PartialDiagnosticAt();
731 HasDiagnostic = false;
732 }
733 break;
734
735 // Unhandled
736 case Sema::TDK_MiscellaneousDeductionFailure:
737 break;
738 }
739}
740
741PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
742 if (HasDiagnostic)
743 return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
744 return nullptr;
745}
746
747TemplateParameter DeductionFailureInfo::getTemplateParameter() {
748 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
749 case Sema::TDK_Success:
750 case Sema::TDK_Invalid:
751 case Sema::TDK_InstantiationDepth:
752 case Sema::TDK_TooManyArguments:
753 case Sema::TDK_TooFewArguments:
754 case Sema::TDK_SubstitutionFailure:
755 case Sema::TDK_DeducedMismatch:
756 case Sema::TDK_DeducedMismatchNested:
757 case Sema::TDK_NonDeducedMismatch:
758 case Sema::TDK_CUDATargetMismatch:
759 case Sema::TDK_NonDependentConversionFailure:
760 case Sema::TDK_ConstraintsNotSatisfied:
761 return TemplateParameter();
762
763 case Sema::TDK_Incomplete:
764 case Sema::TDK_InvalidExplicitArguments:
765 return TemplateParameter::getFromOpaqueValue(Data);
766
767 case Sema::TDK_IncompletePack:
768 case Sema::TDK_Inconsistent:
769 case Sema::TDK_Underqualified:
770 return static_cast<DFIParamWithArguments*>(Data)->Param;
771
772 // Unhandled
773 case Sema::TDK_MiscellaneousDeductionFailure:
774 break;
775 }
776
777 return TemplateParameter();
778}
779
780TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
781 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
782 case Sema::TDK_Success:
783 case Sema::TDK_Invalid:
784 case Sema::TDK_InstantiationDepth:
785 case Sema::TDK_TooManyArguments:
786 case Sema::TDK_TooFewArguments:
787 case Sema::TDK_Incomplete:
788 case Sema::TDK_IncompletePack:
789 case Sema::TDK_InvalidExplicitArguments:
790 case Sema::TDK_Inconsistent:
791 case Sema::TDK_Underqualified:
792 case Sema::TDK_NonDeducedMismatch:
793 case Sema::TDK_CUDATargetMismatch:
794 case Sema::TDK_NonDependentConversionFailure:
795 return nullptr;
796
797 case Sema::TDK_DeducedMismatch:
798 case Sema::TDK_DeducedMismatchNested:
799 return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;
800
801 case Sema::TDK_SubstitutionFailure:
802 return static_cast<TemplateArgumentList*>(Data);
803
804 case Sema::TDK_ConstraintsNotSatisfied:
805 return static_cast<CNSInfo*>(Data)->TemplateArgs;
806
807 // Unhandled
808 case Sema::TDK_MiscellaneousDeductionFailure:
809 break;
810 }
811
812 return nullptr;
813}
814
815const TemplateArgument *DeductionFailureInfo::getFirstArg() {
816 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
817 case Sema::TDK_Success:
818 case Sema::TDK_Invalid:
819 case Sema::TDK_InstantiationDepth:
820 case Sema::TDK_Incomplete:
821 case Sema::TDK_TooManyArguments:
822 case Sema::TDK_TooFewArguments:
823 case Sema::TDK_InvalidExplicitArguments:
824 case Sema::TDK_SubstitutionFailure:
825 case Sema::TDK_CUDATargetMismatch:
826 case Sema::TDK_NonDependentConversionFailure:
827 case Sema::TDK_ConstraintsNotSatisfied:
828 return nullptr;
829
830 case Sema::TDK_IncompletePack:
831 case Sema::TDK_Inconsistent:
832 case Sema::TDK_Underqualified:
833 case Sema::TDK_DeducedMismatch:
834 case Sema::TDK_DeducedMismatchNested:
835 case Sema::TDK_NonDeducedMismatch:
836 return &static_cast<DFIArguments*>(Data)->FirstArg;
837
838 // Unhandled
839 case Sema::TDK_MiscellaneousDeductionFailure:
840 break;
841 }
842
843 return nullptr;
844}
845
846const TemplateArgument *DeductionFailureInfo::getSecondArg() {
847 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
848 case Sema::TDK_Success:
849 case Sema::TDK_Invalid:
850 case Sema::TDK_InstantiationDepth:
851 case Sema::TDK_Incomplete:
852 case Sema::TDK_IncompletePack:
853 case Sema::TDK_TooManyArguments:
854 case Sema::TDK_TooFewArguments:
855 case Sema::TDK_InvalidExplicitArguments:
856 case Sema::TDK_SubstitutionFailure:
857 case Sema::TDK_CUDATargetMismatch:
858 case Sema::TDK_NonDependentConversionFailure:
859 case Sema::TDK_ConstraintsNotSatisfied:
860 return nullptr;
861
862 case Sema::TDK_Inconsistent:
863 case Sema::TDK_Underqualified:
864 case Sema::TDK_DeducedMismatch:
865 case Sema::TDK_DeducedMismatchNested:
866 case Sema::TDK_NonDeducedMismatch:
867 return &static_cast<DFIArguments*>(Data)->SecondArg;
868
869 // Unhandled
870 case Sema::TDK_MiscellaneousDeductionFailure:
871 break;
872 }
873
874 return nullptr;
875}
876
877llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
878 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
879 case Sema::TDK_DeducedMismatch:
880 case Sema::TDK_DeducedMismatchNested:
881 return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;
882
883 default:
884 return llvm::None;
885 }
886}
887
888bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
889 OverloadedOperatorKind Op) {
890 if (!AllowRewrittenCandidates)
891 return false;
892 return Op == OO_EqualEqual || Op == OO_Spaceship;
893}
894
895bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
896 ASTContext &Ctx, const FunctionDecl *FD) {
897 if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator()))
898 return false;
899 // Don't bother adding a reversed candidate that can never be a better
900 // match than the non-reversed version.
901 return FD->getNumParams() != 2 ||
902 !Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(),
903 FD->getParamDecl(1)->getType()) ||
904 FD->hasAttr<EnableIfAttr>();
905}
906
907void OverloadCandidateSet::destroyCandidates() {
908 for (iterator i = begin(), e = end(); i != e; ++i) {
909 for (auto &C : i->Conversions)
910 C.~ImplicitConversionSequence();
911 if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
912 i->DeductionFailure.Destroy();
913 }
914}
915
916void OverloadCandidateSet::clear(CandidateSetKind CSK) {
917 destroyCandidates();
918 SlabAllocator.Reset();
919 NumInlineBytesUsed = 0;
920 Candidates.clear();
921 Functions.clear();
922 Kind = CSK;
923}
924
925namespace {
926 class UnbridgedCastsSet {
927 struct Entry {
928 Expr **Addr;
929 Expr *Saved;
930 };
931 SmallVector<Entry, 2> Entries;
932
933 public:
934 void save(Sema &S, Expr *&E) {
935 assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast))(static_cast <bool> (E->hasPlaceholderType(BuiltinType
::ARCUnbridgedCast)) ? void (0) : __assert_fail ("E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast)"
, "clang/lib/Sema/SemaOverload.cpp", 935, __extension__ __PRETTY_FUNCTION__
))
;
936 Entry entry = { &E, E };
937 Entries.push_back(entry);
938 E = S.stripARCUnbridgedCast(E);
939 }
940
941 void restore() {
942 for (SmallVectorImpl<Entry>::iterator
943 i = Entries.begin(), e = Entries.end(); i != e; ++i)
944 *i->Addr = i->Saved;
945 }
946 };
947}
948
949/// checkPlaceholderForOverload - Do any interesting placeholder-like
950/// preprocessing on the given expression.
951///
952/// \param unbridgedCasts a collection to which to add unbridged casts;
953/// without this, they will be immediately diagnosed as errors
954///
955/// Return true on unrecoverable error.
956static bool
957checkPlaceholderForOverload(Sema &S, Expr *&E,
958 UnbridgedCastsSet *unbridgedCasts = nullptr) {
959 if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) {
960 // We can't handle overloaded expressions here because overload
961 // resolution might reasonably tweak them.
962 if (placeholder->getKind() == BuiltinType::Overload) return false;
963
964 // If the context potentially accepts unbridged ARC casts, strip
965 // the unbridged cast and add it to the collection for later restoration.
966 if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
967 unbridgedCasts) {
968 unbridgedCasts->save(S, E);
969 return false;
970 }
971
972 // Go ahead and check everything else.
973 ExprResult result = S.CheckPlaceholderExpr(E);
974 if (result.isInvalid())
975 return true;
976
977 E = result.get();
978 return false;
979 }
980
981 // Nothing to do.
982 return false;
983}
984
985/// checkArgPlaceholdersForOverload - Check a set of call operands for
986/// placeholders.
987static bool checkArgPlaceholdersForOverload(Sema &S,
988 MultiExprArg Args,
989 UnbridgedCastsSet &unbridged) {
990 for (unsigned i = 0, e = Args.size(); i != e; ++i)
991 if (checkPlaceholderForOverload(S, Args[i], &unbridged))
992 return true;
993
994 return false;
995}
996
997/// Determine whether the given New declaration is an overload of the
998/// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
999/// New and Old cannot be overloaded, e.g., if New has the same signature as
1000/// some function in Old (C++ 1.3.10) or if the Old declarations aren't
1001/// functions (or function templates) at all. When it does return Ovl_Match or
1002/// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
1003/// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
1004/// declaration.
1005///
1006/// Example: Given the following input:
1007///
1008/// void f(int, float); // #1
1009/// void f(int, int); // #2
1010/// int f(int, int); // #3
1011///
1012/// When we process #1, there is no previous declaration of "f", so IsOverload
1013/// will not be used.
1014///
1015/// When we process #2, Old contains only the FunctionDecl for #1. By comparing
1016/// the parameter types, we see that #1 and #2 are overloaded (since they have
1017/// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
1018/// unchanged.
1019///
1020/// When we process #3, Old is an overload set containing #1 and #2. We compare
1021/// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
1022/// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
1023/// functions are not part of the signature), IsOverload returns Ovl_Match and
1024/// MatchedDecl will be set to point to the FunctionDecl for #2.
1025///
1026/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
1027/// by a using declaration. The rules for whether to hide shadow declarations
1028/// ignore some properties which otherwise figure into a function template's
1029/// signature.
1030Sema::OverloadKind
1031Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
1032 NamedDecl *&Match, bool NewIsUsingDecl) {
1033 for (LookupResult::iterator I = Old.begin(), E = Old.end();
1034 I != E; ++I) {
1035 NamedDecl *OldD = *I;
1036
1037 bool OldIsUsingDecl = false;
1038 if (isa<UsingShadowDecl>(OldD)) {
1039 OldIsUsingDecl = true;
1040
1041 // We can always introduce two using declarations into the same
1042 // context, even if they have identical signatures.
1043 if (NewIsUsingDecl) continue;
1044
1045 OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
1046 }
1047
1048 // A using-declaration does not conflict with another declaration
1049 // if one of them is hidden.
1050 if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
1051 continue;
1052
1053 // If either declaration was introduced by a using declaration,
1054 // we'll need to use slightly different rules for matching.
1055 // Essentially, these rules are the normal rules, except that
1056 // function templates hide function templates with different
1057 // return types or template parameter lists.
1058 bool UseMemberUsingDeclRules =
1059 (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
1060 !New->getFriendObjectKind();
1061
1062 if (FunctionDecl *OldF = OldD->getAsFunction()) {
1063 if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
1064 if (UseMemberUsingDeclRules && OldIsUsingDecl) {
1065 HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
1066 continue;
1067 }
1068
1069 if (!isa<FunctionTemplateDecl>(OldD) &&
1070 !shouldLinkPossiblyHiddenDecl(*I, New))
1071 continue;
1072
1073 Match = *I;
1074 return Ovl_Match;
1075 }
1076
1077 // Builtins that have custom typechecking or have a reference should
1078 // not be overloadable or redeclarable.
1079 if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
1080 Match = *I;
1081 return Ovl_NonFunction;
1082 }
1083 } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
1084 // We can overload with these, which can show up when doing
1085 // redeclaration checks for UsingDecls.
1086 assert(Old.getLookupKind() == LookupUsingDeclName)(static_cast <bool> (Old.getLookupKind() == LookupUsingDeclName
) ? void (0) : __assert_fail ("Old.getLookupKind() == LookupUsingDeclName"
, "clang/lib/Sema/SemaOverload.cpp", 1086, __extension__ __PRETTY_FUNCTION__
))
;
1087 } else if (isa<TagDecl>(OldD)) {
1088 // We can always overload with tags by hiding them.
1089 } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
1090 // Optimistically assume that an unresolved using decl will
1091 // overload; if it doesn't, we'll have to diagnose during
1092 // template instantiation.
1093 //
1094 // Exception: if the scope is dependent and this is not a class
1095 // member, the using declaration can only introduce an enumerator.
1096 if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
1097 Match = *I;
1098 return Ovl_NonFunction;
1099 }
1100 } else {
1101 // (C++ 13p1):
1102 // Only function declarations can be overloaded; object and type
1103 // declarations cannot be overloaded.
1104 Match = *I;
1105 return Ovl_NonFunction;
1106 }
1107 }
1108
1109 // C++ [temp.friend]p1:
1110 // For a friend function declaration that is not a template declaration:
1111 // -- if the name of the friend is a qualified or unqualified template-id,
1112 // [...], otherwise
1113 // -- if the name of the friend is a qualified-id and a matching
1114 // non-template function is found in the specified class or namespace,
1115 // the friend declaration refers to that function, otherwise,
1116 // -- if the name of the friend is a qualified-id and a matching function
1117 // template is found in the specified class or namespace, the friend
1118 // declaration refers to the deduced specialization of that function
1119 // template, otherwise
1120 // -- the name shall be an unqualified-id [...]
1121 // If we get here for a qualified friend declaration, we've just reached the
1122 // third bullet. If the type of the friend is dependent, skip this lookup
1123 // until instantiation.
1124 if (New->getFriendObjectKind() && New->getQualifier() &&
1125 !New->getDescribedFunctionTemplate() &&
1126 !New->getDependentSpecializationInfo() &&
1127 !New->getType()->isDependentType()) {
1128 LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
1129 TemplateSpecResult.addAllDecls(Old);
1130 if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
1131 /*QualifiedFriend*/true)) {
1132 New->setInvalidDecl();
1133 return Ovl_Overload;
1134 }
1135
1136 Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
1137 return Ovl_Match;
1138 }
1139
1140 return Ovl_Overload;
1141}
1142
1143bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
1144 bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs,
1145 bool ConsiderRequiresClauses) {
1146 // C++ [basic.start.main]p2: This function shall not be overloaded.
1147 if (New->isMain())
1148 return false;
1149
1150 // MSVCRT user defined entry points cannot be overloaded.
1151 if (New->isMSVCRTEntryPoint())
1152 return false;
1153
1154 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
1155 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
1156
1157 // C++ [temp.fct]p2:
1158 // A function template can be overloaded with other function templates
1159 // and with normal (non-template) functions.
1160 if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
1161 return true;
1162
1163 // Is the function New an overload of the function Old?
1164 QualType OldQType = Context.getCanonicalType(Old->getType());
1165 QualType NewQType = Context.getCanonicalType(New->getType());
1166
1167 // Compare the signatures (C++ 1.3.10) of the two functions to
1168 // determine whether they are overloads. If we find any mismatch
1169 // in the signature, they are overloads.
1170
1171 // If either of these functions is a K&R-style function (no
1172 // prototype), then we consider them to have matching signatures.
1173 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
1174 isa<FunctionNoProtoType>(NewQType.getTypePtr()))
1175 return false;
1176
1177 const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
1178 const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);
1179
1180 // The signature of a function includes the types of its
1181 // parameters (C++ 1.3.10), which includes the presence or absence
1182 // of the ellipsis; see C++ DR 357).
1183 if (OldQType != NewQType &&
1184 (OldType->getNumParams() != NewType->getNumParams() ||
1185 OldType->isVariadic() != NewType->isVariadic() ||
1186 !FunctionParamTypesAreEqual(OldType, NewType)))
1187 return true;
1188
1189 // C++ [temp.over.link]p4:
1190 // The signature of a function template consists of its function
1191 // signature, its return type and its template parameter list. The names
1192 // of the template parameters are significant only for establishing the
1193 // relationship between the template parameters and the rest of the
1194 // signature.
1195 //
1196 // We check the return type and template parameter lists for function
1197 // templates first; the remaining checks follow.
1198 //
1199 // However, we don't consider either of these when deciding whether
1200 // a member introduced by a shadow declaration is hidden.
1201 if (!UseMemberUsingDeclRules && NewTemplate &&
1202 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
1203 OldTemplate->getTemplateParameters(),
1204 false, TPL_TemplateMatch) ||
1205 !Context.hasSameType(Old->getDeclaredReturnType(),
1206 New->getDeclaredReturnType())))
1207 return true;
1208
1209 // If the function is a class member, its signature includes the
1210 // cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
1211 //
1212 // As part of this, also check whether one of the member functions
1213 // is static, in which case they are not overloads (C++
1214 // 13.1p2). While not part of the definition of the signature,
1215 // this check is important to determine whether these functions
1216 // can be overloaded.
1217 CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
1218 CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
1219 if (OldMethod && NewMethod &&
1220 !OldMethod->isStatic() && !NewMethod->isStatic()) {
1221 if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
1222 if (!UseMemberUsingDeclRules &&
1223 (OldMethod->getRefQualifier() == RQ_None ||
1224 NewMethod->getRefQualifier() == RQ_None)) {
1225 // C++0x [over.load]p2:
1226 // - Member function declarations with the same name and the same
1227 // parameter-type-list as well as member function template
1228 // declarations with the same name, the same parameter-type-list, and
1229 // the same template parameter lists cannot be overloaded if any of
1230 // them, but not all, have a ref-qualifier (8.3.5).
1231 Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
1232 << NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
1233 Diag(OldMethod->getLocation(), diag::note_previous_declaration);
1234 }
1235 return true;
1236 }
1237
1238 // We may not have applied the implicit const for a constexpr member
1239 // function yet (because we haven't yet resolved whether this is a static
1240 // or non-static member function). Add it now, on the assumption that this
1241 // is a redeclaration of OldMethod.
1242 auto OldQuals = OldMethod->getMethodQualifiers();
1243 auto NewQuals = NewMethod->getMethodQualifiers();
1244 if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
1245 !isa<CXXConstructorDecl>(NewMethod))
1246 NewQuals.addConst();
1247 // We do not allow overloading based off of '__restrict'.
1248 OldQuals.removeRestrict();
1249 NewQuals.removeRestrict();
1250 if (OldQuals != NewQuals)
1251 return true;
1252 }
1253
1254 // Though pass_object_size is placed on parameters and takes an argument, we
1255 // consider it to be a function-level modifier for the sake of function
1256 // identity. Either the function has one or more parameters with
1257 // pass_object_size or it doesn't.
1258 if (functionHasPassObjectSizeParams(New) !=
1259 functionHasPassObjectSizeParams(Old))
1260 return true;
1261
1262 // enable_if attributes are an order-sensitive part of the signature.
1263 for (specific_attr_iterator<EnableIfAttr>
1264 NewI = New->specific_attr_begin<EnableIfAttr>(),
1265 NewE = New->specific_attr_end<EnableIfAttr>(),
1266 OldI = Old->specific_attr_begin<EnableIfAttr>(),
1267 OldE = Old->specific_attr_end<EnableIfAttr>();
1268 NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
1269 if (NewI == NewE || OldI == OldE)
1270 return true;
1271 llvm::FoldingSetNodeID NewID, OldID;
1272 NewI->getCond()->Profile(NewID, Context, true);
1273 OldI->getCond()->Profile(OldID, Context, true);
1274 if (NewID != OldID)
1275 return true;
1276 }
1277
1278 if (getLangOpts().CUDA && ConsiderCudaAttrs) {
1279 // Don't allow overloading of destructors. (In theory we could, but it
1280 // would be a giant change to clang.)
1281 if (!isa<CXXDestructorDecl>(New)) {
1282 CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
1283 OldTarget = IdentifyCUDATarget(Old);
1284 if (NewTarget != CFT_InvalidTarget) {
1285 assert((OldTarget != CFT_InvalidTarget) &&(static_cast <bool> ((OldTarget != CFT_InvalidTarget) &&
"Unexpected invalid target.") ? void (0) : __assert_fail ("(OldTarget != CFT_InvalidTarget) && \"Unexpected invalid target.\""
, "clang/lib/Sema/SemaOverload.cpp", 1286, __extension__ __PRETTY_FUNCTION__
))
1286 "Unexpected invalid target.")(static_cast <bool> ((OldTarget != CFT_InvalidTarget) &&
"Unexpected invalid target.") ? void (0) : __assert_fail ("(OldTarget != CFT_InvalidTarget) && \"Unexpected invalid target.\""
, "clang/lib/Sema/SemaOverload.cpp", 1286, __extension__ __PRETTY_FUNCTION__
))
;
1287
1288 // Allow overloading of functions with same signature and different CUDA
1289 // target attributes.
1290 if (NewTarget != OldTarget)
1291 return true;
1292 }
1293 }
1294 }
1295
1296 if (ConsiderRequiresClauses) {
1297 Expr *NewRC = New->getTrailingRequiresClause(),
1298 *OldRC = Old->getTrailingRequiresClause();
1299 if ((NewRC != nullptr) != (OldRC != nullptr))
1300 // RC are most certainly different - these are overloads.
1301 return true;
1302
1303 if (NewRC) {
1304 llvm::FoldingSetNodeID NewID, OldID;
1305 NewRC->Profile(NewID, Context, /*Canonical=*/true);
1306 OldRC->Profile(OldID, Context, /*Canonical=*/true);
1307 if (NewID != OldID)
1308 // RCs are not equivalent - these are overloads.
1309 return true;
1310 }
1311 }
1312
1313 // The signatures match; this is not an overload.
1314 return false;
1315}
1316
1317/// Tries a user-defined conversion from From to ToType.
1318///
1319/// Produces an implicit conversion sequence for when a standard conversion
1320/// is not an option. See TryImplicitConversion for more information.
1321static ImplicitConversionSequence
1322TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
1323 bool SuppressUserConversions,
1324 AllowedExplicit AllowExplicit,
1325 bool InOverloadResolution,
1326 bool CStyle,
1327 bool AllowObjCWritebackConversion,
1328 bool AllowObjCConversionOnExplicit) {
1329 ImplicitConversionSequence ICS;
1330
1331 if (SuppressUserConversions) {
1332 // We're not in the case above, so there is no conversion that
1333 // we can perform.
1334 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1335 return ICS;
1336 }
1337
1338 // Attempt user-defined conversion.
1339 OverloadCandidateSet Conversions(From->getExprLoc(),
1340 OverloadCandidateSet::CSK_Normal);
1341 switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
1342 Conversions, AllowExplicit,
1343 AllowObjCConversionOnExplicit)) {
1344 case OR_Success:
1345 case OR_Deleted:
1346 ICS.setUserDefined();
1347 // C++ [over.ics.user]p4:
1348 // A conversion of an expression of class type to the same class
1349 // type is given Exact Match rank, and a conversion of an
1350 // expression of class type to a base class of that type is
1351 // given Conversion rank, in spite of the fact that a copy
1352 // constructor (i.e., a user-defined conversion function) is
1353 // called for those cases.
1354 if (CXXConstructorDecl *Constructor
1355 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
1356 QualType FromCanon
1357 = S.Context.getCanonicalType(From->getType().getUnqualifiedType());
1358 QualType ToCanon
1359 = S.Context.getCanonicalType(ToType).getUnqualifiedType();
1360 if (Constructor->isCopyConstructor() &&
1361 (FromCanon == ToCanon ||
1362 S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
1363 // Turn this into a "standard" conversion sequence, so that it
1364 // gets ranked with standard conversion sequences.
1365 DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
1366 ICS.setStandard();
1367 ICS.Standard.setAsIdentityConversion();
1368 ICS.Standard.setFromType(From->getType());
1369 ICS.Standard.setAllToTypes(ToType);
1370 ICS.Standard.CopyConstructor = Constructor;
1371 ICS.Standard.FoundCopyConstructor = Found;
1372 if (ToCanon != FromCanon)
1373 ICS.Standard.Second = ICK_Derived_To_Base;
1374 }
1375 }
1376 break;
1377
1378 case OR_Ambiguous:
1379 ICS.setAmbiguous();
1380 ICS.Ambiguous.setFromType(From->getType());
1381 ICS.Ambiguous.setToType(ToType);
1382 for (OverloadCandidateSet::iterator Cand = Conversions.begin();
1383 Cand != Conversions.end(); ++Cand)
1384 if (Cand->Best)
1385 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
1386 break;
1387
1388 // Fall through.
1389 case OR_No_Viable_Function:
1390 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1391 break;
1392 }
1393
1394 return ICS;
1395}
1396
1397/// TryImplicitConversion - Attempt to perform an implicit conversion
1398/// from the given expression (Expr) to the given type (ToType). This
1399/// function returns an implicit conversion sequence that can be used
1400/// to perform the initialization. Given
1401///
1402/// void f(float f);
1403/// void g(int i) { f(i); }
1404///
1405/// this routine would produce an implicit conversion sequence to
1406/// describe the initialization of f from i, which will be a standard
1407/// conversion sequence containing an lvalue-to-rvalue conversion (C++
1408/// 4.1) followed by a floating-integral conversion (C++ 4.9).
1409//
1410/// Note that this routine only determines how the conversion can be
1411/// performed; it does not actually perform the conversion. As such,
1412/// it will not produce any diagnostics if no conversion is available,
1413/// but will instead return an implicit conversion sequence of kind
1414/// "BadConversion".
1415///
1416/// If @p SuppressUserConversions, then user-defined conversions are
1417/// not permitted.
1418/// If @p AllowExplicit, then explicit user-defined conversions are
1419/// permitted.
1420///
1421/// \param AllowObjCWritebackConversion Whether we allow the Objective-C
1422/// writeback conversion, which allows __autoreleasing id* parameters to
1423/// be initialized with __strong id* or __weak id* arguments.
1424static ImplicitConversionSequence
1425TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
1426 bool SuppressUserConversions,
1427 AllowedExplicit AllowExplicit,
1428 bool InOverloadResolution,
1429 bool CStyle,
1430 bool AllowObjCWritebackConversion,
1431 bool AllowObjCConversionOnExplicit) {
1432 ImplicitConversionSequence ICS;
1433 if (IsStandardConversion(S, From, ToType, InOverloadResolution,
1434 ICS.Standard, CStyle, AllowObjCWritebackConversion)){
1435 ICS.setStandard();
1436 return ICS;
1437 }
1438
1439 if (!S.getLangOpts().CPlusPlus) {
1440 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1441 return ICS;
1442 }
1443
1444 // C++ [over.ics.user]p4:
1445 // A conversion of an expression of class type to the same class
1446 // type is given Exact Match rank, and a conversion of an
1447 // expression of class type to a base class of that type is
1448 // given Conversion rank, in spite of the fact that a copy/move
1449 // constructor (i.e., a user-defined conversion function) is
1450 // called for those cases.
1451 QualType FromType = From->getType();
1452 if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
1453 (S.Context.hasSameUnqualifiedType(FromType, ToType) ||
1454 S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
1455 ICS.setStandard();
1456 ICS.Standard.setAsIdentityConversion();
1457 ICS.Standard.setFromType(FromType);
1458 ICS.Standard.setAllToTypes(ToType);
1459
1460 // We don't actually check at this point whether there is a valid
1461 // copy/move constructor, since overloading just assumes that it
1462 // exists. When we actually perform initialization, we'll find the
1463 // appropriate constructor to copy the returned object, if needed.
1464 ICS.Standard.CopyConstructor = nullptr;
1465
1466 // Determine whether this is considered a derived-to-base conversion.
1467 if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
1468 ICS.Standard.Second = ICK_Derived_To_Base;
1469
1470 return ICS;
1471 }
1472
1473 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
1474 AllowExplicit, InOverloadResolution, CStyle,
1475 AllowObjCWritebackConversion,
1476 AllowObjCConversionOnExplicit);
1477}
1478
1479ImplicitConversionSequence
1480Sema::TryImplicitConversion(Expr *From, QualType ToType,
1481 bool SuppressUserConversions,
1482 AllowedExplicit AllowExplicit,
1483 bool InOverloadResolution,
1484 bool CStyle,
1485 bool AllowObjCWritebackConversion) {
1486 return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions,
1487 AllowExplicit, InOverloadResolution, CStyle,
1488 AllowObjCWritebackConversion,
1489 /*AllowObjCConversionOnExplicit=*/false);
1490}
1491
1492/// PerformImplicitConversion - Perform an implicit conversion of the
1493/// expression From to the type ToType. Returns the
1494/// converted expression. Flavor is the kind of conversion we're
1495/// performing, used in the error message. If @p AllowExplicit,
1496/// explicit user-defined conversions are permitted.
1497ExprResult Sema::PerformImplicitConversion(Expr *From, QualType ToType,
1498 AssignmentAction Action,
1499 bool AllowExplicit) {
1500 if (checkPlaceholderForOverload(*this, From))
1501 return ExprError();
1502
1503 // Objective-C ARC: Determine whether we will allow the writeback conversion.
1504 bool AllowObjCWritebackConversion
1505 = getLangOpts().ObjCAutoRefCount &&
1506 (Action == AA_Passing || Action == AA_Sending);
1507 if (getLangOpts().ObjC)
1508 CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
1509 From->getType(), From);
1510 ImplicitConversionSequence ICS = ::TryImplicitConversion(
1511 *this, From, ToType,
1512 /*SuppressUserConversions=*/false,
1513 AllowExplicit ? AllowedExplicit::All : AllowedExplicit::None,
1514 /*InOverloadResolution=*/false,
1515 /*CStyle=*/false, AllowObjCWritebackConversion,
1516 /*AllowObjCConversionOnExplicit=*/false);
1517 return PerformImplicitConversion(From, ToType, ICS, Action);
1518}
1519
1520/// Determine whether the conversion from FromType to ToType is a valid
1521/// conversion that strips "noexcept" or "noreturn" off the nested function
1522/// type.
1523bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
1524 QualType &ResultTy) {
1525 if (Context.hasSameUnqualifiedType(FromType, ToType))
1526 return false;
1527
1528 // Permit the conversion F(t __attribute__((noreturn))) -> F(t)
1529 // or F(t noexcept) -> F(t)
1530 // where F adds one of the following at most once:
1531 // - a pointer
1532 // - a member pointer
1533 // - a block pointer
1534 // Changes here need matching changes in FindCompositePointerType.
1535 CanQualType CanTo = Context.getCanonicalType(ToType);
1536 CanQualType CanFrom = Context.getCanonicalType(FromType);
1537 Type::TypeClass TyClass = CanTo->getTypeClass();
1538 if (TyClass != CanFrom->getTypeClass()) return false;
1539 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
1540 if (TyClass == Type::Pointer) {
1541 CanTo = CanTo.castAs<PointerType>()->getPointeeType();
1542 CanFrom = CanFrom.castAs<PointerType>()->getPointeeType();
1543 } else if (TyClass == Type::BlockPointer) {
1544 CanTo = CanTo.castAs<BlockPointerType>()->getPointeeType();
1545 CanFrom = CanFrom.castAs<BlockPointerType>()->getPointeeType();
1546 } else if (TyClass == Type::MemberPointer) {
1547 auto ToMPT = CanTo.castAs<MemberPointerType>();
1548 auto FromMPT = CanFrom.castAs<MemberPointerType>();
1549 // A function pointer conversion cannot change the class of the function.
1550 if (ToMPT->getClass() != FromMPT->getClass())
1551 return false;
1552 CanTo = ToMPT->getPointeeType();
1553 CanFrom = FromMPT->getPointeeType();
1554 } else {
1555 return false;
1556 }
1557
1558 TyClass = CanTo->getTypeClass();
1559 if (TyClass != CanFrom->getTypeClass()) return false;
1560 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
1561 return false;
1562 }
1563
1564 const auto *FromFn = cast<FunctionType>(CanFrom);
1565 FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();
1566
1567 const auto *ToFn = cast<FunctionType>(CanTo);
1568 FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();
1569
1570 bool Changed = false;
1571
1572 // Drop 'noreturn' if not present in target type.
1573 if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
1574 FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
1575 Changed = true;
1576 }
1577
1578 // Drop 'noexcept' if not present in target type.
1579 if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
1580 const auto *ToFPT = cast<FunctionProtoType>(ToFn);
1581 if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
1582 FromFn = cast<FunctionType>(
1583 Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
1584 EST_None)
1585 .getTypePtr());
1586 Changed = true;
1587 }
1588
1589 // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
1590 // only if the ExtParameterInfo lists of the two function prototypes can be
1591 // merged and the merged list is identical to ToFPT's ExtParameterInfo list.
1592 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
1593 bool CanUseToFPT, CanUseFromFPT;
1594 if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
1595 CanUseFromFPT, NewParamInfos) &&
1596 CanUseToFPT && !CanUseFromFPT) {
1597 FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
1598 ExtInfo.ExtParameterInfos =
1599 NewParamInfos.empty() ? nullptr : NewParamInfos.data();
1600 QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
1601 FromFPT->getParamTypes(), ExtInfo);
1602 FromFn = QT->getAs<FunctionType>();
1603 Changed = true;
1604 }
1605 }
1606
1607 if (!Changed)
1608 return false;
1609
1610 assert(QualType(FromFn, 0).isCanonical())(static_cast <bool> (QualType(FromFn, 0).isCanonical())
? void (0) : __assert_fail ("QualType(FromFn, 0).isCanonical()"
, "clang/lib/Sema/SemaOverload.cpp", 1610, __extension__ __PRETTY_FUNCTION__
))
;
1611 if (QualType(FromFn, 0) != CanTo) return false;
1612
1613 ResultTy = ToType;
1614 return true;
1615}
1616
1617/// Determine whether the conversion from FromType to ToType is a valid
1618/// vector conversion.
1619///
1620/// \param ICK Will be set to the vector conversion kind, if this is a vector
1621/// conversion.
1622static bool IsVectorConversion(Sema &S, QualType FromType,
1623 QualType ToType, ImplicitConversionKind &ICK) {
1624 // We need at least one of these types to be a vector type to have a vector
1625 // conversion.
1626 if (!ToType->isVectorType() && !FromType->isVectorType())
1627 return false;
1628
1629 // Identical types require no conversions.
1630 if (S.Context.hasSameUnqualifiedType(FromType, ToType))
1631 return false;
1632
1633 // There are no conversions between extended vector types, only identity.
1634 if (ToType->isExtVectorType()) {
1635 // There are no conversions between extended vector types other than the
1636 // identity conversion.
1637 if (FromType->isExtVectorType())
1638 return false;
1639
1640 // Vector splat from any arithmetic type to a vector.
1641 if (FromType->isArithmeticType()) {
1642 ICK = ICK_Vector_Splat;
1643 return true;
1644 }
1645 }
1646
1647 if (ToType->isSizelessBuiltinType() || FromType->isSizelessBuiltinType())
1648 if (S.Context.areCompatibleSveTypes(FromType, ToType) ||
1649 S.Context.areLaxCompatibleSveTypes(FromType, ToType)) {
1650 ICK = ICK_SVE_Vector_Conversion;
1651 return true;
1652 }
1653
1654 // We can perform the conversion between vector types in the following cases:
1655 // 1)vector types are equivalent AltiVec and GCC vector types
1656 // 2)lax vector conversions are permitted and the vector types are of the
1657 // same size
1658 // 3)the destination type does not have the ARM MVE strict-polymorphism
1659 // attribute, which inhibits lax vector conversion for overload resolution
1660 // only
1661 if (ToType->isVectorType() && FromType->isVectorType()) {
1662 if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
1663 (S.isLaxVectorConversion(FromType, ToType) &&
1664 !ToType->hasAttr(attr::ArmMveStrictPolymorphism))) {
1665 ICK = ICK_Vector_Conversion;
1666 return true;
1667 }
1668 }
1669
1670 return false;
1671}
1672
1673static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
1674 bool InOverloadResolution,
1675 StandardConversionSequence &SCS,
1676 bool CStyle);
1677
1678/// IsStandardConversion - Determines whether there is a standard
1679/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
1680/// expression From to the type ToType. Standard conversion sequences
1681/// only consider non-class types; for conversions that involve class
1682/// types, use TryImplicitConversion. If a conversion exists, SCS will
1683/// contain the standard conversion sequence required to perform this
1684/// conversion and this routine will return true. Otherwise, this
1685/// routine will return false and the value of SCS is unspecified.
1686static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
1687 bool InOverloadResolution,
1688 StandardConversionSequence &SCS,
1689 bool CStyle,
1690 bool AllowObjCWritebackConversion) {
1691 QualType FromType = From->getType();
1692
1693 // Standard conversions (C++ [conv])
1694 SCS.setAsIdentityConversion();
1695 SCS.IncompatibleObjC = false;
1696 SCS.setFromType(FromType);
1697 SCS.CopyConstructor = nullptr;
1698
1699 // There are no standard conversions for class types in C++, so
1700 // abort early. When overloading in C, however, we do permit them.
1701 if (S.getLangOpts().CPlusPlus &&
1702 (FromType->isRecordType() || ToType->isRecordType()))
1703 return false;
1704
1705 // The first conversion can be an lvalue-to-rvalue conversion,
1706 // array-to-pointer conversion, or function-to-pointer conversion
1707 // (C++ 4p1).
1708
1709 if (FromType == S.Context.OverloadTy) {
1710 DeclAccessPair AccessPair;
1711 if (FunctionDecl *Fn
1712 = S.ResolveAddressOfOverloadedFunction(From, ToType, false,
1713 AccessPair)) {
1714 // We were able to resolve the address of the overloaded function,
1715 // so we can convert to the type of that function.
1716 FromType = Fn->getType();
1717 SCS.setFromType(FromType);
1718
1719 // we can sometimes resolve &foo<int> regardless of ToType, so check
1720 // if the type matches (identity) or we are converting to bool
1721 if (!S.Context.hasSameUnqualifiedType(
1722 S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
1723 QualType resultTy;
1724 // if the function type matches except for [[noreturn]], it's ok
1725 if (!S.IsFunctionConversion(FromType,
1726 S.ExtractUnqualifiedFunctionType(ToType), resultTy))
1727 // otherwise, only a boolean conversion is standard
1728 if (!ToType->isBooleanType())
1729 return false;
1730 }
1731
1732 // Check if the "from" expression is taking the address of an overloaded
1733 // function and recompute the FromType accordingly. Take advantage of the
1734 // fact that non-static member functions *must* have such an address-of
1735 // expression.
1736 CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
1737 if (Method && !Method->isStatic()) {
1738 assert(isa<UnaryOperator>(From->IgnoreParens()) &&(static_cast <bool> (isa<UnaryOperator>(From->
IgnoreParens()) && "Non-unary operator on non-static member address"
) ? void (0) : __assert_fail ("isa<UnaryOperator>(From->IgnoreParens()) && \"Non-unary operator on non-static member address\""
, "clang/lib/Sema/SemaOverload.cpp", 1739, __extension__ __PRETTY_FUNCTION__
))
1739 "Non-unary operator on non-static member address")(static_cast <bool> (isa<UnaryOperator>(From->
IgnoreParens()) && "Non-unary operator on non-static member address"
) ? void (0) : __assert_fail ("isa<UnaryOperator>(From->IgnoreParens()) && \"Non-unary operator on non-static member address\""
, "clang/lib/Sema/SemaOverload.cpp", 1739, __extension__ __PRETTY_FUNCTION__
))
;
1740 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator on non-static member address"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator on non-static member address\""
, "clang/lib/Sema/SemaOverload.cpp", 1742, __extension__ __PRETTY_FUNCTION__
))
1741 == UO_AddrOf &&(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator on non-static member address"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator on non-static member address\""
, "clang/lib/Sema/SemaOverload.cpp", 1742, __extension__ __PRETTY_FUNCTION__
))
1742 "Non-address-of operator on non-static member address")(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator on non-static member address"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator on non-static member address\""
, "clang/lib/Sema/SemaOverload.cpp", 1742, __extension__ __PRETTY_FUNCTION__
))
;
1743 const Type *ClassType
1744 = S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
1745 FromType = S.Context.getMemberPointerType(FromType, ClassType);
1746 } else if (isa<UnaryOperator>(From->IgnoreParens())) {
1747 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator for overloaded function expression"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator for overloaded function expression\""
, "clang/lib/Sema/SemaOverload.cpp", 1749, __extension__ __PRETTY_FUNCTION__
))
1748 UO_AddrOf &&(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator for overloaded function expression"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator for overloaded function expression\""
, "clang/lib/Sema/SemaOverload.cpp", 1749, __extension__ __PRETTY_FUNCTION__
))
1749 "Non-address-of operator for overloaded function expression")(static_cast <bool> (cast<UnaryOperator>(From->
IgnoreParens())->getOpcode() == UO_AddrOf && "Non-address-of operator for overloaded function expression"
) ? void (0) : __assert_fail ("cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == UO_AddrOf && \"Non-address-of operator for overloaded function expression\""
, "clang/lib/Sema/SemaOverload.cpp", 1749, __extension__ __PRETTY_FUNCTION__
))
;
1750 FromType = S.Context.getPointerType(FromType);
1751 }
1752
1753 // Check that we've computed the proper type after overload resolution.
1754 // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
1755 // be calling it from within an NDEBUG block.
1756 assert(S.Context.hasSameType((static_cast <bool> (S.Context.hasSameType( FromType, S
.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType
())) ? void (0) : __assert_fail ("S.Context.hasSameType( FromType, S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())"
, "clang/lib/Sema/SemaOverload.cpp", 1758, __extension__ __PRETTY_FUNCTION__
))
1757 FromType,(static_cast <bool> (S.Context.hasSameType( FromType, S
.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType
())) ? void (0) : __assert_fail ("S.Context.hasSameType( FromType, S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())"
, "clang/lib/Sema/SemaOverload.cpp", 1758, __extension__ __PRETTY_FUNCTION__
))
1758 S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()))(static_cast <bool> (S.Context.hasSameType( FromType, S
.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType
())) ? void (0) : __assert_fail ("S.Context.hasSameType( FromType, S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())"
, "clang/lib/Sema/SemaOverload.cpp", 1758, __extension__ __PRETTY_FUNCTION__
))
;
1759 } else {
1760 return false;
1761 }
1762 }
1763 // Lvalue-to-rvalue conversion (C++11 4.1):
1764 // A glvalue (3.10) of a non-function, non-array type T can
1765 // be converted to a prvalue.
1766 bool argIsLValue = From->isGLValue();
1767 if (argIsLValue &&
1768 !FromType->isFunctionType() && !FromType->isArrayType() &&
1769 S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
1770 SCS.First = ICK_Lvalue_To_Rvalue;
1771
1772 // C11 6.3.2.1p2:
1773 // ... if the lvalue has atomic type, the value has the non-atomic version
1774 // of the type of the lvalue ...
1775 if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
1776 FromType = Atomic->getValueType();
1777
1778 // If T is a non-class type, the type of the rvalue is the
1779 // cv-unqualified version of T. Otherwise, the type of the rvalue
1780 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
1781 // just strip the qualifiers because they don't matter.
1782 FromType = FromType.getUnqualifiedType();
1783 } else if (FromType->isArrayType()) {
1784 // Array-to-pointer conversion (C++ 4.2)
1785 SCS.First = ICK_Array_To_Pointer;
1786
1787 // An lvalue or rvalue of type "array of N T" or "array of unknown
1788 // bound of T" can be converted to an rvalue of type "pointer to
1789 // T" (C++ 4.2p1).
1790 FromType = S.Context.getArrayDecayedType(FromType);
1791
1792 if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
1793 // This conversion is deprecated in C++03 (D.4)
1794 SCS.DeprecatedStringLiteralToCharPtr = true;
1795
1796 // For the purpose of ranking in overload resolution
1797 // (13.3.3.1.1), this conversion is considered an
1798 // array-to-pointer conversion followed by a qualification
1799 // conversion (4.4). (C++ 4.2p2)
1800 SCS.Second = ICK_Identity;
1801 SCS.Third = ICK_Qualification;
1802 SCS.QualificationIncludesObjCLifetime = false;
1803 SCS.setAllToTypes(FromType);
1804 return true;
1805 }
1806 } else if (FromType->isFunctionType() && argIsLValue) {
1807 // Function-to-pointer conversion (C++ 4.3).
1808 SCS.First = ICK_Function_To_Pointer;
1809
1810 if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
1811 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
1812 if (!S.checkAddressOfFunctionIsAvailable(FD))
1813 return false;
1814
1815 // An lvalue of function type T can be converted to an rvalue of
1816 // type "pointer to T." The result is a pointer to the
1817 // function. (C++ 4.3p1).
1818 FromType = S.Context.getPointerType(FromType);
1819 } else {
1820 // We don't require any conversions for the first step.
1821 SCS.First = ICK_Identity;
1822 }
1823 SCS.setToType(0, FromType);
1824
1825 // The second conversion can be an integral promotion, floating
1826 // point promotion, integral conversion, floating point conversion,
1827 // floating-integral conversion, pointer conversion,
1828 // pointer-to-member conversion, or boolean conversion (C++ 4p1).
1829 // For overloading in C, this can also be a "compatible-type"
1830 // conversion.
1831 bool IncompatibleObjC = false;
1832 ImplicitConversionKind SecondICK = ICK_Identity;
1833 if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
1834 // The unqualified versions of the types are the same: there's no
1835 // conversion to do.
1836 SCS.Second = ICK_Identity;
1837 } else if (S.IsIntegralPromotion(From, FromType, ToType)) {
1838 // Integral promotion (C++ 4.5).
1839 SCS.Second = ICK_Integral_Promotion;
1840 FromType = ToType.getUnqualifiedType();
1841 } else if (S.IsFloatingPointPromotion(FromType, ToType)) {
1842 // Floating point promotion (C++ 4.6).
1843 SCS.Second = ICK_Floating_Promotion;
1844 FromType = ToType.getUnqualifiedType();
1845 } else if (S.IsComplexPromotion(FromType, ToType)) {
1846 // Complex promotion (Clang extension)
1847 SCS.Second = ICK_Complex_Promotion;
1848 FromType = ToType.getUnqualifiedType();
1849 } else if (ToType->isBooleanType() &&
1850 (FromType->isArithmeticType() ||
1851 FromType->isAnyPointerType() ||
1852 FromType->isBlockPointerType() ||
1853 FromType->isMemberPointerType())) {
1854 // Boolean conversions (C++ 4.12).
1855 SCS.Second = ICK_Boolean_Conversion;
1856 FromType = S.Context.BoolTy;
1857 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
1858 ToType->isIntegralType(S.Context)) {
1859 // Integral conversions (C++ 4.7).
1860 SCS.Second = ICK_Integral_Conversion;
1861 FromType = ToType.getUnqualifiedType();
1862 } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
1863 // Complex conversions (C99 6.3.1.6)
1864 SCS.Second = ICK_Complex_Conversion;
1865 FromType = ToType.getUnqualifiedType();
1866 } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
1867 (ToType->isAnyComplexType() && FromType->isArithmeticType())) {
1868 // Complex-real conversions (C99 6.3.1.7)
1869 SCS.Second = ICK_Complex_Real;
1870 FromType = ToType.getUnqualifiedType();
1871 } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
1872 // FIXME: disable conversions between long double, __ibm128 and __float128
1873 // if their representation is different until there is back end support
1874 // We of course allow this conversion if long double is really double.
1875
1876 // Conversions between bfloat and other floats are not permitted.
1877 if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty)
1878 return false;
1879
1880 // Conversions between IEEE-quad and IBM-extended semantics are not
1881 // permitted.
1882 const llvm::fltSemantics &FromSem =
1883 S.Context.getFloatTypeSemantics(FromType);
1884 const llvm::fltSemantics &ToSem = S.Context.getFloatTypeSemantics(ToType);
1885 if ((&FromSem == &llvm::APFloat::PPCDoubleDouble() &&
1886 &ToSem == &llvm::APFloat::IEEEquad()) ||
1887 (&FromSem == &llvm::APFloat::IEEEquad() &&
1888 &ToSem == &llvm::APFloat::PPCDoubleDouble()))
1889 return false;
1890
1891 // Floating point conversions (C++ 4.8).
1892 SCS.Second = ICK_Floating_Conversion;
1893 FromType = ToType.getUnqualifiedType();
1894 } else if ((FromType->isRealFloatingType() &&
1895 ToType->isIntegralType(S.Context)) ||
1896 (FromType->isIntegralOrUnscopedEnumerationType() &&
1897 ToType->isRealFloatingType())) {
1898 // Conversions between bfloat and int are not permitted.
1899 if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
1900 return false;
1901
1902 // Floating-integral conversions (C++ 4.9).
1903 SCS.Second = ICK_Floating_Integral;
1904 FromType = ToType.getUnqualifiedType();
1905 } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
1906 SCS.Second = ICK_Block_Pointer_Conversion;
1907 } else if (AllowObjCWritebackConversion &&
1908 S.isObjCWritebackConversion(FromType, ToType, FromType)) {
1909 SCS.Second = ICK_Writeback_Conversion;
1910 } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
1911 FromType, IncompatibleObjC)) {
1912 // Pointer conversions (C++ 4.10).
1913 SCS.Second = ICK_Pointer_Conversion;
1914 SCS.IncompatibleObjC = IncompatibleObjC;
1915 FromType = FromType.getUnqualifiedType();
1916 } else if (S.IsMemberPointerConversion(From, FromType, ToType,
1917 InOverloadResolution, FromType)) {
1918 // Pointer to member conversions (4.11).
1919 SCS.Second = ICK_Pointer_Member;
1920 } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
1921 SCS.Second = SecondICK;
1922 FromType = ToType.getUnqualifiedType();
1923 } else if (!S.getLangOpts().CPlusPlus &&
1924 S.Context.typesAreCompatible(ToType, FromType)) {
1925 // Compatible conversions (Clang extension for C function overloading)
1926 SCS.Second = ICK_Compatible_Conversion;
1927 FromType = ToType.getUnqualifiedType();
1928 } else if (IsTransparentUnionStandardConversion(S, From, ToType,
1929 InOverloadResolution,
1930 SCS, CStyle)) {
1931 SCS.Second = ICK_TransparentUnionConversion;
1932 FromType = ToType;
1933 } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
1934 CStyle)) {
1935 // tryAtomicConversion has updated the standard conversion sequence
1936 // appropriately.
1937 return true;
1938 } else if (ToType->isEventT() &&
1939 From->isIntegerConstantExpr(S.getASTContext()) &&
1940 From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
1941 SCS.Second = ICK_Zero_Event_Conversion;
1942 FromType = ToType;
1943 } else if (ToType->isQueueT() &&
1944 From->isIntegerConstantExpr(S.getASTContext()) &&
1945 (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
1946 SCS.Second = ICK_Zero_Queue_Conversion;
1947 FromType = ToType;
1948 } else if (ToType->isSamplerT() &&
1949 From->isIntegerConstantExpr(S.getASTContext())) {
1950 SCS.Second = ICK_Compatible_Conversion;
1951 FromType = ToType;
1952 } else {
1953 // No second conversion required.
1954 SCS.Second = ICK_Identity;
1955 }
1956 SCS.setToType(1, FromType);
1957
1958 // The third conversion can be a function pointer conversion or a
1959 // qualification conversion (C++ [conv.fctptr], [conv.qual]).
1960 bool ObjCLifetimeConversion;
1961 if (S.IsFunctionConversion(FromType, ToType, FromType)) {
1962 // Function pointer conversions (removing 'noexcept') including removal of
1963 // 'noreturn' (Clang extension).
1964 SCS.Third = ICK_Function_Conversion;
1965 } else if (S.IsQualificationConversion(FromType, ToType, CStyle,
1966 ObjCLifetimeConversion)) {
1967 SCS.Third = ICK_Qualification;
1968 SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
1969 FromType = ToType;
1970 } else {
1971 // No conversion required
1972 SCS.Third = ICK_Identity;
1973 }
1974
1975 // C++ [over.best.ics]p6:
1976 // [...] Any difference in top-level cv-qualification is
1977 // subsumed by the initialization itself and does not constitute
1978 // a conversion. [...]
1979 QualType CanonFrom = S.Context.getCanonicalType(FromType);
1980 QualType CanonTo = S.Context.getCanonicalType(ToType);
1981 if (CanonFrom.getLocalUnqualifiedType()
1982 == CanonTo.getLocalUnqualifiedType() &&
1983 CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
1984 FromType = ToType;
1985 CanonFrom = CanonTo;
1986 }
1987
1988 SCS.setToType(2, FromType);
1989
1990 if (CanonFrom == CanonTo)
1991 return true;
1992
1993 // If we have not converted the argument type to the parameter type,
1994 // this is a bad conversion sequence, unless we're resolving an overload in C.
1995 if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
1996 return false;
1997
1998 ExprResult ER = ExprResult{From};
1999 Sema::AssignConvertType Conv =
2000 S.CheckSingleAssignmentConstraints(ToType, ER,
2001 /*Diagnose=*/false,
2002 /*DiagnoseCFAudited=*/false,
2003 /*ConvertRHS=*/false);
2004 ImplicitConversionKind SecondConv;
2005 switch (Conv) {
2006 case Sema::Compatible:
2007 SecondConv = ICK_C_Only_Conversion;
2008 break;
2009 // For our purposes, discarding qualifiers is just as bad as using an
2010 // incompatible pointer. Note that an IncompatiblePointer conversion can drop
2011 // qualifiers, as well.
2012 case Sema::CompatiblePointerDiscardsQualifiers:
2013 case Sema::IncompatiblePointer:
2014 case Sema::IncompatiblePointerSign:
2015 SecondConv = ICK_Incompatible_Pointer_Conversion;
2016 break;
2017 default:
2018 return false;
2019 }
2020
2021 // First can only be an lvalue conversion, so we pretend that this was the
2022 // second conversion. First should already be valid from earlier in the
2023 // function.
2024 SCS.Second = SecondConv;
2025 SCS.setToType(1, ToType);
2026
2027 // Third is Identity, because Second should rank us worse than any other
2028 // conversion. This could also be ICK_Qualification, but it's simpler to just
2029 // lump everything in with the second conversion, and we don't gain anything
2030 // from making this ICK_Qualification.
2031 SCS.Third = ICK_Identity;
2032 SCS.setToType(2, ToType);
2033 return true;
2034}
2035
2036static bool
2037IsTransparentUnionStandardConversion(Sema &S, Expr* From,
2038 QualType &ToType,
2039 bool InOverloadResolution,
2040 StandardConversionSequence &SCS,
2041 bool CStyle) {
2042
2043 const RecordType *UT = ToType->getAsUnionType();
2044 if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
2045 return false;
2046 // The field to initialize within the transparent union.
2047 RecordDecl *UD = UT->getDecl();
2048 // It's compatible if the expression matches any of the fields.
2049 for (const auto *it : UD->fields()) {
2050 if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
2051 CStyle, /*AllowObjCWritebackConversion=*/false)) {
2052 ToType = it->getType();
2053 return true;
2054 }
2055 }
2056 return false;
2057}
2058
2059/// IsIntegralPromotion - Determines whether the conversion from the
2060/// expression From (whose potentially-adjusted type is FromType) to
2061/// ToType is an integral promotion (C++ 4.5). If so, returns true and
2062/// sets PromotedType to the promoted type.
2063bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
2064 const BuiltinType *To = ToType->getAs<BuiltinType>();
2065 // All integers are built-in.
2066 if (!To) {
2067 return false;
2068 }
2069
2070 // An rvalue of type char, signed char, unsigned char, short int, or
2071 // unsigned short int can be converted to an rvalue of type int if
2072 // int can represent all the values of the source type; otherwise,
2073 // the source rvalue can be converted to an rvalue of type unsigned
2074 // int (C++ 4.5p1).
2075 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
2076 !FromType->isEnumeralType()) {
2077 if (// We can promote any signed, promotable integer type to an int
2078 (FromType->isSignedIntegerType() ||
2079 // We can promote any unsigned integer type whose size is
2080 // less than int to an int.
2081 Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
2082 return To->getKind() == BuiltinType::Int;
2083 }
2084
2085 return To->getKind() == BuiltinType::UInt;
2086 }
2087
2088 // C++11 [conv.prom]p3:
2089 // A prvalue of an unscoped enumeration type whose underlying type is not
2090 // fixed (7.2) can be converted to an rvalue a prvalue of the first of the
2091 // following types that can represent all the values of the enumeration
2092 // (i.e., the values in the range bmin to bmax as described in 7.2): int,
2093 // unsigned int, long int, unsigned long int, long long int, or unsigned
2094 // long long int. If none of the types in that list can represent all the
2095 // values of the enumeration, an rvalue a prvalue of an unscoped enumeration
2096 // type can be converted to an rvalue a prvalue of the extended integer type
2097 // with lowest integer conversion rank (4.13) greater than the rank of long
2098 // long in which all the values of the enumeration can be represented. If
2099 // there are two such extended types, the signed one is chosen.
2100 // C++11 [conv.prom]p4:
2101 // A prvalue of an unscoped enumeration type whose underlying type is fixed
2102 // can be converted to a prvalue of its underlying type. Moreover, if
2103 // integral promotion can be applied to its underlying type, a prvalue of an
2104 // unscoped enumeration type whose underlying type is fixed can also be
2105 // converted to a prvalue of the promoted underlying type.
2106 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
2107 // C++0x 7.2p9: Note that this implicit enum to int conversion is not
2108 // provided for a scoped enumeration.
2109 if (FromEnumType->getDecl()->isScoped())
2110 return false;
2111
2112 // We can perform an integral promotion to the underlying type of the enum,
2113 // even if that's not the promoted type. Note that the check for promoting
2114 // the underlying type is based on the type alone, and does not consider
2115 // the bitfield-ness of the actual source expression.
2116 if (FromEnumType->getDecl()->isFixed()) {
2117 QualType Underlying = FromEnumType->getDecl()->getIntegerType();
2118 return Context.hasSameUnqualifiedType(Underlying, ToType) ||
2119 IsIntegralPromotion(nullptr, Underlying, ToType);
2120 }
2121
2122 // We have already pre-calculated the promotion type, so this is trivial.
2123 if (ToType->isIntegerType() &&
2124 isCompleteType(From->getBeginLoc(), FromType))
2125 return Context.hasSameUnqualifiedType(
2126 ToType, FromEnumType->getDecl()->getPromotionType());
2127
2128 // C++ [conv.prom]p5:
2129 // If the bit-field has an enumerated type, it is treated as any other
2130 // value of that type for promotion purposes.
2131 //
2132 // ... so do not fall through into the bit-field checks below in C++.
2133 if (getLangOpts().CPlusPlus)
2134 return false;
2135 }
2136
2137 // C++0x [conv.prom]p2:
2138 // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
2139 // to an rvalue a prvalue of the first of the following types that can
2140 // represent all the values of its underlying type: int, unsigned int,
2141 // long int, unsigned long int, long long int, or unsigned long long int.
2142 // If none of the types in that list can represent all the values of its
2143 // underlying type, an rvalue a prvalue of type char16_t, char32_t,
2144 // or wchar_t can be converted to an rvalue a prvalue of its underlying
2145 // type.
2146 if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
2147 ToType->isIntegerType()) {
2148 // Determine whether the type we're converting from is signed or
2149 // unsigned.
2150 bool FromIsSigned = FromType->isSignedIntegerType();
2151 uint64_t FromSize = Context.getTypeSize(FromType);
2152
2153 // The types we'll try to promote to, in the appropriate
2154 // order. Try each of these types.
2155 QualType PromoteTypes[6] = {
2156 Context.IntTy, Context.UnsignedIntTy,
2157 Context.LongTy, Context.UnsignedLongTy ,
2158 Context.LongLongTy, Context.UnsignedLongLongTy
2159 };
2160 for (int Idx = 0; Idx < 6; ++Idx) {
2161 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
2162 if (FromSize < ToSize ||
2163 (FromSize == ToSize &&
2164 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
2165 // We found the type that we can promote to. If this is the
2166 // type we wanted, we have a promotion. Otherwise, no
2167 // promotion.
2168 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
2169 }
2170 }
2171 }
2172
2173 // An rvalue for an integral bit-field (9.6) can be converted to an
2174 // rvalue of type int if int can represent all the values of the
2175 // bit-field; otherwise, it can be converted to unsigned int if
2176 // unsigned int can represent all the values of the bit-field. If
2177 // the bit-field is larger yet, no integral promotion applies to
2178 // it. If the bit-field has an enumerated type, it is treated as any
2179 // other value of that type for promotion purposes (C++ 4.5p3).
2180 // FIXME: We should delay checking of bit-fields until we actually perform the
2181 // conversion.
2182 //
2183 // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
2184 // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
2185 // bit-fields and those whose underlying type is larger than int) for GCC
2186 // compatibility.
2187 if (From) {
2188 if (FieldDecl *MemberDecl = From->getSourceBitField()) {
2189 Optional<llvm::APSInt> BitWidth;
2190 if (FromType->isIntegralType(Context) &&
2191 (BitWidth =
2192 MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) {
2193 llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned());
2194 ToSize = Context.getTypeSize(ToType);
2195
2196 // Are we promoting to an int from a bitfield that fits in an int?
2197 if (*BitWidth < ToSize ||
2198 (FromType->isSignedIntegerType() && *BitWidth <= ToSize)) {
2199 return To->getKind() == BuiltinType::Int;
2200 }
2201
2202 // Are we promoting to an unsigned int from an unsigned bitfield
2203 // that fits into an unsigned int?
2204 if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) {
2205 return To->getKind() == BuiltinType::UInt;
2206 }
2207
2208 return false;
2209 }
2210 }
2211 }
2212
2213 // An rvalue of type bool can be converted to an rvalue of type int,
2214 // with false becoming zero and true becoming one (C++ 4.5p4).
2215 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
2216 return true;
2217 }
2218
2219 return false;
2220}
2221
2222/// IsFloatingPointPromotion - Determines whether the conversion from
2223/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
2224/// returns true and sets PromotedType to the promoted type.
2225bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
2226 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
2227 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
2228 /// An rvalue of type float can be converted to an rvalue of type
2229 /// double. (C++ 4.6p1).
2230 if (FromBuiltin->getKind() == BuiltinType::Float &&
2231 ToBuiltin->getKind() == BuiltinType::Double)
2232 return true;
2233
2234 // C99 6.3.1.5p1:
2235 // When a float is promoted to double or long double, or a
2236 // double is promoted to long double [...].
2237 if (!getLangOpts().CPlusPlus &&
2238 (FromBuiltin->getKind() == BuiltinType::Float ||
2239 FromBuiltin->getKind() == BuiltinType::Double) &&
2240 (ToBuiltin->getKind() == BuiltinType::LongDouble ||
2241 ToBuiltin->getKind() == BuiltinType::Float128 ||
2242 ToBuiltin->getKind() == BuiltinType::Ibm128))
2243 return true;
2244
2245 // Half can be promoted to float.
2246 if (!getLangOpts().NativeHalfType &&
2247 FromBuiltin->getKind() == BuiltinType::Half &&
2248 ToBuiltin->getKind() == BuiltinType::Float)
2249 return true;
2250 }
2251
2252 return false;
2253}
2254
2255/// Determine if a conversion is a complex promotion.
2256///
2257/// A complex promotion is defined as a complex -> complex conversion
2258/// where the conversion between the underlying real types is a
2259/// floating-point or integral promotion.
2260bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
2261 const ComplexType *FromComplex = FromType->getAs<ComplexType>();
2262 if (!FromComplex)
2263 return false;
2264
2265 const ComplexType *ToComplex = ToType->getAs<ComplexType>();
2266 if (!ToComplex)
2267 return false;
2268
2269 return IsFloatingPointPromotion(FromComplex->getElementType(),
2270 ToComplex->getElementType()) ||
2271 IsIntegralPromotion(nullptr, FromComplex->getElementType(),
2272 ToComplex->getElementType());
2273}
2274
2275/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
2276/// the pointer type FromPtr to a pointer to type ToPointee, with the
2277/// same type qualifiers as FromPtr has on its pointee type. ToType,
2278/// if non-empty, will be a pointer to ToType that may or may not have
2279/// the right set of qualifiers on its pointee.
2280///
2281static QualType
2282BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
2283 QualType ToPointee, QualType ToType,
2284 ASTContext &Context,
2285 bool StripObjCLifetime = false) {
2286 assert((FromPtr->getTypeClass() == Type::Pointer ||(static_cast <bool> ((FromPtr->getTypeClass() == Type
::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer
) && "Invalid similarly-qualified pointer type") ? void
(0) : __assert_fail ("(FromPtr->getTypeClass() == Type::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer) && \"Invalid similarly-qualified pointer type\""
, "clang/lib/Sema/SemaOverload.cpp", 2288, __extension__ __PRETTY_FUNCTION__
))
2287 FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&(static_cast <bool> ((FromPtr->getTypeClass() == Type
::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer
) && "Invalid similarly-qualified pointer type") ? void
(0) : __assert_fail ("(FromPtr->getTypeClass() == Type::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer) && \"Invalid similarly-qualified pointer type\""
, "clang/lib/Sema/SemaOverload.cpp", 2288, __extension__ __PRETTY_FUNCTION__
))
2288 "Invalid similarly-qualified pointer type")(static_cast <bool> ((FromPtr->getTypeClass() == Type
::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer
) && "Invalid similarly-qualified pointer type") ? void
(0) : __assert_fail ("(FromPtr->getTypeClass() == Type::Pointer || FromPtr->getTypeClass() == Type::ObjCObjectPointer) && \"Invalid similarly-qualified pointer type\""
, "clang/lib/Sema/SemaOverload.cpp", 2288, __extension__ __PRETTY_FUNCTION__
))
;
2289
2290 /// Conversions to 'id' subsume cv-qualifier conversions.
2291 if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
2292 return ToType.getUnqualifiedType();
2293
2294 QualType CanonFromPointee
2295 = Context.getCanonicalType(FromPtr->getPointeeType());
2296 QualType CanonToPointee = Context.getCanonicalType(ToPointee);
2297 Qualifiers Quals = CanonFromPointee.getQualifiers();
2298
2299 if (StripObjCLifetime)
2300 Quals.removeObjCLifetime();
2301
2302 // Exact qualifier match -> return the pointer type we're converting to.
2303 if (CanonToPointee.getLocalQualifiers() == Quals) {
2304 // ToType is exactly what we need. Return it.
2305 if (!ToType.isNull())
2306 return ToType.getUnqualifiedType();
2307
2308 // Build a pointer to ToPointee. It has the right qualifiers
2309 // already.
2310 if (isa<ObjCObjectPointerType>(ToType))
2311 return Context.getObjCObjectPointerType(ToPointee);
2312 return Context.getPointerType(ToPointee);
2313 }
2314
2315 // Just build a canonical type that has the right qualifiers.
2316 QualType QualifiedCanonToPointee
2317 = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
2318
2319 if (isa<ObjCObjectPointerType>(ToType))
2320 return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
2321 return Context.getPointerType(QualifiedCanonToPointee);
2322}
2323
2324static bool isNullPointerConstantForConversion(Expr *Expr,
2325 bool InOverloadResolution,
2326 ASTContext &Context) {
2327 // Handle value-dependent integral null pointer constants correctly.
2328 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
2329 if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
2330 Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
2331 return !InOverloadResolution;
2332
2333 return Expr->isNullPointerConstant(Context,
2334 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
2335 : Expr::NPC_ValueDependentIsNull);
2336}
2337
2338/// IsPointerConversion - Determines whether the conversion of the
2339/// expression From, which has the (possibly adjusted) type FromType,
2340/// can be converted to the type ToType via a pointer conversion (C++
2341/// 4.10). If so, returns true and places the converted type (that
2342/// might differ from ToType in its cv-qualifiers at some level) into
2343/// ConvertedType.
2344///
2345/// This routine also supports conversions to and from block pointers
2346/// and conversions with Objective-C's 'id', 'id<protocols...>', and
2347/// pointers to interfaces. FIXME: Once we've determined the
2348/// appropriate overloading rules for Objective-C, we may want to
2349/// split the Objective-C checks into a different routine; however,
2350/// GCC seems to consider all of these conversions to be pointer
2351/// conversions, so for now they live here. IncompatibleObjC will be
2352/// set if the conversion is an allowed Objective-C conversion that
2353/// should result in a warning.
2354bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
2355 bool InOverloadResolution,
2356 QualType& ConvertedType,
2357 bool &IncompatibleObjC) {
2358 IncompatibleObjC = false;
2359 if (isObjCPointerConversion(FromType, ToType, ConvertedType,
2360 IncompatibleObjC))
2361 return true;
2362
2363 // Conversion from a null pointer constant to any Objective-C pointer type.
2364 if (ToType->isObjCObjectPointerType() &&
2365 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2366 ConvertedType = ToType;
2367 return true;
2368 }
2369
2370 // Blocks: Block pointers can be converted to void*.
2371 if (FromType->isBlockPointerType() && ToType->isPointerType() &&
2372 ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
2373 ConvertedType = ToType;
2374 return true;
2375 }
2376 // Blocks: A null pointer constant can be converted to a block
2377 // pointer type.
2378 if (ToType->isBlockPointerType() &&
2379 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2380 ConvertedType = ToType;
2381 return true;
2382 }
2383
2384 // If the left-hand-side is nullptr_t, the right side can be a null
2385 // pointer constant.
2386 if (ToType->isNullPtrType() &&
2387 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2388 ConvertedType = ToType;
2389 return true;
2390 }
2391
2392 const PointerType* ToTypePtr = ToType->getAs<PointerType>();
2393 if (!ToTypePtr)
2394 return false;
2395
2396 // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
2397 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2398 ConvertedType = ToType;
2399 return true;
2400 }
2401
2402 // Beyond this point, both types need to be pointers
2403 // , including objective-c pointers.
2404 QualType ToPointeeType = ToTypePtr->getPointeeType();
2405 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
2406 !getLangOpts().ObjCAutoRefCount) {
2407 ConvertedType = BuildSimilarlyQualifiedPointerType(
2408 FromType->castAs<ObjCObjectPointerType>(), ToPointeeType, ToType,
2409 Context);
2410 return true;
2411 }
2412 const PointerType *FromTypePtr = FromType->getAs<PointerType>();
2413 if (!FromTypePtr)
2414 return false;
2415
2416 QualType FromPointeeType = FromTypePtr->getPointeeType();
2417
2418 // If the unqualified pointee types are the same, this can't be a
2419 // pointer conversion, so don't do all of the work below.
2420 if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
2421 return false;
2422
2423 // An rvalue of type "pointer to cv T," where T is an object type,
2424 // can be converted to an rvalue of type "pointer to cv void" (C++
2425 // 4.10p2).
2426 if (FromPointeeType->isIncompleteOrObjectType() &&
2427 ToPointeeType->isVoidType()) {
2428 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2429 ToPointeeType,
2430 ToType, Context,
2431 /*StripObjCLifetime=*/true);
2432 return true;
2433 }
2434
2435 // MSVC allows implicit function to void* type conversion.
2436 if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
2437 ToPointeeType->isVoidType()) {
2438 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2439 ToPointeeType,
2440 ToType, Context);
2441 return true;
2442 }
2443
2444 // When we're overloading in C, we allow a special kind of pointer
2445 // conversion for compatible-but-not-identical pointee types.
2446 if (!getLangOpts().CPlusPlus &&
2447 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
2448 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2449 ToPointeeType,
2450 ToType, Context);
2451 return true;
2452 }
2453
2454 // C++ [conv.ptr]p3:
2455 //
2456 // An rvalue of type "pointer to cv D," where D is a class type,
2457 // can be converted to an rvalue of type "pointer to cv B," where
2458 // B is a base class (clause 10) of D. If B is an inaccessible
2459 // (clause 11) or ambiguous (10.2) base class of D, a program that
2460 // necessitates this conversion is ill-formed. The result of the
2461 // conversion is a pointer to the base class sub-object of the
2462 // derived class object. The null pointer value is converted to
2463 // the null pointer value of the destination type.
2464 //
2465 // Note that we do not check for ambiguity or inaccessibility
2466 // here. That is handled by CheckPointerConversion.
2467 if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
2468 ToPointeeType->isRecordType() &&
2469 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
2470 IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
2471 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2472 ToPointeeType,
2473 ToType, Context);
2474 return true;
2475 }
2476
2477 if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
2478 Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
2479 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2480 ToPointeeType,
2481 ToType, Context);
2482 return true;
2483 }
2484
2485 return false;
2486}
2487
2488/// Adopt the given qualifiers for the given type.
2489static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
2490 Qualifiers TQs = T.getQualifiers();
2491
2492 // Check whether qualifiers already match.
2493 if (TQs == Qs)
2494 return T;
2495
2496 if (Qs.compatiblyIncludes(TQs))
2497 return Context.getQualifiedType(T, Qs);
2498
2499 return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
2500}
2501
2502/// isObjCPointerConversion - Determines whether this is an
2503/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
2504/// with the same arguments and return values.
2505bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
2506 QualType& ConvertedType,
2507 bool &IncompatibleObjC) {
2508 if (!getLangOpts().ObjC)
2509 return false;
2510
2511 // The set of qualifiers on the type we're converting from.
2512 Qualifiers FromQualifiers = FromType.getQualifiers();
2513
2514 // First, we handle all conversions on ObjC object pointer types.
2515 const ObjCObjectPointerType* ToObjCPtr =
2516 ToType->getAs<ObjCObjectPointerType>();
2517 const ObjCObjectPointerType *FromObjCPtr =
2518 FromType->getAs<ObjCObjectPointerType>();
2519
2520 if (ToObjCPtr && FromObjCPtr) {
2521 // If the pointee types are the same (ignoring qualifications),
2522 // then this is not a pointer conversion.
2523 if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
2524 FromObjCPtr->getPointeeType()))
2525 return false;
2526
2527 // Conversion between Objective-C pointers.
2528 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
2529 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
2530 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
2531 if (getLangOpts().CPlusPlus && LHS && RHS &&
2532 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
2533 FromObjCPtr->getPointeeType()))
2534 return false;
2535 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2536 ToObjCPtr->getPointeeType(),
2537 ToType, Context);
2538 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2539 return true;
2540 }
2541
2542 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
2543 // Okay: this is some kind of implicit downcast of Objective-C
2544 // interfaces, which is permitted. However, we're going to
2545 // complain about it.
2546 IncompatibleObjC = true;
2547 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2548 ToObjCPtr->getPointeeType(),
2549 ToType, Context);
2550 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2551 return true;
2552 }
2553 }
2554 // Beyond this point, both types need to be C pointers or block pointers.
2555 QualType ToPointeeType;
2556 if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
2557 ToPointeeType = ToCPtr->getPointeeType();
2558 else if (const BlockPointerType *ToBlockPtr =
2559 ToType->getAs<BlockPointerType>()) {
2560 // Objective C++: We're able to convert from a pointer to any object
2561 // to a block pointer type.
2562 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
2563 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2564 return true;
2565 }
2566 ToPointeeType = ToBlockPtr->getPointeeType();
2567 }
2568 else if (FromType->getAs<BlockPointerType>() &&
2569 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
2570 // Objective C++: We're able to convert from a block pointer type to a
2571 // pointer to any object.
2572 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2573 return true;
2574 }
2575 else
2576 return false;
2577
2578 QualType FromPointeeType;
2579 if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
2580 FromPointeeType = FromCPtr->getPointeeType();
2581 else if (const BlockPointerType *FromBlockPtr =
2582 FromType->getAs<BlockPointerType>())
2583 FromPointeeType = FromBlockPtr->getPointeeType();
2584 else
2585 return false;
2586
2587 // If we have pointers to pointers, recursively check whether this
2588 // is an Objective-C conversion.
2589 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
2590 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2591 IncompatibleObjC)) {
2592 // We always complain about this conversion.
2593 IncompatibleObjC = true;
2594 ConvertedType = Context.getPointerType(ConvertedType);
2595 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2596 return true;
2597 }
2598 // Allow conversion of pointee being objective-c pointer to another one;
2599 // as in I* to id.
2600 if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
2601 ToPointeeType->getAs<ObjCObjectPointerType>() &&
2602 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2603 IncompatibleObjC)) {
2604
2605 ConvertedType = Context.getPointerType(ConvertedType);
2606 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2607 return true;
2608 }
2609
2610 // If we have pointers to functions or blocks, check whether the only
2611 // differences in the argument and result types are in Objective-C
2612 // pointer conversions. If so, we permit the conversion (but
2613 // complain about it).
2614 const FunctionProtoType *FromFunctionType
2615 = FromPointeeType->getAs<FunctionProtoType>();
2616 const FunctionProtoType *ToFunctionType
2617 = ToPointeeType->getAs<FunctionProtoType>();
2618 if (FromFunctionType && ToFunctionType) {
2619 // If the function types are exactly the same, this isn't an
2620 // Objective-C pointer conversion.
2621 if (Context.getCanonicalType(FromPointeeType)
2622 == Context.getCanonicalType(ToPointeeType))
2623 return false;
2624
2625 // Perform the quick checks that will tell us whether these
2626 // function types are obviously different.
2627 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2628 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
2629 FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
2630 return false;
2631
2632 bool HasObjCConversion = false;
2633 if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
2634 Context.getCanonicalType(ToFunctionType->getReturnType())) {
2635 // Okay, the types match exactly. Nothing to do.
2636 } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
2637 ToFunctionType->getReturnType(),
2638 ConvertedType, IncompatibleObjC)) {
2639 // Okay, we have an Objective-C pointer conversion.
2640 HasObjCConversion = true;
2641 } else {
2642 // Function types are too different. Abort.
2643 return false;
2644 }
2645
2646 // Check argument types.
2647 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2648 ArgIdx != NumArgs; ++ArgIdx) {
2649 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2650 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2651 if (Context.getCanonicalType(FromArgType)
2652 == Context.getCanonicalType(ToArgType)) {
2653 // Okay, the types match exactly. Nothing to do.
2654 } else if (isObjCPointerConversion(FromArgType, ToArgType,
2655 ConvertedType, IncompatibleObjC)) {
2656 // Okay, we have an Objective-C pointer conversion.
2657 HasObjCConversion = true;
2658 } else {
2659 // Argument types are too different. Abort.
2660 return false;
2661 }
2662 }
2663
2664 if (HasObjCConversion) {
2665 // We had an Objective-C conversion. Allow this pointer
2666 // conversion, but complain about it.
2667 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2668 IncompatibleObjC = true;
2669 return true;
2670 }
2671 }
2672
2673 return false;
2674}
2675
2676/// Determine whether this is an Objective-C writeback conversion,
2677/// used for parameter passing when performing automatic reference counting.
2678///
2679/// \param FromType The type we're converting form.
2680///
2681/// \param ToType The type we're converting to.
2682///
2683/// \param ConvertedType The type that will be produced after applying
2684/// this conversion.
2685bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
2686 QualType &ConvertedType) {
2687 if (!getLangOpts().ObjCAutoRefCount ||
2688 Context.hasSameUnqualifiedType(FromType, ToType))
2689 return false;
2690
2691 // Parameter must be a pointer to __autoreleasing (with no other qualifiers).
2692 QualType ToPointee;
2693 if (const PointerType *ToPointer = ToType->getAs<PointerType>())
2694 ToPointee = ToPointer->getPointeeType();
2695 else
2696 return false;
2697
2698 Qualifiers ToQuals = ToPointee.getQualifiers();
2699 if (!ToPointee->isObjCLifetimeType() ||
2700 ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
2701 !ToQuals.withoutObjCLifetime().empty())
2702 return false;
2703
2704 // Argument must be a pointer to __strong to __weak.
2705 QualType FromPointee;
2706 if (const PointerType *FromPointer = FromType->getAs<PointerType>())
2707 FromPointee = FromPointer->getPointeeType();
2708 else
2709 return false;
2710
2711 Qualifiers FromQuals = FromPointee.getQualifiers();
2712 if (!FromPointee->isObjCLifetimeType() ||
2713 (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
2714 FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
2715 return false;
2716
2717 // Make sure that we have compatible qualifiers.
2718 FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
2719 if (!ToQuals.compatiblyIncludes(FromQuals))
2720 return false;
2721
2722 // Remove qualifiers from the pointee type we're converting from; they
2723 // aren't used in the compatibility check belong, and we'll be adding back
2724 // qualifiers (with __autoreleasing) if the compatibility check succeeds.
2725 FromPointee = FromPointee.getUnqualifiedType();
2726
2727 // The unqualified form of the pointee types must be compatible.
2728 ToPointee = ToPointee.getUnqualifiedType();
2729 bool IncompatibleObjC;
2730 if (Context.typesAreCompatible(FromPointee, ToPointee))
2731 FromPointee = ToPointee;
2732 else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
2733 IncompatibleObjC))
2734 return false;
2735
2736 /// Construct the type we're converting to, which is a pointer to
2737 /// __autoreleasing pointee.
2738 FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
2739 ConvertedType = Context.getPointerType(FromPointee);
2740 return true;
2741}
2742
2743bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
2744 QualType& ConvertedType) {
2745 QualType ToPointeeType;
2746 if (const BlockPointerType *ToBlockPtr =
2747 ToType->getAs<BlockPointerType>())
2748 ToPointeeType = ToBlockPtr->getPointeeType();
2749 else
2750 return false;
2751
2752 QualType FromPointeeType;
2753 if (const BlockPointerType *FromBlockPtr =
2754 FromType->getAs<BlockPointerType>())
2755 FromPointeeType = FromBlockPtr->getPointeeType();
2756 else
2757 return false;
2758 // We have pointer to blocks, check whether the only
2759 // differences in the argument and result types are in Objective-C
2760 // pointer conversions. If so, we permit the conversion.
2761
2762 const FunctionProtoType *FromFunctionType
2763 = FromPointeeType->getAs<FunctionProtoType>();
2764 const FunctionProtoType *ToFunctionType
2765 = ToPointeeType->getAs<FunctionProtoType>();
2766
2767 if (!FromFunctionType || !ToFunctionType)
2768 return false;
2769
2770 if (Context.hasSameType(FromPointeeType, ToPointeeType))
2771 return true;
2772
2773 // Perform the quick checks that will tell us whether these
2774 // function types are obviously different.
2775 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2776 FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
2777 return false;
2778
2779 FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
2780 FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
2781 if (FromEInfo != ToEInfo)
2782 return false;
2783
2784 bool IncompatibleObjC = false;
2785 if (Context.hasSameType(FromFunctionType->getReturnType(),
2786 ToFunctionType->getReturnType())) {
2787 // Okay, the types match exactly. Nothing to do.
2788 } else {
2789 QualType RHS = FromFunctionType->getReturnType();
2790 QualType LHS = ToFunctionType->getReturnType();
2791 if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
2792 !RHS.hasQualifiers() && LHS.hasQualifiers())
2793 LHS = LHS.getUnqualifiedType();
2794
2795 if (Context.hasSameType(RHS,LHS)) {
2796 // OK exact match.
2797 } else if (isObjCPointerConversion(RHS, LHS,
2798 ConvertedType, IncompatibleObjC)) {
2799 if (IncompatibleObjC)
2800 return false;
2801 // Okay, we have an Objective-C pointer conversion.
2802 }
2803 else
2804 return false;
2805 }
2806
2807 // Check argument types.
2808 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2809 ArgIdx != NumArgs; ++ArgIdx) {
2810 IncompatibleObjC = false;
2811 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2812 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2813 if (Context.hasSameType(FromArgType, ToArgType)) {
2814 // Okay, the types match exactly. Nothing to do.
2815 } else if (isObjCPointerConversion(ToArgType, FromArgType,
2816 ConvertedType, IncompatibleObjC)) {
2817 if (IncompatibleObjC)
2818 return false;
2819 // Okay, we have an Objective-C pointer conversion.
2820 } else
2821 // Argument types are too different. Abort.
2822 return false;
2823 }
2824
2825 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
2826 bool CanUseToFPT, CanUseFromFPT;
2827 if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
2828 CanUseToFPT, CanUseFromFPT,
2829 NewParamInfos))
2830 return false;
2831
2832 ConvertedType = ToType;
2833 return true;
2834}
2835
2836enum {
2837 ft_default,
2838 ft_different_class,
2839 ft_parameter_arity,
2840 ft_parameter_mismatch,
2841 ft_return_type,
2842 ft_qualifer_mismatch,
2843 ft_noexcept
2844};
2845
2846/// Attempts to get the FunctionProtoType from a Type. Handles
2847/// MemberFunctionPointers properly.
2848static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
2849 if (auto *FPT = FromType->getAs<FunctionProtoType>())
2850 return FPT;
2851
2852 if (auto *MPT = FromType->getAs<MemberPointerType>())
2853 return MPT->getPointeeType()->getAs<FunctionProtoType>();
2854
2855 return nullptr;
2856}
2857
2858/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
2859/// function types. Catches different number of parameter, mismatch in
2860/// parameter types, and different return types.
2861void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
2862 QualType FromType, QualType ToType) {
2863 // If either type is not valid, include no extra info.
2864 if (FromType.isNull() || ToType.isNull()) {
2865 PDiag << ft_default;
2866 return;
2867 }
2868
2869 // Get the function type from the pointers.
2870 if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
2871 const auto *FromMember = FromType->castAs<MemberPointerType>(),
2872 *ToMember = ToType->castAs<MemberPointerType>();
2873 if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
2874 PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
2875 << QualType(FromMember->getClass(), 0);
2876 return;
2877 }
2878 FromType = FromMember->getPointeeType();
2879 ToType = ToMember->getPointeeType();
2880 }
2881
2882 if (FromType->isPointerType())
2883 FromType = FromType->getPointeeType();
2884 if (ToType->isPointerType())
2885 ToType = ToType->getPointeeType();
2886
2887 // Remove references.
2888 FromType = FromType.getNonReferenceType();
2889 ToType = ToType.getNonReferenceType();
2890
2891 // Don't print extra info for non-specialized template functions.
2892 if (FromType->isInstantiationDependentType() &&
2893 !FromType->getAs<TemplateSpecializationType>()) {
2894 PDiag << ft_default;
2895 return;
2896 }
2897
2898 // No extra info for same types.
2899 if (Context.hasSameType(FromType, ToType)) {
2900 PDiag << ft_default;
2901 return;
2902 }
2903
2904 const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
2905 *ToFunction = tryGetFunctionProtoType(ToType);
2906
2907 // Both types need to be function types.
2908 if (!FromFunction || !ToFunction) {
2909 PDiag << ft_default;
2910 return;
2911 }
2912
2913 if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
2914 PDiag << ft_parameter_arity << ToFunction->getNumParams()
2915 << FromFunction->getNumParams();
2916 return;
2917 }
2918
2919 // Handle different parameter types.
2920 unsigned ArgPos;
2921 if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
2922 PDiag << ft_parameter_mismatch << ArgPos + 1
2923 << ToFunction->getParamType(ArgPos)
2924 << FromFunction->getParamType(ArgPos);
2925 return;
2926 }
2927
2928 // Handle different return type.
2929 if (!Context.hasSameType(FromFunction->getReturnType(),
2930 ToFunction->getReturnType())) {
2931 PDiag << ft_return_type << ToFunction->getReturnType()
2932 << FromFunction->getReturnType();
2933 return;
2934 }
2935
2936 if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
2937 PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
2938 << FromFunction->getMethodQuals();
2939 return;
2940 }
2941
2942 // Handle exception specification differences on canonical type (in C++17
2943 // onwards).
2944 if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
2945 ->isNothrow() !=
2946 cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
2947 ->isNothrow()) {
2948 PDiag << ft_noexcept;
2949 return;
2950 }
2951
2952 // Unable to find a difference, so add no extra info.
2953 PDiag << ft_default;
2954}
2955
2956/// FunctionParamTypesAreEqual - This routine checks two function proto types
2957/// for equality of their argument types. Caller has already checked that
2958/// they have same number of arguments. If the parameters are different,
2959/// ArgPos will have the parameter index of the first different parameter.
2960bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
2961 const FunctionProtoType *NewType,
2962 unsigned *ArgPos) {
2963 for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
2964 N = NewType->param_type_begin(),
2965 E = OldType->param_type_end();
2966 O && (O != E); ++O, ++N) {
2967 // Ignore address spaces in pointee type. This is to disallow overloading
2968 // on __ptr32/__ptr64 address spaces.
2969 QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
2970 QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());
2971
2972 if (!Context.hasSameType(Old, New)) {
2973 if (ArgPos)
2974 *ArgPos = O - OldType->param_type_begin();
2975 return false;
2976 }
2977 }
2978 return true;
2979}
2980
2981/// CheckPointerConversion - Check the pointer conversion from the
2982/// expression From to the type ToType. This routine checks for
2983/// ambiguous or inaccessible derived-to-base pointer
2984/// conversions for which IsPointerConversion has already returned
2985/// true. It returns true and produces a diagnostic if there was an
2986/// error, or returns false otherwise.
2987bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
2988 CastKind &Kind,
2989 CXXCastPath& BasePath,
2990 bool IgnoreBaseAccess,
2991 bool Diagnose) {
2992 QualType FromType = From->getType();
2993 bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
2994
2995 Kind = CK_BitCast;
2996
2997 if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
2998 From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
2999 Expr::NPCK_ZeroExpression) {
3000 if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
3001 DiagRuntimeBehavior(From->getExprLoc(), From,
3002 PDiag(diag::warn_impcast_bool_to_null_pointer)
3003 << ToType << From->getSourceRange());
3004 else if (!isUnevaluatedContext())
3005 Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
3006 << ToType << From->getSourceRange();
3007 }
3008 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
3009 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
3010 QualType FromPointeeType = FromPtrType->getPointeeType(),
3011 ToPointeeType = ToPtrType->getPointeeType();
3012
3013 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
3014 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
3015 // We must have a derived-to-base conversion. Check an
3016 // ambiguous or inaccessible conversion.
3017 unsigned InaccessibleID = 0;
3018 unsigned AmbiguousID = 0;
3019 if (Diagnose) {
3020 InaccessibleID = diag::err_upcast_to_inaccessible_base;
3021 AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
3022 }
3023 if (CheckDerivedToBaseConversion(
3024 FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
3025 From->getExprLoc(), From->getSourceRange(), DeclarationName(),
3026 &BasePath, IgnoreBaseAccess))
3027 return true;
3028
3029 // The conversion was successful.
3030 Kind = CK_DerivedToBase;
3031 }
3032
3033 if (Diagnose && !IsCStyleOrFunctionalCast &&
3034 FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
3035 assert(getLangOpts().MSVCCompat &&(static_cast <bool> (getLangOpts().MSVCCompat &&
"this should only be possible with MSVCCompat!") ? void (0) :
__assert_fail ("getLangOpts().MSVCCompat && \"this should only be possible with MSVCCompat!\""
, "clang/lib/Sema/SemaOverload.cpp", 3036, __extension__ __PRETTY_FUNCTION__
))
3036 "this should only be possible with MSVCCompat!")(static_cast <bool> (getLangOpts().MSVCCompat &&
"this should only be possible with MSVCCompat!") ? void (0) :
__assert_fail ("getLangOpts().MSVCCompat && \"this should only be possible with MSVCCompat!\""
, "clang/lib/Sema/SemaOverload.cpp", 3036, __extension__ __PRETTY_FUNCTION__
))
;
3037 Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
3038 << From->getSourceRange();
3039 }
3040 }
3041 } else if (const ObjCObjectPointerType *ToPtrType =
3042 ToType->getAs<ObjCObjectPointerType>()) {
3043 if (const ObjCObjectPointerType *FromPtrType =
3044 FromType->getAs<ObjCObjectPointerType>()) {
3045 // Objective-C++ conversions are always okay.
3046 // FIXME: We should have a different class of conversions for the
3047 // Objective-C++ implicit conversions.
3048 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
3049 return false;
3050 } else if (FromType->isBlockPointerType()) {
3051 Kind = CK_BlockPointerToObjCPointerCast;
3052 } else {
3053 Kind = CK_CPointerToObjCPointerCast;
3054 }
3055 } else if (ToType->isBlockPointerType()) {
3056 if (!FromType->isBlockPointerType())
3057 Kind = CK_AnyPointerToBlockPointerCast;
3058 }
3059
3060 // We shouldn't fall into this case unless it's valid for other
3061 // reasons.
3062 if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
3063 Kind = CK_NullToPointer;
3064
3065 return false;
3066}
3067
3068/// IsMemberPointerConversion - Determines whether the conversion of the
3069/// expression From, which has the (possibly adjusted) type FromType, can be
3070/// converted to the type ToType via a member pointer conversion (C++ 4.11).
3071/// If so, returns true and places the converted type (that might differ from
3072/// ToType in its cv-qualifiers at some level) into ConvertedType.
3073bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
3074 QualType ToType,
3075 bool InOverloadResolution,
3076 QualType &ConvertedType) {
3077 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
3078 if (!ToTypePtr)
3079 return false;
3080
3081 // A null pointer constant can be converted to a member pointer (C++ 4.11p1)
3082 if (From->isNullPointerConstant(Context,
3083 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
3084 : Expr::NPC_ValueDependentIsNull)) {
3085 ConvertedType = ToType;
3086 return true;
3087 }
3088
3089 // Otherwise, both types have to be member pointers.
3090 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
3091 if (!FromTypePtr)
3092 return false;
3093
3094 // A pointer to member of B can be converted to a pointer to member of D,
3095 // where D is derived from B (C++ 4.11p2).
3096 QualType FromClass(FromTypePtr->getClass(), 0);
3097 QualType ToClass(ToTypePtr->getClass(), 0);
3098
3099 if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
3100 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
3101 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
3102 ToClass.getTypePtr());
3103 return true;
3104 }
3105
3106 return false;
3107}
3108
3109/// CheckMemberPointerConversion - Check the member pointer conversion from the
3110/// expression From to the type ToType. This routine checks for ambiguous or
3111/// virtual or inaccessible base-to-derived member pointer conversions
3112/// for which IsMemberPointerConversion has already returned true. It returns
3113/// true and produces a diagnostic if there was an error, or returns false
3114/// otherwise.
3115bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
3116 CastKind &Kind,
3117 CXXCastPath &BasePath,
3118 bool IgnoreBaseAccess) {
3119 QualType FromType = From->getType();
3120 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
3121 if (!FromPtrType) {
3122 // This must be a null pointer to member pointer conversion
3123 assert(From->isNullPointerConstant(Context,(static_cast <bool> (From->isNullPointerConstant(Context
, Expr::NPC_ValueDependentIsNull) && "Expr must be null pointer constant!"
) ? void (0) : __assert_fail ("From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull) && \"Expr must be null pointer constant!\""
, "clang/lib/Sema/SemaOverload.cpp", 3125, __extension__ __PRETTY_FUNCTION__
))
3124 Expr::NPC_ValueDependentIsNull) &&(static_cast <bool> (From->isNullPointerConstant(Context
, Expr::NPC_ValueDependentIsNull) && "Expr must be null pointer constant!"
) ? void (0) : __assert_fail ("From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull) && \"Expr must be null pointer constant!\""
, "clang/lib/Sema/SemaOverload.cpp", 3125, __extension__ __PRETTY_FUNCTION__
))
3125 "Expr must be null pointer constant!")(static_cast <bool> (From->isNullPointerConstant(Context
, Expr::NPC_ValueDependentIsNull) && "Expr must be null pointer constant!"
) ? void (0) : __assert_fail ("From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull) && \"Expr must be null pointer constant!\""
, "clang/lib/Sema/SemaOverload.cpp", 3125, __extension__ __PRETTY_FUNCTION__
))
;
3126 Kind = CK_NullToMemberPointer;
3127 return false;
3128 }
3129
3130 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
3131 assert(ToPtrType && "No member pointer cast has a target type "(static_cast <bool> (ToPtrType && "No member pointer cast has a target type "
"that is not a member pointer.") ? void (0) : __assert_fail (
"ToPtrType && \"No member pointer cast has a target type \" \"that is not a member pointer.\""
, "clang/lib/Sema/SemaOverload.cpp", 3132, __extension__ __PRETTY_FUNCTION__
))
3132 "that is not a member pointer.")(static_cast <bool> (ToPtrType && "No member pointer cast has a target type "
"that is not a member pointer.") ? void (0) : __assert_fail (
"ToPtrType && \"No member pointer cast has a target type \" \"that is not a member pointer.\""
, "clang/lib/Sema/SemaOverload.cpp", 3132, __extension__ __PRETTY_FUNCTION__
))
;
3133
3134 QualType FromClass = QualType(FromPtrType->getClass(), 0);
3135 QualType ToClass = QualType(ToPtrType->getClass(), 0);
3136
3137 // FIXME: What about dependent types?
3138 assert(FromClass->isRecordType() && "Pointer into non-class.")(static_cast <bool> (FromClass->isRecordType() &&
"Pointer into non-class.") ? void (0) : __assert_fail ("FromClass->isRecordType() && \"Pointer into non-class.\""
, "clang/lib/Sema/SemaOverload.cpp", 3138, __extension__ __PRETTY_FUNCTION__
))
;
3139 assert(ToClass->isRecordType() && "Pointer into non-class.")(static_cast <bool> (ToClass->isRecordType() &&
"Pointer into non-class.") ? void (0) : __assert_fail ("ToClass->isRecordType() && \"Pointer into non-class.\""
, "clang/lib/Sema/SemaOverload.cpp", 3139, __extension__ __PRETTY_FUNCTION__
))
;
3140
3141 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3142 /*DetectVirtual=*/true);
3143 bool DerivationOkay =
3144 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
3145 assert(DerivationOkay &&(static_cast <bool> (DerivationOkay && "Should not have been called if derivation isn't OK."
) ? void (0) : __assert_fail ("DerivationOkay && \"Should not have been called if derivation isn't OK.\""
, "clang/lib/Sema/SemaOverload.cpp", 3146, __extension__ __PRETTY_FUNCTION__
))
3146 "Should not have been called if derivation isn't OK.")(static_cast <bool> (DerivationOkay && "Should not have been called if derivation isn't OK."
) ? void (0) : __assert_fail ("DerivationOkay && \"Should not have been called if derivation isn't OK.\""
, "clang/lib/Sema/SemaOverload.cpp", 3146, __extension__ __PRETTY_FUNCTION__
))
;
3147 (void)DerivationOkay;
3148
3149 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
3150 getUnqualifiedType())) {
3151 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
3152 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
3153 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
3154 return true;
3155 }
3156
3157 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
3158 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
3159 << FromClass << ToClass << QualType(VBase, 0)
3160 << From->getSourceRange();
3161 return true;
3162 }
3163
3164 if (!IgnoreBaseAccess)
3165 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
3166 Paths.front(),
3167 diag::err_downcast_from_inaccessible_base);
3168
3169 // Must be a base to derived member conversion.
3170 BuildBasePathArray(Paths, BasePath);
3171 Kind = CK_BaseToDerivedMemberPointer;
3172 return false;
3173}
3174
3175/// Determine whether the lifetime conversion between the two given
3176/// qualifiers sets is nontrivial.
3177static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
3178 Qualifiers ToQuals) {
3179 // Converting anything to const __unsafe_unretained is trivial.
3180 if (ToQuals.hasConst() &&
3181 ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
3182 return false;
3183
3184 return true;
3185}
3186
3187/// Perform a single iteration of the loop for checking if a qualification
3188/// conversion is valid.
3189///
3190/// Specifically, check whether any change between the qualifiers of \p
3191/// FromType and \p ToType is permissible, given knowledge about whether every
3192/// outer layer is const-qualified.
3193static bool isQualificationConversionStep(QualType FromType, QualType ToType,
3194 bool CStyle, bool IsTopLevel,
3195 bool &PreviousToQualsIncludeConst,
3196 bool &ObjCLifetimeConversion) {
3197 Qualifiers FromQuals = FromType.getQualifiers();
3198 Qualifiers ToQuals = ToType.getQualifiers();
3199
3200 // Ignore __unaligned qualifier if this type is void.
3201 if (ToType.getUnqualifiedType()->isVoidType())
3202 FromQuals.removeUnaligned();
3203
3204 // Objective-C ARC:
3205 // Check Objective-C lifetime conversions.
3206 if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
3207 if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
3208 if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
3209 ObjCLifetimeConversion = true;
3210 FromQuals.removeObjCLifetime();
3211 ToQuals.removeObjCLifetime();
3212 } else {
3213 // Qualification conversions cannot cast between different
3214 // Objective-C lifetime qualifiers.
3215 return false;
3216 }
3217 }
3218
3219 // Allow addition/removal of GC attributes but not changing GC attributes.
3220 if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
3221 (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
3222 FromQuals.removeObjCGCAttr();
3223 ToQuals.removeObjCGCAttr();
3224 }
3225
3226 // -- for every j > 0, if const is in cv 1,j then const is in cv
3227 // 2,j, and similarly for volatile.
3228 if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
3229 return false;
3230
3231 // If address spaces mismatch:
3232 // - in top level it is only valid to convert to addr space that is a
3233 // superset in all cases apart from C-style casts where we allow
3234 // conversions between overlapping address spaces.
3235 // - in non-top levels it is not a valid conversion.
3236 if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
3237 (!IsTopLevel ||
3238 !(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
3239 (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
3240 return false;
3241
3242 // -- if the cv 1,j and cv 2,j are different, then const is in
3243 // every cv for 0 < k < j.
3244 if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
3245 !PreviousToQualsIncludeConst)
3246 return false;
3247
3248 // The following wording is from C++20, where the result of the conversion
3249 // is T3, not T2.
3250 // -- if [...] P1,i [...] is "array of unknown bound of", P3,i is
3251 // "array of unknown bound of"
3252 if (FromType->isIncompleteArrayType() && !ToType->isIncompleteArrayType())
3253 return false;
3254
3255 // -- if the resulting P3,i is different from P1,i [...], then const is
3256 // added to every cv 3_k for 0 < k < i.
3257 if (!CStyle && FromType->isConstantArrayType() &&
3258 ToType->isIncompleteArrayType() && !PreviousToQualsIncludeConst)
3259 return false;
3260
3261 // Keep track of whether all prior cv-qualifiers in the "to" type
3262 // include const.
3263 PreviousToQualsIncludeConst =
3264 PreviousToQualsIncludeConst && ToQuals.hasConst();
3265 return true;
3266}
3267
3268/// IsQualificationConversion - Determines whether the conversion from
3269/// an rvalue of type FromType to ToType is a qualification conversion
3270/// (C++ 4.4).
3271///
3272/// \param ObjCLifetimeConversion Output parameter that will be set to indicate
3273/// when the qualification conversion involves a change in the Objective-C
3274/// object lifetime.
3275bool
3276Sema::IsQualificationConversion(QualType FromType, QualType ToType,
3277 bool CStyle, bool &ObjCLifetimeConversion) {
3278 FromType = Context.getCanonicalType(FromType);
3279 ToType = Context.getCanonicalType(ToType);
3280 ObjCLifetimeConversion = false;
3281
3282 // If FromType and ToType are the same type, this is not a
3283 // qualification conversion.
3284 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
3285 return false;
3286
3287 // (C++ 4.4p4):
3288 // A conversion can add cv-qualifiers at levels other than the first
3289 // in multi-level pointers, subject to the following rules: [...]
3290 bool PreviousToQualsIncludeConst = true;
3291 bool UnwrappedAnyPointer = false;
3292 while (Context.UnwrapSimilarTypes(FromType, ToType)) {
3293 if (!isQualificationConversionStep(
3294 FromType, ToType, CStyle, !UnwrappedAnyPointer,
3295 PreviousToQualsIncludeConst, ObjCLifetimeConversion))
3296 return false;
3297 UnwrappedAnyPointer = true;
3298 }
3299
3300 // We are left with FromType and ToType being the pointee types
3301 // after unwrapping the original FromType and ToType the same number
3302 // of times. If we unwrapped any pointers, and if FromType and
3303 // ToType have the same unqualified type (since we checked
3304 // qualifiers above), then this is a qualification conversion.
3305 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
3306}
3307
3308/// - Determine whether this is a conversion from a scalar type to an
3309/// atomic type.
3310///
3311/// If successful, updates \c SCS's second and third steps in the conversion
3312/// sequence to finish the conversion.
3313static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
3314 bool InOverloadResolution,
3315 StandardConversionSequence &SCS,
3316 bool CStyle) {
3317 const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
3318 if (!ToAtomic)
3319 return false;
3320
3321 StandardConversionSequence InnerSCS;
3322 if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
3323 InOverloadResolution, InnerSCS,
3324 CStyle, /*AllowObjCWritebackConversion=*/false))
3325 return false;
3326
3327 SCS.Second = InnerSCS.Second;
3328 SCS.setToType(1, InnerSCS.getToType(1));
3329 SCS.Third = InnerSCS.Third;
3330 SCS.QualificationIncludesObjCLifetime
3331 = InnerSCS.QualificationIncludesObjCLifetime;
3332 SCS.setToType(2, InnerSCS.getToType(2));
3333 return true;
3334}
3335
3336static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
3337 CXXConstructorDecl *Constructor,
3338 QualType Type) {
3339 const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
3340 if (CtorType->getNumParams() > 0) {
3341 QualType FirstArg = CtorType->getParamType(0);
3342 if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
3343 return true;
3344 }
3345 return false;
3346}
3347
3348static OverloadingResult
3349IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
3350 CXXRecordDecl *To,
3351 UserDefinedConversionSequence &User,
3352 OverloadCandidateSet &CandidateSet,
3353 bool AllowExplicit) {
3354 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3355 for (auto *D : S.LookupConstructors(To)) {
3356 auto Info = getConstructorInfo(D);
3357 if (!Info)
3358 continue;
3359
3360 bool Usable = !Info.Constructor->isInvalidDecl() &&
3361 S.isInitListConstructor(Info.Constructor);
3362 if (Usable) {
3363 bool SuppressUserConversions = false;
3364 if (Info.ConstructorTmpl)
3365 S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
3366 /*ExplicitArgs*/ nullptr, From,
3367 CandidateSet, SuppressUserConversions,
3368 /*PartialOverloading*/ false,
3369 AllowExplicit);
3370 else
3371 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
3372 CandidateSet, SuppressUserConversions,
3373 /*PartialOverloading*/ false, AllowExplicit);
3374 }
3375 }
3376
3377 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3378
3379 OverloadCandidateSet::iterator Best;
3380 switch (auto Result =
3381 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3382 case OR_Deleted:
3383 case OR_Success: {
3384 // Record the standard conversion we used and the conversion function.
3385 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
3386 QualType ThisType = Constructor->getThisType();
3387 // Initializer lists don't have conversions as such.
3388 User.Before.setAsIdentityConversion();
3389 User.HadMultipleCandidates = HadMultipleCandidates;
3390 User.ConversionFunction = Constructor;
3391 User.FoundConversionFunction = Best->FoundDecl;
3392 User.After.setAsIdentityConversion();
3393 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3394 User.After.setAllToTypes(ToType);
3395 return Result;
3396 }
3397
3398 case OR_No_Viable_Function:
3399 return OR_No_Viable_Function;
3400 case OR_Ambiguous:
3401 return OR_Ambiguous;
3402 }
3403
3404 llvm_unreachable("Invalid OverloadResult!")::llvm::llvm_unreachable_internal("Invalid OverloadResult!", "clang/lib/Sema/SemaOverload.cpp"
, 3404)
;
3405}
3406
3407/// Determines whether there is a user-defined conversion sequence
3408/// (C++ [over.ics.user]) that converts expression From to the type
3409/// ToType. If such a conversion exists, User will contain the
3410/// user-defined conversion sequence that performs such a conversion
3411/// and this routine will return true. Otherwise, this routine returns
3412/// false and User is unspecified.
3413///
3414/// \param AllowExplicit true if the conversion should consider C++0x
3415/// "explicit" conversion functions as well as non-explicit conversion
3416/// functions (C++0x [class.conv.fct]p2).
3417///
3418/// \param AllowObjCConversionOnExplicit true if the conversion should
3419/// allow an extra Objective-C pointer conversion on uses of explicit
3420/// constructors. Requires \c AllowExplicit to also be set.
3421static OverloadingResult
3422IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
3423 UserDefinedConversionSequence &User,
3424 OverloadCandidateSet &CandidateSet,
3425 AllowedExplicit AllowExplicit,
3426 bool AllowObjCConversionOnExplicit) {
3427 assert(AllowExplicit != AllowedExplicit::None ||(static_cast <bool> (AllowExplicit != AllowedExplicit::
None || !AllowObjCConversionOnExplicit) ? void (0) : __assert_fail
("AllowExplicit != AllowedExplicit::None || !AllowObjCConversionOnExplicit"
, "clang/lib/Sema/SemaOverload.cpp", 3428, __extension__ __PRETTY_FUNCTION__
))
3428 !AllowObjCConversionOnExplicit)(static_cast <bool> (AllowExplicit != AllowedExplicit::
None || !AllowObjCConversionOnExplicit) ? void (0) : __assert_fail
("AllowExplicit != AllowedExplicit::None || !AllowObjCConversionOnExplicit"
, "clang/lib/Sema/SemaOverload.cpp", 3428, __extension__ __PRETTY_FUNCTION__
))
;
3429 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3430
3431 // Whether we will only visit constructors.
3432 bool ConstructorsOnly = false;
3433
3434 // If the type we are conversion to is a class type, enumerate its
3435 // constructors.
3436 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
3437 // C++ [over.match.ctor]p1:
3438 // When objects of class type are direct-initialized (8.5), or
3439 // copy-initialized from an expression of the same or a
3440 // derived class type (8.5), overload resolution selects the
3441 // constructor. [...] For copy-initialization, the candidate
3442 // functions are all the converting constructors (12.3.1) of
3443 // that class. The argument list is the expression-list within
3444 // the parentheses of the initializer.
3445 if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
3446 (From->getType()->getAs<RecordType>() &&
3447 S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
3448 ConstructorsOnly = true;
3449
3450 if (!S.isCompleteType(From->getExprLoc(), ToType)) {
3451 // We're not going to find any constructors.
3452 } else if (CXXRecordDecl *ToRecordDecl
3453 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
3454
3455 Expr **Args = &From;
3456 unsigned NumArgs = 1;
3457 bool ListInitializing = false;
3458 if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
3459 // But first, see if there is an init-list-constructor that will work.
3460 OverloadingResult Result = IsInitializerListConstructorConversion(
3461 S, From, ToType, ToRecordDecl, User, CandidateSet,
3462 AllowExplicit == AllowedExplicit::All);
3463 if (Result != OR_No_Viable_Function)
3464 return Result;
3465 // Never mind.
3466 CandidateSet.clear(
3467 OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3468
3469 // If we're list-initializing, we pass the individual elements as
3470 // arguments, not the entire list.
3471 Args = InitList->getInits();
3472 NumArgs = InitList->getNumInits();
3473 ListInitializing = true;
3474 }
3475
3476 for (auto *D : S.LookupConstructors(ToRecordDecl)) {
3477 auto Info = getConstructorInfo(D);
3478 if (!Info)
3479 continue;
3480
3481 bool Usable = !Info.Constructor->isInvalidDecl();
3482 if (!ListInitializing)
3483 Usable = Usable && Info.Constructor->isConvertingConstructor(
3484 /*AllowExplicit*/ true);
3485 if (Usable) {
3486 bool SuppressUserConversions = !ConstructorsOnly;
3487 // C++20 [over.best.ics.general]/4.5:
3488 // if the target is the first parameter of a constructor [of class
3489 // X] and the constructor [...] is a candidate by [...] the second
3490 // phase of [over.match.list] when the initializer list has exactly
3491 // one element that is itself an initializer list, [...] and the
3492 // conversion is to X or reference to cv X, user-defined conversion
3493 // sequences are not cnosidered.
3494 if (SuppressUserConversions && ListInitializing) {
3495 SuppressUserConversions =
3496 NumArgs == 1 && isa<InitListExpr>(Args[0]) &&
3497 isFirstArgumentCompatibleWithType(S.Context, Info.Constructor,
3498 ToType);
3499 }
3500 if (Info.ConstructorTmpl)
3501 S.AddTemplateOverloadCandidate(
3502 Info.ConstructorTmpl, Info.FoundDecl,
3503 /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
3504 CandidateSet, SuppressUserConversions,
3505 /*PartialOverloading*/ false,
3506 AllowExplicit == AllowedExplicit::All);
3507 else
3508 // Allow one user-defined conversion when user specifies a
3509 // From->ToType conversion via an static cast (c-style, etc).
3510 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
3511 llvm::makeArrayRef(Args, NumArgs),
3512 CandidateSet, SuppressUserConversions,
3513 /*PartialOverloading*/ false,
3514 AllowExplicit == AllowedExplicit::All);
3515 }
3516 }
3517 }
3518 }
3519
3520 // Enumerate conversion functions, if we're allowed to.
3521 if (ConstructorsOnly || isa<InitListExpr>(From)) {
3522 } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
3523 // No conversion functions from incomplete types.
3524 } else if (const RecordType *FromRecordType =
3525 From->getType()->getAs<RecordType>()) {
3526 if (CXXRecordDecl *FromRecordDecl
3527 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
3528 // Add all of the conversion functions as candidates.
3529 const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
3530 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3531 DeclAccessPair FoundDecl = I.getPair();
3532 NamedDecl *D = FoundDecl.getDecl();
3533 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
3534 if (isa<UsingShadowDecl>(D))
3535 D = cast<UsingShadowDecl>(D)->getTargetDecl();
3536
3537 CXXConversionDecl *Conv;
3538 FunctionTemplateDecl *ConvTemplate;
3539 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
3540 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3541 else
3542 Conv = cast<CXXConversionDecl>(D);
3543
3544 if (ConvTemplate)
3545 S.AddTemplateConversionCandidate(
3546 ConvTemplate, FoundDecl, ActingContext, From, ToType,
3547 CandidateSet, AllowObjCConversionOnExplicit,
3548 AllowExplicit != AllowedExplicit::None);
3549 else
3550 S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
3551 CandidateSet, AllowObjCConversionOnExplicit,
3552 AllowExplicit != AllowedExplicit::None);
3553 }
3554 }
3555 }
3556
3557 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3558
3559 OverloadCandidateSet::iterator Best;
3560 switch (auto Result =
3561 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3562 case OR_Success:
3563 case OR_Deleted:
3564 // Record the standard conversion we used and the conversion function.
3565 if (CXXConstructorDecl *Constructor
3566 = dyn_cast<CXXConstructorDecl>(Best->Function)) {
3567 // C++ [over.ics.user]p1:
3568 // If the user-defined conversion is specified by a
3569 // constructor (12.3.1), the initial standard conversion
3570 // sequence converts the source type to the type required by
3571 // the argument of the constructor.
3572 //
3573 QualType ThisType = Constructor->getThisType();
3574 if (isa<InitListExpr>(From)) {
3575 // Initializer lists don't have conversions as such.
3576 User.Before.setAsIdentityConversion();
3577 } else {
3578 if (Best->Conversions[0].isEllipsis())
3579 User.EllipsisConversion = true;
3580 else {
3581 User.Before = Best->Conversions[0].Standard;
3582 User.EllipsisConversion = false;
3583 }
3584 }
3585 User.HadMultipleCandidates = HadMultipleCandidates;
3586 User.ConversionFunction = Constructor;
3587 User.FoundConversionFunction = Best->FoundDecl;
3588 User.After.setAsIdentityConversion();
3589 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3590 User.After.setAllToTypes(ToType);
3591 return Result;
3592 }
3593 if (CXXConversionDecl *Conversion
3594 = dyn_cast<CXXConversionDecl>(Best->Function)) {
3595 // C++ [over.ics.user]p1:
3596 //
3597 // [...] If the user-defined conversion is specified by a
3598 // conversion function (12.3.2), the initial standard
3599 // conversion sequence converts the source type to the
3600 // implicit object parameter of the conversion function.
3601 User.Before = Best->Conversions[0].Standard;
3602 User.HadMultipleCandidates = HadMultipleCandidates;
3603 User.ConversionFunction = Conversion;
3604 User.FoundConversionFunction = Best->FoundDecl;
3605 User.EllipsisConversion = false;
3606
3607 // C++ [over.ics.user]p2:
3608 // The second standard conversion sequence converts the
3609 // result of the user-defined conversion to the target type
3610 // for the sequence. Since an implicit conversion sequence
3611 // is an initialization, the special rules for
3612 // initialization by user-defined conversion apply when
3613 // selecting the best user-defined conversion for a
3614 // user-defined conversion sequence (see 13.3.3 and
3615 // 13.3.3.1).
3616 User.After = Best->FinalConversion;
3617 return Result;
3618 }
3619 llvm_unreachable("Not a constructor or conversion function?")::llvm::llvm_unreachable_internal("Not a constructor or conversion function?"
, "clang/lib/Sema/SemaOverload.cpp", 3619)
;
3620
3621 case OR_No_Viable_Function:
3622 return OR_No_Viable_Function;
3623
3624 case OR_Ambiguous:
3625 return OR_Ambiguous;
3626 }
3627
3628 llvm_unreachable("Invalid OverloadResult!")::llvm::llvm_unreachable_internal("Invalid OverloadResult!", "clang/lib/Sema/SemaOverload.cpp"
, 3628)
;
3629}
3630
3631bool
3632Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
3633 ImplicitConversionSequence ICS;
3634 OverloadCandidateSet CandidateSet(From->getExprLoc(),
3635 OverloadCandidateSet::CSK_Normal);
3636 OverloadingResult OvResult =
3637 IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
3638 CandidateSet, AllowedExplicit::None, false);
3639
3640 if (!(OvResult == OR_Ambiguous ||
3641 (OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
3642 return false;
3643
3644 auto Cands = CandidateSet.CompleteCandidates(
3645 *this,
3646 OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
3647 From);
3648 if (OvResult == OR_Ambiguous)
3649 Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
3650 << From->getType() << ToType << From->getSourceRange();
3651 else { // OR_No_Viable_Function && !CandidateSet.empty()
3652 if (!RequireCompleteType(From->getBeginLoc(), ToType,
3653 diag::err_typecheck_nonviable_condition_incomplete,
3654 From->getType(), From->getSourceRange()))
3655 Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
3656 << false << From->getType() << From->getSourceRange() << ToType;
3657 }
3658
3659 CandidateSet.NoteCandidates(
3660 *this, From, Cands);
3661 return true;
3662}
3663
3664// Helper for compareConversionFunctions that gets the FunctionType that the
3665// conversion-operator return value 'points' to, or nullptr.
3666static const FunctionType *
3667getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) {
3668 const FunctionType *ConvFuncTy = Conv->getType()->castAs<FunctionType>();
3669 const PointerType *RetPtrTy =
3670 ConvFuncTy->getReturnType()->getAs<PointerType>();
3671
3672 if (!RetPtrTy)
3673 return nullptr;
3674
3675 return RetPtrTy->getPointeeType()->getAs<FunctionType>();
3676}
3677
3678/// Compare the user-defined conversion functions or constructors
3679/// of two user-defined conversion sequences to determine whether any ordering
3680/// is possible.
3681static ImplicitConversionSequence::CompareKind
3682compareConversionFunctions(Sema &S, FunctionDecl *Function1,
3683 FunctionDecl *Function2) {
3684 CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
3685 CXXConversionDecl *Conv2 = dyn_cast_or_null<CXXConversionDecl>(Function2);
3686 if (!Conv1 || !Conv2)
3687 return ImplicitConversionSequence::Indistinguishable;
3688
3689 if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda())
3690 return ImplicitConversionSequence::Indistinguishable;
3691
3692 // Objective-C++:
3693 // If both conversion functions are implicitly-declared conversions from
3694 // a lambda closure type to a function pointer and a block pointer,
3695 // respectively, always prefer the conversion to a function pointer,
3696 // because the function pointer is more lightweight and is more likely
3697 // to keep code working.
3698 if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) {
3699 bool Block1 = Conv1->getConversionType()->isBlockPointerType();
3700 bool Block2 = Conv2->getConversionType()->isBlockPointerType();
3701 if (Block1 != Block2)
3702 return Block1 ? ImplicitConversionSequence::Worse
3703 : ImplicitConversionSequence::Better;
3704 }
3705
3706 // In order to support multiple calling conventions for the lambda conversion
3707 // operator (such as when the free and member function calling convention is
3708 // different), prefer the 'free' mechanism, followed by the calling-convention
3709 // of operator(). The latter is in place to support the MSVC-like solution of
3710 // defining ALL of the possible conversions in regards to calling-convention.
3711 const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1);
3712 const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2);
3713
3714 if (Conv1FuncRet && Conv2FuncRet &&
3715 Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) {
3716 CallingConv Conv1CC = Conv1FuncRet->getCallConv();
3717 CallingConv Conv2CC = Conv2FuncRet->getCallConv();
3718
3719 CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator();
3720 const auto *CallOpProto = CallOp->getType()->castAs<FunctionProtoType>();
3721
3722 CallingConv CallOpCC =
3723 CallOp->getType()->castAs<FunctionType>()->getCallConv();
3724 CallingConv DefaultFree = S.Context.getDefaultCallingConvention(
3725 CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
3726 CallingConv DefaultMember = S.Context.getDefaultCallingConvention(
3727 CallOpProto->isVariadic(), /*IsCXXMethod=*/true);
3728
3729 CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC};
3730 for (CallingConv CC : PrefOrder) {
3731 if (Conv1CC == CC)
3732 return ImplicitConversionSequence::Better;
3733 if (Conv2CC == CC)
3734 return ImplicitConversionSequence::Worse;
3735 }
3736 }
3737
3738 return ImplicitConversionSequence::Indistinguishable;
3739}
3740
3741static bool hasDeprecatedStringLiteralToCharPtrConversion(
3742 const ImplicitConversionSequence &ICS) {
3743 return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
3744 (ICS.isUserDefined() &&
3745 ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
3746}
3747
3748/// CompareImplicitConversionSequences - Compare two implicit
3749/// conversion sequences to determine whether one is better than the
3750/// other or if they are indistinguishable (C++ 13.3.3.2).
3751static ImplicitConversionSequence::CompareKind
3752CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
3753 const ImplicitConversionSequence& ICS1,
3754 const ImplicitConversionSequence& ICS2)
3755{
3756 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
3757 // conversion sequences (as defined in 13.3.3.1)
3758 // -- a standard conversion sequence (13.3.3.1.1) is a better
3759 // conversion sequence than a user-defined conversion sequence or
3760 // an ellipsis conversion sequence, and
3761 // -- a user-defined conversion sequence (13.3.3.1.2) is a better
3762 // conversion sequence than an ellipsis conversion sequence
3763 // (13.3.3.1.3).
3764 //
3765 // C++0x [over.best.ics]p10:
3766 // For the purpose of ranking implicit conversion sequences as
3767 // described in 13.3.3.2, the ambiguous conversion sequence is
3768 // treated as a user-defined sequence that is indistinguishable
3769 // from any other user-defined conversion sequence.
3770
3771 // String literal to 'char *' conversion has been deprecated in C++03. It has
3772 // been removed from C++11. We still accept this conversion, if it happens at
3773 // the best viable function. Otherwise, this conversion is considered worse
3774 // than ellipsis conversion. Consider this as an extension; this is not in the
3775 // standard. For example:
3776 //
3777 // int &f(...); // #1
3778 // void f(char*); // #2
3779 // void g() { int &r = f("foo"); }
3780 //
3781 // In C++03, we pick #2 as the best viable function.
3782 // In C++11, we pick #1 as the best viable function, because ellipsis
3783 // conversion is better than string-literal to char* conversion (since there
3784 // is no such conversion in C++11). If there was no #1 at all or #1 couldn't
3785 // convert arguments, #2 would be the best viable function in C++11.
3786 // If the best viable function has this conversion, a warning will be issued
3787 // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
3788
3789 if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
3790 hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
3791 hasDeprecatedStringLiteralToCharPtrConversion(ICS2) &&
3792 // Ill-formedness must not differ
3793 ICS1.isBad() == ICS2.isBad())
3794 return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
3795 ? ImplicitConversionSequence::Worse
3796 : ImplicitConversionSequence::Better;
3797
3798 if (ICS1.getKindRank() < ICS2.getKindRank())
3799 return ImplicitConversionSequence::Better;
3800 if (ICS2.getKindRank() < ICS1.getKindRank())
3801 return ImplicitConversionSequence::Worse;
3802
3803 // The following checks require both conversion sequences to be of
3804 // the same kind.
3805 if (ICS1.getKind() != ICS2.getKind())
3806 return ImplicitConversionSequence::Indistinguishable;
3807
3808 ImplicitConversionSequence::CompareKind Result =
3809 ImplicitConversionSequence::Indistinguishable;
3810
3811 // Two implicit conversion sequences of the same form are
3812 // indistinguishable conversion sequences unless one of the
3813 // following rules apply: (C++ 13.3.3.2p3):
3814
3815 // List-initialization sequence L1 is a better conversion sequence than
3816 // list-initialization sequence L2 if:
3817 // - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
3818 // if not that,
3819 // — L1 and L2 convert to arrays of the same element type, and either the
3820 // number of elements n_1 initialized by L1 is less than the number of
3821 // elements n_2 initialized by L2, or (C++20) n_1 = n_2 and L2 converts to
3822 // an array of unknown bound and L1 does not,
3823 // even if one of the other rules in this paragraph would otherwise apply.
3824 if (!ICS1.isBad()) {
3825 bool StdInit1 = false, StdInit2 = false;
3826 if (ICS1.hasInitializerListContainerType())
3827 StdInit1 = S.isStdInitializerList(ICS1.getInitializerListContainerType(),
3828 nullptr);
3829 if (ICS2.hasInitializerListContainerType())
3830 StdInit2 = S.isStdInitializerList(ICS2.getInitializerListContainerType(),
3831 nullptr);
3832 if (StdInit1 != StdInit2)
3833 return StdInit1 ? ImplicitConversionSequence::Better
3834 : ImplicitConversionSequence::Worse;
3835
3836 if (ICS1.hasInitializerListContainerType() &&
3837 ICS2.hasInitializerListContainerType())
3838 if (auto *CAT1 = S.Context.getAsConstantArrayType(
3839 ICS1.getInitializerListContainerType()))
3840 if (auto *CAT2 = S.Context.getAsConstantArrayType(
3841 ICS2.getInitializerListContainerType())) {
3842 if (S.Context.hasSameUnqualifiedType(CAT1->getElementType(),
3843 CAT2->getElementType())) {
3844 // Both to arrays of the same element type
3845 if (CAT1->getSize() != CAT2->getSize())
3846 // Different sized, the smaller wins
3847 return CAT1->getSize().ult(CAT2->getSize())
3848 ? ImplicitConversionSequence::Better
3849 : ImplicitConversionSequence::Worse;
3850 if (ICS1.isInitializerListOfIncompleteArray() !=
3851 ICS2.isInitializerListOfIncompleteArray())
3852 // One is incomplete, it loses
3853 return ICS2.isInitializerListOfIncompleteArray()
3854 ? ImplicitConversionSequence::Better
3855 : ImplicitConversionSequence::Worse;
3856 }
3857 }
3858 }
3859
3860 if (ICS1.isStandard())
3861 // Standard conversion sequence S1 is a better conversion sequence than
3862 // standard conversion sequence S2 if [...]
3863 Result = CompareStandardConversionSequences(S, Loc,
3864 ICS1.Standard, ICS2.Standard);
3865 else if (ICS1.isUserDefined()) {
3866 // User-defined conversion sequence U1 is a better conversion
3867 // sequence than another user-defined conversion sequence U2 if
3868 // they contain the same user-defined conversion function or
3869 // constructor and if the second standard conversion sequence of
3870 // U1 is better than the second standard conversion sequence of
3871 // U2 (C++ 13.3.3.2p3).
3872 if (ICS1.UserDefined.ConversionFunction ==
3873 ICS2.UserDefined.ConversionFunction)
3874 Result = CompareStandardConversionSequences(S, Loc,
3875 ICS1.UserDefined.After,
3876 ICS2.UserDefined.After);
3877 else
3878 Result = compareConversionFunctions(S,
3879 ICS1.UserDefined.ConversionFunction,
3880 ICS2.UserDefined.ConversionFunction);
3881 }
3882
3883 return Result;
3884}
3885
3886// Per 13.3.3.2p3, compare the given standard conversion sequences to
3887// determine if one is a proper subset of the other.
3888static ImplicitConversionSequence::CompareKind
3889compareStandardConversionSubsets(ASTContext &Context,
3890 const StandardConversionSequence& SCS1,
3891 const StandardConversionSequence& SCS2) {
3892 ImplicitConversionSequence::CompareKind Result
3893 = ImplicitConversionSequence::Indistinguishable;
3894
3895 // the identity conversion sequence is considered to be a subsequence of
3896 // any non-identity conversion sequence
3897 if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
3898 return ImplicitConversionSequence::Better;
3899 else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
3900 return ImplicitConversionSequence::Worse;
3901
3902 if (SCS1.Second != SCS2.Second) {
3903 if (SCS1.Second == ICK_Identity)
3904 Result = ImplicitConversionSequence::Better;
3905 else if (SCS2.Second == ICK_Identity)
3906 Result = ImplicitConversionSequence::Worse;
3907 else
3908 return ImplicitConversionSequence::Indistinguishable;
3909 } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
3910 return ImplicitConversionSequence::Indistinguishable;
3911
3912 if (SCS1.Third == SCS2.Third) {
3913 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
3914 : ImplicitConversionSequence::Indistinguishable;
3915 }
3916
3917 if (SCS1.Third == ICK_Identity)
3918 return Result == ImplicitConversionSequence::Worse
3919 ? ImplicitConversionSequence::Indistinguishable
3920 : ImplicitConversionSequence::Better;
3921
3922 if (SCS2.Third == ICK_Identity)
3923 return Result == ImplicitConversionSequence::Better
3924 ? ImplicitConversionSequence::Indistinguishable
3925 : ImplicitConversionSequence::Worse;
3926
3927 return ImplicitConversionSequence::Indistinguishable;
3928}
3929
3930/// Determine whether one of the given reference bindings is better
3931/// than the other based on what kind of bindings they are.
3932static bool
3933isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
3934 const StandardConversionSequence &SCS2) {
3935 // C++0x [over.ics.rank]p3b4:
3936 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
3937 // implicit object parameter of a non-static member function declared
3938 // without a ref-qualifier, and *either* S1 binds an rvalue reference
3939 // to an rvalue and S2 binds an lvalue reference *or S1 binds an
3940 // lvalue reference to a function lvalue and S2 binds an rvalue
3941 // reference*.
3942 //
3943 // FIXME: Rvalue references. We're going rogue with the above edits,
3944 // because the semantics in the current C++0x working paper (N3225 at the
3945 // time of this writing) break the standard definition of std::forward
3946 // and std::reference_wrapper when dealing with references to functions.
3947 // Proposed wording changes submitted to CWG for consideration.
3948 if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
3949 SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
3950 return false;
3951
3952 return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
3953 SCS2.IsLvalueReference) ||
3954 (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
3955 !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
3956}
3957
3958enum class FixedEnumPromotion {
3959 None,
3960 ToUnderlyingType,
3961 ToPromotedUnderlyingType
3962};
3963
3964/// Returns kind of fixed enum promotion the \a SCS uses.
3965static FixedEnumPromotion
3966getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {
3967
3968 if (SCS.Second != ICK_Integral_Promotion)
3969 return FixedEnumPromotion::None;
3970
3971 QualType FromType = SCS.getFromType();
3972 if (!FromType->isEnumeralType())
3973 return FixedEnumPromotion::None;
3974
3975 EnumDecl *Enum = FromType->castAs<EnumType>()->getDecl();
3976 if (!Enum->isFixed())
3977 return FixedEnumPromotion::None;
3978
3979 QualType UnderlyingType = Enum->getIntegerType();
3980 if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
3981 return FixedEnumPromotion::ToUnderlyingType;
3982
3983 return FixedEnumPromotion::ToPromotedUnderlyingType;
3984}
3985
3986/// CompareStandardConversionSequences - Compare two standard
3987/// conversion sequences to determine whether one is better than the
3988/// other or if they are indistinguishable (C++ 13.3.3.2p3).
3989static ImplicitConversionSequence::CompareKind
3990CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
3991 const StandardConversionSequence& SCS1,
3992 const StandardConversionSequence& SCS2)
3993{
3994 // Standard conversion sequence S1 is a better conversion sequence
3995 // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
3996
3997 // -- S1 is a proper subsequence of S2 (comparing the conversion
3998 // sequences in the canonical form defined by 13.3.3.1.1,
3999 // excluding any Lvalue Transformation; the identity conversion
4000 // sequence is considered to be a subsequence of any
4001 // non-identity conversion sequence) or, if not that,
4002 if (ImplicitConversionSequence::CompareKind CK
4003 = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
4004 return CK;
4005
4006 // -- the rank of S1 is better than the rank of S2 (by the rules
4007 // defined below), or, if not that,
4008 ImplicitConversionRank Rank1 = SCS1.getRank();
4009 ImplicitConversionRank Rank2 = SCS2.getRank();
4010 if (Rank1 < Rank2)
4011 return ImplicitConversionSequence::Better;
4012 else if (Rank2 < Rank1)
4013 return ImplicitConversionSequence::Worse;
4014
4015 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
4016 // are indistinguishable unless one of the following rules
4017 // applies:
4018
4019 // A conversion that is not a conversion of a pointer, or
4020 // pointer to member, to bool is better than another conversion
4021 // that is such a conversion.
4022 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
4023 return SCS2.isPointerConversionToBool()
4024 ? ImplicitConversionSequence::Better
4025 : ImplicitConversionSequence::Worse;
4026
4027 // C++14 [over.ics.rank]p4b2:
4028 // This is retroactively applied to C++11 by CWG 1601.
4029 //
4030 // A conversion that promotes an enumeration whose underlying type is fixed
4031 // to its underlying type is better than one that promotes to the promoted
4032 // underlying type, if the two are different.
4033 FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
4034 FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
4035 if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
4036 FEP1 != FEP2)
4037 return FEP1 == FixedEnumPromotion::ToUnderlyingType
4038 ? ImplicitConversionSequence::Better
4039 : ImplicitConversionSequence::Worse;
4040
4041 // C++ [over.ics.rank]p4b2:
4042 //
4043 // If class B is derived directly or indirectly from class A,
4044 // conversion of B* to A* is better than conversion of B* to
4045 // void*, and conversion of A* to void* is better than conversion
4046 // of B* to void*.
4047 bool SCS1ConvertsToVoid
4048 = SCS1.isPointerConversionToVoidPointer(S.Context);
4049 bool SCS2ConvertsToVoid
4050 = SCS2.isPointerConversionToVoidPointer(S.Context);
4051 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
4052 // Exactly one of the conversion sequences is a conversion to
4053 // a void pointer; it's the worse conversion.
4054 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
4055 : ImplicitConversionSequence::Worse;
4056 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
4057 // Neither conversion sequence converts to a void pointer; compare
4058 // their derived-to-base conversions.
4059 if (ImplicitConversionSequence::CompareKind DerivedCK
4060 = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
4061 return DerivedCK;
4062 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
4063 !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
4064 // Both conversion sequences are conversions to void
4065 // pointers. Compare the source types to determine if there's an
4066 // inheritance relationship in their sources.
4067 QualType FromType1 = SCS1.getFromType();
4068 QualType FromType2 = SCS2.getFromType();
4069
4070 // Adjust the types we're converting from via the array-to-pointer
4071 // conversion, if we need to.
4072 if (SCS1.First == ICK_Array_To_Pointer)
4073 FromType1 = S.Context.getArrayDecayedType(FromType1);
4074 if (SCS2.First == ICK_Array_To_Pointer)
4075 FromType2 = S.Context.getArrayDecayedType(FromType2);
4076
4077 QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
4078 QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
4079
4080 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4081 return ImplicitConversionSequence::Better;
4082 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4083 return ImplicitConversionSequence::Worse;
4084
4085 // Objective-C++: If one interface is more specific than the
4086 // other, it is the better one.
4087 const ObjCObjectPointerType* FromObjCPtr1
4088 = FromType1->getAs<ObjCObjectPointerType>();
4089 const ObjCObjectPointerType* FromObjCPtr2
4090 = FromType2->getAs<ObjCObjectPointerType>();
4091 if (FromObjCPtr1 && FromObjCPtr2) {
4092 bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
4093 FromObjCPtr2);
4094 bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
4095 FromObjCPtr1);
4096 if (AssignLeft != AssignRight) {
4097 return AssignLeft? ImplicitConversionSequence::Better
4098 : ImplicitConversionSequence::Worse;
4099 }
4100 }
4101 }
4102
4103 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4104 // Check for a better reference binding based on the kind of bindings.
4105 if (isBetterReferenceBindingKind(SCS1, SCS2))
4106 return ImplicitConversionSequence::Better;
4107 else if (isBetterReferenceBindingKind(SCS2, SCS1))
4108 return ImplicitConversionSequence::Worse;
4109 }
4110
4111 // Compare based on qualification conversions (C++ 13.3.3.2p3,
4112 // bullet 3).
4113 if (ImplicitConversionSequence::CompareKind QualCK
4114 = CompareQualificationConversions(S, SCS1, SCS2))
4115 return QualCK;
4116
4117 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4118 // C++ [over.ics.rank]p3b4:
4119 // -- S1 and S2 are reference bindings (8.5.3), and the types to
4120 // which the references refer are the same type except for
4121 // top-level cv-qualifiers, and the type to which the reference
4122 // initialized by S2 refers is more cv-qualified than the type
4123 // to which the reference initialized by S1 refers.
4124 QualType T1 = SCS1.getToType(2);
4125 QualType T2 = SCS2.getToType(2);
4126 T1 = S.Context.getCanonicalType(T1);
4127 T2 = S.Context.getCanonicalType(T2);
4128 Qualifiers T1Quals, T2Quals;
4129 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4130 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4131 if (UnqualT1 == UnqualT2) {
4132 // Objective-C++ ARC: If the references refer to objects with different
4133 // lifetimes, prefer bindings that don't change lifetime.
4134 if (SCS1.ObjCLifetimeConversionBinding !=
4135 SCS2.ObjCLifetimeConversionBinding) {
4136 return SCS1.ObjCLifetimeConversionBinding
4137 ? ImplicitConversionSequence::Worse
4138 : ImplicitConversionSequence::Better;
4139 }
4140
4141 // If the type is an array type, promote the element qualifiers to the
4142 // type for comparison.
4143 if (isa<ArrayType>(T1) && T1Quals)
4144 T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
4145 if (isa<ArrayType>(T2) && T2Quals)
4146 T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
4147 if (T2.isMoreQualifiedThan(T1))
4148 return ImplicitConversionSequence::Better;
4149 if (T1.isMoreQualifiedThan(T2))
4150 return ImplicitConversionSequence::Worse;
4151 }
4152 }
4153
4154 // In Microsoft mode (below 19.28), prefer an integral conversion to a
4155 // floating-to-integral conversion if the integral conversion
4156 // is between types of the same size.
4157 // For example:
4158 // void f(float);
4159 // void f(int);
4160 // int main {
4161 // long a;
4162 // f(a);
4163 // }
4164 // Here, MSVC will call f(int) instead of generating a compile error
4165 // as clang will do in standard mode.
4166 if (S.getLangOpts().MSVCCompat &&
4167 !S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) &&
4168 SCS1.Second == ICK_Integral_Conversion &&
4169 SCS2.Second == ICK_Floating_Integral &&
4170 S.Context.getTypeSize(SCS1.getFromType()) ==
4171 S.Context.getTypeSize(SCS1.getToType(2)))
4172 return ImplicitConversionSequence::Better;
4173
4174 // Prefer a compatible vector conversion over a lax vector conversion
4175 // For example:
4176 //
4177 // typedef float __v4sf __attribute__((__vector_size__(16)));
4178 // void f(vector float);
4179 // void f(vector signed int);
4180 // int main() {
4181 // __v4sf a;
4182 // f(a);
4183 // }
4184 // Here, we'd like to choose f(vector float) and not
4185 // report an ambiguous call error
4186 if (SCS1.Second == ICK_Vector_Conversion &&
4187 SCS2.Second == ICK_Vector_Conversion) {
4188 bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4189 SCS1.getFromType(), SCS1.getToType(2));
4190 bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4191 SCS2.getFromType(), SCS2.getToType(2));
4192
4193 if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
4194 return SCS1IsCompatibleVectorConversion
4195 ? ImplicitConversionSequence::Better
4196 : ImplicitConversionSequence::Worse;
4197 }
4198
4199 if (SCS1.Second == ICK_SVE_Vector_Conversion &&
4200 SCS2.Second == ICK_SVE_Vector_Conversion) {
4201 bool SCS1IsCompatibleSVEVectorConversion =
4202 S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2));
4203 bool SCS2IsCompatibleSVEVectorConversion =
4204 S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2));
4205
4206 if (SCS1IsCompatibleSVEVectorConversion !=
4207 SCS2IsCompatibleSVEVectorConversion)
4208 return SCS1IsCompatibleSVEVectorConversion
4209 ? ImplicitConversionSequence::Better
4210 : ImplicitConversionSequence::Worse;
4211 }
4212
4213 return ImplicitConversionSequence::Indistinguishable;
4214}
4215
4216/// CompareQualificationConversions - Compares two standard conversion
4217/// sequences to determine whether they can be ranked based on their
4218/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
4219static ImplicitConversionSequence::CompareKind
4220CompareQualificationConversions(Sema &S,
4221 const StandardConversionSequence& SCS1,
4222 const StandardConversionSequence& SCS2) {
4223 // C++ [over.ics.rank]p3:
4224 // -- S1 and S2 differ only in their qualification conversion and
4225 // yield similar types T1 and T2 (C++ 4.4), respectively, [...]
4226 // [C++98]
4227 // [...] and the cv-qualification signature of type T1 is a proper subset
4228 // of the cv-qualification signature of type T2, and S1 is not the
4229 // deprecated string literal array-to-pointer conversion (4.2).
4230 // [C++2a]
4231 // [...] where T1 can be converted to T2 by a qualification conversion.
4232 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
4233 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
4234 return ImplicitConversionSequence::Indistinguishable;
4235
4236 // FIXME: the example in the standard doesn't use a qualification
4237 // conversion (!)
4238 QualType T1 = SCS1.getToType(2);
4239 QualType T2 = SCS2.getToType(2);
4240 T1 = S.Context.getCanonicalType(T1);
4241 T2 = S.Context.getCanonicalType(T2);
4242 assert(!T1->isReferenceType() && !T2->isReferenceType())(static_cast <bool> (!T1->isReferenceType() &&
!T2->isReferenceType()) ? void (0) : __assert_fail ("!T1->isReferenceType() && !T2->isReferenceType()"
, "clang/lib/Sema/SemaOverload.cpp", 4242, __extension__ __PRETTY_FUNCTION__
))
;
4243 Qualifiers T1Quals, T2Quals;
4244 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4245 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4246
4247 // If the types are the same, we won't learn anything by unwrapping
4248 // them.
4249 if (UnqualT1 == UnqualT2)
4250 return ImplicitConversionSequence::Indistinguishable;
4251
4252 // Don't ever prefer a standard conversion sequence that uses the deprecated
4253 // string literal array to pointer conversion.
4254 bool CanPick1 = !SCS1.DeprecatedStringLiteralToCharPtr;
4255 bool CanPick2 = !SCS2.DeprecatedStringLiteralToCharPtr;
4256
4257 // Objective-C++ ARC:
4258 // Prefer qualification conversions not involving a change in lifetime
4259 // to qualification conversions that do change lifetime.
4260 if (SCS1.QualificationIncludesObjCLifetime &&
4261 !SCS2.QualificationIncludesObjCLifetime)
4262 CanPick1 = false;
4263 if (SCS2.QualificationIncludesObjCLifetime &&
4264 !SCS1.QualificationIncludesObjCLifetime)
4265 CanPick2 = false;
4266
4267 bool ObjCLifetimeConversion;
4268 if (CanPick1 &&
4269 !S.IsQualificationConversion(T1, T2, false, ObjCLifetimeConversion))
4270 CanPick1 = false;
4271 // FIXME: In Objective-C ARC, we can have qualification conversions in both
4272 // directions, so we can't short-cut this second check in general.
4273 if (CanPick2 &&
4274 !S.IsQualificationConversion(T2, T1, false, ObjCLifetimeConversion))
4275 CanPick2 = false;
4276
4277 if (CanPick1 != CanPick2)
4278 return CanPick1 ? ImplicitConversionSequence::Better
4279 : ImplicitConversionSequence::Worse;
4280 return ImplicitConversionSequence::Indistinguishable;
4281}
4282
4283/// CompareDerivedToBaseConversions - Compares two standard conversion
4284/// sequences to determine whether they can be ranked based on their
4285/// various kinds of derived-to-base conversions (C++
4286/// [over.ics.rank]p4b3). As part of these checks, we also look at
4287/// conversions between Objective-C interface types.
4288static ImplicitConversionSequence::CompareKind
4289CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
4290 const StandardConversionSequence& SCS1,
4291 const StandardConversionSequence& SCS2) {
4292 QualType FromType1 = SCS1.getFromType();
4293 QualType ToType1 = SCS1.getToType(1);
4294 QualType FromType2 = SCS2.getFromType();
4295 QualType ToType2 = SCS2.getToType(1);
4296
4297 // Adjust the types we're converting from via the array-to-pointer
4298 // conversion, if we need to.
4299 if (SCS1.First == ICK_Array_To_Pointer)
4300 FromType1 = S.Context.getArrayDecayedType(FromType1);
4301 if (SCS2.First == ICK_Array_To_Pointer)
4302 FromType2 = S.Context.getArrayDecayedType(FromType2);
4303
4304 // Canonicalize all of the types.
4305 FromType1 = S.Context.getCanonicalType(FromType1);
4306 ToType1 = S.Context.getCanonicalType(ToType1);
4307 FromType2 = S.Context.getCanonicalType(FromType2);
4308 ToType2 = S.Context.getCanonicalType(ToType2);
4309
4310 // C++ [over.ics.rank]p4b3:
4311 //
4312 // If class B is derived directly or indirectly from class A and
4313 // class C is derived directly or indirectly from B,
4314 //
4315 // Compare based on pointer conversions.
4316 if (SCS1.Second == ICK_Pointer_Conversion &&
4317 SCS2.Second == ICK_Pointer_Conversion &&
4318 /*FIXME: Remove if Objective-C id conversions get their own rank*/
4319 FromType1->isPointerType() && FromType2->isPointerType() &&
4320 ToType1->isPointerType() && ToType2->isPointerType()) {
4321 QualType FromPointee1 =
4322 FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4323 QualType ToPointee1 =
4324 ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4325 QualType FromPointee2 =
4326 FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4327 QualType ToPointee2 =
4328 ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4329
4330 // -- conversion of C* to B* is better than conversion of C* to A*,
4331 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4332 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4333 return ImplicitConversionSequence::Better;
4334 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4335 return ImplicitConversionSequence::Worse;
4336 }
4337
4338 // -- conversion of B* to A* is better than conversion of C* to A*,
4339 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
4340 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4341 return ImplicitConversionSequence::Better;
4342 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4343 return ImplicitConversionSequence::Worse;
4344 }
4345 } else if (SCS1.Second == ICK_Pointer_Conversion &&
4346 SCS2.Second == ICK_Pointer_Conversion) {
4347 const ObjCObjectPointerType *FromPtr1
4348 = FromType1->getAs<ObjCObjectPointerType>();
4349 const ObjCObjectPointerType *FromPtr2
4350 = FromType2->getAs<ObjCObjectPointerType>();
4351 const ObjCObjectPointerType *ToPtr1
4352 = ToType1->getAs<ObjCObjectPointerType>();
4353 const ObjCObjectPointerType *ToPtr2
4354 = ToType2->getAs<ObjCObjectPointerType>();
4355
4356 if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
4357 // Apply the same conversion ranking rules for Objective-C pointer types
4358 // that we do for C++ pointers to class types. However, we employ the
4359 // Objective-C pseudo-subtyping relationship used for assignment of
4360 // Objective-C pointer types.
4361 bool FromAssignLeft
4362 = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
4363 bool FromAssignRight
4364 = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
4365 bool ToAssignLeft
4366 = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
4367 bool ToAssignRight
4368 = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
4369
4370 // A conversion to an a non-id object pointer type or qualified 'id'
4371 // type is better than a conversion to 'id'.
4372 if (ToPtr1->isObjCIdType() &&
4373 (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
4374 return ImplicitConversionSequence::Worse;
4375 if (ToPtr2->isObjCIdType() &&
4376 (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
4377 return ImplicitConversionSequence::Better;
4378
4379 // A conversion to a non-id object pointer type is better than a
4380 // conversion to a qualified 'id' type
4381 if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
4382 return ImplicitConversionSequence::Worse;
4383 if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
4384 return ImplicitConversionSequence::Better;
4385
4386 // A conversion to an a non-Class object pointer type or qualified 'Class'
4387 // type is better than a conversion to 'Class'.
4388 if (ToPtr1->isObjCClassType() &&
4389 (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
4390 return ImplicitConversionSequence::Worse;
4391 if (ToPtr2->isObjCClassType() &&
4392 (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
4393 return ImplicitConversionSequence::Better;
4394
4395 // A conversion to a non-Class object pointer type is better than a
4396 // conversion to a qualified 'Class' type.
4397 if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
4398 return ImplicitConversionSequence::Worse;
4399 if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
4400 return ImplicitConversionSequence::Better;
4401
4402 // -- "conversion of C* to B* is better than conversion of C* to A*,"
4403 if (S.Context.hasSameType(FromType1, FromType2) &&
4404 !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
4405 (ToAssignLeft != ToAssignRight)) {
4406 if (FromPtr1->isSpecialized()) {
4407 // "conversion of B<A> * to B * is better than conversion of B * to
4408 // C *.
4409 bool IsFirstSame =
4410 FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
4411 bool IsSecondSame =
4412 FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
4413 if (IsFirstSame) {
4414 if (!IsSecondSame)
4415 return ImplicitConversionSequence::Better;
4416 } else if (IsSecondSame)
4417 return ImplicitConversionSequence::Worse;
4418 }
4419 return ToAssignLeft? ImplicitConversionSequence::Worse
4420 : ImplicitConversionSequence::Better;
4421 }
4422
4423 // -- "conversion of B* to A* is better than conversion of C* to A*,"
4424 if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
4425 (FromAssignLeft != FromAssignRight))
4426 return FromAssignLeft? ImplicitConversionSequence::Better
4427 : ImplicitConversionSequence::Worse;
4428 }
4429 }
4430
4431 // Ranking of member-pointer types.
4432 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
4433 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
4434 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
4435 const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
4436 const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
4437 const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
4438 const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
4439 const Type *FromPointeeType1 = FromMemPointer1->getClass();
4440 const Type *ToPointeeType1 = ToMemPointer1->getClass();
4441 const Type *FromPointeeType2 = FromMemPointer2->getClass();
4442 const Type *ToPointeeType2 = ToMemPointer2->getClass();
4443 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
4444 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
4445 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
4446 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
4447 // conversion of A::* to B::* is better than conversion of A::* to C::*,
4448 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4449 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4450 return ImplicitConversionSequence::Worse;
4451 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4452 return ImplicitConversionSequence::Better;
4453 }
4454 // conversion of B::* to C::* is better than conversion of A::* to C::*
4455 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
4456 if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4457 return ImplicitConversionSequence::Better;
4458 else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4459 return ImplicitConversionSequence::Worse;
4460 }
4461 }
4462
4463 if (SCS1.Second == ICK_Derived_To_Base) {
4464 // -- conversion of C to B is better than conversion of C to A,
4465 // -- binding of an expression of type C to a reference of type
4466 // B& is better than binding an expression of type C to a
4467 // reference of type A&,
4468 if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4469 !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4470 if (S.IsDerivedFrom(Loc, ToType1, ToType2))
4471 return ImplicitConversionSequence::Better;
4472 else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
4473 return ImplicitConversionSequence::Worse;
4474 }
4475
4476 // -- conversion of B to A is better than conversion of C to A.
4477 // -- binding of an expression of type B to a reference of type
4478 // A& is better than binding an expression of type C to a
4479 // reference of type A&,
4480 if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4481 S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4482 if (S.IsDerivedFrom(Loc, FromType2, FromType1))
4483 return ImplicitConversionSequence::Better;
4484 else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
4485 return ImplicitConversionSequence::Worse;
4486 }
4487 }
4488
4489 return ImplicitConversionSequence::Indistinguishable;
4490}
4491
4492/// Determine whether the given type is valid, e.g., it is not an invalid
4493/// C++ class.
4494static bool isTypeValid(QualType T) {
4495 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
4496 return !Record->isInvalidDecl();
4497
4498 return true;
4499}
4500
4501static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
4502 if (!T.getQualifiers().hasUnaligned())
4503 return T;
4504
4505 Qualifiers Q;
4506 T = Ctx.getUnqualifiedArrayType(T, Q);
4507 Q.removeUnaligned();
4508 return Ctx.getQualifiedType(T, Q);
4509}
4510
4511/// CompareReferenceRelationship - Compare the two types T1 and T2 to
4512/// determine whether they are reference-compatible,
4513/// reference-related, or incompatible, for use in C++ initialization by
4514/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
4515/// type, and the first type (T1) is the pointee type of the reference
4516/// type being initialized.
4517Sema::ReferenceCompareResult
4518Sema::CompareReferenceRelationship(SourceLocation Loc,
4519 QualType OrigT1, QualType OrigT2,
4520 ReferenceConversions *ConvOut) {
4521 assert(!OrigT1->isReferenceType() &&(static_cast <bool> (!OrigT1->isReferenceType() &&
"T1 must be the pointee type of the reference type") ? void (
0) : __assert_fail ("!OrigT1->isReferenceType() && \"T1 must be the pointee type of the reference type\""
, "clang/lib/Sema/SemaOverload.cpp", 4522, __extension__ __PRETTY_FUNCTION__
))
4522 "T1 must be the pointee type of the reference type")(static_cast <bool> (!OrigT1->isReferenceType() &&
"T1 must be the pointee type of the reference type") ? void (
0) : __assert_fail ("!OrigT1->isReferenceType() && \"T1 must be the pointee type of the reference type\""
, "clang/lib/Sema/SemaOverload.cpp", 4522, __extension__ __PRETTY_FUNCTION__
))
;
4523 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type")(static_cast <bool> (!OrigT2->isReferenceType() &&
"T2 cannot be a reference type") ? void (0) : __assert_fail (
"!OrigT2->isReferenceType() && \"T2 cannot be a reference type\""
, "clang/lib/Sema/SemaOverload.cpp", 4523, __extension__ __PRETTY_FUNCTION__
))
;
4524
4525 QualType T1 = Context.getCanonicalType(OrigT1);
4526 QualType T2 = Context.getCanonicalType(OrigT2);
4527 Qualifiers T1Quals, T2Quals;
4528 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
4529 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
4530
4531 ReferenceConversions ConvTmp;
4532 ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
4533 Conv = ReferenceConversions();
4534
4535 // C++2a [dcl.init.ref]p4:
4536 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
4537 // reference-related to "cv2 T2" if T1 is similar to T2, or
4538 // T1 is a base class of T2.
4539 // "cv1 T1" is reference-compatible with "cv2 T2" if
4540 // a prvalue of type "pointer to cv2 T2" can be converted to the type
4541 // "pointer to cv1 T1" via a standard conversion sequence.
4542
4543 // Check for standard conversions we can apply to pointers: derived-to-base
4544 // conversions, ObjC pointer conversions, and function pointer conversions.
4545 // (Qualification conversions are checked last.)
4546 QualType ConvertedT2;
4547 if (UnqualT1 == UnqualT2) {
4548 // Nothing to do.
4549 } else if (isCompleteType(Loc, OrigT2) &&
4550 isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
4551 IsDerivedFrom(Loc, UnqualT2, UnqualT1))
4552 Conv |= ReferenceConversions::DerivedToBase;
4553 else if (UnqualT1->isObjCObjectOrInterfaceType() &&
4554 UnqualT2->isObjCObjectOrInterfaceType() &&
4555 Context.canBindObjCObjectType(UnqualT1, UnqualT2))
4556 Conv |= ReferenceConversions::ObjC;
4557 else if (UnqualT2->isFunctionType() &&
4558 IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
4559 Conv |= ReferenceConversions::Function;
4560 // No need to check qualifiers; function types don't have them.
4561 return Ref_Compatible;
4562 }
4563 bool ConvertedReferent = Conv != 0;
4564
4565 // We can have a qualification conversion. Compute whether the types are
4566 // similar at the same time.
4567 bool PreviousToQualsIncludeConst = true;
4568 bool TopLevel = true;
4569 do {
4570 if (T1 == T2)
4571 break;
4572
4573 // We will need a qualification conversion.
4574 Conv |= ReferenceConversions::Qualification;
4575
4576 // Track whether we performed a qualification conversion anywhere other
4577 // than the top level. This matters for ranking reference bindings in
4578 // overload resolution.
4579 if (!TopLevel)
4580 Conv |= ReferenceConversions::NestedQualification;
4581
4582 // MS compiler ignores __unaligned qualifier for references; do the same.
4583 T1 = withoutUnaligned(Context, T1);
4584 T2 = withoutUnaligned(Context, T2);
4585
4586 // If we find a qualifier mismatch, the types are not reference-compatible,
4587 // but are still be reference-related if they're similar.
4588 bool ObjCLifetimeConversion = false;
4589 if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
4590 PreviousToQualsIncludeConst,
4591 ObjCLifetimeConversion))
4592 return (ConvertedReferent || Context.hasSimilarType(T1, T2))
4593 ? Ref_Related
4594 : Ref_Incompatible;
4595
4596 // FIXME: Should we track this for any level other than the first?
4597 if (ObjCLifetimeConversion)
4598 Conv |= ReferenceConversions::ObjCLifetime;
4599
4600 TopLevel = false;
4601 } while (Context.UnwrapSimilarTypes(T1, T2));
4602
4603 // At this point, if the types are reference-related, we must either have the
4604 // same inner type (ignoring qualifiers), or must have already worked out how
4605 // to convert the referent.
4606 return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
4607 ? Ref_Compatible
4608 : Ref_Incompatible;
4609}
4610
4611/// Look for a user-defined conversion to a value reference-compatible
4612/// with DeclType. Return true if something definite is found.
4613static bool
4614FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
4615 QualType DeclType, SourceLocation DeclLoc,
4616 Expr *Init, QualType T2, bool AllowRvalues,
4617 bool AllowExplicit) {
4618 assert(T2->isRecordType() && "Can only find conversions of record types.")(static_cast <bool> (T2->isRecordType() && "Can only find conversions of record types."
) ? void (0) : __assert_fail ("T2->isRecordType() && \"Can only find conversions of record types.\""
, "clang/lib/Sema/SemaOverload.cpp", 4618, __extension__ __PRETTY_FUNCTION__
))
;
4619 auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());
4620
4621 OverloadCandidateSet CandidateSet(
4622 DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4623 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4624 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4625 NamedDecl *D = *I;
4626 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4627 if (isa<UsingShadowDecl>(D))
4628 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4629
4630 FunctionTemplateDecl *ConvTemplate
4631 = dyn_cast<FunctionTemplateDecl>(D);
4632 CXXConversionDecl *Conv;
4633 if (ConvTemplate)
4634 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4635 else
4636 Conv = cast<CXXConversionDecl>(D);
4637
4638 if (AllowRvalues) {
4639 // If we are initializing an rvalue reference, don't permit conversion
4640 // functions that return lvalues.
4641 if (!ConvTemplate && DeclType->isRValueReferenceType()) {
4642 const ReferenceType *RefType
4643 = Conv->getConversionType()->getAs<LValueReferenceType>();
4644 if (RefType && !RefType->getPointeeType()->isFunctionType())
4645 continue;
4646 }
4647
4648 if (!ConvTemplate &&
4649 S.CompareReferenceRelationship(
4650 DeclLoc,
4651 Conv->getConversionType()
4652 .getNonReferenceType()
4653 .getUnqualifiedType(),
4654 DeclType.getNonReferenceType().getUnqualifiedType()) ==
4655 Sema::Ref_Incompatible)
4656 continue;
4657 } else {
4658 // If the conversion function doesn't return a reference type,
4659 // it can't be considered for this conversion. An rvalue reference
4660 // is only acceptable if its referencee is a function type.
4661
4662 const ReferenceType *RefType =
4663 Conv->getConversionType()->getAs<ReferenceType>();
4664 if (!RefType ||
4665 (!RefType->isLValueReferenceType() &&
4666 !RefType->getPointeeType()->isFunctionType()))
4667 continue;
4668 }
4669
4670 if (ConvTemplate)
4671 S.AddTemplateConversionCandidate(
4672 ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4673 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4674 else
4675 S.AddConversionCandidate(
4676 Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4677 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4678 }
4679
4680 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4681
4682 OverloadCandidateSet::iterator Best;
4683 switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
4684 case OR_Success:
4685 // C++ [over.ics.ref]p1:
4686 //
4687 // [...] If the parameter binds directly to the result of
4688 // applying a conversion function to the argument
4689 // expression, the implicit conversion sequence is a
4690 // user-defined conversion sequence (13.3.3.1.2), with the
4691 // second standard conversion sequence either an identity
4692 // conversion or, if the conversion function returns an
4693 // entity of a type that is a derived class of the parameter
4694 // type, a derived-to-base Conversion.
4695 if (!Best->FinalConversion.DirectBinding)
4696 return false;
4697
4698 ICS.setUserDefined();
4699 ICS.UserDefined.Before = Best->Conversions[0].Standard;
4700 ICS.UserDefined.After = Best->FinalConversion;
4701 ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
4702 ICS.UserDefined.ConversionFunction = Best->Function;
4703 ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
4704 ICS.UserDefined.EllipsisConversion = false;
4705 assert(ICS.UserDefined.After.ReferenceBinding &&(static_cast <bool> (ICS.UserDefined.After.ReferenceBinding
&& ICS.UserDefined.After.DirectBinding && "Expected a direct reference binding!"
) ? void (0) : __assert_fail ("ICS.UserDefined.After.ReferenceBinding && ICS.UserDefined.After.DirectBinding && \"Expected a direct reference binding!\""
, "clang/lib/Sema/SemaOverload.cpp", 4707, __extension__ __PRETTY_FUNCTION__
))
4706 ICS.UserDefined.After.DirectBinding &&(static_cast <bool> (ICS.UserDefined.After.ReferenceBinding
&& ICS.UserDefined.After.DirectBinding && "Expected a direct reference binding!"
) ? void (0) : __assert_fail ("ICS.UserDefined.After.ReferenceBinding && ICS.UserDefined.After.DirectBinding && \"Expected a direct reference binding!\""
, "clang/lib/Sema/SemaOverload.cpp", 4707, __extension__ __PRETTY_FUNCTION__
))
4707 "Expected a direct reference binding!")(static_cast <bool> (ICS.UserDefined.After.ReferenceBinding
&& ICS.UserDefined.After.DirectBinding && "Expected a direct reference binding!"
) ? void (0) : __assert_fail ("ICS.UserDefined.After.ReferenceBinding && ICS.UserDefined.After.DirectBinding && \"Expected a direct reference binding!\""
, "clang/lib/Sema/SemaOverload.cpp", 4707, __extension__ __PRETTY_FUNCTION__
))
;
4708 return true;
4709
4710 case OR_Ambiguous:
4711 ICS.setAmbiguous();
4712 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
4713 Cand != CandidateSet.end(); ++Cand)
4714 if (Cand->Best)
4715 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
4716 return true;
4717
4718 case OR_No_Viable_Function:
4719 case OR_Deleted:
4720 // There was no suitable conversion, or we found a deleted
4721 // conversion; continue with other checks.
4722 return false;
4723 }
4724
4725 llvm_unreachable("Invalid OverloadResult!")::llvm::llvm_unreachable_internal("Invalid OverloadResult!", "clang/lib/Sema/SemaOverload.cpp"
, 4725)
;
4726}
4727
4728/// Compute an implicit conversion sequence for reference
4729/// initialization.
4730static ImplicitConversionSequence
4731TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
4732 SourceLocation DeclLoc,
4733 bool SuppressUserConversions,
4734 bool AllowExplicit) {
4735 assert(DeclType->isReferenceType() && "Reference init needs a reference")(static_cast <bool> (DeclType->isReferenceType() &&
"Reference init needs a reference") ? void (0) : __assert_fail
("DeclType->isReferenceType() && \"Reference init needs a reference\""
, "clang/lib/Sema/SemaOverload.cpp", 4735, __extension__ __PRETTY_FUNCTION__
))
;
4736
4737 // Most paths end in a failed conversion.
4738 ImplicitConversionSequence ICS;
4739 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4740
4741 QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
4742 QualType T2 = Init->getType();
4743
4744 // If the initializer is the address of an overloaded function, try
4745 // to resolve the overloaded function. If all goes well, T2 is the
4746 // type of the resulting function.
4747 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
4748 DeclAccessPair Found;
4749 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
4750 false, Found))
4751 T2 = Fn->getType();
4752 }
4753
4754 // Compute some basic properties of the types and the initializer.
4755 bool isRValRef = DeclType->isRValueReferenceType();
4756 Expr::Classification InitCategory = Init->Classify(S.Context);
4757
4758 Sema::ReferenceConversions RefConv;
4759 Sema::ReferenceCompareResult RefRelationship =
4760 S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);
4761
4762 auto SetAsReferenceBinding = [&](bool BindsDirectly) {
4763 ICS.setStandard();
4764 ICS.Standard.First = ICK_Identity;
4765 // FIXME: A reference binding can be a function conversion too. We should
4766 // consider that when ordering reference-to-function bindings.
4767 ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
4768 ? ICK_Derived_To_Base
4769 : (RefConv & Sema::ReferenceConversions::ObjC)
4770 ? ICK_Compatible_Conversion
4771 : ICK_Identity;
4772 // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
4773 // a reference binding that performs a non-top-level qualification
4774 // conversion as a qualification conversion, not as an identity conversion.
4775 ICS.Standard.Third = (RefConv &
4776 Sema::ReferenceConversions::NestedQualification)
4777 ? ICK_Qualification
4778 : ICK_Identity;
4779 ICS.Standard.setFromType(T2);
4780 ICS.Standard.setToType(0, T2);
4781 ICS.Standard.setToType(1, T1);
4782 ICS.Standard.setToType(2, T1);
4783 ICS.Standard.ReferenceBinding = true;
4784 ICS.Standard.DirectBinding = BindsDirectly;
4785 ICS.Standard.IsLvalueReference = !isRValRef;
4786 ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
4787 ICS.Standard.BindsToRvalue = InitCategory.isRValue();
4788 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4789 ICS.Standard.ObjCLifetimeConversionBinding =
4790 (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
4791 ICS.Standard.CopyConstructor = nullptr;
4792 ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
4793 };
4794
4795 // C++0x [dcl.init.ref]p5:
4796 // A reference to type "cv1 T1" is initialized by an expression
4797 // of type "cv2 T2" as follows:
4798
4799 // -- If reference is an lvalue reference and the initializer expression
4800 if (!isRValRef) {
4801 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is
4802 // reference-compatible with "cv2 T2," or
4803 //
4804 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
4805 if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
4806 // C++ [over.ics.ref]p1:
4807 // When a parameter of reference type binds directly (8.5.3)
4808 // to an argument expression, the implicit conversion sequence
4809 // is the identity conversion, unless the argument expression
4810 // has a type that is a derived class of the parameter type,
4811 // in which case the implicit conversion sequence is a
4812 // derived-to-base Conversion (13.3.3.1).
4813 SetAsReferenceBinding(/*BindsDirectly=*/true);
4814
4815 // Nothing more to do: the inaccessibility/ambiguity check for
4816 // derived-to-base conversions is suppressed when we're
4817 // computing the implicit conversion sequence (C++
4818 // [over.best.ics]p2).
4819 return ICS;
4820 }
4821
4822 // -- has a class type (i.e., T2 is a class type), where T1 is
4823 // not reference-related to T2, and can be implicitly
4824 // converted to an lvalue of type "cv3 T3," where "cv1 T1"
4825 // is reference-compatible with "cv3 T3" 92) (this
4826 // conversion is selected by enumerating the applicable
4827 // conversion functions (13.3.1.6) and choosing the best
4828 // one through overload resolution (13.3)),
4829 if (!SuppressUserConversions && T2->isRecordType() &&
4830 S.isCompleteType(DeclLoc, T2) &&
4831 RefRelationship == Sema::Ref_Incompatible) {
4832 if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4833 Init, T2, /*AllowRvalues=*/false,
4834 AllowExplicit))
4835 return ICS;
4836 }
4837 }
4838
4839 // -- Otherwise, the reference shall be an lvalue reference to a
4840 // non-volatile const type (i.e., cv1 shall be const), or the reference
4841 // shall be an rvalue reference.
4842 if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) {
4843 if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible)
4844 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
4845 return ICS;
4846 }
4847
4848 // -- If the initializer expression
4849 //
4850 // -- is an xvalue, class prvalue, array prvalue or function
4851 // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
4852 if (RefRelationship == Sema::Ref_Compatible &&
4853 (InitCategory.isXValue() ||
4854 (InitCategory.isPRValue() &&
4855 (T2->isRecordType() || T2->isArrayType())) ||
4856 (InitCategory.isLValue() && T2->isFunctionType()))) {
4857 // In C++11, this is always a direct binding. In C++98/03, it's a direct
4858 // binding unless we're binding to a class prvalue.
4859 // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
4860 // allow the use of rvalue references in C++98/03 for the benefit of
4861 // standard library implementors; therefore, we need the xvalue check here.
4862 SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
4863 !(InitCategory.isPRValue() || T2->isRecordType()));
4864 return ICS;
4865 }
4866
4867 // -- has a class type (i.e., T2 is a class type), where T1 is not
4868 // reference-related to T2, and can be implicitly converted to
4869 // an xvalue, class prvalue, or function lvalue of type
4870 // "cv3 T3", where "cv1 T1" is reference-compatible with
4871 // "cv3 T3",
4872 //
4873 // then the reference is bound to the value of the initializer
4874 // expression in the first case and to the result of the conversion
4875 // in the second case (or, in either case, to an appropriate base
4876 // class subobject).
4877 if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4878 T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
4879 FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4880 Init, T2, /*AllowRvalues=*/true,
4881 AllowExplicit)) {
4882 // In the second case, if the reference is an rvalue reference
4883 // and the second standard conversion sequence of the
4884 // user-defined conversion sequence includes an lvalue-to-rvalue
4885 // conversion, the program is ill-formed.
4886 if (ICS.isUserDefined() && isRValRef &&
4887 ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
4888 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4889
4890 return ICS;
4891 }
4892
4893 // A temporary of function type cannot be created; don't even try.
4894 if (T1->isFunctionType())
4895 return ICS;
4896
4897 // -- Otherwise, a temporary of type "cv1 T1" is created and
4898 // initialized from the initializer expression using the
4899 // rules for a non-reference copy initialization (8.5). The
4900 // reference is then bound to the temporary. If T1 is
4901 // reference-related to T2, cv1 must be the same
4902 // cv-qualification as, or greater cv-qualification than,
4903 // cv2; otherwise, the program is ill-formed.
4904 if (RefRelationship == Sema::Ref_Related) {
4905 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
4906 // we would be reference-compatible or reference-compatible with
4907 // added qualification. But that wasn't the case, so the reference
4908 // initialization fails.
4909 //
4910 // Note that we only want to check address spaces and cvr-qualifiers here.
4911 // ObjC GC, lifetime and unaligned qualifiers aren't important.
4912 Qualifiers T1Quals = T1.getQualifiers();
4913 Qualifiers T2Quals = T2.getQualifiers();
4914 T1Quals.removeObjCGCAttr();
4915 T1Quals.removeObjCLifetime();
4916 T2Quals.removeObjCGCAttr();
4917 T2Quals.removeObjCLifetime();
4918 // MS compiler ignores __unaligned qualifier for references; do the same.
4919 T1Quals.removeUnaligned();
4920 T2Quals.removeUnaligned();
4921 if (!T1Quals.compatiblyIncludes(T2Quals))
4922 return ICS;
4923 }
4924
4925 // If at least one of the types is a class type, the types are not
4926 // related, and we aren't allowed any user conversions, the
4927 // reference binding fails. This case is important for breaking
4928 // recursion, since TryImplicitConversion below will attempt to
4929 // create a temporary through the use of a copy constructor.
4930 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4931 (T1->isRecordType() || T2->isRecordType()))
4932 return ICS;
4933
4934 // If T1 is reference-related to T2 and the reference is an rvalue
4935 // reference, the initializer expression shall not be an lvalue.
4936 if (RefRelationship >= Sema::Ref_Related && isRValRef &&
4937 Init->Classify(S.Context).isLValue()) {
4938 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType);
4939 return ICS;
4940 }
4941
4942 // C++ [over.ics.ref]p2:
4943 // When a parameter of reference type is not bound directly to
4944 // an argument expression, the conversion sequence is the one
4945 // required to convert the argument expression to the
4946 // underlying type of the reference according to
4947 // 13.3.3.1. Conceptually, this conversion sequence corresponds
4948 // to copy-initializing a temporary of the underlying type with
4949 // the argument expression. Any difference in top-level
4950 // cv-qualification is subsumed by the initialization itself
4951 // and does not constitute a conversion.
4952 ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
4953 AllowedExplicit::None,
4954 /*InOverloadResolution=*/false,
4955 /*CStyle=*/false,
4956 /*AllowObjCWritebackConversion=*/false,
4957 /*AllowObjCConversionOnExplicit=*/false);
4958
4959 // Of course, that's still a reference binding.
4960 if (ICS.isStandard()) {
4961 ICS.Standard.ReferenceBinding = true;
4962 ICS.Standard.IsLvalueReference = !isRValRef;
4963 ICS.Standard.BindsToFunctionLvalue = false;
4964 ICS.Standard.BindsToRvalue = true;
4965 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4966 ICS.Standard.ObjCLifetimeConversionBinding = false;
4967 } else if (ICS.isUserDefined()) {
4968 const ReferenceType *LValRefType =
4969 ICS.UserDefined.ConversionFunction->getReturnType()
4970 ->getAs<LValueReferenceType>();
4971
4972 // C++ [over.ics.ref]p3:
4973 // Except for an implicit object parameter, for which see 13.3.1, a
4974 // standard conversion sequence cannot be formed if it requires [...]
4975 // binding an rvalue reference to an lvalue other than a function
4976 // lvalue.
4977 // Note that the function case is not possible here.
4978 if (isRValRef && LValRefType) {
4979 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4980 return ICS;
4981 }
4982
4983 ICS.UserDefined.After.ReferenceBinding = true;
4984 ICS.UserDefined.After.IsLvalueReference = !isRValRef;
4985 ICS.UserDefined.After.BindsToFunctionLvalue = false;
4986 ICS.UserDefined.After.BindsToRvalue = !LValRefType;
4987 ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4988 ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
4989 }
4990
4991 return ICS;
4992}
4993
4994static ImplicitConversionSequence
4995TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
4996 bool SuppressUserConversions,
4997 bool InOverloadResolution,
4998 bool AllowObjCWritebackConversion,
4999 bool AllowExplicit = false);
5000
5001/// TryListConversion - Try to copy-initialize a value of type ToType from the
5002/// initializer list From.
5003static ImplicitConversionSequence
5004TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
5005 bool SuppressUserConversions,
5006 bool InOverloadResolution,
5007 bool AllowObjCWritebackConversion) {
5008 // C++11 [over.ics.list]p1:
5009 // When an argument is an initializer list, it is not an expression and
5010 // special rules apply for converting it to a parameter type.
5011
5012 ImplicitConversionSequence Result;
5013 Result.setBad(BadConversionSequence::no_conversion, From, ToType);
5014
5015 // We need a complete type for what follows. With one C++20 exception,
5016 // incomplete types can never be initialized from init lists.
5017 QualType InitTy = ToType;
5018 const ArrayType *AT = S.Context.getAsArrayType(ToType);
5019 if (AT && S.getLangOpts().CPlusPlus20)
5020 if (const auto *IAT = dyn_cast<IncompleteArrayType>(AT))
5021 // C++20 allows list initialization of an incomplete array type.
5022 InitTy = IAT->getElementType();
5023 if (!S.isCompleteType(From->getBeginLoc(), InitTy))
5024 return Result;
5025
5026 // Per DR1467:
5027 // If the parameter type is a class X and the initializer list has a single
5028 // element of type cv U, where U is X or a class derived from X, the
5029 // implicit conversion sequence is the one required to convert the element
5030 // to the parameter type.
5031 //
5032 // Otherwise, if the parameter type is a character array [... ]
5033 // and the initializer list has a single element that is an
5034 // appropriately-typed string literal (8.5.2 [dcl.init.string]), the
5035 // implicit conversion sequence is the identity conversion.
5036 if (From->getNumInits() == 1) {
5037 if (ToType->isRecordType()) {
5038 QualType InitType = From->getInit(0)->getType();
5039 if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
5040 S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
5041 return TryCopyInitialization(S, From->getInit(0), ToType,
5042 SuppressUserConversions,
5043 InOverloadResolution,
5044 AllowObjCWritebackConversion);
5045 }
5046
5047 if (AT && S.IsStringInit(From->getInit(0), AT)) {
5048 InitializedEntity Entity =
5049 InitializedEntity::InitializeParameter(S.Context, ToType,
5050 /*Consumed=*/false);
5051 if (S.CanPerformCopyInitialization(Entity, From)) {
5052 Result.setStandard();
5053 Result.Standard.setAsIdentityConversion();
5054 Result.Standard.setFromType(ToType);
5055 Result.Standard.setAllToTypes(ToType);
5056 return Result;
5057 }
5058 }
5059 }
5060
5061 // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
5062 // C++11 [over.ics.list]p2:
5063 // If the parameter type is std::initializer_list<X> or "array of X" and
5064 // all the elements can be implicitly converted to X, the implicit
5065 // conversion sequence is the worst conversion necessary to convert an
5066 // element of the list to X.
5067 //
5068 // C++14 [over.ics.list]p3:
5069 // Otherwise, if the parameter type is "array of N X", if the initializer
5070 // list has exactly N elements or if it has fewer than N elements and X is
5071 // default-constructible, and if all the elements of the initializer list
5072 // can be implicitly converted to X, the implicit conversion sequence is
5073 // the worst conversion necessary to convert an element of the list to X.
5074 if (AT || S.isStdInitializerList(ToType, &InitTy)) {
5075 unsigned e = From->getNumInits();
5076 ImplicitConversionSequence DfltElt;
5077 DfltElt.setBad(BadConversionSequence::no_conversion, QualType(),
5078 QualType());
5079 QualType ContTy = ToType;
5080 bool IsUnbounded = false;
5081 if (AT) {
5082 InitTy = AT->getElementType();
5083 if (ConstantArrayType const *CT = dyn_cast<ConstantArrayType>(AT)) {
5084 if (CT->getSize().ult(e)) {
5085 // Too many inits, fatally bad
5086 Result.setBad(BadConversionSequence::too_many_initializers, From,
5087 ToType);
5088 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5089 return Result;
5090 }
5091 if (CT->getSize().ugt(e)) {
5092 // Need an init from empty {}, is there one?
5093 InitListExpr EmptyList(S.Context, From->getEndLoc(), None,
5094 From->getEndLoc());
5095 EmptyList.setType(S.Context.VoidTy);
5096 DfltElt = TryListConversion(
5097 S, &EmptyList, InitTy, SuppressUserConversions,
5098 InOverloadResolution, AllowObjCWritebackConversion);
5099 if (DfltElt.isBad()) {
5100 // No {} init, fatally bad
5101 Result.setBad(BadConversionSequence::too_few_initializers, From,
5102 ToType);
5103 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5104 return Result;
5105 }
5106 }
5107 } else {
5108 assert(isa<IncompleteArrayType>(AT) && "Expected incomplete array")(static_cast <bool> (isa<IncompleteArrayType>(AT)
&& "Expected incomplete array") ? void (0) : __assert_fail
("isa<IncompleteArrayType>(AT) && \"Expected incomplete array\""
, "clang/lib/Sema/SemaOverload.cpp", 5108, __extension__ __PRETTY_FUNCTION__
))
;
5109 IsUnbounded = true;
5110 if (!e) {
5111 // Cannot convert to zero-sized.
5112 Result.setBad(BadConversionSequence::too_few_initializers, From,
5113 ToType);
5114 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5115 return Result;
5116 }
5117 llvm::APInt Size(S.Context.getTypeSize(S.Context.getSizeType()), e);
5118 ContTy = S.Context.getConstantArrayType(InitTy, Size, nullptr,
5119 ArrayType::Normal, 0);
5120 }
5121 }
5122
5123 Result.setStandard();
5124 Result.Standard.setAsIdentityConversion();
5125 Result.Standard.setFromType(InitTy);
5126 Result.Standard.setAllToTypes(InitTy);
5127 for (unsigned i = 0; i < e; ++i) {
5128 Expr *Init = From->getInit(i);
5129 ImplicitConversionSequence ICS = TryCopyInitialization(
5130 S, Init, InitTy, SuppressUserConversions, InOverloadResolution,
5131 AllowObjCWritebackConversion);
5132
5133 // Keep the worse conversion seen so far.
5134 // FIXME: Sequences are not totally ordered, so 'worse' can be
5135 // ambiguous. CWG has been informed.
5136 if (CompareImplicitConversionSequences(S, From->getBeginLoc(), ICS,
5137 Result) ==
5138 ImplicitConversionSequence::Worse) {
5139 Result = ICS;
5140 // Bail as soon as we find something unconvertible.
5141 if (Result.isBad()) {
5142 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5143 return Result;
5144 }
5145 }
5146 }
5147
5148 // If we needed any implicit {} initialization, compare that now.
5149 // over.ics.list/6 indicates we should compare that conversion. Again CWG
5150 // has been informed that this might not be the best thing.
5151 if (!DfltElt.isBad() && CompareImplicitConversionSequences(
5152 S, From->getEndLoc(), DfltElt, Result) ==
5153 ImplicitConversionSequence::Worse)
5154 Result = DfltElt;
5155 // Record the type being initialized so that we may compare sequences
5156 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5157 return Result;
5158 }
5159
5160 // C++14 [over.ics.list]p4:
5161 // C++11 [over.ics.list]p3:
5162 // Otherwise, if the parameter is a non-aggregate class X and overload
5163 // resolution chooses a single best constructor [...] the implicit
5164 // conversion sequence is a user-defined conversion sequence. If multiple
5165 // constructors are viable but none is better than the others, the
5166 // implicit conversion sequence is a user-defined conversion sequence.
5167 if (ToType->isRecordType() && !ToType->isAggregateType()) {
5168 // This function can deal with initializer lists.
5169 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
5170 AllowedExplicit::None,
5171 InOverloadResolution, /*CStyle=*/false,
5172 AllowObjCWritebackConversion,
5173 /*AllowObjCConversionOnExplicit=*/false);
5174 }
5175
5176 // C++14 [over.ics.list]p5:
5177 // C++11 [over.ics.list]p4:
5178 // Otherwise, if the parameter has an aggregate type which can be
5179 // initialized from the initializer list [...] the implicit conversion
5180 // sequence is a user-defined conversion sequence.
5181 if (ToType->isAggregateType()) {
5182 // Type is an aggregate, argument is an init list. At this point it comes
5183 // down to checking whether the initialization works.
5184 // FIXME: Find out whether this parameter is consumed or not.
5185 InitializedEntity Entity =
5186 InitializedEntity::InitializeParameter(S.Context, ToType,
5187 /*Consumed=*/false);
5188 if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
5189 From)) {
5190 Result.setUserDefined();
5191 Result.UserDefined.Before.setAsIdentityConversion();
5192 // Initializer lists don't have a type.
5193 Result.UserDefined.Before.setFromType(QualType());
5194 Result.UserDefined.Before.setAllToTypes(QualType());
5195
5196 Result.UserDefined.After.setAsIdentityConversion();
5197 Result.UserDefined.After.setFromType(ToType);
5198 Result.UserDefined.After.setAllToTypes(ToType);
5199 Result.UserDefined.ConversionFunction = nullptr;
5200 }
5201 return Result;
5202 }
5203
5204 // C++14 [over.ics.list]p6:
5205 // C++11 [over.ics.list]p5:
5206 // Otherwise, if the parameter is a reference, see 13.3.3.1.4.
5207 if (ToType->isReferenceType()) {
5208 // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
5209 // mention initializer lists in any way. So we go by what list-
5210 // initialization would do and try to extrapolate from that.
5211
5212 QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();
5213
5214 // If the initializer list has a single element that is reference-related
5215 // to the parameter type, we initialize the reference from that.
5216 if (From->getNumInits() == 1) {
5217 Expr *Init = From->getInit(0);
5218
5219 QualType T2 = Init->getType();
5220
5221 // If the initializer is the address of an overloaded function, try
5222 // to resolve the overloaded function. If all goes well, T2 is the
5223 // type of the resulting function.
5224 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
5225 DeclAccessPair Found;
5226 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
5227 Init, ToType, false, Found))
5228 T2 = Fn->getType();
5229 }
5230
5231 // Compute some basic properties of the types and the initializer.
5232 Sema::ReferenceCompareResult RefRelationship =
5233 S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);
5234
5235 if (RefRelationship >= Sema::Ref_Related) {
5236 return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
5237 SuppressUserConversions,
5238 /*AllowExplicit=*/false);
5239 }
5240 }
5241
5242 // Otherwise, we bind the reference to a temporary created from the
5243 // initializer list.
5244 Result = TryListConversion(S, From, T1, SuppressUserConversions,
5245 InOverloadResolution,
5246 AllowObjCWritebackConversion);
5247 if (Result.isFailure())
5248 return Result;
5249 assert(!Result.isEllipsis() &&(static_cast <bool> (!Result.isEllipsis() && "Sub-initialization cannot result in ellipsis conversion."
) ? void (0) : __assert_fail ("!Result.isEllipsis() && \"Sub-initialization cannot result in ellipsis conversion.\""
, "clang/lib/Sema/SemaOverload.cpp", 5250, __extension__ __PRETTY_FUNCTION__
))
5250 "Sub-initialization cannot result in ellipsis conversion.")(static_cast <bool> (!Result.isEllipsis() && "Sub-initialization cannot result in ellipsis conversion."
) ? void (0) : __assert_fail ("!Result.isEllipsis() && \"Sub-initialization cannot result in ellipsis conversion.\""
, "clang/lib/Sema/SemaOverload.cpp", 5250, __extension__ __PRETTY_FUNCTION__
))
;
5251
5252 // Can we even bind to a temporary?
5253 if (ToType->isRValueReferenceType() ||
5254 (T1.isConstQualified() && !T1.isVolatileQualified())) {
5255 StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
5256 Result.UserDefined.After;
5257 SCS.ReferenceBinding = true;
5258 SCS.IsLvalueReference = ToType->isLValueReferenceType();
5259 SCS.BindsToRvalue = true;
5260 SCS.BindsToFunctionLvalue = false;
5261 SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
5262 SCS.ObjCLifetimeConversionBinding = false;
5263 } else
5264 Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
5265 From, ToType);
5266 return Result;
5267 }
5268
5269 // C++14 [over.ics.list]p7:
5270 // C++11 [over.ics.list]p6:
5271 // Otherwise, if the parameter type is not a class:
5272 if (!ToType->isRecordType()) {
5273 // - if the initializer list has one element that is not itself an
5274 // initializer list, the implicit conversion sequence is the one
5275 // required to convert the element to the parameter type.
5276 unsigned NumInits = From->getNumInits();
5277 if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
5278 Result = TryCopyInitialization(S, From->getInit(0), ToType,
5279 SuppressUserConversions,
5280 InOverloadResolution,
5281 AllowObjCWritebackConversion);
5282 // - if the initializer list has no elements, the implicit conversion
5283 // sequence is the identity conversion.
5284 else if (NumInits == 0) {
5285 Result.setStandard();
5286 Result.Standard.setAsIdentityConversion();
5287 Result.Standard.setFromType(ToType);
5288 Result.Standard.setAllToTypes(ToType);
5289 }
5290 return Result;
5291 }
5292
5293 // C++14 [over.ics.list]p8:
5294 // C++11 [over.ics.list]p7:
5295 // In all cases other than those enumerated above, no conversion is possible
5296 return Result;
5297}
5298
5299/// TryCopyInitialization - Try to copy-initialize a value of type
5300/// ToType from the expression From. Return the implicit conversion
5301/// sequence required to pass this argument, which may be a bad
5302/// conversion sequence (meaning that the argument cannot be passed to
5303/// a parameter of this type). If @p SuppressUserConversions, then we
5304/// do not permit any user-defined conversion sequences.
5305static ImplicitConversionSequence
5306TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
5307 bool SuppressUserConversions,
5308 bool InOverloadResolution,
5309 bool AllowObjCWritebackConversion,
5310 bool AllowExplicit) {
5311 if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
5312 return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
5313 InOverloadResolution,AllowObjCWritebackConversion);
5314
5315 if (ToType->isReferenceType())
5316 return TryReferenceInit(S, From, ToType,
5317 /*FIXME:*/ From->getBeginLoc(),
5318 SuppressUserConversions, AllowExplicit);
5319
5320 return TryImplicitConversion(S, From, ToType,
5321 SuppressUserConversions,
5322 AllowedExplicit::None,
5323 InOverloadResolution,
5324 /*CStyle=*/false,
5325 AllowObjCWritebackConversion,
5326 /*AllowObjCConversionOnExplicit=*/false);
5327}
5328
5329static bool TryCopyInitialization(const CanQualType FromQTy,
5330 const CanQualType ToQTy,
5331 Sema &S,
5332 SourceLocation Loc,
5333 ExprValueKind FromVK) {
5334 OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
5335 ImplicitConversionSequence ICS =
5336 TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
5337
5338 return !ICS.isBad();
5339}
5340
5341/// TryObjectArgumentInitialization - Try to initialize the object
5342/// parameter of the given member function (@c Method) from the
5343/// expression @p From.
5344static ImplicitConversionSequence
5345TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
5346 Expr::Classification FromClassification,
5347 CXXMethodDecl *Method,
5348 CXXRecordDecl *ActingContext) {
5349 QualType ClassType = S.Context.getTypeDeclType(ActingContext);
5350 // [class.dtor]p2: A destructor can be invoked for a const, volatile or
5351 // const volatile object.
5352 Qualifiers Quals = Method->getMethodQualifiers();
5353 if (isa<CXXDestructorDecl>(Method)) {
5354 Quals.addConst();
5355 Quals.addVolatile();
5356 }
5357
5358 QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
5359
5360 // Set up the conversion sequence as a "bad" conversion, to allow us
5361 // to exit early.
5362 ImplicitConversionSequence ICS;
5363
5364 // We need to have an object of class type.
5365 if (const PointerType *PT = FromType->getAs<PointerType>()) {
5366 FromType = PT->getPointeeType();
5367
5368 // When we had a pointer, it's implicitly dereferenced, so we
5369 // better have an lvalue.
5370 assert(FromClassification.isLValue())(static_cast <bool> (FromClassification.isLValue()) ? void
(0) : __assert_fail ("FromClassification.isLValue()", "clang/lib/Sema/SemaOverload.cpp"
, 5370, __extension__ __PRETTY_FUNCTION__))
;
5371 }
5372
5373 assert(FromType->isRecordType())(static_cast <bool> (FromType->isRecordType()) ? void
(0) : __assert_fail ("FromType->isRecordType()", "clang/lib/Sema/SemaOverload.cpp"
, 5373, __extension__ __PRETTY_FUNCTION__))
;
5374
5375 // C++0x [over.match.funcs]p4:
5376 // For non-static member functions, the type of the implicit object
5377 // parameter is
5378 //
5379 // - "lvalue reference to cv X" for functions declared without a
5380 // ref-qualifier or with the & ref-qualifier
5381 // - "rvalue reference to cv X" for functions declared with the &&
5382 // ref-qualifier
5383 //
5384 // where X is the class of which the function is a member and cv is the
5385 // cv-qualification on the member function declaration.
5386 //
5387 // However, when finding an implicit conversion sequence for the argument, we
5388 // are not allowed to perform user-defined conversions
5389 // (C++ [over.match.funcs]p5). We perform a simplified version of
5390 // reference binding here, that allows class rvalues to bind to
5391 // non-constant references.
5392
5393 // First check the qualifiers.
5394 QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
5395 if (ImplicitParamType.getCVRQualifiers()
5396 != FromTypeCanon.getLocalCVRQualifiers() &&
5397 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
5398 ICS.setBad(BadConversionSequence::bad_qualifiers,
5399 FromType, ImplicitParamType);
5400 return ICS;
5401 }
5402
5403 if (FromTypeCanon.hasAddressSpace()) {
5404 Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
5405 Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
5406 if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
5407 ICS.setBad(BadConversionSequence::bad_qualifiers,
5408 FromType, ImplicitParamType);
5409 return ICS;
5410 }
5411 }
5412
5413 // Check that we have either the same type or a derived type. It
5414 // affects the conversion rank.
5415 QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
5416 ImplicitConversionKind SecondKind;
5417 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
5418 SecondKind = ICK_Identity;
5419 } else if (S.IsDerivedFrom(Loc, FromType, ClassType))
5420 SecondKind = ICK_Derived_To_Base;
5421 else {
5422 ICS.setBad(BadConversionSequence::unrelated_class,
5423 FromType, ImplicitParamType);
5424 return ICS;
5425 }
5426
5427 // Check the ref-qualifier.
5428 switch (Method->getRefQualifier()) {
5429 case RQ_None:
5430 // Do nothing; we don't care about lvalueness or rvalueness.
5431 break;
5432
5433 case RQ_LValue:
5434 if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
5435 // non-const lvalue reference cannot bind to an rvalue
5436 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
5437 ImplicitParamType);
5438 return ICS;
5439 }
5440 break;
5441
5442 case RQ_RValue:
5443 if (!FromClassification.isRValue()) {
5444 // rvalue reference cannot bind to an lvalue
5445 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
5446 ImplicitParamType);
5447 return ICS;
5448 }
5449 break;
5450 }
5451
5452 // Success. Mark this as a reference binding.
5453 ICS.setStandard();
5454 ICS.Standard.setAsIdentityConversion();
5455 ICS.Standard.Second = SecondKind;
5456 ICS.Standard.setFromType(FromType);
5457 ICS.Standard.setAllToTypes(ImplicitParamType);
5458 ICS.Standard.ReferenceBinding = true;
5459 ICS.Standard.DirectBinding = true;
5460 ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
5461 ICS.Standard.BindsToFunctionLvalue = false;
5462 ICS.Standard.BindsToRvalue = FromClassification.isRValue();
5463 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
5464 = (Method->getRefQualifier() == RQ_None);
5465 return ICS;
5466}
5467
5468/// PerformObjectArgumentInitialization - Perform initialization of
5469/// the implicit object parameter for the given Method with the given
5470/// expression.
5471ExprResult
5472Sema::PerformObjectArgumentInitialization(Expr *From,
5473 NestedNameSpecifier *Qualifier,
5474 NamedDecl *FoundDecl,
5475 CXXMethodDecl *Method) {
5476 QualType FromRecordType, DestType;
5477 QualType ImplicitParamRecordType =
5478 Method->getThisType()->castAs<PointerType>()->getPointeeType();
5479
5480 Expr::Classification FromClassification;
5481 if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
5482 FromRecordType = PT->getPointeeType();
5483 DestType = Method->getThisType();
5484 FromClassification = Expr::Classification::makeSimpleLValue();
5485 } else {
5486 FromRecordType = From->getType();
5487 DestType = ImplicitParamRecordType;
5488 FromClassification = From->Classify(Context);
5489
5490 // When performing member access on a prvalue, materialize a temporary.
5491 if (From->isPRValue()) {
5492 From = CreateMaterializeTemporaryExpr(FromRecordType, From,
5493 Method->getRefQualifier() !=
5494 RefQualifierKind::RQ_RValue);
5495 }
5496 }
5497
5498 // Note that we always use the true parent context when performing
5499 // the actual argument initialization.
5500 ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
5501 *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
5502 Method->getParent());
5503 if (ICS.isBad()) {
5504 switch (ICS.Bad.Kind) {
5505 case BadConversionSequence::bad_qualifiers: {
5506 Qualifiers FromQs = FromRecordType.getQualifiers();
5507 Qualifiers ToQs = DestType.getQualifiers();
5508 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
5509 if (CVR) {
5510 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
5511 << Method->getDeclName() << FromRecordType << (CVR - 1)
5512 << From->getSourceRange();
5513 Diag(Method->getLocation(), diag::note_previous_decl)
5514 << Method->getDeclName();
5515 return ExprError();
5516 }
5517 break;
5518 }
5519
5520 case BadConversionSequence::lvalue_ref_to_rvalue:
5521 case BadConversionSequence::rvalue_ref_to_lvalue: {
5522 bool IsRValueQualified =
5523 Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
5524 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
5525 << Method->getDeclName() << FromClassification.isRValue()
5526 << IsRValueQualified;
5527 Diag(Method->getLocation(), diag::note_previous_decl)
5528 << Method->getDeclName();
5529 return ExprError();
5530 }
5531
5532 case BadConversionSequence::no_conversion:
5533 case BadConversionSequence::unrelated_class:
5534 break;
5535
5536 case BadConversionSequence::too_few_initializers:
5537 case BadConversionSequence::too_many_initializers:
5538 llvm_unreachable("Lists are not objects")::llvm::llvm_unreachable_internal("Lists are not objects", "clang/lib/Sema/SemaOverload.cpp"
, 5538)
;
5539 }
5540
5541 return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
5542 << ImplicitParamRecordType << FromRecordType
5543 << From->getSourceRange();
5544 }
5545
5546 if (ICS.Standard.Second == ICK_Derived_To_Base) {
5547 ExprResult FromRes =
5548 PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
5549 if (FromRes.isInvalid())
5550 return ExprError();
5551 From = FromRes.get();
5552 }
5553
5554 if (!Context.hasSameType(From->getType(), DestType)) {
5555 CastKind CK;
5556 QualType PteeTy = DestType->getPointeeType();
5557 LangAS DestAS =
5558 PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
5559 if (FromRecordType.getAddressSpace() != DestAS)
5560 CK = CK_AddressSpaceConversion;
5561 else
5562 CK = CK_NoOp;
5563 From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
5564 }
5565 return From;
5566}
5567
5568/// TryContextuallyConvertToBool - Attempt to contextually convert the
5569/// expression From to bool (C++0x [conv]p3).
5570static ImplicitConversionSequence
5571TryContextuallyConvertToBool(Sema &S, Expr *From) {
5572 // C++ [dcl.init]/17.8:
5573 // - Otherwise, if the initialization is direct-initialization, the source
5574 // type is std::nullptr_t, and the destination type is bool, the initial
5575 // value of the object being initialized is false.
5576 if (From->getType()->isNullPtrType())
5577 return ImplicitConversionSequence::getNullptrToBool(From->getType(),
5578 S.Context.BoolTy,
5579 From->isGLValue());
5580
5581 // All other direct-initialization of bool is equivalent to an implicit
5582 // conversion to bool in which explicit conversions are permitted.
5583 return TryImplicitConversion(S, From, S.Context.BoolTy,
5584 /*SuppressUserConversions=*/false,
5585 AllowedExplicit::Conversions,
5586 /*InOverloadResolution=*/false,
5587 /*CStyle=*/false,
5588 /*AllowObjCWritebackConversion=*/false,
5589 /*AllowObjCConversionOnExplicit=*/false);
5590}
5591
5592/// PerformContextuallyConvertToBool - Perform a contextual conversion
5593/// of the expression From to bool (C++0x [conv]p3).
5594ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
5595 if (checkPlaceholderForOverload(*this, From))
5596 return ExprError();
5597
5598 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
5599 if (!ICS.isBad())
5600 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
5601
5602 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
5603 return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
5604 << From->getType() << From->getSourceRange();
5605 return ExprError();
5606}
5607
5608/// Check that the specified conversion is permitted in a converted constant
5609/// expression, according to C++11 [expr.const]p3. Return true if the conversion
5610/// is acceptable.
5611static bool CheckConvertedConstantConversions(Sema &S,
5612 StandardConversionSequence &SCS) {
5613 // Since we know that the target type is an integral or unscoped enumeration
5614 // type, most conversion kinds are impossible. All possible First and Third
5615 // conversions are fine.
5616 switch (SCS.Second) {
5617 case ICK_Identity:
5618 case ICK_Integral_Promotion:
5619 case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
5620 case ICK_Zero_Queue_Conversion:
5621 return true;
5622
5623 case ICK_Boolean_Conversion:
5624 // Conversion from an integral or unscoped enumeration type to bool is
5625 // classified as ICK_Boolean_Conversion, but it's also arguably an integral
5626 // conversion, so we allow it in a converted constant expression.
5627 //
5628 // FIXME: Per core issue 1407, we should not allow this, but that breaks
5629 // a lot of popular code. We should at least add a warning for this
5630 // (non-conforming) extension.
5631 return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
5632 SCS.getToType(2)->isBooleanType();
5633
5634 case ICK_Pointer_Conversion:
5635 case ICK_Pointer_Member:
5636 // C++1z: null pointer conversions and null member pointer conversions are
5637 // only permitted if the source type is std::nullptr_t.
5638 return SCS.getFromType()->isNullPtrType();
5639
5640 case ICK_Floating_Promotion:
5641 case ICK_Complex_Promotion:
5642 case ICK_Floating_Conversion:
5643 case ICK_Complex_Conversion:
5644 case ICK_Floating_Integral:
5645 case ICK_Compatible_Conversion:
5646 case ICK_Derived_To_Base:
5647 case ICK_Vector_Conversion:
5648 case ICK_SVE_Vector_Conversion:
5649 case ICK_Vector_Splat:
5650 case ICK_Complex_Real:
5651 case ICK_Block_Pointer_Conversion:
5652 case ICK_TransparentUnionConversion:
5653 case ICK_Writeback_Conversion:
5654 case ICK_Zero_Event_Conversion:
5655 case ICK_C_Only_Conversion:
5656 case ICK_Incompatible_Pointer_Conversion:
5657 return false;
5658
5659 case ICK_Lvalue_To_Rvalue:
5660 case ICK_Array_To_Pointer:
5661 case ICK_Function_To_Pointer:
5662 llvm_unreachable("found a first conversion kind in Second")::llvm::llvm_unreachable_internal("found a first conversion kind in Second"
, "clang/lib/Sema/SemaOverload.cpp", 5662)
;
5663
5664 case ICK_Function_Conversion:
5665 case ICK_Qualification:
5666 llvm_unreachable("found a third conversion kind in Second")::llvm::llvm_unreachable_internal("found a third conversion kind in Second"
, "clang/lib/Sema/SemaOverload.cpp", 5666)
;
5667
5668 case ICK_Num_Conversion_Kinds:
5669 break;
5670 }
5671
5672 llvm_unreachable("unknown conversion kind")::llvm::llvm_unreachable_internal("unknown conversion kind", "clang/lib/Sema/SemaOverload.cpp"
, 5672)
;
5673}
5674
5675/// CheckConvertedConstantExpression - Check that the expression From is a
5676/// converted constant expression of type T, perform the conversion and produce
5677/// the converted expression, per C++11 [expr.const]p3.
5678static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
5679 QualType T, APValue &Value,
5680 Sema::CCEKind CCE,
5681 bool RequireInt,
5682 NamedDecl *Dest) {
5683 assert(S.getLangOpts().CPlusPlus11 &&(static_cast <bool> (S.getLangOpts().CPlusPlus11 &&
"converted constant expression outside C++11") ? void (0) : __assert_fail
("S.getLangOpts().CPlusPlus11 && \"converted constant expression outside C++11\""
, "clang/lib/Sema/SemaOverload.cpp", 5684, __extension__ __PRETTY_FUNCTION__
))
5684 "converted constant expression outside C++11")(static_cast <bool> (S.getLangOpts().CPlusPlus11 &&
"converted constant expression outside C++11") ? void (0) : __assert_fail
("S.getLangOpts().CPlusPlus11 && \"converted constant expression outside C++11\""
, "clang/lib/Sema/SemaOverload.cpp", 5684, __extension__ __PRETTY_FUNCTION__
))
;
5685
5686 if (checkPlaceholderForOverload(S, From))
5687 return ExprError();
5688
5689 // C++1z [expr.const]p3:
5690 // A converted constant expression of type T is an expression,
5691 // implicitly converted to type T, where the converted
5692 // expression is a constant expression and the implicit conversion
5693 // sequence contains only [... list of conversions ...].
5694 ImplicitConversionSequence ICS =
5695 (CCE == Sema::CCEK_ExplicitBool || CCE == Sema::CCEK_Noexcept)
5696 ? TryContextuallyConvertToBool(S, From)
5697 : TryCopyInitialization(S, From, T,
5698 /*SuppressUserConversions=*/false,
5699 /*InOverloadResolution=*/false,
5700 /*AllowObjCWritebackConversion=*/false,
5701 /*AllowExplicit=*/false);
5702 StandardConversionSequence *SCS = nullptr;
5703 switch (ICS.getKind()) {
5704 case ImplicitConversionSequence::StandardConversion:
5705 SCS = &ICS.Standard;
5706 break;
5707 case ImplicitConversionSequence::UserDefinedConversion:
5708 if (T->isRecordType())
5709 SCS = &ICS.UserDefined.Before;
5710 else
5711 SCS = &ICS.UserDefined.After;
5712 break;
5713 case ImplicitConversionSequence::AmbiguousConversion:
5714 case ImplicitConversionSequence::BadConversion:
5715 if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
5716 return S.Diag(From->getBeginLoc(),
5717 diag::err_typecheck_converted_constant_expression)
5718 << From->getType() << From->getSourceRange() << T;
5719 return ExprError();
5720
5721 case ImplicitConversionSequence::EllipsisConversion:
5722 llvm_unreachable("ellipsis conversion in converted constant expression")::llvm::llvm_unreachable_internal("ellipsis conversion in converted constant expression"
, "clang/lib/Sema/SemaOverload.cpp", 5722)
;
5723 }
5724
5725 // Check that we would only use permitted conversions.
5726 if (!CheckConvertedConstantConversions(S, *SCS)) {
5727 return S.Diag(From->getBeginLoc(),
5728 diag::err_typecheck_converted_constant_expression_disallowed)
5729 << From->getType() << From->getSourceRange() << T;
5730 }
5731 // [...] and where the reference binding (if any) binds directly.
5732 if (SCS->ReferenceBinding && !SCS->DirectBinding) {
5733 return S.Diag(From->getBeginLoc(),
5734 diag::err_typecheck_converted_constant_expression_indirect)
5735 << From->getType() << From->getSourceRange() << T;
5736 }
5737
5738 // Usually we can simply apply the ImplicitConversionSequence we formed
5739 // earlier, but that's not guaranteed to work when initializing an object of
5740 // class type.
5741 ExprResult Result;
5742 if (T->isRecordType()) {
5743 assert(CCE == Sema::CCEK_TemplateArg &&(static_cast <bool> (CCE == Sema::CCEK_TemplateArg &&
"unexpected class type converted constant expr") ? void (0) :
__assert_fail ("CCE == Sema::CCEK_TemplateArg && \"unexpected class type converted constant expr\""
, "clang/lib/Sema/SemaOverload.cpp", 5744, __extension__ __PRETTY_FUNCTION__
))
5744 "unexpected class type converted constant expr")(static_cast <bool> (CCE == Sema::CCEK_TemplateArg &&
"unexpected class type converted constant expr") ? void (0) :
__assert_fail ("CCE == Sema::CCEK_TemplateArg && \"unexpected class type converted constant expr\""
, "clang/lib/Sema/SemaOverload.cpp", 5744, __extension__ __PRETTY_FUNCTION__
))
;
5745 Result = S.PerformCopyInitialization(
5746 InitializedEntity::InitializeTemplateParameter(
5747 T, cast<NonTypeTemplateParmDecl>(Dest)),
5748 SourceLocation(), From);
5749 } else {
5750 Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
5751 }
5752 if (Result.isInvalid())
5753 return Result;
5754
5755 // C++2a [intro.execution]p5:
5756 // A full-expression is [...] a constant-expression [...]
5757 Result =
5758 S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
5759 /*DiscardedValue=*/false, /*IsConstexpr=*/true);
5760 if (Result.isInvalid())
5761 return Result;
5762
5763 // Check for a narrowing implicit conversion.
5764 bool ReturnPreNarrowingValue = false;
5765 APValue PreNarrowingValue;
5766 QualType PreNarrowingType;
5767 switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
5768 PreNarrowingType)) {
5769 case NK_Dependent_Narrowing:
5770 // Implicit conversion to a narrower type, but the expression is
5771 // value-dependent so we can't tell whether it's actually narrowing.
5772 case NK_Variable_Narrowing:
5773 // Implicit conversion to a narrower type, and the value is not a constant
5774 // expression. We'll diagnose this in a moment.
5775 case NK_Not_Narrowing:
5776 break;
5777
5778 case NK_Constant_Narrowing:
5779 if (CCE == Sema::CCEK_ArrayBound &&
5780 PreNarrowingType->isIntegralOrEnumerationType() &&
5781 PreNarrowingValue.isInt()) {
5782 // Don't diagnose array bound narrowing here; we produce more precise
5783 // errors by allowing the un-narrowed value through.
5784 ReturnPreNarrowingValue = true;
5785 break;
5786 }
5787 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5788 << CCE << /*Constant*/ 1
5789 << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
5790 break;
5791
5792 case NK_Type_Narrowing:
5793 // FIXME: It would be better to diagnose that the expression is not a
5794 // constant expression.
5795 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5796 << CCE << /*Constant*/ 0 << From->getType() << T;
5797 break;
5798 }
5799
5800 if (Result.get()->isValueDependent()) {
5801 Value = APValue();
5802 return Result;
5803 }
5804
5805 // Check the expression is a constant expression.
5806 SmallVector<PartialDiagnosticAt, 8> Notes;
5807 Expr::EvalResult Eval;
5808 Eval.Diag = &Notes;
5809
5810 ConstantExprKind Kind;
5811 if (CCE == Sema::CCEK_TemplateArg && T->isRecordType())
5812 Kind = ConstantExprKind::ClassTemplateArgument;
5813 else if (CCE == Sema::CCEK_TemplateArg)
5814 Kind = ConstantExprKind::NonClassTemplateArgument;
5815 else
5816 Kind = ConstantExprKind::Normal;
5817
5818 if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) ||
5819 (RequireInt && !Eval.Val.isInt())) {
5820 // The expression can't be folded, so we can't keep it at this position in
5821 // the AST.
5822 Result = ExprError();
5823 } else {
5824 Value = Eval.Val;
5825
5826 if (Notes.empty()) {
5827 // It's a constant expression.
5828 Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value);
5829 if (ReturnPreNarrowingValue)
5830 Value = std::move(PreNarrowingValue);
5831 return E;
5832 }
5833 }
5834
5835 // It's not a constant expression. Produce an appropriate diagnostic.
5836 if (Notes.size() == 1 &&
5837 Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) {
5838 S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
5839 } else if (!Notes.empty() && Notes[0].second.getDiagID() ==
5840 diag::note_constexpr_invalid_template_arg) {
5841 Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg);
5842 for (unsigned I = 0; I < Notes.size(); ++I)
5843 S.Diag(Notes[I].first, Notes[I].second);
5844 } else {
5845 S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
5846 << CCE << From->getSourceRange();
5847 for (unsigned I = 0; I < Notes.size(); ++I)
5848 S.Diag(Notes[I].first, Notes[I].second);
5849 }
5850 return ExprError();
5851}
5852
5853ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5854 APValue &Value, CCEKind CCE,
5855 NamedDecl *Dest) {
5856 return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false,
5857 Dest);
5858}
5859
5860ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5861 llvm::APSInt &Value,
5862 CCEKind CCE) {
5863 assert(T->isIntegralOrEnumerationType() && "unexpected converted const type")(static_cast <bool> (T->isIntegralOrEnumerationType(
) && "unexpected converted const type") ? void (0) : __assert_fail
("T->isIntegralOrEnumerationType() && \"unexpected converted const type\""
, "clang/lib/Sema/SemaOverload.cpp", 5863, __extension__ __PRETTY_FUNCTION__
))
;
5864
5865 APValue V;
5866 auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true,
5867 /*Dest=*/nullptr);
5868 if (!R.isInvalid() && !R.get()->isValueDependent())
5869 Value = V.getInt();
5870 return R;
5871}
5872
5873
5874/// dropPointerConversions - If the given standard conversion sequence
5875/// involves any pointer conversions, remove them. This may change
5876/// the result type of the conversion sequence.
5877static void dropPointerConversion(StandardConversionSequence &SCS) {
5878 if (SCS.Second == ICK_Pointer_Conversion) {
5879 SCS.Second = ICK_Identity;
5880 SCS.Third = ICK_Identity;
5881 SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
5882 }
5883}
5884
5885/// TryContextuallyConvertToObjCPointer - Attempt to contextually
5886/// convert the expression From to an Objective-C pointer type.
5887static ImplicitConversionSequence
5888TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
5889 // Do an implicit conversion to 'id'.
5890 QualType Ty = S.Context.getObjCIdType();
5891 ImplicitConversionSequence ICS
5892 = TryImplicitConversion(S, From, Ty,
5893 // FIXME: Are these flags correct?
5894 /*SuppressUserConversions=*/false,
5895 AllowedExplicit::Conversions,
5896 /*InOverloadResolution=*/false,
5897 /*CStyle=*/false,
5898