Bug Summary

File:clang/lib/Sema/SemaOverload.cpp
Warning:line 9871, column 44
Called C++ object pointer is null

Annotated Source Code

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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~++20220125101009+ceec4383681c/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~++20220125101009+ceec4383681c/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/clang/include -I tools/clang/include -I include -I /build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/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~++20220125101009+ceec4383681c/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/= -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~++20220125101009+ceec4383681c/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/= -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-2022-01-25-232935-20746-1 -x c++ /build/llvm-toolchain-snapshot-14~++20220125101009+ceec4383681c/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 }