Bug Summary

File:clang/lib/Sema/SemaOverload.cpp
Warning:line 13687, column 21
Although the value stored to 'RHS' is used in the enclosing expression, the value is never actually read from 'RHS'

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -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 -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D 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 -O2 -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~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -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-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/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<void> (0));
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<void> (0));
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<void> (0));
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<void> (0));
425 assert(ToType->isIntegralOrUnscopedEnumerationType())(static_cast<void> (0));
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 (isStdInitializerListElement())
545 OS << "Worst std::initializer_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")__builtin_unreachable();
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<void> (0));
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<void> (0));
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<void> (0))
1286 "Unexpected invalid target.")(static_cast<void> (0));
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<void> (0));
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<void> (0))
1739 "Non-unary operator on non-static member address")(static_cast<void> (0));
1740 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()(static_cast<void> (0))
1741 == UO_AddrOf &&(static_cast<void> (0))
1742 "Non-address-of operator on non-static member address")(static_cast<void> (0));
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<void> (0))
1748 UO_AddrOf &&(static_cast<void> (0))
1749 "Non-address-of operator for overloaded function expression")(static_cast<void> (0));
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<void> (0))
1757 FromType,(static_cast<void> (0))
1758 S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()))(static_cast<void> (0));
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 and __float128 if
1873 // 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 if (&S.Context.getFloatTypeSemantics(FromType) !=
1880 &S.Context.getFloatTypeSemantics(ToType)) {
1881 bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty &&
1882 ToType == S.Context.LongDoubleTy) ||
1883 (FromType == S.Context.LongDoubleTy &&
1884 ToType == S.Context.Float128Ty));
1885 if (Float128AndLongDouble &&
1886 (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) ==
1887 &llvm::APFloat::PPCDoubleDouble()))
1888 return false;
1889 }
1890 // Floating point conversions (C++ 4.8).
1891 SCS.Second = ICK_Floating_Conversion;
1892 FromType = ToType.getUnqualifiedType();
1893 } else if ((FromType->isRealFloatingType() &&
1894 ToType->isIntegralType(S.Context)) ||
1895 (FromType->isIntegralOrUnscopedEnumerationType() &&
1896 ToType->isRealFloatingType())) {
1897 // Conversions between bfloat and int are not permitted.
1898 if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
1899 return false;
1900
1901 // Floating-integral conversions (C++ 4.9).
1902 SCS.Second = ICK_Floating_Integral;
1903 FromType = ToType.getUnqualifiedType();
1904 } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
1905 SCS.Second = ICK_Block_Pointer_Conversion;
1906 } else if (AllowObjCWritebackConversion &&
1907 S.isObjCWritebackConversion(FromType, ToType, FromType)) {
1908 SCS.Second = ICK_Writeback_Conversion;
1909 } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
1910 FromType, IncompatibleObjC)) {
1911 // Pointer conversions (C++ 4.10).
1912 SCS.Second = ICK_Pointer_Conversion;
1913 SCS.IncompatibleObjC = IncompatibleObjC;
1914 FromType = FromType.getUnqualifiedType();
1915 } else if (S.IsMemberPointerConversion(From, FromType, ToType,
1916 InOverloadResolution, FromType)) {
1917 // Pointer to member conversions (4.11).
1918 SCS.Second = ICK_Pointer_Member;
1919 } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
1920 SCS.Second = SecondICK;
1921 FromType = ToType.getUnqualifiedType();
1922 } else if (!S.getLangOpts().CPlusPlus &&
1923 S.Context.typesAreCompatible(ToType, FromType)) {
1924 // Compatible conversions (Clang extension for C function overloading)
1925 SCS.Second = ICK_Compatible_Conversion;
1926 FromType = ToType.getUnqualifiedType();
1927 } else if (IsTransparentUnionStandardConversion(S, From, ToType,
1928 InOverloadResolution,
1929 SCS, CStyle)) {
1930 SCS.Second = ICK_TransparentUnionConversion;
1931 FromType = ToType;
1932 } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
1933 CStyle)) {
1934 // tryAtomicConversion has updated the standard conversion sequence
1935 // appropriately.
1936 return true;
1937 } else if (ToType->isEventT() &&
1938 From->isIntegerConstantExpr(S.getASTContext()) &&
1939 From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
1940 SCS.Second = ICK_Zero_Event_Conversion;
1941 FromType = ToType;
1942 } else if (ToType->isQueueT() &&
1943 From->isIntegerConstantExpr(S.getASTContext()) &&
1944 (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
1945 SCS.Second = ICK_Zero_Queue_Conversion;
1946 FromType = ToType;
1947 } else if (ToType->isSamplerT() &&
1948 From->isIntegerConstantExpr(S.getASTContext())) {
1949 SCS.Second = ICK_Compatible_Conversion;
1950 FromType = ToType;
1951 } else {
1952 // No second conversion required.
1953 SCS.Second = ICK_Identity;
1954 }
1955 SCS.setToType(1, FromType);
1956
1957 // The third conversion can be a function pointer conversion or a
1958 // qualification conversion (C++ [conv.fctptr], [conv.qual]).
1959 bool ObjCLifetimeConversion;
1960 if (S.IsFunctionConversion(FromType, ToType, FromType)) {
1961 // Function pointer conversions (removing 'noexcept') including removal of
1962 // 'noreturn' (Clang extension).
1963 SCS.Third = ICK_Function_Conversion;
1964 } else if (S.IsQualificationConversion(FromType, ToType, CStyle,
1965 ObjCLifetimeConversion)) {
1966 SCS.Third = ICK_Qualification;
1967 SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
1968 FromType = ToType;
1969 } else {
1970 // No conversion required
1971 SCS.Third = ICK_Identity;
1972 }
1973
1974 // C++ [over.best.ics]p6:
1975 // [...] Any difference in top-level cv-qualification is
1976 // subsumed by the initialization itself and does not constitute
1977 // a conversion. [...]
1978 QualType CanonFrom = S.Context.getCanonicalType(FromType);
1979 QualType CanonTo = S.Context.getCanonicalType(ToType);
1980 if (CanonFrom.getLocalUnqualifiedType()
1981 == CanonTo.getLocalUnqualifiedType() &&
1982 CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
1983 FromType = ToType;
1984 CanonFrom = CanonTo;
1985 }
1986
1987 SCS.setToType(2, FromType);
1988
1989 if (CanonFrom == CanonTo)
1990 return true;
1991
1992 // If we have not converted the argument type to the parameter type,
1993 // this is a bad conversion sequence, unless we're resolving an overload in C.
1994 if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
1995 return false;
1996
1997 ExprResult ER = ExprResult{From};
1998 Sema::AssignConvertType Conv =
1999 S.CheckSingleAssignmentConstraints(ToType, ER,
2000 /*Diagnose=*/false,
2001 /*DiagnoseCFAudited=*/false,
2002 /*ConvertRHS=*/false);
2003 ImplicitConversionKind SecondConv;
2004 switch (Conv) {
2005 case Sema::Compatible:
2006 SecondConv = ICK_C_Only_Conversion;
2007 break;
2008 // For our purposes, discarding qualifiers is just as bad as using an
2009 // incompatible pointer. Note that an IncompatiblePointer conversion can drop
2010 // qualifiers, as well.
2011 case Sema::CompatiblePointerDiscardsQualifiers:
2012 case Sema::IncompatiblePointer:
2013 case Sema::IncompatiblePointerSign:
2014 SecondConv = ICK_Incompatible_Pointer_Conversion;
2015 break;
2016 default:
2017 return false;
2018 }
2019
2020 // First can only be an lvalue conversion, so we pretend that this was the
2021 // second conversion. First should already be valid from earlier in the
2022 // function.
2023 SCS.Second = SecondConv;
2024 SCS.setToType(1, ToType);
2025
2026 // Third is Identity, because Second should rank us worse than any other
2027 // conversion. This could also be ICK_Qualification, but it's simpler to just
2028 // lump everything in with the second conversion, and we don't gain anything
2029 // from making this ICK_Qualification.
2030 SCS.Third = ICK_Identity;
2031 SCS.setToType(2, ToType);
2032 return true;
2033}
2034
2035static bool
2036IsTransparentUnionStandardConversion(Sema &S, Expr* From,
2037 QualType &ToType,
2038 bool InOverloadResolution,
2039 StandardConversionSequence &SCS,
2040 bool CStyle) {
2041
2042 const RecordType *UT = ToType->getAsUnionType();
2043 if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
2044 return false;
2045 // The field to initialize within the transparent union.
2046 RecordDecl *UD = UT->getDecl();
2047 // It's compatible if the expression matches any of the fields.
2048 for (const auto *it : UD->fields()) {
2049 if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
2050 CStyle, /*AllowObjCWritebackConversion=*/false)) {
2051 ToType = it->getType();
2052 return true;
2053 }
2054 }
2055 return false;
2056}
2057
2058/// IsIntegralPromotion - Determines whether the conversion from the
2059/// expression From (whose potentially-adjusted type is FromType) to
2060/// ToType is an integral promotion (C++ 4.5). If so, returns true and
2061/// sets PromotedType to the promoted type.
2062bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
2063 const BuiltinType *To = ToType->getAs<BuiltinType>();
2064 // All integers are built-in.
2065 if (!To) {
2066 return false;
2067 }
2068
2069 // An rvalue of type char, signed char, unsigned char, short int, or
2070 // unsigned short int can be converted to an rvalue of type int if
2071 // int can represent all the values of the source type; otherwise,
2072 // the source rvalue can be converted to an rvalue of type unsigned
2073 // int (C++ 4.5p1).
2074 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
2075 !FromType->isEnumeralType()) {
2076 if (// We can promote any signed, promotable integer type to an int
2077 (FromType->isSignedIntegerType() ||
2078 // We can promote any unsigned integer type whose size is
2079 // less than int to an int.
2080 Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
2081 return To->getKind() == BuiltinType::Int;
2082 }
2083
2084 return To->getKind() == BuiltinType::UInt;
2085 }
2086
2087 // C++11 [conv.prom]p3:
2088 // A prvalue of an unscoped enumeration type whose underlying type is not
2089 // fixed (7.2) can be converted to an rvalue a prvalue of the first of the
2090 // following types that can represent all the values of the enumeration
2091 // (i.e., the values in the range bmin to bmax as described in 7.2): int,
2092 // unsigned int, long int, unsigned long int, long long int, or unsigned
2093 // long long int. If none of the types in that list can represent all the
2094 // values of the enumeration, an rvalue a prvalue of an unscoped enumeration
2095 // type can be converted to an rvalue a prvalue of the extended integer type
2096 // with lowest integer conversion rank (4.13) greater than the rank of long
2097 // long in which all the values of the enumeration can be represented. If
2098 // there are two such extended types, the signed one is chosen.
2099 // C++11 [conv.prom]p4:
2100 // A prvalue of an unscoped enumeration type whose underlying type is fixed
2101 // can be converted to a prvalue of its underlying type. Moreover, if
2102 // integral promotion can be applied to its underlying type, a prvalue of an
2103 // unscoped enumeration type whose underlying type is fixed can also be
2104 // converted to a prvalue of the promoted underlying type.
2105 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
2106 // C++0x 7.2p9: Note that this implicit enum to int conversion is not
2107 // provided for a scoped enumeration.
2108 if (FromEnumType->getDecl()->isScoped())
2109 return false;
2110
2111 // We can perform an integral promotion to the underlying type of the enum,
2112 // even if that's not the promoted type. Note that the check for promoting
2113 // the underlying type is based on the type alone, and does not consider
2114 // the bitfield-ness of the actual source expression.
2115 if (FromEnumType->getDecl()->isFixed()) {
2116 QualType Underlying = FromEnumType->getDecl()->getIntegerType();
2117 return Context.hasSameUnqualifiedType(Underlying, ToType) ||
2118 IsIntegralPromotion(nullptr, Underlying, ToType);
2119 }
2120
2121 // We have already pre-calculated the promotion type, so this is trivial.
2122 if (ToType->isIntegerType() &&
2123 isCompleteType(From->getBeginLoc(), FromType))
2124 return Context.hasSameUnqualifiedType(
2125 ToType, FromEnumType->getDecl()->getPromotionType());
2126
2127 // C++ [conv.prom]p5:
2128 // If the bit-field has an enumerated type, it is treated as any other
2129 // value of that type for promotion purposes.
2130 //
2131 // ... so do not fall through into the bit-field checks below in C++.
2132 if (getLangOpts().CPlusPlus)
2133 return false;
2134 }
2135
2136 // C++0x [conv.prom]p2:
2137 // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
2138 // to an rvalue a prvalue of the first of the following types that can
2139 // represent all the values of its underlying type: int, unsigned int,
2140 // long int, unsigned long int, long long int, or unsigned long long int.
2141 // If none of the types in that list can represent all the values of its
2142 // underlying type, an rvalue a prvalue of type char16_t, char32_t,
2143 // or wchar_t can be converted to an rvalue a prvalue of its underlying
2144 // type.
2145 if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
2146 ToType->isIntegerType()) {
2147 // Determine whether the type we're converting from is signed or
2148 // unsigned.
2149 bool FromIsSigned = FromType->isSignedIntegerType();
2150 uint64_t FromSize = Context.getTypeSize(FromType);
2151
2152 // The types we'll try to promote to, in the appropriate
2153 // order. Try each of these types.
2154 QualType PromoteTypes[6] = {
2155 Context.IntTy, Context.UnsignedIntTy,
2156 Context.LongTy, Context.UnsignedLongTy ,
2157 Context.LongLongTy, Context.UnsignedLongLongTy
2158 };
2159 for (int Idx = 0; Idx < 6; ++Idx) {
2160 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
2161 if (FromSize < ToSize ||
2162 (FromSize == ToSize &&
2163 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
2164 // We found the type that we can promote to. If this is the
2165 // type we wanted, we have a promotion. Otherwise, no
2166 // promotion.
2167 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
2168 }
2169 }
2170 }
2171
2172 // An rvalue for an integral bit-field (9.6) can be converted to an
2173 // rvalue of type int if int can represent all the values of the
2174 // bit-field; otherwise, it can be converted to unsigned int if
2175 // unsigned int can represent all the values of the bit-field. If
2176 // the bit-field is larger yet, no integral promotion applies to
2177 // it. If the bit-field has an enumerated type, it is treated as any
2178 // other value of that type for promotion purposes (C++ 4.5p3).
2179 // FIXME: We should delay checking of bit-fields until we actually perform the
2180 // conversion.
2181 //
2182 // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
2183 // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
2184 // bit-fields and those whose underlying type is larger than int) for GCC
2185 // compatibility.
2186 if (From) {
2187 if (FieldDecl *MemberDecl = From->getSourceBitField()) {
2188 Optional<llvm::APSInt> BitWidth;
2189 if (FromType->isIntegralType(Context) &&
2190 (BitWidth =
2191 MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) {
2192 llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned());
2193 ToSize = Context.getTypeSize(ToType);
2194
2195 // Are we promoting to an int from a bitfield that fits in an int?
2196 if (*BitWidth < ToSize ||
2197 (FromType->isSignedIntegerType() && *BitWidth <= ToSize)) {
2198 return To->getKind() == BuiltinType::Int;
2199 }
2200
2201 // Are we promoting to an unsigned int from an unsigned bitfield
2202 // that fits into an unsigned int?
2203 if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) {
2204 return To->getKind() == BuiltinType::UInt;
2205 }
2206
2207 return false;
2208 }
2209 }
2210 }
2211
2212 // An rvalue of type bool can be converted to an rvalue of type int,
2213 // with false becoming zero and true becoming one (C++ 4.5p4).
2214 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
2215 return true;
2216 }
2217
2218 return false;
2219}
2220
2221/// IsFloatingPointPromotion - Determines whether the conversion from
2222/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
2223/// returns true and sets PromotedType to the promoted type.
2224bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
2225 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
2226 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
2227 /// An rvalue of type float can be converted to an rvalue of type
2228 /// double. (C++ 4.6p1).
2229 if (FromBuiltin->getKind() == BuiltinType::Float &&
2230 ToBuiltin->getKind() == BuiltinType::Double)
2231 return true;
2232
2233 // C99 6.3.1.5p1:
2234 // When a float is promoted to double or long double, or a
2235 // double is promoted to long double [...].
2236 if (!getLangOpts().CPlusPlus &&
2237 (FromBuiltin->getKind() == BuiltinType::Float ||
2238 FromBuiltin->getKind() == BuiltinType::Double) &&
2239 (ToBuiltin->getKind() == BuiltinType::LongDouble ||
2240 ToBuiltin->getKind() == BuiltinType::Float128))
2241 return true;
2242
2243 // Half can be promoted to float.
2244 if (!getLangOpts().NativeHalfType &&
2245 FromBuiltin->getKind() == BuiltinType::Half &&
2246 ToBuiltin->getKind() == BuiltinType::Float)
2247 return true;
2248 }
2249
2250 return false;
2251}
2252
2253/// Determine if a conversion is a complex promotion.
2254///
2255/// A complex promotion is defined as a complex -> complex conversion
2256/// where the conversion between the underlying real types is a
2257/// floating-point or integral promotion.
2258bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
2259 const ComplexType *FromComplex = FromType->getAs<ComplexType>();
2260 if (!FromComplex)
2261 return false;
2262
2263 const ComplexType *ToComplex = ToType->getAs<ComplexType>();
2264 if (!ToComplex)
2265 return false;
2266
2267 return IsFloatingPointPromotion(FromComplex->getElementType(),
2268 ToComplex->getElementType()) ||
2269 IsIntegralPromotion(nullptr, FromComplex->getElementType(),
2270 ToComplex->getElementType());
2271}
2272
2273/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
2274/// the pointer type FromPtr to a pointer to type ToPointee, with the
2275/// same type qualifiers as FromPtr has on its pointee type. ToType,
2276/// if non-empty, will be a pointer to ToType that may or may not have
2277/// the right set of qualifiers on its pointee.
2278///
2279static QualType
2280BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
2281 QualType ToPointee, QualType ToType,
2282 ASTContext &Context,
2283 bool StripObjCLifetime = false) {
2284 assert((FromPtr->getTypeClass() == Type::Pointer ||(static_cast<void> (0))
2285 FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&(static_cast<void> (0))
2286 "Invalid similarly-qualified pointer type")(static_cast<void> (0));
2287
2288 /// Conversions to 'id' subsume cv-qualifier conversions.
2289 if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
2290 return ToType.getUnqualifiedType();
2291
2292 QualType CanonFromPointee
2293 = Context.getCanonicalType(FromPtr->getPointeeType());
2294 QualType CanonToPointee = Context.getCanonicalType(ToPointee);
2295 Qualifiers Quals = CanonFromPointee.getQualifiers();
2296
2297 if (StripObjCLifetime)
2298 Quals.removeObjCLifetime();
2299
2300 // Exact qualifier match -> return the pointer type we're converting to.
2301 if (CanonToPointee.getLocalQualifiers() == Quals) {
2302 // ToType is exactly what we need. Return it.
2303 if (!ToType.isNull())
2304 return ToType.getUnqualifiedType();
2305
2306 // Build a pointer to ToPointee. It has the right qualifiers
2307 // already.
2308 if (isa<ObjCObjectPointerType>(ToType))
2309 return Context.getObjCObjectPointerType(ToPointee);
2310 return Context.getPointerType(ToPointee);
2311 }
2312
2313 // Just build a canonical type that has the right qualifiers.
2314 QualType QualifiedCanonToPointee
2315 = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
2316
2317 if (isa<ObjCObjectPointerType>(ToType))
2318 return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
2319 return Context.getPointerType(QualifiedCanonToPointee);
2320}
2321
2322static bool isNullPointerConstantForConversion(Expr *Expr,
2323 bool InOverloadResolution,
2324 ASTContext &Context) {
2325 // Handle value-dependent integral null pointer constants correctly.
2326 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
2327 if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
2328 Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
2329 return !InOverloadResolution;
2330
2331 return Expr->isNullPointerConstant(Context,
2332 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
2333 : Expr::NPC_ValueDependentIsNull);
2334}
2335
2336/// IsPointerConversion - Determines whether the conversion of the
2337/// expression From, which has the (possibly adjusted) type FromType,
2338/// can be converted to the type ToType via a pointer conversion (C++
2339/// 4.10). If so, returns true and places the converted type (that
2340/// might differ from ToType in its cv-qualifiers at some level) into
2341/// ConvertedType.
2342///
2343/// This routine also supports conversions to and from block pointers
2344/// and conversions with Objective-C's 'id', 'id<protocols...>', and
2345/// pointers to interfaces. FIXME: Once we've determined the
2346/// appropriate overloading rules for Objective-C, we may want to
2347/// split the Objective-C checks into a different routine; however,
2348/// GCC seems to consider all of these conversions to be pointer
2349/// conversions, so for now they live here. IncompatibleObjC will be
2350/// set if the conversion is an allowed Objective-C conversion that
2351/// should result in a warning.
2352bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
2353 bool InOverloadResolution,
2354 QualType& ConvertedType,
2355 bool &IncompatibleObjC) {
2356 IncompatibleObjC = false;
2357 if (isObjCPointerConversion(FromType, ToType, ConvertedType,
2358 IncompatibleObjC))
2359 return true;
2360
2361 // Conversion from a null pointer constant to any Objective-C pointer type.
2362 if (ToType->isObjCObjectPointerType() &&
2363 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2364 ConvertedType = ToType;
2365 return true;
2366 }
2367
2368 // Blocks: Block pointers can be converted to void*.
2369 if (FromType->isBlockPointerType() && ToType->isPointerType() &&
2370 ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
2371 ConvertedType = ToType;
2372 return true;
2373 }
2374 // Blocks: A null pointer constant can be converted to a block
2375 // pointer type.
2376 if (ToType->isBlockPointerType() &&
2377 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2378 ConvertedType = ToType;
2379 return true;
2380 }
2381
2382 // If the left-hand-side is nullptr_t, the right side can be a null
2383 // pointer constant.
2384 if (ToType->isNullPtrType() &&
2385 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2386 ConvertedType = ToType;
2387 return true;
2388 }
2389
2390 const PointerType* ToTypePtr = ToType->getAs<PointerType>();
2391 if (!ToTypePtr)
2392 return false;
2393
2394 // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
2395 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2396 ConvertedType = ToType;
2397 return true;
2398 }
2399
2400 // Beyond this point, both types need to be pointers
2401 // , including objective-c pointers.
2402 QualType ToPointeeType = ToTypePtr->getPointeeType();
2403 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
2404 !getLangOpts().ObjCAutoRefCount) {
2405 ConvertedType = BuildSimilarlyQualifiedPointerType(
2406 FromType->getAs<ObjCObjectPointerType>(),
2407 ToPointeeType,
2408 ToType, Context);
2409 return true;
2410 }
2411 const PointerType *FromTypePtr = FromType->getAs<PointerType>();
2412 if (!FromTypePtr)
2413 return false;
2414
2415 QualType FromPointeeType = FromTypePtr->getPointeeType();
2416
2417 // If the unqualified pointee types are the same, this can't be a
2418 // pointer conversion, so don't do all of the work below.
2419 if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
2420 return false;
2421
2422 // An rvalue of type "pointer to cv T," where T is an object type,
2423 // can be converted to an rvalue of type "pointer to cv void" (C++
2424 // 4.10p2).
2425 if (FromPointeeType->isIncompleteOrObjectType() &&
2426 ToPointeeType->isVoidType()) {
2427 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2428 ToPointeeType,
2429 ToType, Context,
2430 /*StripObjCLifetime=*/true);
2431 return true;
2432 }
2433
2434 // MSVC allows implicit function to void* type conversion.
2435 if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
2436 ToPointeeType->isVoidType()) {
2437 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2438 ToPointeeType,
2439 ToType, Context);
2440 return true;
2441 }
2442
2443 // When we're overloading in C, we allow a special kind of pointer
2444 // conversion for compatible-but-not-identical pointee types.
2445 if (!getLangOpts().CPlusPlus &&
2446 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
2447 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2448 ToPointeeType,
2449 ToType, Context);
2450 return true;
2451 }
2452
2453 // C++ [conv.ptr]p3:
2454 //
2455 // An rvalue of type "pointer to cv D," where D is a class type,
2456 // can be converted to an rvalue of type "pointer to cv B," where
2457 // B is a base class (clause 10) of D. If B is an inaccessible
2458 // (clause 11) or ambiguous (10.2) base class of D, a program that
2459 // necessitates this conversion is ill-formed. The result of the
2460 // conversion is a pointer to the base class sub-object of the
2461 // derived class object. The null pointer value is converted to
2462 // the null pointer value of the destination type.
2463 //
2464 // Note that we do not check for ambiguity or inaccessibility
2465 // here. That is handled by CheckPointerConversion.
2466 if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
2467 ToPointeeType->isRecordType() &&
2468 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
2469 IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
2470 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2471 ToPointeeType,
2472 ToType, Context);
2473 return true;
2474 }
2475
2476 if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
2477 Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
2478 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2479 ToPointeeType,
2480 ToType, Context);
2481 return true;
2482 }
2483
2484 return false;
2485}
2486
2487/// Adopt the given qualifiers for the given type.
2488static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
2489 Qualifiers TQs = T.getQualifiers();
2490
2491 // Check whether qualifiers already match.
2492 if (TQs == Qs)
2493 return T;
2494
2495 if (Qs.compatiblyIncludes(TQs))
2496 return Context.getQualifiedType(T, Qs);
2497
2498 return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
2499}
2500
2501/// isObjCPointerConversion - Determines whether this is an
2502/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
2503/// with the same arguments and return values.
2504bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
2505 QualType& ConvertedType,
2506 bool &IncompatibleObjC) {
2507 if (!getLangOpts().ObjC)
2508 return false;
2509
2510 // The set of qualifiers on the type we're converting from.
2511 Qualifiers FromQualifiers = FromType.getQualifiers();
2512
2513 // First, we handle all conversions on ObjC object pointer types.
2514 const ObjCObjectPointerType* ToObjCPtr =
2515 ToType->getAs<ObjCObjectPointerType>();
2516 const ObjCObjectPointerType *FromObjCPtr =
2517 FromType->getAs<ObjCObjectPointerType>();
2518
2519 if (ToObjCPtr && FromObjCPtr) {
2520 // If the pointee types are the same (ignoring qualifications),
2521 // then this is not a pointer conversion.
2522 if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
2523 FromObjCPtr->getPointeeType()))
2524 return false;
2525
2526 // Conversion between Objective-C pointers.
2527 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
2528 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
2529 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
2530 if (getLangOpts().CPlusPlus && LHS && RHS &&
2531 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
2532 FromObjCPtr->getPointeeType()))
2533 return false;
2534 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2535 ToObjCPtr->getPointeeType(),
2536 ToType, Context);
2537 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2538 return true;
2539 }
2540
2541 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
2542 // Okay: this is some kind of implicit downcast of Objective-C
2543 // interfaces, which is permitted. However, we're going to
2544 // complain about it.
2545 IncompatibleObjC = true;
2546 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2547 ToObjCPtr->getPointeeType(),
2548 ToType, Context);
2549 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2550 return true;
2551 }
2552 }
2553 // Beyond this point, both types need to be C pointers or block pointers.
2554 QualType ToPointeeType;
2555 if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
2556 ToPointeeType = ToCPtr->getPointeeType();
2557 else if (const BlockPointerType *ToBlockPtr =
2558 ToType->getAs<BlockPointerType>()) {
2559 // Objective C++: We're able to convert from a pointer to any object
2560 // to a block pointer type.
2561 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
2562 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2563 return true;
2564 }
2565 ToPointeeType = ToBlockPtr->getPointeeType();
2566 }
2567 else if (FromType->getAs<BlockPointerType>() &&
2568 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
2569 // Objective C++: We're able to convert from a block pointer type to a
2570 // pointer to any object.
2571 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2572 return true;
2573 }
2574 else
2575 return false;
2576
2577 QualType FromPointeeType;
2578 if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
2579 FromPointeeType = FromCPtr->getPointeeType();
2580 else if (const BlockPointerType *FromBlockPtr =
2581 FromType->getAs<BlockPointerType>())
2582 FromPointeeType = FromBlockPtr->getPointeeType();
2583 else
2584 return false;
2585
2586 // If we have pointers to pointers, recursively check whether this
2587 // is an Objective-C conversion.
2588 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
2589 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2590 IncompatibleObjC)) {
2591 // We always complain about this conversion.
2592 IncompatibleObjC = true;
2593 ConvertedType = Context.getPointerType(ConvertedType);
2594 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2595 return true;
2596 }
2597 // Allow conversion of pointee being objective-c pointer to another one;
2598 // as in I* to id.
2599 if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
2600 ToPointeeType->getAs<ObjCObjectPointerType>() &&
2601 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2602 IncompatibleObjC)) {
2603
2604 ConvertedType = Context.getPointerType(ConvertedType);
2605 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2606 return true;
2607 }
2608
2609 // If we have pointers to functions or blocks, check whether the only
2610 // differences in the argument and result types are in Objective-C
2611 // pointer conversions. If so, we permit the conversion (but
2612 // complain about it).
2613 const FunctionProtoType *FromFunctionType
2614 = FromPointeeType->getAs<FunctionProtoType>();
2615 const FunctionProtoType *ToFunctionType
2616 = ToPointeeType->getAs<FunctionProtoType>();
2617 if (FromFunctionType && ToFunctionType) {
2618 // If the function types are exactly the same, this isn't an
2619 // Objective-C pointer conversion.
2620 if (Context.getCanonicalType(FromPointeeType)
2621 == Context.getCanonicalType(ToPointeeType))
2622 return false;
2623
2624 // Perform the quick checks that will tell us whether these
2625 // function types are obviously different.
2626 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2627 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
2628 FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
2629 return false;
2630
2631 bool HasObjCConversion = false;
2632 if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
2633 Context.getCanonicalType(ToFunctionType->getReturnType())) {
2634 // Okay, the types match exactly. Nothing to do.
2635 } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
2636 ToFunctionType->getReturnType(),
2637 ConvertedType, IncompatibleObjC)) {
2638 // Okay, we have an Objective-C pointer conversion.
2639 HasObjCConversion = true;
2640 } else {
2641 // Function types are too different. Abort.
2642 return false;
2643 }
2644
2645 // Check argument types.
2646 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2647 ArgIdx != NumArgs; ++ArgIdx) {
2648 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2649 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2650 if (Context.getCanonicalType(FromArgType)
2651 == Context.getCanonicalType(ToArgType)) {
2652 // Okay, the types match exactly. Nothing to do.
2653 } else if (isObjCPointerConversion(FromArgType, ToArgType,
2654 ConvertedType, IncompatibleObjC)) {
2655 // Okay, we have an Objective-C pointer conversion.
2656 HasObjCConversion = true;
2657 } else {
2658 // Argument types are too different. Abort.
2659 return false;
2660 }
2661 }
2662
2663 if (HasObjCConversion) {
2664 // We had an Objective-C conversion. Allow this pointer
2665 // conversion, but complain about it.
2666 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2667 IncompatibleObjC = true;
2668 return true;
2669 }
2670 }
2671
2672 return false;
2673}
2674
2675/// Determine whether this is an Objective-C writeback conversion,
2676/// used for parameter passing when performing automatic reference counting.
2677///
2678/// \param FromType The type we're converting form.
2679///
2680/// \param ToType The type we're converting to.
2681///
2682/// \param ConvertedType The type that will be produced after applying
2683/// this conversion.
2684bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
2685 QualType &ConvertedType) {
2686 if (!getLangOpts().ObjCAutoRefCount ||
2687 Context.hasSameUnqualifiedType(FromType, ToType))
2688 return false;
2689
2690 // Parameter must be a pointer to __autoreleasing (with no other qualifiers).
2691 QualType ToPointee;
2692 if (const PointerType *ToPointer = ToType->getAs<PointerType>())
2693 ToPointee = ToPointer->getPointeeType();
2694 else
2695 return false;
2696
2697 Qualifiers ToQuals = ToPointee.getQualifiers();
2698 if (!ToPointee->isObjCLifetimeType() ||
2699 ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
2700 !ToQuals.withoutObjCLifetime().empty())
2701 return false;
2702
2703 // Argument must be a pointer to __strong to __weak.
2704 QualType FromPointee;
2705 if (const PointerType *FromPointer = FromType->getAs<PointerType>())
2706 FromPointee = FromPointer->getPointeeType();
2707 else
2708 return false;
2709
2710 Qualifiers FromQuals = FromPointee.getQualifiers();
2711 if (!FromPointee->isObjCLifetimeType() ||
2712 (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
2713 FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
2714 return false;
2715
2716 // Make sure that we have compatible qualifiers.
2717 FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
2718 if (!ToQuals.compatiblyIncludes(FromQuals))
2719 return false;
2720
2721 // Remove qualifiers from the pointee type we're converting from; they
2722 // aren't used in the compatibility check belong, and we'll be adding back
2723 // qualifiers (with __autoreleasing) if the compatibility check succeeds.
2724 FromPointee = FromPointee.getUnqualifiedType();
2725
2726 // The unqualified form of the pointee types must be compatible.
2727 ToPointee = ToPointee.getUnqualifiedType();
2728 bool IncompatibleObjC;
2729 if (Context.typesAreCompatible(FromPointee, ToPointee))
2730 FromPointee = ToPointee;
2731 else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
2732 IncompatibleObjC))
2733 return false;
2734
2735 /// Construct the type we're converting to, which is a pointer to
2736 /// __autoreleasing pointee.
2737 FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
2738 ConvertedType = Context.getPointerType(FromPointee);
2739 return true;
2740}
2741
2742bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
2743 QualType& ConvertedType) {
2744 QualType ToPointeeType;
2745 if (const BlockPointerType *ToBlockPtr =
2746 ToType->getAs<BlockPointerType>())
2747 ToPointeeType = ToBlockPtr->getPointeeType();
2748 else
2749 return false;
2750
2751 QualType FromPointeeType;
2752 if (const BlockPointerType *FromBlockPtr =
2753 FromType->getAs<BlockPointerType>())
2754 FromPointeeType = FromBlockPtr->getPointeeType();
2755 else
2756 return false;
2757 // We have pointer to blocks, check whether the only
2758 // differences in the argument and result types are in Objective-C
2759 // pointer conversions. If so, we permit the conversion.
2760
2761 const FunctionProtoType *FromFunctionType
2762 = FromPointeeType->getAs<FunctionProtoType>();
2763 const FunctionProtoType *ToFunctionType
2764 = ToPointeeType->getAs<FunctionProtoType>();
2765
2766 if (!FromFunctionType || !ToFunctionType)
2767 return false;
2768
2769 if (Context.hasSameType(FromPointeeType, ToPointeeType))
2770 return true;
2771
2772 // Perform the quick checks that will tell us whether these
2773 // function types are obviously different.
2774 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2775 FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
2776 return false;
2777
2778 FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
2779 FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
2780 if (FromEInfo != ToEInfo)
2781 return false;
2782
2783 bool IncompatibleObjC = false;
2784 if (Context.hasSameType(FromFunctionType->getReturnType(),
2785 ToFunctionType->getReturnType())) {
2786 // Okay, the types match exactly. Nothing to do.
2787 } else {
2788 QualType RHS = FromFunctionType->getReturnType();
2789 QualType LHS = ToFunctionType->getReturnType();
2790 if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
2791 !RHS.hasQualifiers() && LHS.hasQualifiers())
2792 LHS = LHS.getUnqualifiedType();
2793
2794 if (Context.hasSameType(RHS,LHS)) {
2795 // OK exact match.
2796 } else if (isObjCPointerConversion(RHS, LHS,
2797 ConvertedType, IncompatibleObjC)) {
2798 if (IncompatibleObjC)
2799 return false;
2800 // Okay, we have an Objective-C pointer conversion.
2801 }
2802 else
2803 return false;
2804 }
2805
2806 // Check argument types.
2807 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2808 ArgIdx != NumArgs; ++ArgIdx) {
2809 IncompatibleObjC = false;
2810 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2811 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2812 if (Context.hasSameType(FromArgType, ToArgType)) {
2813 // Okay, the types match exactly. Nothing to do.
2814 } else if (isObjCPointerConversion(ToArgType, FromArgType,
2815 ConvertedType, IncompatibleObjC)) {
2816 if (IncompatibleObjC)
2817 return false;
2818 // Okay, we have an Objective-C pointer conversion.
2819 } else
2820 // Argument types are too different. Abort.
2821 return false;
2822 }
2823
2824 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
2825 bool CanUseToFPT, CanUseFromFPT;
2826 if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
2827 CanUseToFPT, CanUseFromFPT,
2828 NewParamInfos))
2829 return false;
2830
2831 ConvertedType = ToType;
2832 return true;
2833}
2834
2835enum {
2836 ft_default,
2837 ft_different_class,
2838 ft_parameter_arity,
2839 ft_parameter_mismatch,
2840 ft_return_type,
2841 ft_qualifer_mismatch,
2842 ft_noexcept
2843};
2844
2845/// Attempts to get the FunctionProtoType from a Type. Handles
2846/// MemberFunctionPointers properly.
2847static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
2848 if (auto *FPT = FromType->getAs<FunctionProtoType>())
2849 return FPT;
2850
2851 if (auto *MPT = FromType->getAs<MemberPointerType>())
2852 return MPT->getPointeeType()->getAs<FunctionProtoType>();
2853
2854 return nullptr;
2855}
2856
2857/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
2858/// function types. Catches different number of parameter, mismatch in
2859/// parameter types, and different return types.
2860void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
2861 QualType FromType, QualType ToType) {
2862 // If either type is not valid, include no extra info.
2863 if (FromType.isNull() || ToType.isNull()) {
2864 PDiag << ft_default;
2865 return;
2866 }
2867
2868 // Get the function type from the pointers.
2869 if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
2870 const auto *FromMember = FromType->castAs<MemberPointerType>(),
2871 *ToMember = ToType->castAs<MemberPointerType>();
2872 if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
2873 PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
2874 << QualType(FromMember->getClass(), 0);
2875 return;
2876 }
2877 FromType = FromMember->getPointeeType();
2878 ToType = ToMember->getPointeeType();
2879 }
2880
2881 if (FromType->isPointerType())
2882 FromType = FromType->getPointeeType();
2883 if (ToType->isPointerType())
2884 ToType = ToType->getPointeeType();
2885
2886 // Remove references.
2887 FromType = FromType.getNonReferenceType();
2888 ToType = ToType.getNonReferenceType();
2889
2890 // Don't print extra info for non-specialized template functions.
2891 if (FromType->isInstantiationDependentType() &&
2892 !FromType->getAs<TemplateSpecializationType>()) {
2893 PDiag << ft_default;
2894 return;
2895 }
2896
2897 // No extra info for same types.
2898 if (Context.hasSameType(FromType, ToType)) {
2899 PDiag << ft_default;
2900 return;
2901 }
2902
2903 const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
2904 *ToFunction = tryGetFunctionProtoType(ToType);
2905
2906 // Both types need to be function types.
2907 if (!FromFunction || !ToFunction) {
2908 PDiag << ft_default;
2909 return;
2910 }
2911
2912 if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
2913 PDiag << ft_parameter_arity << ToFunction->getNumParams()
2914 << FromFunction->getNumParams();
2915 return;
2916 }
2917
2918 // Handle different parameter types.
2919 unsigned ArgPos;
2920 if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
2921 PDiag << ft_parameter_mismatch << ArgPos + 1
2922 << ToFunction->getParamType(ArgPos)
2923 << FromFunction->getParamType(ArgPos);
2924 return;
2925 }
2926
2927 // Handle different return type.
2928 if (!Context.hasSameType(FromFunction->getReturnType(),
2929 ToFunction->getReturnType())) {
2930 PDiag << ft_return_type << ToFunction->getReturnType()
2931 << FromFunction->getReturnType();
2932 return;
2933 }
2934
2935 if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
2936 PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
2937 << FromFunction->getMethodQuals();
2938 return;
2939 }
2940
2941 // Handle exception specification differences on canonical type (in C++17
2942 // onwards).
2943 if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
2944 ->isNothrow() !=
2945 cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
2946 ->isNothrow()) {
2947 PDiag << ft_noexcept;
2948 return;
2949 }
2950
2951 // Unable to find a difference, so add no extra info.
2952 PDiag << ft_default;
2953}
2954
2955/// FunctionParamTypesAreEqual - This routine checks two function proto types
2956/// for equality of their argument types. Caller has already checked that
2957/// they have same number of arguments. If the parameters are different,
2958/// ArgPos will have the parameter index of the first different parameter.
2959bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
2960 const FunctionProtoType *NewType,
2961 unsigned *ArgPos) {
2962 for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
2963 N = NewType->param_type_begin(),
2964 E = OldType->param_type_end();
2965 O && (O != E); ++O, ++N) {
2966 // Ignore address spaces in pointee type. This is to disallow overloading
2967 // on __ptr32/__ptr64 address spaces.
2968 QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
2969 QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());
2970
2971 if (!Context.hasSameType(Old, New)) {
2972 if (ArgPos)
2973 *ArgPos = O - OldType->param_type_begin();
2974 return false;
2975 }
2976 }
2977 return true;
2978}
2979
2980/// CheckPointerConversion - Check the pointer conversion from the
2981/// expression From to the type ToType. This routine checks for
2982/// ambiguous or inaccessible derived-to-base pointer
2983/// conversions for which IsPointerConversion has already returned
2984/// true. It returns true and produces a diagnostic if there was an
2985/// error, or returns false otherwise.
2986bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
2987 CastKind &Kind,
2988 CXXCastPath& BasePath,
2989 bool IgnoreBaseAccess,
2990 bool Diagnose) {
2991 QualType FromType = From->getType();
2992 bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
2993
2994 Kind = CK_BitCast;
2995
2996 if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
2997 From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
2998 Expr::NPCK_ZeroExpression) {
2999 if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
3000 DiagRuntimeBehavior(From->getExprLoc(), From,
3001 PDiag(diag::warn_impcast_bool_to_null_pointer)
3002 << ToType << From->getSourceRange());
3003 else if (!isUnevaluatedContext())
3004 Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
3005 << ToType << From->getSourceRange();
3006 }
3007 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
3008 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
3009 QualType FromPointeeType = FromPtrType->getPointeeType(),
3010 ToPointeeType = ToPtrType->getPointeeType();
3011
3012 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
3013 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
3014 // We must have a derived-to-base conversion. Check an
3015 // ambiguous or inaccessible conversion.
3016 unsigned InaccessibleID = 0;
3017 unsigned AmbiguousID = 0;
3018 if (Diagnose) {
3019 InaccessibleID = diag::err_upcast_to_inaccessible_base;
3020 AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
3021 }
3022 if (CheckDerivedToBaseConversion(
3023 FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
3024 From->getExprLoc(), From->getSourceRange(), DeclarationName(),
3025 &BasePath, IgnoreBaseAccess))
3026 return true;
3027
3028 // The conversion was successful.
3029 Kind = CK_DerivedToBase;
3030 }
3031
3032 if (Diagnose && !IsCStyleOrFunctionalCast &&
3033 FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
3034 assert(getLangOpts().MSVCCompat &&(static_cast<void> (0))
3035 "this should only be possible with MSVCCompat!")(static_cast<void> (0));
3036 Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
3037 << From->getSourceRange();
3038 }
3039 }
3040 } else if (const ObjCObjectPointerType *ToPtrType =
3041 ToType->getAs<ObjCObjectPointerType>()) {
3042 if (const ObjCObjectPointerType *FromPtrType =
3043 FromType->getAs<ObjCObjectPointerType>()) {
3044 // Objective-C++ conversions are always okay.
3045 // FIXME: We should have a different class of conversions for the
3046 // Objective-C++ implicit conversions.
3047 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
3048 return false;
3049 } else if (FromType->isBlockPointerType()) {
3050 Kind = CK_BlockPointerToObjCPointerCast;
3051 } else {
3052 Kind = CK_CPointerToObjCPointerCast;
3053 }
3054 } else if (ToType->isBlockPointerType()) {
3055 if (!FromType->isBlockPointerType())
3056 Kind = CK_AnyPointerToBlockPointerCast;
3057 }
3058
3059 // We shouldn't fall into this case unless it's valid for other
3060 // reasons.
3061 if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
3062 Kind = CK_NullToPointer;
3063
3064 return false;
3065}
3066
3067/// IsMemberPointerConversion - Determines whether the conversion of the
3068/// expression From, which has the (possibly adjusted) type FromType, can be
3069/// converted to the type ToType via a member pointer conversion (C++ 4.11).
3070/// If so, returns true and places the converted type (that might differ from
3071/// ToType in its cv-qualifiers at some level) into ConvertedType.
3072bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
3073 QualType ToType,
3074 bool InOverloadResolution,
3075 QualType &ConvertedType) {
3076 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
3077 if (!ToTypePtr)
3078 return false;
3079
3080 // A null pointer constant can be converted to a member pointer (C++ 4.11p1)
3081 if (From->isNullPointerConstant(Context,
3082 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
3083 : Expr::NPC_ValueDependentIsNull)) {
3084 ConvertedType = ToType;
3085 return true;
3086 }
3087
3088 // Otherwise, both types have to be member pointers.
3089 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
3090 if (!FromTypePtr)
3091 return false;
3092
3093 // A pointer to member of B can be converted to a pointer to member of D,
3094 // where D is derived from B (C++ 4.11p2).
3095 QualType FromClass(FromTypePtr->getClass(), 0);
3096 QualType ToClass(ToTypePtr->getClass(), 0);
3097
3098 if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
3099 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
3100 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
3101 ToClass.getTypePtr());
3102 return true;
3103 }
3104
3105 return false;
3106}
3107
3108/// CheckMemberPointerConversion - Check the member pointer conversion from the
3109/// expression From to the type ToType. This routine checks for ambiguous or
3110/// virtual or inaccessible base-to-derived member pointer conversions
3111/// for which IsMemberPointerConversion has already returned true. It returns
3112/// true and produces a diagnostic if there was an error, or returns false
3113/// otherwise.
3114bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
3115 CastKind &Kind,
3116 CXXCastPath &BasePath,
3117 bool IgnoreBaseAccess) {
3118 QualType FromType = From->getType();
3119 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
3120 if (!FromPtrType) {
3121 // This must be a null pointer to member pointer conversion
3122 assert(From->isNullPointerConstant(Context,(static_cast<void> (0))
3123 Expr::NPC_ValueDependentIsNull) &&(static_cast<void> (0))
3124 "Expr must be null pointer constant!")(static_cast<void> (0));
3125 Kind = CK_NullToMemberPointer;
3126 return false;
3127 }
3128
3129 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
3130 assert(ToPtrType && "No member pointer cast has a target type "(static_cast<void> (0))
3131 "that is not a member pointer.")(static_cast<void> (0));
3132
3133 QualType FromClass = QualType(FromPtrType->getClass(), 0);
3134 QualType ToClass = QualType(ToPtrType->getClass(), 0);
3135
3136 // FIXME: What about dependent types?
3137 assert(FromClass->isRecordType() && "Pointer into non-class.")(static_cast<void> (0));
3138 assert(ToClass->isRecordType() && "Pointer into non-class.")(static_cast<void> (0));
3139
3140 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3141 /*DetectVirtual=*/true);
3142 bool DerivationOkay =
3143 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
3144 assert(DerivationOkay &&(static_cast<void> (0))
3145 "Should not have been called if derivation isn't OK.")(static_cast<void> (0));
3146 (void)DerivationOkay;
3147
3148 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
3149 getUnqualifiedType())) {
3150 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
3151 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
3152 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
3153 return true;
3154 }
3155
3156 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
3157 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
3158 << FromClass << ToClass << QualType(VBase, 0)
3159 << From->getSourceRange();
3160 return true;
3161 }
3162
3163 if (!IgnoreBaseAccess)
3164 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
3165 Paths.front(),
3166 diag::err_downcast_from_inaccessible_base);
3167
3168 // Must be a base to derived member conversion.
3169 BuildBasePathArray(Paths, BasePath);
3170 Kind = CK_BaseToDerivedMemberPointer;
3171 return false;
3172}
3173
3174/// Determine whether the lifetime conversion between the two given
3175/// qualifiers sets is nontrivial.
3176static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
3177 Qualifiers ToQuals) {
3178 // Converting anything to const __unsafe_unretained is trivial.
3179 if (ToQuals.hasConst() &&
3180 ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
3181 return false;
3182
3183 return true;
3184}
3185
3186/// Perform a single iteration of the loop for checking if a qualification
3187/// conversion is valid.
3188///
3189/// Specifically, check whether any change between the qualifiers of \p
3190/// FromType and \p ToType is permissible, given knowledge about whether every
3191/// outer layer is const-qualified.
3192static bool isQualificationConversionStep(QualType FromType, QualType ToType,
3193 bool CStyle, bool IsTopLevel,
3194 bool &PreviousToQualsIncludeConst,
3195 bool &ObjCLifetimeConversion) {
3196 Qualifiers FromQuals = FromType.getQualifiers();
3197 Qualifiers ToQuals = ToType.getQualifiers();
3198
3199 // Ignore __unaligned qualifier if this type is void.
3200 if (ToType.getUnqualifiedType()->isVoidType())
3201 FromQuals.removeUnaligned();
3202
3203 // Objective-C ARC:
3204 // Check Objective-C lifetime conversions.
3205 if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
3206 if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
3207 if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
3208 ObjCLifetimeConversion = true;
3209 FromQuals.removeObjCLifetime();
3210 ToQuals.removeObjCLifetime();
3211 } else {
3212 // Qualification conversions cannot cast between different
3213 // Objective-C lifetime qualifiers.
3214 return false;
3215 }
3216 }
3217
3218 // Allow addition/removal of GC attributes but not changing GC attributes.
3219 if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
3220 (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
3221 FromQuals.removeObjCGCAttr();
3222 ToQuals.removeObjCGCAttr();
3223 }
3224
3225 // -- for every j > 0, if const is in cv 1,j then const is in cv
3226 // 2,j, and similarly for volatile.
3227 if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
3228 return false;
3229
3230 // If address spaces mismatch:
3231 // - in top level it is only valid to convert to addr space that is a
3232 // superset in all cases apart from C-style casts where we allow
3233 // conversions between overlapping address spaces.
3234 // - in non-top levels it is not a valid conversion.
3235 if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
3236 (!IsTopLevel ||
3237 !(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
3238 (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
3239 return false;
3240
3241 // -- if the cv 1,j and cv 2,j are different, then const is in
3242 // every cv for 0 < k < j.
3243 if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
3244 !PreviousToQualsIncludeConst)
3245 return false;
3246
3247 // Keep track of whether all prior cv-qualifiers in the "to" type
3248 // include const.
3249 PreviousToQualsIncludeConst =
3250 PreviousToQualsIncludeConst && ToQuals.hasConst();
3251 return true;
3252}
3253
3254/// IsQualificationConversion - Determines whether the conversion from
3255/// an rvalue of type FromType to ToType is a qualification conversion
3256/// (C++ 4.4).
3257///
3258/// \param ObjCLifetimeConversion Output parameter that will be set to indicate
3259/// when the qualification conversion involves a change in the Objective-C
3260/// object lifetime.
3261bool
3262Sema::IsQualificationConversion(QualType FromType, QualType ToType,
3263 bool CStyle, bool &ObjCLifetimeConversion) {
3264 FromType = Context.getCanonicalType(FromType);
3265 ToType = Context.getCanonicalType(ToType);
3266 ObjCLifetimeConversion = false;
3267
3268 // If FromType and ToType are the same type, this is not a
3269 // qualification conversion.
3270 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
3271 return false;
3272
3273 // (C++ 4.4p4):
3274 // A conversion can add cv-qualifiers at levels other than the first
3275 // in multi-level pointers, subject to the following rules: [...]
3276 bool PreviousToQualsIncludeConst = true;
3277 bool UnwrappedAnyPointer = false;
3278 while (Context.UnwrapSimilarTypes(FromType, ToType)) {
3279 if (!isQualificationConversionStep(
3280 FromType, ToType, CStyle, !UnwrappedAnyPointer,
3281 PreviousToQualsIncludeConst, ObjCLifetimeConversion))
3282 return false;
3283 UnwrappedAnyPointer = true;
3284 }
3285
3286 // We are left with FromType and ToType being the pointee types
3287 // after unwrapping the original FromType and ToType the same number
3288 // of times. If we unwrapped any pointers, and if FromType and
3289 // ToType have the same unqualified type (since we checked
3290 // qualifiers above), then this is a qualification conversion.
3291 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
3292}
3293
3294/// - Determine whether this is a conversion from a scalar type to an
3295/// atomic type.
3296///
3297/// If successful, updates \c SCS's second and third steps in the conversion
3298/// sequence to finish the conversion.
3299static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
3300 bool InOverloadResolution,
3301 StandardConversionSequence &SCS,
3302 bool CStyle) {
3303 const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
3304 if (!ToAtomic)
3305 return false;
3306
3307 StandardConversionSequence InnerSCS;
3308 if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
3309 InOverloadResolution, InnerSCS,
3310 CStyle, /*AllowObjCWritebackConversion=*/false))
3311 return false;
3312
3313 SCS.Second = InnerSCS.Second;
3314 SCS.setToType(1, InnerSCS.getToType(1));
3315 SCS.Third = InnerSCS.Third;
3316 SCS.QualificationIncludesObjCLifetime
3317 = InnerSCS.QualificationIncludesObjCLifetime;
3318 SCS.setToType(2, InnerSCS.getToType(2));
3319 return true;
3320}
3321
3322static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
3323 CXXConstructorDecl *Constructor,
3324 QualType Type) {
3325 const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
3326 if (CtorType->getNumParams() > 0) {
3327 QualType FirstArg = CtorType->getParamType(0);
3328 if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
3329 return true;
3330 }
3331 return false;
3332}
3333
3334static OverloadingResult
3335IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
3336 CXXRecordDecl *To,
3337 UserDefinedConversionSequence &User,
3338 OverloadCandidateSet &CandidateSet,
3339 bool AllowExplicit) {
3340 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3341 for (auto *D : S.LookupConstructors(To)) {
3342 auto Info = getConstructorInfo(D);
3343 if (!Info)
3344 continue;
3345
3346 bool Usable = !Info.Constructor->isInvalidDecl() &&
3347 S.isInitListConstructor(Info.Constructor);
3348 if (Usable) {
3349 bool SuppressUserConversions = false;
3350 if (Info.ConstructorTmpl)
3351 S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
3352 /*ExplicitArgs*/ nullptr, From,
3353 CandidateSet, SuppressUserConversions,
3354 /*PartialOverloading*/ false,
3355 AllowExplicit);
3356 else
3357 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
3358 CandidateSet, SuppressUserConversions,
3359 /*PartialOverloading*/ false, AllowExplicit);
3360 }
3361 }
3362
3363 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3364
3365 OverloadCandidateSet::iterator Best;
3366 switch (auto Result =
3367 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3368 case OR_Deleted:
3369 case OR_Success: {
3370 // Record the standard conversion we used and the conversion function.
3371 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
3372 QualType ThisType = Constructor->getThisType();
3373 // Initializer lists don't have conversions as such.
3374 User.Before.setAsIdentityConversion();
3375 User.HadMultipleCandidates = HadMultipleCandidates;
3376 User.ConversionFunction = Constructor;
3377 User.FoundConversionFunction = Best->FoundDecl;
3378 User.After.setAsIdentityConversion();
3379 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3380 User.After.setAllToTypes(ToType);
3381 return Result;
3382 }
3383
3384 case OR_No_Viable_Function:
3385 return OR_No_Viable_Function;
3386 case OR_Ambiguous:
3387 return OR_Ambiguous;
3388 }
3389
3390 llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
3391}
3392
3393/// Determines whether there is a user-defined conversion sequence
3394/// (C++ [over.ics.user]) that converts expression From to the type
3395/// ToType. If such a conversion exists, User will contain the
3396/// user-defined conversion sequence that performs such a conversion
3397/// and this routine will return true. Otherwise, this routine returns
3398/// false and User is unspecified.
3399///
3400/// \param AllowExplicit true if the conversion should consider C++0x
3401/// "explicit" conversion functions as well as non-explicit conversion
3402/// functions (C++0x [class.conv.fct]p2).
3403///
3404/// \param AllowObjCConversionOnExplicit true if the conversion should
3405/// allow an extra Objective-C pointer conversion on uses of explicit
3406/// constructors. Requires \c AllowExplicit to also be set.
3407static OverloadingResult
3408IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
3409 UserDefinedConversionSequence &User,
3410 OverloadCandidateSet &CandidateSet,
3411 AllowedExplicit AllowExplicit,
3412 bool AllowObjCConversionOnExplicit) {
3413 assert(AllowExplicit != AllowedExplicit::None ||(static_cast<void> (0))
3414 !AllowObjCConversionOnExplicit)(static_cast<void> (0));
3415 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3416
3417 // Whether we will only visit constructors.
3418 bool ConstructorsOnly = false;
3419
3420 // If the type we are conversion to is a class type, enumerate its
3421 // constructors.
3422 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
3423 // C++ [over.match.ctor]p1:
3424 // When objects of class type are direct-initialized (8.5), or
3425 // copy-initialized from an expression of the same or a
3426 // derived class type (8.5), overload resolution selects the
3427 // constructor. [...] For copy-initialization, the candidate
3428 // functions are all the converting constructors (12.3.1) of
3429 // that class. The argument list is the expression-list within
3430 // the parentheses of the initializer.
3431 if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
3432 (From->getType()->getAs<RecordType>() &&
3433 S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
3434 ConstructorsOnly = true;
3435
3436 if (!S.isCompleteType(From->getExprLoc(), ToType)) {
3437 // We're not going to find any constructors.
3438 } else if (CXXRecordDecl *ToRecordDecl
3439 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
3440
3441 Expr **Args = &From;
3442 unsigned NumArgs = 1;
3443 bool ListInitializing = false;
3444 if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
3445 // But first, see if there is an init-list-constructor that will work.
3446 OverloadingResult Result = IsInitializerListConstructorConversion(
3447 S, From, ToType, ToRecordDecl, User, CandidateSet,
3448 AllowExplicit == AllowedExplicit::All);
3449 if (Result != OR_No_Viable_Function)
3450 return Result;
3451 // Never mind.
3452 CandidateSet.clear(
3453 OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3454
3455 // If we're list-initializing, we pass the individual elements as
3456 // arguments, not the entire list.
3457 Args = InitList->getInits();
3458 NumArgs = InitList->getNumInits();
3459 ListInitializing = true;
3460 }
3461
3462 for (auto *D : S.LookupConstructors(ToRecordDecl)) {
3463 auto Info = getConstructorInfo(D);
3464 if (!Info)
3465 continue;
3466
3467 bool Usable = !Info.Constructor->isInvalidDecl();
3468 if (!ListInitializing)
3469 Usable = Usable && Info.Constructor->isConvertingConstructor(
3470 /*AllowExplicit*/ true);
3471 if (Usable) {
3472 bool SuppressUserConversions = !ConstructorsOnly;
3473 // C++20 [over.best.ics.general]/4.5:
3474 // if the target is the first parameter of a constructor [of class
3475 // X] and the constructor [...] is a candidate by [...] the second
3476 // phase of [over.match.list] when the initializer list has exactly
3477 // one element that is itself an initializer list, [...] and the
3478 // conversion is to X or reference to cv X, user-defined conversion
3479 // sequences are not cnosidered.
3480 if (SuppressUserConversions && ListInitializing) {
3481 SuppressUserConversions =
3482 NumArgs == 1 && isa<InitListExpr>(Args[0]) &&
3483 isFirstArgumentCompatibleWithType(S.Context, Info.Constructor,
3484 ToType);
3485 }
3486 if (Info.ConstructorTmpl)
3487 S.AddTemplateOverloadCandidate(
3488 Info.ConstructorTmpl, Info.FoundDecl,
3489 /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
3490 CandidateSet, SuppressUserConversions,
3491 /*PartialOverloading*/ false,
3492 AllowExplicit == AllowedExplicit::All);
3493 else
3494 // Allow one user-defined conversion when user specifies a
3495 // From->ToType conversion via an static cast (c-style, etc).
3496 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
3497 llvm::makeArrayRef(Args, NumArgs),
3498 CandidateSet, SuppressUserConversions,
3499 /*PartialOverloading*/ false,
3500 AllowExplicit == AllowedExplicit::All);
3501 }
3502 }
3503 }
3504 }
3505
3506 // Enumerate conversion functions, if we're allowed to.
3507 if (ConstructorsOnly || isa<InitListExpr>(From)) {
3508 } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
3509 // No conversion functions from incomplete types.
3510 } else if (const RecordType *FromRecordType =
3511 From->getType()->getAs<RecordType>()) {
3512 if (CXXRecordDecl *FromRecordDecl
3513 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
3514 // Add all of the conversion functions as candidates.
3515 const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
3516 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3517 DeclAccessPair FoundDecl = I.getPair();
3518 NamedDecl *D = FoundDecl.getDecl();
3519 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
3520 if (isa<UsingShadowDecl>(D))
3521 D = cast<UsingShadowDecl>(D)->getTargetDecl();
3522
3523 CXXConversionDecl *Conv;
3524 FunctionTemplateDecl *ConvTemplate;
3525 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
3526 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3527 else
3528 Conv = cast<CXXConversionDecl>(D);
3529
3530 if (ConvTemplate)
3531 S.AddTemplateConversionCandidate(
3532 ConvTemplate, FoundDecl, ActingContext, From, ToType,
3533 CandidateSet, AllowObjCConversionOnExplicit,
3534 AllowExplicit != AllowedExplicit::None);
3535 else
3536 S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
3537 CandidateSet, AllowObjCConversionOnExplicit,
3538 AllowExplicit != AllowedExplicit::None);
3539 }
3540 }
3541 }
3542
3543 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3544
3545 OverloadCandidateSet::iterator Best;
3546 switch (auto Result =
3547 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3548 case OR_Success:
3549 case OR_Deleted:
3550 // Record the standard conversion we used and the conversion function.
3551 if (CXXConstructorDecl *Constructor
3552 = dyn_cast<CXXConstructorDecl>(Best->Function)) {
3553 // C++ [over.ics.user]p1:
3554 // If the user-defined conversion is specified by a
3555 // constructor (12.3.1), the initial standard conversion
3556 // sequence converts the source type to the type required by
3557 // the argument of the constructor.
3558 //
3559 QualType ThisType = Constructor->getThisType();
3560 if (isa<InitListExpr>(From)) {
3561 // Initializer lists don't have conversions as such.
3562 User.Before.setAsIdentityConversion();
3563 } else {
3564 if (Best->Conversions[0].isEllipsis())
3565 User.EllipsisConversion = true;
3566 else {
3567 User.Before = Best->Conversions[0].Standard;
3568 User.EllipsisConversion = false;
3569 }
3570 }
3571 User.HadMultipleCandidates = HadMultipleCandidates;
3572 User.ConversionFunction = Constructor;
3573 User.FoundConversionFunction = Best->FoundDecl;
3574 User.After.setAsIdentityConversion();
3575 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3576 User.After.setAllToTypes(ToType);
3577 return Result;
3578 }
3579 if (CXXConversionDecl *Conversion
3580 = dyn_cast<CXXConversionDecl>(Best->Function)) {
3581 // C++ [over.ics.user]p1:
3582 //
3583 // [...] If the user-defined conversion is specified by a
3584 // conversion function (12.3.2), the initial standard
3585 // conversion sequence converts the source type to the
3586 // implicit object parameter of the conversion function.
3587 User.Before = Best->Conversions[0].Standard;
3588 User.HadMultipleCandidates = HadMultipleCandidates;
3589 User.ConversionFunction = Conversion;
3590 User.FoundConversionFunction = Best->FoundDecl;
3591 User.EllipsisConversion = false;
3592
3593 // C++ [over.ics.user]p2:
3594 // The second standard conversion sequence converts the
3595 // result of the user-defined conversion to the target type
3596 // for the sequence. Since an implicit conversion sequence
3597 // is an initialization, the special rules for
3598 // initialization by user-defined conversion apply when
3599 // selecting the best user-defined conversion for a
3600 // user-defined conversion sequence (see 13.3.3 and
3601 // 13.3.3.1).
3602 User.After = Best->FinalConversion;
3603 return Result;
3604 }
3605 llvm_unreachable("Not a constructor or conversion function?")__builtin_unreachable();
3606
3607 case OR_No_Viable_Function:
3608 return OR_No_Viable_Function;
3609
3610 case OR_Ambiguous:
3611 return OR_Ambiguous;
3612 }
3613
3614 llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
3615}
3616
3617bool
3618Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
3619 ImplicitConversionSequence ICS;
3620 OverloadCandidateSet CandidateSet(From->getExprLoc(),
3621 OverloadCandidateSet::CSK_Normal);
3622 OverloadingResult OvResult =
3623 IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
3624 CandidateSet, AllowedExplicit::None, false);
3625
3626 if (!(OvResult == OR_Ambiguous ||
3627 (OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
3628 return false;
3629
3630 auto Cands = CandidateSet.CompleteCandidates(
3631 *this,
3632 OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
3633 From);
3634 if (OvResult == OR_Ambiguous)
3635 Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
3636 << From->getType() << ToType << From->getSourceRange();
3637 else { // OR_No_Viable_Function && !CandidateSet.empty()
3638 if (!RequireCompleteType(From->getBeginLoc(), ToType,
3639 diag::err_typecheck_nonviable_condition_incomplete,
3640 From->getType(), From->getSourceRange()))
3641 Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
3642 << false << From->getType() << From->getSourceRange() << ToType;
3643 }
3644
3645 CandidateSet.NoteCandidates(
3646 *this, From, Cands);
3647 return true;
3648}
3649
3650// Helper for compareConversionFunctions that gets the FunctionType that the
3651// conversion-operator return value 'points' to, or nullptr.
3652static const FunctionType *
3653getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) {
3654 const FunctionType *ConvFuncTy = Conv->getType()->castAs<FunctionType>();
3655 const PointerType *RetPtrTy =
3656 ConvFuncTy->getReturnType()->getAs<PointerType>();
3657
3658 if (!RetPtrTy)
3659 return nullptr;
3660
3661 return RetPtrTy->getPointeeType()->getAs<FunctionType>();
3662}
3663
3664/// Compare the user-defined conversion functions or constructors
3665/// of two user-defined conversion sequences to determine whether any ordering
3666/// is possible.
3667static ImplicitConversionSequence::CompareKind
3668compareConversionFunctions(Sema &S, FunctionDecl *Function1,
3669 FunctionDecl *Function2) {
3670 CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
3671 CXXConversionDecl *Conv2 = dyn_cast_or_null<CXXConversionDecl>(Function2);
3672 if (!Conv1 || !Conv2)
3673 return ImplicitConversionSequence::Indistinguishable;
3674
3675 if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda())
3676 return ImplicitConversionSequence::Indistinguishable;
3677
3678 // Objective-C++:
3679 // If both conversion functions are implicitly-declared conversions from
3680 // a lambda closure type to a function pointer and a block pointer,
3681 // respectively, always prefer the conversion to a function pointer,
3682 // because the function pointer is more lightweight and is more likely
3683 // to keep code working.
3684 if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) {
3685 bool Block1 = Conv1->getConversionType()->isBlockPointerType();
3686 bool Block2 = Conv2->getConversionType()->isBlockPointerType();
3687 if (Block1 != Block2)
3688 return Block1 ? ImplicitConversionSequence::Worse
3689 : ImplicitConversionSequence::Better;
3690 }
3691
3692 // In order to support multiple calling conventions for the lambda conversion
3693 // operator (such as when the free and member function calling convention is
3694 // different), prefer the 'free' mechanism, followed by the calling-convention
3695 // of operator(). The latter is in place to support the MSVC-like solution of
3696 // defining ALL of the possible conversions in regards to calling-convention.
3697 const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1);
3698 const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2);
3699
3700 if (Conv1FuncRet && Conv2FuncRet &&
3701 Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) {
3702 CallingConv Conv1CC = Conv1FuncRet->getCallConv();
3703 CallingConv Conv2CC = Conv2FuncRet->getCallConv();
3704
3705 CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator();
3706 const FunctionProtoType *CallOpProto =
3707 CallOp->getType()->getAs<FunctionProtoType>();
3708
3709 CallingConv CallOpCC =
3710 CallOp->getType()->castAs<FunctionType>()->getCallConv();
3711 CallingConv DefaultFree = S.Context.getDefaultCallingConvention(
3712 CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
3713 CallingConv DefaultMember = S.Context.getDefaultCallingConvention(
3714 CallOpProto->isVariadic(), /*IsCXXMethod=*/true);
3715
3716 CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC};
3717 for (CallingConv CC : PrefOrder) {
3718 if (Conv1CC == CC)
3719 return ImplicitConversionSequence::Better;
3720 if (Conv2CC == CC)
3721 return ImplicitConversionSequence::Worse;
3722 }
3723 }
3724
3725 return ImplicitConversionSequence::Indistinguishable;
3726}
3727
3728static bool hasDeprecatedStringLiteralToCharPtrConversion(
3729 const ImplicitConversionSequence &ICS) {
3730 return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
3731 (ICS.isUserDefined() &&
3732 ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
3733}
3734
3735/// CompareImplicitConversionSequences - Compare two implicit
3736/// conversion sequences to determine whether one is better than the
3737/// other or if they are indistinguishable (C++ 13.3.3.2).
3738static ImplicitConversionSequence::CompareKind
3739CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
3740 const ImplicitConversionSequence& ICS1,
3741 const ImplicitConversionSequence& ICS2)
3742{
3743 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
3744 // conversion sequences (as defined in 13.3.3.1)
3745 // -- a standard conversion sequence (13.3.3.1.1) is a better
3746 // conversion sequence than a user-defined conversion sequence or
3747 // an ellipsis conversion sequence, and
3748 // -- a user-defined conversion sequence (13.3.3.1.2) is a better
3749 // conversion sequence than an ellipsis conversion sequence
3750 // (13.3.3.1.3).
3751 //
3752 // C++0x [over.best.ics]p10:
3753 // For the purpose of ranking implicit conversion sequences as
3754 // described in 13.3.3.2, the ambiguous conversion sequence is
3755 // treated as a user-defined sequence that is indistinguishable
3756 // from any other user-defined conversion sequence.
3757
3758 // String literal to 'char *' conversion has been deprecated in C++03. It has
3759 // been removed from C++11. We still accept this conversion, if it happens at
3760 // the best viable function. Otherwise, this conversion is considered worse
3761 // than ellipsis conversion. Consider this as an extension; this is not in the
3762 // standard. For example:
3763 //
3764 // int &f(...); // #1
3765 // void f(char*); // #2
3766 // void g() { int &r = f("foo"); }
3767 //
3768 // In C++03, we pick #2 as the best viable function.
3769 // In C++11, we pick #1 as the best viable function, because ellipsis
3770 // conversion is better than string-literal to char* conversion (since there
3771 // is no such conversion in C++11). If there was no #1 at all or #1 couldn't
3772 // convert arguments, #2 would be the best viable function in C++11.
3773 // If the best viable function has this conversion, a warning will be issued
3774 // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
3775
3776 if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
3777 hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
3778 hasDeprecatedStringLiteralToCharPtrConversion(ICS2))
3779 return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
3780 ? ImplicitConversionSequence::Worse
3781 : ImplicitConversionSequence::Better;
3782
3783 if (ICS1.getKindRank() < ICS2.getKindRank())
3784 return ImplicitConversionSequence::Better;
3785 if (ICS2.getKindRank() < ICS1.getKindRank())
3786 return ImplicitConversionSequence::Worse;
3787
3788 // The following checks require both conversion sequences to be of
3789 // the same kind.
3790 if (ICS1.getKind() != ICS2.getKind())
3791 return ImplicitConversionSequence::Indistinguishable;
3792
3793 ImplicitConversionSequence::CompareKind Result =
3794 ImplicitConversionSequence::Indistinguishable;
3795
3796 // Two implicit conversion sequences of the same form are
3797 // indistinguishable conversion sequences unless one of the
3798 // following rules apply: (C++ 13.3.3.2p3):
3799
3800 // List-initialization sequence L1 is a better conversion sequence than
3801 // list-initialization sequence L2 if:
3802 // - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
3803 // if not that,
3804 // - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T",
3805 // and N1 is smaller than N2.,
3806 // even if one of the other rules in this paragraph would otherwise apply.
3807 if (!ICS1.isBad()) {
3808 if (ICS1.isStdInitializerListElement() &&
3809 !ICS2.isStdInitializerListElement())
3810 return ImplicitConversionSequence::Better;
3811 if (!ICS1.isStdInitializerListElement() &&
3812 ICS2.isStdInitializerListElement())
3813 return ImplicitConversionSequence::Worse;
3814 }
3815
3816 if (ICS1.isStandard())
3817 // Standard conversion sequence S1 is a better conversion sequence than
3818 // standard conversion sequence S2 if [...]
3819 Result = CompareStandardConversionSequences(S, Loc,
3820 ICS1.Standard, ICS2.Standard);
3821 else if (ICS1.isUserDefined()) {
3822 // User-defined conversion sequence U1 is a better conversion
3823 // sequence than another user-defined conversion sequence U2 if
3824 // they contain the same user-defined conversion function or
3825 // constructor and if the second standard conversion sequence of
3826 // U1 is better than the second standard conversion sequence of
3827 // U2 (C++ 13.3.3.2p3).
3828 if (ICS1.UserDefined.ConversionFunction ==
3829 ICS2.UserDefined.ConversionFunction)
3830 Result = CompareStandardConversionSequences(S, Loc,
3831 ICS1.UserDefined.After,
3832 ICS2.UserDefined.After);
3833 else
3834 Result = compareConversionFunctions(S,
3835 ICS1.UserDefined.ConversionFunction,
3836 ICS2.UserDefined.ConversionFunction);
3837 }
3838
3839 return Result;
3840}
3841
3842// Per 13.3.3.2p3, compare the given standard conversion sequences to
3843// determine if one is a proper subset of the other.
3844static ImplicitConversionSequence::CompareKind
3845compareStandardConversionSubsets(ASTContext &Context,
3846 const StandardConversionSequence& SCS1,
3847 const StandardConversionSequence& SCS2) {
3848 ImplicitConversionSequence::CompareKind Result
3849 = ImplicitConversionSequence::Indistinguishable;
3850
3851 // the identity conversion sequence is considered to be a subsequence of
3852 // any non-identity conversion sequence
3853 if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
3854 return ImplicitConversionSequence::Better;
3855 else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
3856 return ImplicitConversionSequence::Worse;
3857
3858 if (SCS1.Second != SCS2.Second) {
3859 if (SCS1.Second == ICK_Identity)
3860 Result = ImplicitConversionSequence::Better;
3861 else if (SCS2.Second == ICK_Identity)
3862 Result = ImplicitConversionSequence::Worse;
3863 else
3864 return ImplicitConversionSequence::Indistinguishable;
3865 } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
3866 return ImplicitConversionSequence::Indistinguishable;
3867
3868 if (SCS1.Third == SCS2.Third) {
3869 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
3870 : ImplicitConversionSequence::Indistinguishable;
3871 }
3872
3873 if (SCS1.Third == ICK_Identity)
3874 return Result == ImplicitConversionSequence::Worse
3875 ? ImplicitConversionSequence::Indistinguishable
3876 : ImplicitConversionSequence::Better;
3877
3878 if (SCS2.Third == ICK_Identity)
3879 return Result == ImplicitConversionSequence::Better
3880 ? ImplicitConversionSequence::Indistinguishable
3881 : ImplicitConversionSequence::Worse;
3882
3883 return ImplicitConversionSequence::Indistinguishable;
3884}
3885
3886/// Determine whether one of the given reference bindings is better
3887/// than the other based on what kind of bindings they are.
3888static bool
3889isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
3890 const StandardConversionSequence &SCS2) {
3891 // C++0x [over.ics.rank]p3b4:
3892 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
3893 // implicit object parameter of a non-static member function declared
3894 // without a ref-qualifier, and *either* S1 binds an rvalue reference
3895 // to an rvalue and S2 binds an lvalue reference *or S1 binds an
3896 // lvalue reference to a function lvalue and S2 binds an rvalue
3897 // reference*.
3898 //
3899 // FIXME: Rvalue references. We're going rogue with the above edits,
3900 // because the semantics in the current C++0x working paper (N3225 at the
3901 // time of this writing) break the standard definition of std::forward
3902 // and std::reference_wrapper when dealing with references to functions.
3903 // Proposed wording changes submitted to CWG for consideration.
3904 if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
3905 SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
3906 return false;
3907
3908 return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
3909 SCS2.IsLvalueReference) ||
3910 (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
3911 !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
3912}
3913
3914enum class FixedEnumPromotion {
3915 None,
3916 ToUnderlyingType,
3917 ToPromotedUnderlyingType
3918};
3919
3920/// Returns kind of fixed enum promotion the \a SCS uses.
3921static FixedEnumPromotion
3922getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {
3923
3924 if (SCS.Second != ICK_Integral_Promotion)
3925 return FixedEnumPromotion::None;
3926
3927 QualType FromType = SCS.getFromType();
3928 if (!FromType->isEnumeralType())
3929 return FixedEnumPromotion::None;
3930
3931 EnumDecl *Enum = FromType->castAs<EnumType>()->getDecl();
3932 if (!Enum->isFixed())
3933 return FixedEnumPromotion::None;
3934
3935 QualType UnderlyingType = Enum->getIntegerType();
3936 if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
3937 return FixedEnumPromotion::ToUnderlyingType;
3938
3939 return FixedEnumPromotion::ToPromotedUnderlyingType;
3940}
3941
3942/// CompareStandardConversionSequences - Compare two standard
3943/// conversion sequences to determine whether one is better than the
3944/// other or if they are indistinguishable (C++ 13.3.3.2p3).
3945static ImplicitConversionSequence::CompareKind
3946CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
3947 const StandardConversionSequence& SCS1,
3948 const StandardConversionSequence& SCS2)
3949{
3950 // Standard conversion sequence S1 is a better conversion sequence
3951 // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
3952
3953 // -- S1 is a proper subsequence of S2 (comparing the conversion
3954 // sequences in the canonical form defined by 13.3.3.1.1,
3955 // excluding any Lvalue Transformation; the identity conversion
3956 // sequence is considered to be a subsequence of any
3957 // non-identity conversion sequence) or, if not that,
3958 if (ImplicitConversionSequence::CompareKind CK
3959 = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
3960 return CK;
3961
3962 // -- the rank of S1 is better than the rank of S2 (by the rules
3963 // defined below), or, if not that,
3964 ImplicitConversionRank Rank1 = SCS1.getRank();
3965 ImplicitConversionRank Rank2 = SCS2.getRank();
3966 if (Rank1 < Rank2)
3967 return ImplicitConversionSequence::Better;
3968 else if (Rank2 < Rank1)
3969 return ImplicitConversionSequence::Worse;
3970
3971 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
3972 // are indistinguishable unless one of the following rules
3973 // applies:
3974
3975 // A conversion that is not a conversion of a pointer, or
3976 // pointer to member, to bool is better than another conversion
3977 // that is such a conversion.
3978 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
3979 return SCS2.isPointerConversionToBool()
3980 ? ImplicitConversionSequence::Better
3981 : ImplicitConversionSequence::Worse;
3982
3983 // C++14 [over.ics.rank]p4b2:
3984 // This is retroactively applied to C++11 by CWG 1601.
3985 //
3986 // A conversion that promotes an enumeration whose underlying type is fixed
3987 // to its underlying type is better than one that promotes to the promoted
3988 // underlying type, if the two are different.
3989 FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
3990 FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
3991 if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
3992 FEP1 != FEP2)
3993 return FEP1 == FixedEnumPromotion::ToUnderlyingType
3994 ? ImplicitConversionSequence::Better
3995 : ImplicitConversionSequence::Worse;
3996
3997 // C++ [over.ics.rank]p4b2:
3998 //
3999 // If class B is derived directly or indirectly from class A,
4000 // conversion of B* to A* is better than conversion of B* to
4001 // void*, and conversion of A* to void* is better than conversion
4002 // of B* to void*.
4003 bool SCS1ConvertsToVoid
4004 = SCS1.isPointerConversionToVoidPointer(S.Context);
4005 bool SCS2ConvertsToVoid
4006 = SCS2.isPointerConversionToVoidPointer(S.Context);
4007 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
4008 // Exactly one of the conversion sequences is a conversion to
4009 // a void pointer; it's the worse conversion.
4010 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
4011 : ImplicitConversionSequence::Worse;
4012 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
4013 // Neither conversion sequence converts to a void pointer; compare
4014 // their derived-to-base conversions.
4015 if (ImplicitConversionSequence::CompareKind DerivedCK
4016 = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
4017 return DerivedCK;
4018 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
4019 !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
4020 // Both conversion sequences are conversions to void
4021 // pointers. Compare the source types to determine if there's an
4022 // inheritance relationship in their sources.
4023 QualType FromType1 = SCS1.getFromType();
4024 QualType FromType2 = SCS2.getFromType();
4025
4026 // Adjust the types we're converting from via the array-to-pointer
4027 // conversion, if we need to.
4028 if (SCS1.First == ICK_Array_To_Pointer)
4029 FromType1 = S.Context.getArrayDecayedType(FromType1);
4030 if (SCS2.First == ICK_Array_To_Pointer)
4031 FromType2 = S.Context.getArrayDecayedType(FromType2);
4032
4033 QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
4034 QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
4035
4036 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4037 return ImplicitConversionSequence::Better;
4038 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4039 return ImplicitConversionSequence::Worse;
4040
4041 // Objective-C++: If one interface is more specific than the
4042 // other, it is the better one.
4043 const ObjCObjectPointerType* FromObjCPtr1
4044 = FromType1->getAs<ObjCObjectPointerType>();
4045 const ObjCObjectPointerType* FromObjCPtr2
4046 = FromType2->getAs<ObjCObjectPointerType>();
4047 if (FromObjCPtr1 && FromObjCPtr2) {
4048 bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
4049 FromObjCPtr2);
4050 bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
4051 FromObjCPtr1);
4052 if (AssignLeft != AssignRight) {
4053 return AssignLeft? ImplicitConversionSequence::Better
4054 : ImplicitConversionSequence::Worse;
4055 }
4056 }
4057 }
4058
4059 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4060 // Check for a better reference binding based on the kind of bindings.
4061 if (isBetterReferenceBindingKind(SCS1, SCS2))
4062 return ImplicitConversionSequence::Better;
4063 else if (isBetterReferenceBindingKind(SCS2, SCS1))
4064 return ImplicitConversionSequence::Worse;
4065 }
4066
4067 // Compare based on qualification conversions (C++ 13.3.3.2p3,
4068 // bullet 3).
4069 if (ImplicitConversionSequence::CompareKind QualCK
4070 = CompareQualificationConversions(S, SCS1, SCS2))
4071 return QualCK;
4072
4073 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4074 // C++ [over.ics.rank]p3b4:
4075 // -- S1 and S2 are reference bindings (8.5.3), and the types to
4076 // which the references refer are the same type except for
4077 // top-level cv-qualifiers, and the type to which the reference
4078 // initialized by S2 refers is more cv-qualified than the type
4079 // to which the reference initialized by S1 refers.
4080 QualType T1 = SCS1.getToType(2);
4081 QualType T2 = SCS2.getToType(2);
4082 T1 = S.Context.getCanonicalType(T1);
4083 T2 = S.Context.getCanonicalType(T2);
4084 Qualifiers T1Quals, T2Quals;
4085 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4086 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4087 if (UnqualT1 == UnqualT2) {
4088 // Objective-C++ ARC: If the references refer to objects with different
4089 // lifetimes, prefer bindings that don't change lifetime.
4090 if (SCS1.ObjCLifetimeConversionBinding !=
4091 SCS2.ObjCLifetimeConversionBinding) {
4092 return SCS1.ObjCLifetimeConversionBinding
4093 ? ImplicitConversionSequence::Worse
4094 : ImplicitConversionSequence::Better;
4095 }
4096
4097 // If the type is an array type, promote the element qualifiers to the
4098 // type for comparison.
4099 if (isa<ArrayType>(T1) && T1Quals)
4100 T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
4101 if (isa<ArrayType>(T2) && T2Quals)
4102 T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
4103 if (T2.isMoreQualifiedThan(T1))
4104 return ImplicitConversionSequence::Better;
4105 if (T1.isMoreQualifiedThan(T2))
4106 return ImplicitConversionSequence::Worse;
4107 }
4108 }
4109
4110 // In Microsoft mode (below 19.28), prefer an integral conversion to a
4111 // floating-to-integral conversion if the integral conversion
4112 // is between types of the same size.
4113 // For example:
4114 // void f(float);
4115 // void f(int);
4116 // int main {
4117 // long a;
4118 // f(a);
4119 // }
4120 // Here, MSVC will call f(int) instead of generating a compile error
4121 // as clang will do in standard mode.
4122 if (S.getLangOpts().MSVCCompat &&
4123 !S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) &&
4124 SCS1.Second == ICK_Integral_Conversion &&
4125 SCS2.Second == ICK_Floating_Integral &&
4126 S.Context.getTypeSize(SCS1.getFromType()) ==
4127 S.Context.getTypeSize(SCS1.getToType(2)))
4128 return ImplicitConversionSequence::Better;
4129
4130 // Prefer a compatible vector conversion over a lax vector conversion
4131 // For example:
4132 //
4133 // typedef float __v4sf __attribute__((__vector_size__(16)));
4134 // void f(vector float);
4135 // void f(vector signed int);
4136 // int main() {
4137 // __v4sf a;
4138 // f(a);
4139 // }
4140 // Here, we'd like to choose f(vector float) and not
4141 // report an ambiguous call error
4142 if (SCS1.Second == ICK_Vector_Conversion &&
4143 SCS2.Second == ICK_Vector_Conversion) {
4144 bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4145 SCS1.getFromType(), SCS1.getToType(2));
4146 bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4147 SCS2.getFromType(), SCS2.getToType(2));
4148
4149 if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
4150 return SCS1IsCompatibleVectorConversion
4151 ? ImplicitConversionSequence::Better
4152 : ImplicitConversionSequence::Worse;
4153 }
4154
4155 if (SCS1.Second == ICK_SVE_Vector_Conversion &&
4156 SCS2.Second == ICK_SVE_Vector_Conversion) {
4157 bool SCS1IsCompatibleSVEVectorConversion =
4158 S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2));
4159 bool SCS2IsCompatibleSVEVectorConversion =
4160 S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2));
4161
4162 if (SCS1IsCompatibleSVEVectorConversion !=
4163 SCS2IsCompatibleSVEVectorConversion)
4164 return SCS1IsCompatibleSVEVectorConversion
4165 ? ImplicitConversionSequence::Better
4166 : ImplicitConversionSequence::Worse;
4167 }
4168
4169 return ImplicitConversionSequence::Indistinguishable;
4170}
4171
4172/// CompareQualificationConversions - Compares two standard conversion
4173/// sequences to determine whether they can be ranked based on their
4174/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
4175static ImplicitConversionSequence::CompareKind
4176CompareQualificationConversions(Sema &S,
4177 const StandardConversionSequence& SCS1,
4178 const StandardConversionSequence& SCS2) {
4179 // C++ 13.3.3.2p3:
4180 // -- S1 and S2 differ only in their qualification conversion and
4181 // yield similar types T1 and T2 (C++ 4.4), respectively, and the
4182 // cv-qualification signature of type T1 is a proper subset of
4183 // the cv-qualification signature of type T2, and S1 is not the
4184 // deprecated string literal array-to-pointer conversion (4.2).
4185 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
4186 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
4187 return ImplicitConversionSequence::Indistinguishable;
4188
4189 // FIXME: the example in the standard doesn't use a qualification
4190 // conversion (!)
4191 QualType T1 = SCS1.getToType(2);
4192 QualType T2 = SCS2.getToType(2);
4193 T1 = S.Context.getCanonicalType(T1);
4194 T2 = S.Context.getCanonicalType(T2);
4195 assert(!T1->isReferenceType() && !T2->isReferenceType())(static_cast<void> (0));
4196 Qualifiers T1Quals, T2Quals;
4197 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4198 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4199
4200 // If the types are the same, we won't learn anything by unwrapping
4201 // them.
4202 if (UnqualT1 == UnqualT2)
4203 return ImplicitConversionSequence::Indistinguishable;
4204
4205 ImplicitConversionSequence::CompareKind Result
4206 = ImplicitConversionSequence::Indistinguishable;
4207
4208 // Objective-C++ ARC:
4209 // Prefer qualification conversions not involving a change in lifetime
4210 // to qualification conversions that do not change lifetime.
4211 if (SCS1.QualificationIncludesObjCLifetime !=
4212 SCS2.QualificationIncludesObjCLifetime) {
4213 Result = SCS1.QualificationIncludesObjCLifetime
4214 ? ImplicitConversionSequence::Worse
4215 : ImplicitConversionSequence::Better;
4216 }
4217
4218 while (S.Context.UnwrapSimilarTypes(T1, T2)) {
4219 // Within each iteration of the loop, we check the qualifiers to
4220 // determine if this still looks like a qualification
4221 // conversion. Then, if all is well, we unwrap one more level of
4222 // pointers or pointers-to-members and do it all again
4223 // until there are no more pointers or pointers-to-members left
4224 // to unwrap. This essentially mimics what
4225 // IsQualificationConversion does, but here we're checking for a
4226 // strict subset of qualifiers.
4227 if (T1.getQualifiers().withoutObjCLifetime() ==
4228 T2.getQualifiers().withoutObjCLifetime())
4229 // The qualifiers are the same, so this doesn't tell us anything
4230 // about how the sequences rank.
4231 // ObjC ownership quals are omitted above as they interfere with
4232 // the ARC overload rule.
4233 ;
4234 else if (T2.isMoreQualifiedThan(T1)) {
4235 // T1 has fewer qualifiers, so it could be the better sequence.
4236 if (Result == ImplicitConversionSequence::Worse)
4237 // Neither has qualifiers that are a subset of the other's
4238 // qualifiers.
4239 return ImplicitConversionSequence::Indistinguishable;
4240
4241 Result = ImplicitConversionSequence::Better;
4242 } else if (T1.isMoreQualifiedThan(T2)) {
4243 // T2 has fewer qualifiers, so it could be the better sequence.
4244 if (Result == ImplicitConversionSequence::Better)
4245 // Neither has qualifiers that are a subset of the other's
4246 // qualifiers.
4247 return ImplicitConversionSequence::Indistinguishable;
4248
4249 Result = ImplicitConversionSequence::Worse;
4250 } else {
4251 // Qualifiers are disjoint.
4252 return ImplicitConversionSequence::Indistinguishable;
4253 }
4254
4255 // If the types after this point are equivalent, we're done.
4256 if (S.Context.hasSameUnqualifiedType(T1, T2))
4257 break;
4258 }
4259
4260 // Check that the winning standard conversion sequence isn't using
4261 // the deprecated string literal array to pointer conversion.
4262 switch (Result) {
4263 case ImplicitConversionSequence::Better:
4264 if (SCS1.DeprecatedStringLiteralToCharPtr)
4265 Result = ImplicitConversionSequence::Indistinguishable;
4266 break;
4267
4268 case ImplicitConversionSequence::Indistinguishable:
4269 break;
4270
4271 case ImplicitConversionSequence::Worse:
4272 if (SCS2.DeprecatedStringLiteralToCharPtr)
4273 Result = ImplicitConversionSequence::Indistinguishable;
4274 break;
4275 }
4276
4277 return Result;
4278}
4279
4280/// CompareDerivedToBaseConversions - Compares two standard conversion
4281/// sequences to determine whether they can be ranked based on their
4282/// various kinds of derived-to-base conversions (C++
4283/// [over.ics.rank]p4b3). As part of these checks, we also look at
4284/// conversions between Objective-C interface types.
4285static ImplicitConversionSequence::CompareKind
4286CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
4287 const StandardConversionSequence& SCS1,
4288 const StandardConversionSequence& SCS2) {
4289 QualType FromType1 = SCS1.getFromType();
4290 QualType ToType1 = SCS1.getToType(1);
4291 QualType FromType2 = SCS2.getFromType();
4292 QualType ToType2 = SCS2.getToType(1);
4293
4294 // Adjust the types we're converting from via the array-to-pointer
4295 // conversion, if we need to.
4296 if (SCS1.First == ICK_Array_To_Pointer)
4297 FromType1 = S.Context.getArrayDecayedType(FromType1);
4298 if (SCS2.First == ICK_Array_To_Pointer)
4299 FromType2 = S.Context.getArrayDecayedType(FromType2);
4300
4301 // Canonicalize all of the types.
4302 FromType1 = S.Context.getCanonicalType(FromType1);
4303 ToType1 = S.Context.getCanonicalType(ToType1);
4304 FromType2 = S.Context.getCanonicalType(FromType2);
4305 ToType2 = S.Context.getCanonicalType(ToType2);
4306
4307 // C++ [over.ics.rank]p4b3:
4308 //
4309 // If class B is derived directly or indirectly from class A and
4310 // class C is derived directly or indirectly from B,
4311 //
4312 // Compare based on pointer conversions.
4313 if (SCS1.Second == ICK_Pointer_Conversion &&
4314 SCS2.Second == ICK_Pointer_Conversion &&
4315 /*FIXME: Remove if Objective-C id conversions get their own rank*/
4316 FromType1->isPointerType() && FromType2->isPointerType() &&
4317 ToType1->isPointerType() && ToType2->isPointerType()) {
4318 QualType FromPointee1 =
4319 FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4320 QualType ToPointee1 =
4321 ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4322 QualType FromPointee2 =
4323 FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4324 QualType ToPointee2 =
4325 ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4326
4327 // -- conversion of C* to B* is better than conversion of C* to A*,
4328 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4329 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4330 return ImplicitConversionSequence::Better;
4331 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4332 return ImplicitConversionSequence::Worse;
4333 }
4334
4335 // -- conversion of B* to A* is better than conversion of C* to A*,
4336 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
4337 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4338 return ImplicitConversionSequence::Better;
4339 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4340 return ImplicitConversionSequence::Worse;
4341 }
4342 } else if (SCS1.Second == ICK_Pointer_Conversion &&
4343 SCS2.Second == ICK_Pointer_Conversion) {
4344 const ObjCObjectPointerType *FromPtr1
4345 = FromType1->getAs<ObjCObjectPointerType>();
4346 const ObjCObjectPointerType *FromPtr2
4347 = FromType2->getAs<ObjCObjectPointerType>();
4348 const ObjCObjectPointerType *ToPtr1
4349 = ToType1->getAs<ObjCObjectPointerType>();
4350 const ObjCObjectPointerType *ToPtr2
4351 = ToType2->getAs<ObjCObjectPointerType>();
4352
4353 if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
4354 // Apply the same conversion ranking rules for Objective-C pointer types
4355 // that we do for C++ pointers to class types. However, we employ the
4356 // Objective-C pseudo-subtyping relationship used for assignment of
4357 // Objective-C pointer types.
4358 bool FromAssignLeft
4359 = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
4360 bool FromAssignRight
4361 = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
4362 bool ToAssignLeft
4363 = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
4364 bool ToAssignRight
4365 = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
4366
4367 // A conversion to an a non-id object pointer type or qualified 'id'
4368 // type is better than a conversion to 'id'.
4369 if (ToPtr1->isObjCIdType() &&
4370 (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
4371 return ImplicitConversionSequence::Worse;
4372 if (ToPtr2->isObjCIdType() &&
4373 (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
4374 return ImplicitConversionSequence::Better;
4375
4376 // A conversion to a non-id object pointer type is better than a
4377 // conversion to a qualified 'id' type
4378 if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
4379 return ImplicitConversionSequence::Worse;
4380 if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
4381 return ImplicitConversionSequence::Better;
4382
4383 // A conversion to an a non-Class object pointer type or qualified 'Class'
4384 // type is better than a conversion to 'Class'.
4385 if (ToPtr1->isObjCClassType() &&
4386 (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
4387 return ImplicitConversionSequence::Worse;
4388 if (ToPtr2->isObjCClassType() &&
4389 (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
4390 return ImplicitConversionSequence::Better;
4391
4392 // A conversion to a non-Class object pointer type is better than a
4393 // conversion to a qualified 'Class' type.
4394 if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
4395 return ImplicitConversionSequence::Worse;
4396 if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
4397 return ImplicitConversionSequence::Better;
4398
4399 // -- "conversion of C* to B* is better than conversion of C* to A*,"
4400 if (S.Context.hasSameType(FromType1, FromType2) &&
4401 !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
4402 (ToAssignLeft != ToAssignRight)) {
4403 if (FromPtr1->isSpecialized()) {
4404 // "conversion of B<A> * to B * is better than conversion of B * to
4405 // C *.
4406 bool IsFirstSame =
4407 FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
4408 bool IsSecondSame =
4409 FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
4410 if (IsFirstSame) {
4411 if (!IsSecondSame)
4412 return ImplicitConversionSequence::Better;
4413 } else if (IsSecondSame)
4414 return ImplicitConversionSequence::Worse;
4415 }
4416 return ToAssignLeft? ImplicitConversionSequence::Worse
4417 : ImplicitConversionSequence::Better;
4418 }
4419
4420 // -- "conversion of B* to A* is better than conversion of C* to A*,"
4421 if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
4422 (FromAssignLeft != FromAssignRight))
4423 return FromAssignLeft? ImplicitConversionSequence::Better
4424 : ImplicitConversionSequence::Worse;
4425 }
4426 }
4427
4428 // Ranking of member-pointer types.
4429 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
4430 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
4431 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
4432 const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
4433 const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
4434 const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
4435 const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
4436 const Type *FromPointeeType1 = FromMemPointer1->getClass();
4437 const Type *ToPointeeType1 = ToMemPointer1->getClass();
4438 const Type *FromPointeeType2 = FromMemPointer2->getClass();
4439 const Type *ToPointeeType2 = ToMemPointer2->getClass();
4440 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
4441 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
4442 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
4443 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
4444 // conversion of A::* to B::* is better than conversion of A::* to C::*,
4445 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4446 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4447 return ImplicitConversionSequence::Worse;
4448 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4449 return ImplicitConversionSequence::Better;
4450 }
4451 // conversion of B::* to C::* is better than conversion of A::* to C::*
4452 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
4453 if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4454 return ImplicitConversionSequence::Better;
4455 else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4456 return ImplicitConversionSequence::Worse;
4457 }
4458 }
4459
4460 if (SCS1.Second == ICK_Derived_To_Base) {
4461 // -- conversion of C to B is better than conversion of C to A,
4462 // -- binding of an expression of type C to a reference of type
4463 // B& is better than binding an expression of type C to a
4464 // reference of type A&,
4465 if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4466 !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4467 if (S.IsDerivedFrom(Loc, ToType1, ToType2))
4468 return ImplicitConversionSequence::Better;
4469 else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
4470 return ImplicitConversionSequence::Worse;
4471 }
4472
4473 // -- conversion of B to A is better than conversion of C to A.
4474 // -- binding of an expression of type B to a reference of type
4475 // A& is better than binding an expression of type C to a
4476 // reference of type A&,
4477 if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4478 S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4479 if (S.IsDerivedFrom(Loc, FromType2, FromType1))
4480 return ImplicitConversionSequence::Better;
4481 else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
4482 return ImplicitConversionSequence::Worse;
4483 }
4484 }
4485
4486 return ImplicitConversionSequence::Indistinguishable;
4487}
4488
4489/// Determine whether the given type is valid, e.g., it is not an invalid
4490/// C++ class.
4491static bool isTypeValid(QualType T) {
4492 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
4493 return !Record->isInvalidDecl();
4494
4495 return true;
4496}
4497
4498static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
4499 if (!T.getQualifiers().hasUnaligned())
4500 return T;
4501
4502 Qualifiers Q;
4503 T = Ctx.getUnqualifiedArrayType(T, Q);
4504 Q.removeUnaligned();
4505 return Ctx.getQualifiedType(T, Q);
4506}
4507
4508/// CompareReferenceRelationship - Compare the two types T1 and T2 to
4509/// determine whether they are reference-compatible,
4510/// reference-related, or incompatible, for use in C++ initialization by
4511/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
4512/// type, and the first type (T1) is the pointee type of the reference
4513/// type being initialized.
4514Sema::ReferenceCompareResult
4515Sema::CompareReferenceRelationship(SourceLocation Loc,
4516 QualType OrigT1, QualType OrigT2,
4517 ReferenceConversions *ConvOut) {
4518 assert(!OrigT1->isReferenceType() &&(static_cast<void> (0))
4519 "T1 must be the pointee type of the reference type")(static_cast<void> (0));
4520 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type")(static_cast<void> (0));
4521
4522 QualType T1 = Context.getCanonicalType(OrigT1);
4523 QualType T2 = Context.getCanonicalType(OrigT2);
4524 Qualifiers T1Quals, T2Quals;
4525 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
4526 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
4527
4528 ReferenceConversions ConvTmp;
4529 ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
4530 Conv = ReferenceConversions();
4531
4532 // C++2a [dcl.init.ref]p4:
4533 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
4534 // reference-related to "cv2 T2" if T1 is similar to T2, or
4535 // T1 is a base class of T2.
4536 // "cv1 T1" is reference-compatible with "cv2 T2" if
4537 // a prvalue of type "pointer to cv2 T2" can be converted to the type
4538 // "pointer to cv1 T1" via a standard conversion sequence.
4539
4540 // Check for standard conversions we can apply to pointers: derived-to-base
4541 // conversions, ObjC pointer conversions, and function pointer conversions.
4542 // (Qualification conversions are checked last.)
4543 QualType ConvertedT2;
4544 if (UnqualT1 == UnqualT2) {
4545 // Nothing to do.
4546 } else if (isCompleteType(Loc, OrigT2) &&
4547 isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
4548 IsDerivedFrom(Loc, UnqualT2, UnqualT1))
4549 Conv |= ReferenceConversions::DerivedToBase;
4550 else if (UnqualT1->isObjCObjectOrInterfaceType() &&
4551 UnqualT2->isObjCObjectOrInterfaceType() &&
4552 Context.canBindObjCObjectType(UnqualT1, UnqualT2))
4553 Conv |= ReferenceConversions::ObjC;
4554 else if (UnqualT2->isFunctionType() &&
4555 IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
4556 Conv |= ReferenceConversions::Function;
4557 // No need to check qualifiers; function types don't have them.
4558 return Ref_Compatible;
4559 }
4560 bool ConvertedReferent = Conv != 0;
4561
4562 // We can have a qualification conversion. Compute whether the types are
4563 // similar at the same time.
4564 bool PreviousToQualsIncludeConst = true;
4565 bool TopLevel = true;
4566 do {
4567 if (T1 == T2)
4568 break;
4569
4570 // We will need a qualification conversion.
4571 Conv |= ReferenceConversions::Qualification;
4572
4573 // Track whether we performed a qualification conversion anywhere other
4574 // than the top level. This matters for ranking reference bindings in
4575 // overload resolution.
4576 if (!TopLevel)
4577 Conv |= ReferenceConversions::NestedQualification;
4578
4579 // MS compiler ignores __unaligned qualifier for references; do the same.
4580 T1 = withoutUnaligned(Context, T1);
4581 T2 = withoutUnaligned(Context, T2);
4582
4583 // If we find a qualifier mismatch, the types are not reference-compatible,
4584 // but are still be reference-related if they're similar.
4585 bool ObjCLifetimeConversion = false;
4586 if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
4587 PreviousToQualsIncludeConst,
4588 ObjCLifetimeConversion))
4589 return (ConvertedReferent || Context.hasSimilarType(T1, T2))
4590 ? Ref_Related
4591 : Ref_Incompatible;
4592
4593 // FIXME: Should we track this for any level other than the first?
4594 if (ObjCLifetimeConversion)
4595 Conv |= ReferenceConversions::ObjCLifetime;
4596
4597 TopLevel = false;
4598 } while (Context.UnwrapSimilarTypes(T1, T2));
4599
4600 // At this point, if the types are reference-related, we must either have the
4601 // same inner type (ignoring qualifiers), or must have already worked out how
4602 // to convert the referent.
4603 return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
4604 ? Ref_Compatible
4605 : Ref_Incompatible;
4606}
4607
4608/// Look for a user-defined conversion to a value reference-compatible
4609/// with DeclType. Return true if something definite is found.
4610static bool
4611FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
4612 QualType DeclType, SourceLocation DeclLoc,
4613 Expr *Init, QualType T2, bool AllowRvalues,
4614 bool AllowExplicit) {
4615 assert(T2->isRecordType() && "Can only find conversions of record types.")(static_cast<void> (0));
4616 auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());
4617
4618 OverloadCandidateSet CandidateSet(
4619 DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4620 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4621 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4622 NamedDecl *D = *I;
4623 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4624 if (isa<UsingShadowDecl>(D))
4625 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4626
4627 FunctionTemplateDecl *ConvTemplate
4628 = dyn_cast<FunctionTemplateDecl>(D);
4629 CXXConversionDecl *Conv;
4630 if (ConvTemplate)
4631 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4632 else
4633 Conv = cast<CXXConversionDecl>(D);
4634
4635 if (AllowRvalues) {
4636 // If we are initializing an rvalue reference, don't permit conversion
4637 // functions that return lvalues.
4638 if (!ConvTemplate && DeclType->isRValueReferenceType()) {
4639 const ReferenceType *RefType
4640 = Conv->getConversionType()->getAs<LValueReferenceType>();
4641 if (RefType && !RefType->getPointeeType()->isFunctionType())
4642 continue;
4643 }
4644
4645 if (!ConvTemplate &&
4646 S.CompareReferenceRelationship(
4647 DeclLoc,
4648 Conv->getConversionType()
4649 .getNonReferenceType()
4650 .getUnqualifiedType(),
4651 DeclType.getNonReferenceType().getUnqualifiedType()) ==
4652 Sema::Ref_Incompatible)
4653 continue;
4654 } else {
4655 // If the conversion function doesn't return a reference type,
4656 // it can't be considered for this conversion. An rvalue reference
4657 // is only acceptable if its referencee is a function type.
4658
4659 const ReferenceType *RefType =
4660 Conv->getConversionType()->getAs<ReferenceType>();
4661 if (!RefType ||
4662 (!RefType->isLValueReferenceType() &&
4663 !RefType->getPointeeType()->isFunctionType()))
4664 continue;
4665 }
4666
4667 if (ConvTemplate)
4668 S.AddTemplateConversionCandidate(
4669 ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4670 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4671 else
4672 S.AddConversionCandidate(
4673 Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4674 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4675 }
4676
4677 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4678
4679 OverloadCandidateSet::iterator Best;
4680 switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
4681 case OR_Success:
4682 // C++ [over.ics.ref]p1:
4683 //
4684 // [...] If the parameter binds directly to the result of
4685 // applying a conversion function to the argument
4686 // expression, the implicit conversion sequence is a
4687 // user-defined conversion sequence (13.3.3.1.2), with the
4688 // second standard conversion sequence either an identity
4689 // conversion or, if the conversion function returns an
4690 // entity of a type that is a derived class of the parameter
4691 // type, a derived-to-base Conversion.
4692 if (!Best->FinalConversion.DirectBinding)
4693 return false;
4694
4695 ICS.setUserDefined();
4696 ICS.UserDefined.Before = Best->Conversions[0].Standard;
4697 ICS.UserDefined.After = Best->FinalConversion;
4698 ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
4699 ICS.UserDefined.ConversionFunction = Best->Function;
4700 ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
4701 ICS.UserDefined.EllipsisConversion = false;
4702 assert(ICS.UserDefined.After.ReferenceBinding &&(static_cast<void> (0))
4703 ICS.UserDefined.After.DirectBinding &&(static_cast<void> (0))
4704 "Expected a direct reference binding!")(static_cast<void> (0));
4705 return true;
4706
4707 case OR_Ambiguous:
4708 ICS.setAmbiguous();
4709 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
4710 Cand != CandidateSet.end(); ++Cand)
4711 if (Cand->Best)
4712 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
4713 return true;
4714
4715 case OR_No_Viable_Function:
4716 case OR_Deleted:
4717 // There was no suitable conversion, or we found a deleted
4718 // conversion; continue with other checks.
4719 return false;
4720 }
4721
4722 llvm_unreachable("Invalid OverloadResult!")__builtin_unreachable();
4723}
4724
4725/// Compute an implicit conversion sequence for reference
4726/// initialization.
4727static ImplicitConversionSequence
4728TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
4729 SourceLocation DeclLoc,
4730 bool SuppressUserConversions,
4731 bool AllowExplicit) {
4732 assert(DeclType->isReferenceType() && "Reference init needs a reference")(static_cast<void> (0));
4733
4734 // Most paths end in a failed conversion.
4735 ImplicitConversionSequence ICS;
4736 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4737
4738 QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
4739 QualType T2 = Init->getType();
4740
4741 // If the initializer is the address of an overloaded function, try
4742 // to resolve the overloaded function. If all goes well, T2 is the
4743 // type of the resulting function.
4744 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
4745 DeclAccessPair Found;
4746 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
4747 false, Found))
4748 T2 = Fn->getType();
4749 }
4750
4751 // Compute some basic properties of the types and the initializer.
4752 bool isRValRef = DeclType->isRValueReferenceType();
4753 Expr::Classification InitCategory = Init->Classify(S.Context);
4754
4755 Sema::ReferenceConversions RefConv;
4756 Sema::ReferenceCompareResult RefRelationship =
4757 S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);
4758
4759 auto SetAsReferenceBinding = [&](bool BindsDirectly) {
4760 ICS.setStandard();
4761 ICS.Standard.First = ICK_Identity;
4762 // FIXME: A reference binding can be a function conversion too. We should
4763 // consider that when ordering reference-to-function bindings.
4764 ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
4765 ? ICK_Derived_To_Base
4766 : (RefConv & Sema::ReferenceConversions::ObjC)
4767 ? ICK_Compatible_Conversion
4768 : ICK_Identity;
4769 // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
4770 // a reference binding that performs a non-top-level qualification
4771 // conversion as a qualification conversion, not as an identity conversion.
4772 ICS.Standard.Third = (RefConv &
4773 Sema::ReferenceConversions::NestedQualification)
4774 ? ICK_Qualification
4775 : ICK_Identity;
4776 ICS.Standard.setFromType(T2);
4777 ICS.Standard.setToType(0, T2);
4778 ICS.Standard.setToType(1, T1);
4779 ICS.Standard.setToType(2, T1);
4780 ICS.Standard.ReferenceBinding = true;
4781 ICS.Standard.DirectBinding = BindsDirectly;
4782 ICS.Standard.IsLvalueReference = !isRValRef;
4783 ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
4784 ICS.Standard.BindsToRvalue = InitCategory.isRValue();
4785 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4786 ICS.Standard.ObjCLifetimeConversionBinding =
4787 (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
4788 ICS.Standard.CopyConstructor = nullptr;
4789 ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
4790 };
4791
4792 // C++0x [dcl.init.ref]p5:
4793 // A reference to type "cv1 T1" is initialized by an expression
4794 // of type "cv2 T2" as follows:
4795
4796 // -- If reference is an lvalue reference and the initializer expression
4797 if (!isRValRef) {
4798 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is
4799 // reference-compatible with "cv2 T2," or
4800 //
4801 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
4802 if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
4803 // C++ [over.ics.ref]p1:
4804 // When a parameter of reference type binds directly (8.5.3)
4805 // to an argument expression, the implicit conversion sequence
4806 // is the identity conversion, unless the argument expression
4807 // has a type that is a derived class of the parameter type,
4808 // in which case the implicit conversion sequence is a
4809 // derived-to-base Conversion (13.3.3.1).
4810 SetAsReferenceBinding(/*BindsDirectly=*/true);
4811
4812 // Nothing more to do: the inaccessibility/ambiguity check for
4813 // derived-to-base conversions is suppressed when we're
4814 // computing the implicit conversion sequence (C++
4815 // [over.best.ics]p2).
4816 return ICS;
4817 }
4818
4819 // -- has a class type (i.e., T2 is a class type), where T1 is
4820 // not reference-related to T2, and can be implicitly
4821 // converted to an lvalue of type "cv3 T3," where "cv1 T1"
4822 // is reference-compatible with "cv3 T3" 92) (this
4823 // conversion is selected by enumerating the applicable
4824 // conversion functions (13.3.1.6) and choosing the best
4825 // one through overload resolution (13.3)),
4826 if (!SuppressUserConversions && T2->isRecordType() &&
4827 S.isCompleteType(DeclLoc, T2) &&
4828 RefRelationship == Sema::Ref_Incompatible) {
4829 if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4830 Init, T2, /*AllowRvalues=*/false,
4831 AllowExplicit))
4832 return ICS;
4833 }
4834 }
4835
4836 // -- Otherwise, the reference shall be an lvalue reference to a
4837 // non-volatile const type (i.e., cv1 shall be const), or the reference
4838 // shall be an rvalue reference.
4839 if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) {
4840 if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible)
4841 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
4842 return ICS;
4843 }
4844
4845 // -- If the initializer expression
4846 //
4847 // -- is an xvalue, class prvalue, array prvalue or function
4848 // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
4849 if (RefRelationship == Sema::Ref_Compatible &&
4850 (InitCategory.isXValue() ||
4851 (InitCategory.isPRValue() &&
4852 (T2->isRecordType() || T2->isArrayType())) ||
4853 (InitCategory.isLValue() && T2->isFunctionType()))) {
4854 // In C++11, this is always a direct binding. In C++98/03, it's a direct
4855 // binding unless we're binding to a class prvalue.
4856 // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
4857 // allow the use of rvalue references in C++98/03 for the benefit of
4858 // standard library implementors; therefore, we need the xvalue check here.
4859 SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
4860 !(InitCategory.isPRValue() || T2->isRecordType()));
4861 return ICS;
4862 }
4863
4864 // -- has a class type (i.e., T2 is a class type), where T1 is not
4865 // reference-related to T2, and can be implicitly converted to
4866 // an xvalue, class prvalue, or function lvalue of type
4867 // "cv3 T3", where "cv1 T1" is reference-compatible with
4868 // "cv3 T3",
4869 //
4870 // then the reference is bound to the value of the initializer
4871 // expression in the first case and to the result of the conversion
4872 // in the second case (or, in either case, to an appropriate base
4873 // class subobject).
4874 if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4875 T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
4876 FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4877 Init, T2, /*AllowRvalues=*/true,
4878 AllowExplicit)) {
4879 // In the second case, if the reference is an rvalue reference
4880 // and the second standard conversion sequence of the
4881 // user-defined conversion sequence includes an lvalue-to-rvalue
4882 // conversion, the program is ill-formed.
4883 if (ICS.isUserDefined() && isRValRef &&
4884 ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
4885 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4886
4887 return ICS;
4888 }
4889
4890 // A temporary of function type cannot be created; don't even try.
4891 if (T1->isFunctionType())
4892 return ICS;
4893
4894 // -- Otherwise, a temporary of type "cv1 T1" is created and
4895 // initialized from the initializer expression using the
4896 // rules for a non-reference copy initialization (8.5). The
4897 // reference is then bound to the temporary. If T1 is
4898 // reference-related to T2, cv1 must be the same
4899 // cv-qualification as, or greater cv-qualification than,
4900 // cv2; otherwise, the program is ill-formed.
4901 if (RefRelationship == Sema::Ref_Related) {
4902 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
4903 // we would be reference-compatible or reference-compatible with
4904 // added qualification. But that wasn't the case, so the reference
4905 // initialization fails.
4906 //
4907 // Note that we only want to check address spaces and cvr-qualifiers here.
4908 // ObjC GC, lifetime and unaligned qualifiers aren't important.
4909 Qualifiers T1Quals = T1.getQualifiers();
4910 Qualifiers T2Quals = T2.getQualifiers();
4911 T1Quals.removeObjCGCAttr();
4912 T1Quals.removeObjCLifetime();
4913 T2Quals.removeObjCGCAttr();
4914 T2Quals.removeObjCLifetime();
4915 // MS compiler ignores __unaligned qualifier for references; do the same.
4916 T1Quals.removeUnaligned();
4917 T2Quals.removeUnaligned();
4918 if (!T1Quals.compatiblyIncludes(T2Quals))
4919 return ICS;
4920 }
4921
4922 // If at least one of the types is a class type, the types are not
4923 // related, and we aren't allowed any user conversions, the
4924 // reference binding fails. This case is important for breaking
4925 // recursion, since TryImplicitConversion below will attempt to
4926 // create a temporary through the use of a copy constructor.
4927 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4928 (T1->isRecordType() || T2->isRecordType()))
4929 return ICS;
4930
4931 // If T1 is reference-related to T2 and the reference is an rvalue
4932 // reference, the initializer expression shall not be an lvalue.
4933 if (RefRelationship >= Sema::Ref_Related && isRValRef &&
4934 Init->Classify(S.Context).isLValue()) {
4935 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType);
4936 return ICS;
4937 }
4938
4939 // C++ [over.ics.ref]p2:
4940 // When a parameter of reference type is not bound directly to
4941 // an argument expression, the conversion sequence is the one
4942 // required to convert the argument expression to the
4943 // underlying type of the reference according to
4944 // 13.3.3.1. Conceptually, this conversion sequence corresponds
4945 // to copy-initializing a temporary of the underlying type with
4946 // the argument expression. Any difference in top-level
4947 // cv-qualification is subsumed by the initialization itself
4948 // and does not constitute a conversion.
4949 ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
4950 AllowedExplicit::None,
4951 /*InOverloadResolution=*/false,
4952 /*CStyle=*/false,
4953 /*AllowObjCWritebackConversion=*/false,
4954 /*AllowObjCConversionOnExplicit=*/false);
4955
4956 // Of course, that's still a reference binding.
4957 if (ICS.isStandard()) {
4958 ICS.Standard.ReferenceBinding = true;
4959 ICS.Standard.IsLvalueReference = !isRValRef;
4960 ICS.Standard.BindsToFunctionLvalue = false;
4961 ICS.Standard.BindsToRvalue = true;
4962 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4963 ICS.Standard.ObjCLifetimeConversionBinding = false;
4964 } else if (ICS.isUserDefined()) {
4965 const ReferenceType *LValRefType =
4966 ICS.UserDefined.ConversionFunction->getReturnType()
4967 ->getAs<LValueReferenceType>();
4968
4969 // C++ [over.ics.ref]p3:
4970 // Except for an implicit object parameter, for which see 13.3.1, a
4971 // standard conversion sequence cannot be formed if it requires [...]
4972 // binding an rvalue reference to an lvalue other than a function
4973 // lvalue.
4974 // Note that the function case is not possible here.
4975 if (isRValRef && LValRefType) {
4976 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4977 return ICS;
4978 }
4979
4980 ICS.UserDefined.After.ReferenceBinding = true;
4981 ICS.UserDefined.After.IsLvalueReference = !isRValRef;
4982 ICS.UserDefined.After.BindsToFunctionLvalue = false;
4983 ICS.UserDefined.After.BindsToRvalue = !LValRefType;
4984 ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4985 ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
4986 }
4987
4988 return ICS;
4989}
4990
4991static ImplicitConversionSequence
4992TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
4993 bool SuppressUserConversions,
4994 bool InOverloadResolution,
4995 bool AllowObjCWritebackConversion,
4996 bool AllowExplicit = false);
4997
4998/// TryListConversion - Try to copy-initialize a value of type ToType from the
4999/// initializer list From.
5000static ImplicitConversionSequence
5001TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
5002 bool SuppressUserConversions,
5003 bool InOverloadResolution,
5004 bool AllowObjCWritebackConversion) {
5005 // C++11 [over.ics.list]p1:
5006 // When an argument is an initializer list, it is not an expression and
5007 // special rules apply for converting it to a parameter type.
5008
5009 ImplicitConversionSequence Result;
5010 Result.setBad(BadConversionSequence::no_conversion, From, ToType);
5011
5012 // We need a complete type for what follows. Incomplete types can never be
5013 // initialized from init lists.
5014 if (!S.isCompleteType(From->getBeginLoc(), ToType))
5015 return Result;
5016
5017 // Per DR1467:
5018 // If the parameter type is a class X and the initializer list has a single
5019 // element of type cv U, where U is X or a class derived from X, the
5020 // implicit conversion sequence is the one required to convert the element
5021 // to the parameter type.
5022 //
5023 // Otherwise, if the parameter type is a character array [... ]
5024 // and the initializer list has a single element that is an
5025 // appropriately-typed string literal (8.5.2 [dcl.init.string]), the
5026 // implicit conversion sequence is the identity conversion.
5027 if (From->getNumInits() == 1) {
5028 if (ToType->isRecordType()) {
5029 QualType InitType = From->getInit(0)->getType();
5030 if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
5031 S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
5032 return TryCopyInitialization(S, From->getInit(0), ToType,
5033 SuppressUserConversions,
5034 InOverloadResolution,
5035 AllowObjCWritebackConversion);
5036 }
5037
5038 if (const auto *AT = S.Context.getAsArrayType(ToType)) {
5039 if (S.IsStringInit(From->getInit(0), AT)) {
5040 InitializedEntity Entity =
5041 InitializedEntity::InitializeParameter(S.Context, ToType,
5042 /*Consumed=*/false);
5043 if (S.CanPerformCopyInitialization(Entity, From)) {
5044 Result.setStandard();
5045 Result.Standard.setAsIdentityConversion();
5046 Result.Standard.setFromType(ToType);
5047 Result.Standard.setAllToTypes(ToType);
5048 return Result;
5049 }
5050 }
5051 }
5052 }
5053
5054 // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
5055 // C++11 [over.ics.list]p2:
5056 // If the parameter type is std::initializer_list<X> or "array of X" and
5057 // all the elements can be implicitly converted to X, the implicit
5058 // conversion sequence is the worst conversion necessary to convert an
5059 // element of the list to X.
5060 //
5061 // C++14 [over.ics.list]p3:
5062 // Otherwise, if the parameter type is "array of N X", if the initializer
5063 // list has exactly N elements or if it has fewer than N elements and X is
5064 // default-constructible, and if all the elements of the initializer list
5065 // can be implicitly converted to X, the implicit conversion sequence is
5066 // the worst conversion necessary to convert an element of the list to X.
5067 //
5068 // FIXME: We're missing a lot of these checks.
5069 bool toStdInitializerList = false;
5070 QualType X;
5071 if (ToType->isArrayType())
5072 X = S.Context.getAsArrayType(ToType)->getElementType();
5073 else
5074 toStdInitializerList = S.isStdInitializerList(ToType, &X);
5075 if (!X.isNull()) {
5076 for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) {
5077 Expr *Init = From->getInit(i);
5078 ImplicitConversionSequence ICS =
5079 TryCopyInitialization(S, Init, X, SuppressUserConversions,
5080 InOverloadResolution,
5081 AllowObjCWritebackConversion);
5082 // If a single element isn't convertible, fail.
5083 if (ICS.isBad()) {
5084 Result = ICS;
5085 break;
5086 }
5087 // Otherwise, look for the worst conversion.
5088 if (Result.isBad() || CompareImplicitConversionSequences(
5089 S, From->getBeginLoc(), ICS, Result) ==
5090 ImplicitConversionSequence::Worse)
5091 Result = ICS;
5092 }
5093
5094 // For an empty list, we won't have computed any conversion sequence.
5095 // Introduce the identity conversion sequence.
5096 if (From->getNumInits() == 0) {
5097 Result.setStandard();
5098 Result.Standard.setAsIdentityConversion();
5099 Result.Standard.setFromType(ToType);
5100 Result.Standard.setAllToTypes(ToType);
5101 }
5102
5103 Result.setStdInitializerListElement(toStdInitializerList);
5104 return Result;
5105 }
5106
5107 // C++14 [over.ics.list]p4:
5108 // C++11 [over.ics.list]p3:
5109 // Otherwise, if the parameter is a non-aggregate class X and overload
5110 // resolution chooses a single best constructor [...] the implicit
5111 // conversion sequence is a user-defined conversion sequence. If multiple
5112 // constructors are viable but none is better than the others, the
5113 // implicit conversion sequence is a user-defined conversion sequence.
5114 if (ToType->isRecordType() && !ToType->isAggregateType()) {
5115 // This function can deal with initializer lists.
5116 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
5117 AllowedExplicit::None,
5118 InOverloadResolution, /*CStyle=*/false,
5119 AllowObjCWritebackConversion,
5120 /*AllowObjCConversionOnExplicit=*/false);
5121 }
5122
5123 // C++14 [over.ics.list]p5:
5124 // C++11 [over.ics.list]p4:
5125 // Otherwise, if the parameter has an aggregate type which can be
5126 // initialized from the initializer list [...] the implicit conversion
5127 // sequence is a user-defined conversion sequence.
5128 if (ToType->isAggregateType()) {
5129 // Type is an aggregate, argument is an init list. At this point it comes
5130 // down to checking whether the initialization works.
5131 // FIXME: Find out whether this parameter is consumed or not.
5132 InitializedEntity Entity =
5133 InitializedEntity::InitializeParameter(S.Context, ToType,
5134 /*Consumed=*/false);
5135 if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
5136 From)) {
5137 Result.setUserDefined();
5138 Result.UserDefined.Before.setAsIdentityConversion();
5139 // Initializer lists don't have a type.
5140 Result.UserDefined.Before.setFromType(QualType());
5141 Result.UserDefined.Before.setAllToTypes(QualType());
5142
5143 Result.UserDefined.After.setAsIdentityConversion();
5144 Result.UserDefined.After.setFromType(ToType);
5145 Result.UserDefined.After.setAllToTypes(ToType);
5146 Result.UserDefined.ConversionFunction = nullptr;
5147 }
5148 return Result;
5149 }
5150
5151 // C++14 [over.ics.list]p6:
5152 // C++11 [over.ics.list]p5:
5153 // Otherwise, if the parameter is a reference, see 13.3.3.1.4.
5154 if (ToType->isReferenceType()) {
5155 // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
5156 // mention initializer lists in any way. So we go by what list-
5157 // initialization would do and try to extrapolate from that.
5158
5159 QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();
5160
5161 // If the initializer list has a single element that is reference-related
5162 // to the parameter type, we initialize the reference from that.
5163 if (From->getNumInits() == 1) {
5164 Expr *Init = From->getInit(0);
5165
5166 QualType T2 = Init->getType();
5167
5168 // If the initializer is the address of an overloaded function, try
5169 // to resolve the overloaded function. If all goes well, T2 is the
5170 // type of the resulting function.
5171 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
5172 DeclAccessPair Found;
5173 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
5174 Init, ToType, false, Found))
5175 T2 = Fn->getType();
5176 }
5177
5178 // Compute some basic properties of the types and the initializer.
5179 Sema::ReferenceCompareResult RefRelationship =
5180 S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);
5181
5182 if (RefRelationship >= Sema::Ref_Related) {
5183 return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
5184 SuppressUserConversions,
5185 /*AllowExplicit=*/false);
5186 }
5187 }
5188
5189 // Otherwise, we bind the reference to a temporary created from the
5190 // initializer list.
5191 Result = TryListConversion(S, From, T1, SuppressUserConversions,
5192 InOverloadResolution,
5193 AllowObjCWritebackConversion);
5194 if (Result.isFailure())
5195 return Result;
5196 assert(!Result.isEllipsis() &&(static_cast<void> (0))
5197 "Sub-initialization cannot result in ellipsis conversion.")(static_cast<void> (0));
5198
5199 // Can we even bind to a temporary?
5200 if (ToType->isRValueReferenceType() ||
5201 (T1.isConstQualified() && !T1.isVolatileQualified())) {
5202 StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
5203 Result.UserDefined.After;
5204 SCS.ReferenceBinding = true;
5205 SCS.IsLvalueReference = ToType->isLValueReferenceType();
5206 SCS.BindsToRvalue = true;
5207 SCS.BindsToFunctionLvalue = false;
5208 SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
5209 SCS.ObjCLifetimeConversionBinding = false;
5210 } else
5211 Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
5212 From, ToType);
5213 return Result;
5214 }
5215
5216 // C++14 [over.ics.list]p7:
5217 // C++11 [over.ics.list]p6:
5218 // Otherwise, if the parameter type is not a class:
5219 if (!ToType->isRecordType()) {
5220 // - if the initializer list has one element that is not itself an
5221 // initializer list, the implicit conversion sequence is the one
5222 // required to convert the element to the parameter type.
5223 unsigned NumInits = From->getNumInits();
5224 if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
5225 Result = TryCopyInitialization(S, From->getInit(0), ToType,
5226 SuppressUserConversions,
5227 InOverloadResolution,
5228 AllowObjCWritebackConversion);
5229 // - if the initializer list has no elements, the implicit conversion
5230 // sequence is the identity conversion.
5231 else if (NumInits == 0) {
5232 Result.setStandard();
5233 Result.Standard.setAsIdentityConversion();
5234 Result.Standard.setFromType(ToType);
5235 Result.Standard.setAllToTypes(ToType);
5236 }
5237 return Result;
5238 }
5239
5240 // C++14 [over.ics.list]p8:
5241 // C++11 [over.ics.list]p7:
5242 // In all cases other than those enumerated above, no conversion is possible
5243 return Result;
5244}
5245
5246/// TryCopyInitialization - Try to copy-initialize a value of type
5247/// ToType from the expression From. Return the implicit conversion
5248/// sequence required to pass this argument, which may be a bad
5249/// conversion sequence (meaning that the argument cannot be passed to
5250/// a parameter of this type). If @p SuppressUserConversions, then we
5251/// do not permit any user-defined conversion sequences.
5252static ImplicitConversionSequence
5253TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
5254 bool SuppressUserConversions,
5255 bool InOverloadResolution,
5256 bool AllowObjCWritebackConversion,
5257 bool AllowExplicit) {
5258 if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
5259 return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
5260 InOverloadResolution,AllowObjCWritebackConversion);
5261
5262 if (ToType->isReferenceType())
5263 return TryReferenceInit(S, From, ToType,
5264 /*FIXME:*/ From->getBeginLoc(),
5265 SuppressUserConversions, AllowExplicit);
5266
5267 return TryImplicitConversion(S, From, ToType,
5268 SuppressUserConversions,
5269 AllowedExplicit::None,
5270 InOverloadResolution,
5271 /*CStyle=*/false,
5272 AllowObjCWritebackConversion,
5273 /*AllowObjCConversionOnExplicit=*/false);
5274}
5275
5276static bool TryCopyInitialization(const CanQualType FromQTy,
5277 const CanQualType ToQTy,
5278 Sema &S,
5279 SourceLocation Loc,
5280 ExprValueKind FromVK) {
5281 OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
5282 ImplicitConversionSequence ICS =
5283 TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
5284
5285 return !ICS.isBad();
5286}
5287
5288/// TryObjectArgumentInitialization - Try to initialize the object
5289/// parameter of the given member function (@c Method) from the
5290/// expression @p From.
5291static ImplicitConversionSequence
5292TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
5293 Expr::Classification FromClassification,
5294 CXXMethodDecl *Method,
5295 CXXRecordDecl *ActingContext) {
5296 QualType ClassType = S.Context.getTypeDeclType(ActingContext);
5297 // [class.dtor]p2: A destructor can be invoked for a const, volatile or
5298 // const volatile object.
5299 Qualifiers Quals = Method->getMethodQualifiers();
5300 if (isa<CXXDestructorDecl>(Method)) {
5301 Quals.addConst();
5302 Quals.addVolatile();
5303 }
5304
5305 QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
5306
5307 // Set up the conversion sequence as a "bad" conversion, to allow us
5308 // to exit early.
5309 ImplicitConversionSequence ICS;
5310
5311 // We need to have an object of class type.
5312 if (const PointerType *PT = FromType->getAs<PointerType>()) {
5313 FromType = PT->getPointeeType();
5314
5315 // When we had a pointer, it's implicitly dereferenced, so we
5316 // better have an lvalue.
5317 assert(FromClassification.isLValue())(static_cast<void> (0));
5318 }
5319
5320 assert(FromType->isRecordType())(static_cast<void> (0));
5321
5322 // C++0x [over.match.funcs]p4:
5323 // For non-static member functions, the type of the implicit object
5324 // parameter is
5325 //
5326 // - "lvalue reference to cv X" for functions declared without a
5327 // ref-qualifier or with the & ref-qualifier
5328 // - "rvalue reference to cv X" for functions declared with the &&
5329 // ref-qualifier
5330 //
5331 // where X is the class of which the function is a member and cv is the
5332 // cv-qualification on the member function declaration.
5333 //
5334 // However, when finding an implicit conversion sequence for the argument, we
5335 // are not allowed to perform user-defined conversions
5336 // (C++ [over.match.funcs]p5). We perform a simplified version of
5337 // reference binding here, that allows class rvalues to bind to
5338 // non-constant references.
5339
5340 // First check the qualifiers.
5341 QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
5342 if (ImplicitParamType.getCVRQualifiers()
5343 != FromTypeCanon.getLocalCVRQualifiers() &&
5344 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
5345 ICS.setBad(BadConversionSequence::bad_qualifiers,
5346 FromType, ImplicitParamType);
5347 return ICS;
5348 }
5349
5350 if (FromTypeCanon.hasAddressSpace()) {
5351 Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
5352 Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
5353 if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
5354 ICS.setBad(BadConversionSequence::bad_qualifiers,
5355 FromType, ImplicitParamType);
5356 return ICS;
5357 }
5358 }
5359
5360 // Check that we have either the same type or a derived type. It
5361 // affects the conversion rank.
5362 QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
5363 ImplicitConversionKind SecondKind;
5364 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
5365 SecondKind = ICK_Identity;
5366 } else if (S.IsDerivedFrom(Loc, FromType, ClassType))
5367 SecondKind = ICK_Derived_To_Base;
5368 else {
5369 ICS.setBad(BadConversionSequence::unrelated_class,
5370 FromType, ImplicitParamType);
5371 return ICS;
5372 }
5373
5374 // Check the ref-qualifier.
5375 switch (Method->getRefQualifier()) {
5376 case RQ_None:
5377 // Do nothing; we don't care about lvalueness or rvalueness.
5378 break;
5379
5380 case RQ_LValue:
5381 if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
5382 // non-const lvalue reference cannot bind to an rvalue
5383 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
5384 ImplicitParamType);
5385 return ICS;
5386 }
5387 break;
5388
5389 case RQ_RValue:
5390 if (!FromClassification.isRValue()) {
5391 // rvalue reference cannot bind to an lvalue
5392 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
5393 ImplicitParamType);
5394 return ICS;
5395 }
5396 break;
5397 }
5398
5399 // Success. Mark this as a reference binding.
5400 ICS.setStandard();
5401 ICS.Standard.setAsIdentityConversion();
5402 ICS.Standard.Second = SecondKind;
5403 ICS.Standard.setFromType(FromType);
5404 ICS.Standard.setAllToTypes(ImplicitParamType);
5405 ICS.Standard.ReferenceBinding = true;
5406 ICS.Standard.DirectBinding = true;
5407 ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
5408 ICS.Standard.BindsToFunctionLvalue = false;
5409 ICS.Standard.BindsToRvalue = FromClassification.isRValue();
5410 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
5411 = (Method->getRefQualifier() == RQ_None);
5412 return ICS;
5413}
5414
5415/// PerformObjectArgumentInitialization - Perform initialization of
5416/// the implicit object parameter for the given Method with the given
5417/// expression.
5418ExprResult
5419Sema::PerformObjectArgumentInitialization(Expr *From,
5420 NestedNameSpecifier *Qualifier,
5421 NamedDecl *FoundDecl,
5422 CXXMethodDecl *Method) {
5423 QualType FromRecordType, DestType;
5424 QualType ImplicitParamRecordType =
5425 Method->getThisType()->castAs<PointerType>()->getPointeeType();
5426
5427 Expr::Classification FromClassification;
5428 if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
5429 FromRecordType = PT->getPointeeType();
5430 DestType = Method->getThisType();
5431 FromClassification = Expr::Classification::makeSimpleLValue();
5432 } else {
5433 FromRecordType = From->getType();
5434 DestType = ImplicitParamRecordType;
5435 FromClassification = From->Classify(Context);
5436
5437 // When performing member access on a prvalue, materialize a temporary.
5438 if (From->isPRValue()) {
5439 From = CreateMaterializeTemporaryExpr(FromRecordType, From,
5440 Method->getRefQualifier() !=
5441 RefQualifierKind::RQ_RValue);
5442 }
5443 }
5444
5445 // Note that we always use the true parent context when performing
5446 // the actual argument initialization.
5447 ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
5448 *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
5449 Method->getParent());
5450 if (ICS.isBad()) {
5451 switch (ICS.Bad.Kind) {
5452 case BadConversionSequence::bad_qualifiers: {
5453 Qualifiers FromQs = FromRecordType.getQualifiers();
5454 Qualifiers ToQs = DestType.getQualifiers();
5455 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
5456 if (CVR) {
5457 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
5458 << Method->getDeclName() << FromRecordType << (CVR - 1)
5459 << From->getSourceRange();
5460 Diag(Method->getLocation(), diag::note_previous_decl)
5461 << Method->getDeclName();
5462 return ExprError();
5463 }
5464 break;
5465 }
5466
5467 case BadConversionSequence::lvalue_ref_to_rvalue:
5468 case BadConversionSequence::rvalue_ref_to_lvalue: {
5469 bool IsRValueQualified =
5470 Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
5471 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
5472 << Method->getDeclName() << FromClassification.isRValue()
5473 << IsRValueQualified;
5474 Diag(Method->getLocation(), diag::note_previous_decl)
5475 << Method->getDeclName();
5476 return ExprError();
5477 }
5478
5479 case BadConversionSequence::no_conversion:
5480 case BadConversionSequence::unrelated_class:
5481 break;
5482 }
5483
5484 return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
5485 << ImplicitParamRecordType << FromRecordType
5486 << From->getSourceRange();
5487 }
5488
5489 if (ICS.Standard.Second == ICK_Derived_To_Base) {
5490 ExprResult FromRes =
5491 PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
5492 if (FromRes.isInvalid())
5493 return ExprError();
5494 From = FromRes.get();
5495 }
5496
5497 if (!Context.hasSameType(From->getType(), DestType)) {
5498 CastKind CK;
5499 QualType PteeTy = DestType->getPointeeType();
5500 LangAS DestAS =
5501 PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
5502 if (FromRecordType.getAddressSpace() != DestAS)
5503 CK = CK_AddressSpaceConversion;
5504 else
5505 CK = CK_NoOp;
5506 From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
5507 }
5508 return From;
5509}
5510
5511/// TryContextuallyConvertToBool - Attempt to contextually convert the
5512/// expression From to bool (C++0x [conv]p3).
5513static ImplicitConversionSequence
5514TryContextuallyConvertToBool(Sema &S, Expr *From) {
5515 // C++ [dcl.init]/17.8:
5516 // - Otherwise, if the initialization is direct-initialization, the source
5517 // type is std::nullptr_t, and the destination type is bool, the initial
5518 // value of the object being initialized is false.
5519 if (From->getType()->isNullPtrType())
5520 return ImplicitConversionSequence::getNullptrToBool(From->getType(),
5521 S.Context.BoolTy,
5522 From->isGLValue());
5523
5524 // All other direct-initialization of bool is equivalent to an implicit
5525 // conversion to bool in which explicit conversions are permitted.
5526 return TryImplicitConversion(S, From, S.Context.BoolTy,
5527 /*SuppressUserConversions=*/false,
5528 AllowedExplicit::Conversions,
5529 /*InOverloadResolution=*/false,
5530 /*CStyle=*/false,
5531 /*AllowObjCWritebackConversion=*/false,
5532 /*AllowObjCConversionOnExplicit=*/false);
5533}
5534
5535/// PerformContextuallyConvertToBool - Perform a contextual conversion
5536/// of the expression From to bool (C++0x [conv]p3).
5537ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
5538 if (checkPlaceholderForOverload(*this, From))
5539 return ExprError();
5540
5541 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
5542 if (!ICS.isBad())
5543 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
5544
5545 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
5546 return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
5547 << From->getType() << From->getSourceRange();
5548 return ExprError();
5549}
5550
5551/// Check that the specified conversion is permitted in a converted constant
5552/// expression, according to C++11 [expr.const]p3. Return true if the conversion
5553/// is acceptable.
5554static bool CheckConvertedConstantConversions(Sema &S,
5555 StandardConversionSequence &SCS) {
5556 // Since we know that the target type is an integral or unscoped enumeration
5557 // type, most conversion kinds are impossible. All possible First and Third
5558 // conversions are fine.
5559 switch (SCS.Second) {
5560 case ICK_Identity:
5561 case ICK_Integral_Promotion:
5562 case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
5563 case ICK_Zero_Queue_Conversion:
5564 return true;
5565
5566 case ICK_Boolean_Conversion:
5567 // Conversion from an integral or unscoped enumeration type to bool is
5568 // classified as ICK_Boolean_Conversion, but it's also arguably an integral
5569 // conversion, so we allow it in a converted constant expression.
5570 //
5571 // FIXME: Per core issue 1407, we should not allow this, but that breaks
5572 // a lot of popular code. We should at least add a warning for this
5573 // (non-conforming) extension.
5574 return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
5575 SCS.getToType(2)->isBooleanType();
5576
5577 case ICK_Pointer_Conversion:
5578 case ICK_Pointer_Member:
5579 // C++1z: null pointer conversions and null member pointer conversions are
5580 // only permitted if the source type is std::nullptr_t.
5581 return SCS.getFromType()->isNullPtrType();
5582
5583 case ICK_Floating_Promotion:
5584 case ICK_Complex_Promotion:
5585 case ICK_Floating_Conversion:
5586 case ICK_Complex_Conversion:
5587 case ICK_Floating_Integral:
5588 case ICK_Compatible_Conversion:
5589 case ICK_Derived_To_Base:
5590 case ICK_Vector_Conversion:
5591 case ICK_SVE_Vector_Conversion:
5592 case ICK_Vector_Splat:
5593 case ICK_Complex_Real:
5594 case ICK_Block_Pointer_Conversion:
5595 case ICK_TransparentUnionConversion:
5596 case ICK_Writeback_Conversion:
5597 case ICK_Zero_Event_Conversion:
5598 case ICK_C_Only_Conversion:
5599 case ICK_Incompatible_Pointer_Conversion:
5600 return false;
5601
5602 case ICK_Lvalue_To_Rvalue:
5603 case ICK_Array_To_Pointer:
5604 case ICK_Function_To_Pointer:
5605 llvm_unreachable("found a first conversion kind in Second")__builtin_unreachable();
5606
5607 case ICK_Function_Conversion:
5608 case ICK_Qualification:
5609 llvm_unreachable("found a third conversion kind in Second")__builtin_unreachable();
5610
5611 case ICK_Num_Conversion_Kinds:
5612 break;
5613 }
5614
5615 llvm_unreachable("unknown conversion kind")__builtin_unreachable();
5616}
5617
5618/// CheckConvertedConstantExpression - Check that the expression From is a
5619/// converted constant expression of type T, perform the conversion and produce
5620/// the converted expression, per C++11 [expr.const]p3.
5621static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
5622 QualType T, APValue &Value,
5623 Sema::CCEKind CCE,
5624 bool RequireInt,
5625 NamedDecl *Dest) {
5626 assert(S.getLangOpts().CPlusPlus11 &&(static_cast<void> (0))
5627 "converted constant expression outside C++11")(static_cast<void> (0));
5628
5629 if (checkPlaceholderForOverload(S, From))
5630 return ExprError();
5631
5632 // C++1z [expr.const]p3:
5633 // A converted constant expression of type T is an expression,
5634 // implicitly converted to type T, where the converted
5635 // expression is a constant expression and the implicit conversion
5636 // sequence contains only [... list of conversions ...].
5637 ImplicitConversionSequence ICS =
5638 (CCE == Sema::CCEK_ExplicitBool || CCE == Sema::CCEK_Noexcept)
5639 ? TryContextuallyConvertToBool(S, From)
5640 : TryCopyInitialization(S, From, T,
5641 /*SuppressUserConversions=*/false,
5642 /*InOverloadResolution=*/false,
5643 /*AllowObjCWritebackConversion=*/false,
5644 /*AllowExplicit=*/false);
5645 StandardConversionSequence *SCS = nullptr;
5646 switch (ICS.getKind()) {
5647 case ImplicitConversionSequence::StandardConversion:
5648 SCS = &ICS.Standard;
5649 break;
5650 case ImplicitConversionSequence::UserDefinedConversion:
5651 if (T->isRecordType())
5652 SCS = &ICS.UserDefined.Before;
5653 else
5654 SCS = &ICS.UserDefined.After;
5655 break;
5656 case ImplicitConversionSequence::AmbiguousConversion:
5657 case ImplicitConversionSequence::BadConversion:
5658 if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
5659 return S.Diag(From->getBeginLoc(),
5660 diag::err_typecheck_converted_constant_expression)
5661 << From->getType() << From->getSourceRange() << T;
5662 return ExprError();
5663
5664 case ImplicitConversionSequence::EllipsisConversion:
5665 llvm_unreachable("ellipsis conversion in converted constant expression")__builtin_unreachable();
5666 }
5667
5668 // Check that we would only use permitted conversions.
5669 if (!CheckConvertedConstantConversions(S, *SCS)) {
5670 return S.Diag(From->getBeginLoc(),
5671 diag::err_typecheck_converted_constant_expression_disallowed)
5672 << From->getType() << From->getSourceRange() << T;
5673 }
5674 // [...] and where the reference binding (if any) binds directly.
5675 if (SCS->ReferenceBinding && !SCS->DirectBinding) {
5676 return S.Diag(From->getBeginLoc(),
5677 diag::err_typecheck_converted_constant_expression_indirect)
5678 << From->getType() << From->getSourceRange() << T;
5679 }
5680
5681 // Usually we can simply apply the ImplicitConversionSequence we formed
5682 // earlier, but that's not guaranteed to work when initializing an object of
5683 // class type.
5684 ExprResult Result;
5685 if (T->isRecordType()) {
5686 assert(CCE == Sema::CCEK_TemplateArg &&(static_cast<void> (0))
5687 "unexpected class type converted constant expr")(static_cast<void> (0));
5688 Result = S.PerformCopyInitialization(
5689 InitializedEntity::InitializeTemplateParameter(
5690 T, cast<NonTypeTemplateParmDecl>(Dest)),
5691 SourceLocation(), From);
5692 } else {
5693 Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
5694 }
5695 if (Result.isInvalid())
5696 return Result;
5697
5698 // C++2a [intro.execution]p5:
5699 // A full-expression is [...] a constant-expression [...]
5700 Result =
5701 S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
5702 /*DiscardedValue=*/false, /*IsConstexpr=*/true);
5703 if (Result.isInvalid())
5704 return Result;
5705
5706 // Check for a narrowing implicit conversion.
5707 bool ReturnPreNarrowingValue = false;
5708 APValue PreNarrowingValue;
5709 QualType PreNarrowingType;
5710 switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
5711 PreNarrowingType)) {
5712 case NK_Dependent_Narrowing:
5713 // Implicit conversion to a narrower type, but the expression is
5714 // value-dependent so we can't tell whether it's actually narrowing.
5715 case NK_Variable_Narrowing:
5716 // Implicit conversion to a narrower type, and the value is not a constant
5717 // expression. We'll diagnose this in a moment.
5718 case NK_Not_Narrowing:
5719 break;
5720
5721 case NK_Constant_Narrowing:
5722 if (CCE == Sema::CCEK_ArrayBound &&
5723 PreNarrowingType->isIntegralOrEnumerationType() &&
5724 PreNarrowingValue.isInt()) {
5725 // Don't diagnose array bound narrowing here; we produce more precise
5726 // errors by allowing the un-narrowed value through.
5727 ReturnPreNarrowingValue = true;
5728 break;
5729 }
5730 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5731 << CCE << /*Constant*/ 1
5732 << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
5733 break;
5734
5735 case NK_Type_Narrowing:
5736 // FIXME: It would be better to diagnose that the expression is not a
5737 // constant expression.
5738 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5739 << CCE << /*Constant*/ 0 << From->getType() << T;
5740 break;
5741 }
5742
5743 if (Result.get()->isValueDependent()) {
5744 Value = APValue();
5745 return Result;
5746 }
5747
5748 // Check the expression is a constant expression.
5749 SmallVector<PartialDiagnosticAt, 8> Notes;
5750 Expr::EvalResult Eval;
5751 Eval.Diag = &Notes;
5752
5753 ConstantExprKind Kind;
5754 if (CCE == Sema::CCEK_TemplateArg && T->isRecordType())
5755 Kind = ConstantExprKind::ClassTemplateArgument;
5756 else if (CCE == Sema::CCEK_TemplateArg)
5757 Kind = ConstantExprKind::NonClassTemplateArgument;
5758 else
5759 Kind = ConstantExprKind::Normal;
5760
5761 if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) ||
5762 (RequireInt && !Eval.Val.isInt())) {
5763 // The expression can't be folded, so we can't keep it at this position in
5764 // the AST.
5765 Result = ExprError();
5766 } else {
5767 Value = Eval.Val;
5768
5769 if (Notes.empty()) {
5770 // It's a constant expression.
5771 Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value);
5772 if (ReturnPreNarrowingValue)
5773 Value = std::move(PreNarrowingValue);
5774 return E;
5775 }
5776 }
5777
5778 // It's not a constant expression. Produce an appropriate diagnostic.
5779 if (Notes.size() == 1 &&
5780 Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) {
5781 S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
5782 } else if (!Notes.empty() && Notes[0].second.getDiagID() ==
5783 diag::note_constexpr_invalid_template_arg) {
5784 Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg);
5785 for (unsigned I = 0; I < Notes.size(); ++I)
5786 S.Diag(Notes[I].first, Notes[I].second);
5787 } else {
5788 S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
5789 << CCE << From->getSourceRange();
5790 for (unsigned I = 0; I < Notes.size(); ++I)
5791 S.Diag(Notes[I].first, Notes[I].second);
5792 }
5793 return ExprError();
5794}
5795
5796ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5797 APValue &Value, CCEKind CCE,
5798 NamedDecl *Dest) {
5799 return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false,
5800 Dest);
5801}
5802
5803ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5804 llvm::APSInt &Value,
5805 CCEKind CCE) {
5806 assert(T->isIntegralOrEnumerationType() && "unexpected converted const type")(static_cast<void> (0));
5807
5808 APValue V;
5809 auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true,
5810 /*Dest=*/nullptr);
5811 if (!R.isInvalid() && !R.get()->isValueDependent())
5812 Value = V.getInt();
5813 return R;
5814}
5815
5816
5817/// dropPointerConversions - If the given standard conversion sequence
5818/// involves any pointer conversions, remove them. This may change
5819/// the result type of the conversion sequence.
5820static void dropPointerConversion(StandardConversionSequence &SCS) {
5821 if (SCS.Second == ICK_Pointer_Conversion) {
5822 SCS.Second = ICK_Identity;
5823 SCS.Third = ICK_Identity;
5824 SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
5825 }
5826}
5827
5828/// TryContextuallyConvertToObjCPointer - Attempt to contextually
5829/// convert the expression From to an Objective-C pointer type.
5830static ImplicitConversionSequence
5831TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
5832 // Do an implicit conversion to 'id'.
5833 QualType Ty = S.Context.getObjCIdType();
5834 ImplicitConversionSequence ICS
5835 = TryImplicitConversion(S, From, Ty,
5836 // FIXME: Are these flags correct?
5837 /*SuppressUserConversions=*/false,
5838 AllowedExplicit::Conversions,
5839 /*InOverloadResolution=*/false,
5840 /*CStyle=*/false,
5841 /*AllowObjCWritebackConversion=*/false,
5842 /*AllowObjCConversionOnExplicit=*/true);
5843
5844 // Strip off any final conversions to 'id'.
5845 switch (ICS.getKind()) {
5846 case ImplicitConversionSequence::BadConversion:
5847 case ImplicitConversionSequence::AmbiguousConversion:
5848 case ImplicitConversionSequence::EllipsisConversion:
5849 break;
5850
5851 case ImplicitConversionSequence::UserDefinedConversion:
5852 dropPointerConversion(ICS.UserDefined.After);
5853 break;
5854
5855 case ImplicitConversionSequence::StandardConversion:
5856 dropPointerConversion(ICS.Standard);
5857 break;
5858 }
5859
5860 return ICS;
5861}
5862
5863/// PerformContextuallyConvertToObjCPointer - Perform a contextual
5864/// conversion of the expression From to an Objective-C pointer type.
5865/// Returns a valid but null ExprResult if no conversion sequence exists.
5866ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
5867 if (checkPlaceholderForOverload(*this, From))
5868 return ExprError();
5869
5870 QualType Ty = Context.getObjCIdType();
5871 ImplicitConversionSequence ICS =
5872 TryContextuallyConvertToObjCPointer(*this, From);
5873 if (!ICS.isBad())
5874 return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
5875 return ExprResult();
5876}
5877
5878/// Determine whether the provided type is an integral type, or an enumeration
5879/// type of a permitted flavor.
5880bool Sema::ICEConvertDiagnoser::match(QualType T) {
5881 return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
5882 : T->isIntegralOrUnscopedEnumerationType();
5883}
5884
5885static ExprResult
5886diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
5887 Sema::ContextualImplicitConverter &Converter,
5888 QualType T, UnresolvedSetImpl &ViableConversions) {
5889
5890 if (Converter.Suppress)
5891 return ExprError();
5892
5893 Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
5894 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
5895 CXXConversionDecl *Conv =
5896 cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
5897 QualType ConvTy = Conv->getConversionType().getNonReferenceType();
5898 Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
5899 }
5900 return From;
5901}
5902
5903static bool
5904diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
5905 Sema::ContextualImplicitConverter &Converter,
5906 QualType T, bool HadMultipleCandidates,
5907 UnresolvedSetImpl &ExplicitConversions) {
5908 if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
5909 DeclAccessPair Found = ExplicitConversions[0];
5910 CXXConversionDecl *Conversion =
5911 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
5912
5913 // The user probably meant to invoke the given explicit
5914 // conversion; use it.
5915 QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
5916 std::string TypeStr;
5917 ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());
5918
5919 Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
5920 << FixItHint::CreateInsertion(From->getBeginLoc(),
5921 "static_cast<" + TypeStr + ">(")
5922 << FixItHint::CreateInsertion(
5923 SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
5924 Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);
5925
5926 // If we aren't in a SFINAE context, build a call to the
5927 // explicit conversion function.
5928 if (SemaRef.isSFINAEContext())
5929 return true;
5930
5931 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
5932 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
5933 HadMultipleCandidates);
5934 if (Result.isInvalid())
5935 return true;
5936 // Record usage of conversion in an implicit cast.
5937 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
5938 CK_UserDefinedConversion, Result.get(),
5939 nullptr, Result.get()->getValueKind(),
5940 SemaRef.CurFPFeatureOverrides());
5941 }
5942 return false;
5943}
5944
5945static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
5946 Sema::ContextualImplicitConverter &Converter,
5947 QualType T, bool HadMultipleCandidates,
5948 DeclAccessPair &Found) {
5949 CXXConversionDecl *Conversion =
5950 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
5951 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
5952
5953 QualType ToType = Conversion->getConversionType().getNonReferenceType();
5954 if (!Converter.SuppressConversion) {
5955 if (SemaRef.isSFINAEContext())
5956 return true;
5957
5958 Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
5959 << From->getSourceRange();
5960 }
5961
5962 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
5963 HadMultipleCandidates);
5964 if (Result.isInvalid())
5965 return true;
5966 // Record usage of conversion in an implicit cast.
5967 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
5968 CK_UserDefinedConversion, Result.get(),
5969 nullptr, Result.get()->getValueKind(),
5970 SemaRef.CurFPFeatureOverrides());
5971 return false;
5972}
5973
5974static ExprResult finishContextualImplicitConversion(
5975 Sema &SemaRef, SourceLocation Loc, Expr *From,
5976 Sema::ContextualImplicitConverter &Converter) {
5977 if (!Converter.match(From->getType()) && !Converter.Suppress)
5978 Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
5979 << From->getSourceRange();
5980
5981 return SemaRef.DefaultLvalueConversion(From);
5982}
5983
5984static void
5985collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
5986 UnresolvedSetImpl &ViableConversions,
5987 OverloadCandidateSet &CandidateSet) {
5988 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
5989 DeclAccessPair FoundDecl = ViableConversions[I];
5990 NamedDecl *D = FoundDecl.getDecl();
5991 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
5992 if (isa<UsingShadowDecl>(D))
5993 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5994
5995 CXXConversionDecl *Conv;
5996 FunctionTemplateDecl *ConvTemplate;
5997 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
5998 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5999 else
6000 Conv = cast<CXXConversionDecl>(D);
6001
6002 if (ConvTemplate)
6003 SemaRef.AddTemplateConversionCandidate(
6004 ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
6005 /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true);
6006 else
6007 SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
6008 ToType, CandidateSet,
6009 /*AllowObjCConversionOnExplicit=*/false,
6010 /*AllowExplicit*/ true);
6011 }
6012}
6013
6014/// Attempt to convert the given expression to a type which is accepted
6015/// by the given converter.
6016///