1	//===--- SemaDeclObjC.cpp - Semantic Analysis for ObjC Declarations -------===//
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 implements semantic analysis for Objective C declarations.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "TypeLocBuilder.h"
14	#include "clang/AST/ASTConsumer.h"
15	#include "clang/AST/ASTContext.h"
16	#include "clang/AST/ASTMutationListener.h"
17	#include "clang/AST/DeclObjC.h"
18	#include "clang/AST/Expr.h"
19	#include "clang/AST/ExprObjC.h"
20	#include "clang/AST/RecursiveASTVisitor.h"
21	#include "clang/Basic/SourceManager.h"
22	#include "clang/Basic/TargetInfo.h"
23	#include "clang/Sema/DeclSpec.h"
24	#include "clang/Sema/Lookup.h"
25	#include "clang/Sema/Scope.h"
26	#include "clang/Sema/ScopeInfo.h"
27	#include "clang/Sema/SemaInternal.h"
28	#include "llvm/ADT/DenseMap.h"
29	#include "llvm/ADT/DenseSet.h"
30
31	using namespace clang;
32
33	/// Check whether the given method, which must be in the 'init'
34	/// family, is a valid member of that family.
35	///
36	/// \param receiverTypeIfCall - if null, check this as if declaring it;
37	/// if non-null, check this as if making a call to it with the given
38	/// receiver type
39	///
40	/// \return true to indicate that there was an error and appropriate
41	/// actions were taken
42	bool Sema::checkInitMethod(ObjCMethodDecl *method,
43	QualType receiverTypeIfCall) {
44	if (method->isInvalidDecl()) return true;
45
46	// This castAs is safe: methods that don't return an object
47	// pointer won't be inferred as inits and will reject an explicit
48	// objc_method_family(init).
49
50	// We ignore protocols here. Should we? What about Class?
51
52	const ObjCObjectType *result =
53	method->getReturnType()->castAs<ObjCObjectPointerType>()->getObjectType();
54
55	if (result->isObjCId()) {
56	return false;
57	} else if (result->isObjCClass()) {
58	// fall through: always an error
59	} else {
60	ObjCInterfaceDecl *resultClass = result->getInterface();
61	assert(resultClass && "unexpected object type!");
62
63	// It's okay for the result type to still be a forward declaration
64	// if we're checking an interface declaration.
65	if (!resultClass->hasDefinition()) {
66	if (receiverTypeIfCall.isNull() &&
67	!isa<ObjCImplementationDecl>(method->getDeclContext()))
68	return false;
69
70	// Otherwise, we try to compare class types.
71	} else {
72	// If this method was declared in a protocol, we can't check
73	// anything unless we have a receiver type that's an interface.
74	const ObjCInterfaceDecl *receiverClass = nullptr;
75	if (isa<ObjCProtocolDecl>(method->getDeclContext())) {
76	if (receiverTypeIfCall.isNull())
77	return false;
78
79	receiverClass = receiverTypeIfCall->castAs<ObjCObjectPointerType>()
80	->getInterfaceDecl();
81
82	// This can be null for calls to e.g. id<Foo>.
83	if (!receiverClass) return false;
84	} else {
85	receiverClass = method->getClassInterface();
86	assert(receiverClass && "method not associated with a class!");
87	}
88
89	// If either class is a subclass of the other, it's fine.
90	if (receiverClass->isSuperClassOf(I: resultClass) ||
91	resultClass->isSuperClassOf(I: receiverClass))
92	return false;
93	}
94	}
95
96	SourceLocation loc = method->getLocation();
97
98	// If we're in a system header, and this is not a call, just make
99	// the method unusable.
100	if (receiverTypeIfCall.isNull() && getSourceManager().isInSystemHeader(Loc: loc)) {
101	method->addAttr(UnavailableAttr::CreateImplicit(Context, "",
102	UnavailableAttr::IR_ARCInitReturnsUnrelated, loc));
103	return true;
104	}
105
106	// Otherwise, it's an error.
107	Diag(loc, diag::err_arc_init_method_unrelated_result_type);
108	method->setInvalidDecl();
109	return true;
110	}
111
112	/// Issue a warning if the parameter of the overridden method is non-escaping
113	/// but the parameter of the overriding method is not.
114	static bool diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
115	Sema &S) {
116	if (OldD->hasAttr<NoEscapeAttr>() && !NewD->hasAttr<NoEscapeAttr>()) {
117	S.Diag(NewD->getLocation(), diag::warn_overriding_method_missing_noescape);
118	S.Diag(OldD->getLocation(), diag::note_overridden_marked_noescape);
119	return false;
120	}
121
122	return true;
123	}
124
125	/// Produce additional diagnostics if a category conforms to a protocol that
126	/// defines a method taking a non-escaping parameter.
127	static void diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
128	const ObjCCategoryDecl *CD,
129	const ObjCProtocolDecl *PD, Sema &S) {
130	if (!diagnoseNoescape(NewD, OldD, S))
131	S.Diag(CD->getLocation(), diag::note_cat_conform_to_noescape_prot)
132	<< CD->IsClassExtension() << PD
133	<< cast<ObjCMethodDecl>(NewD->getDeclContext());
134	}
135
136	void Sema::CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
137	const ObjCMethodDecl *Overridden) {
138	if (Overridden->hasRelatedResultType() &&
139	!NewMethod->hasRelatedResultType()) {
140	// This can only happen when the method follows a naming convention that
141	// implies a related result type, and the original (overridden) method has
142	// a suitable return type, but the new (overriding) method does not have
143	// a suitable return type.
144	QualType ResultType = NewMethod->getReturnType();
145	SourceRange ResultTypeRange = NewMethod->getReturnTypeSourceRange();
146
147	// Figure out which class this method is part of, if any.
148	ObjCInterfaceDecl *CurrentClass
149	= dyn_cast<ObjCInterfaceDecl>(NewMethod->getDeclContext());
150	if (!CurrentClass) {
151	DeclContext *DC = NewMethod->getDeclContext();
152	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: DC))
153	CurrentClass = Cat->getClassInterface();
154	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: DC))
155	CurrentClass = Impl->getClassInterface();
156	else if (ObjCCategoryImplDecl *CatImpl
157	= dyn_cast<ObjCCategoryImplDecl>(Val: DC))
158	CurrentClass = CatImpl->getClassInterface();
159	}
160
161	if (CurrentClass) {
162	Diag(NewMethod->getLocation(),
163	diag::warn_related_result_type_compatibility_class)
164	<< Context.getObjCInterfaceType(CurrentClass)
165	<< ResultType
166	<< ResultTypeRange;
167	} else {
168	Diag(NewMethod->getLocation(),
169	diag::warn_related_result_type_compatibility_protocol)
170	<< ResultType
171	<< ResultTypeRange;
172	}
173
174	if (ObjCMethodFamily Family = Overridden->getMethodFamily())
175	Diag(Overridden->getLocation(),
176	diag::note_related_result_type_family)
177	<< /*overridden method*/ 0
178	<< Family;
179	else
180	Diag(Overridden->getLocation(),
181	diag::note_related_result_type_overridden);
182	}
183
184	if ((NewMethod->hasAttr<NSReturnsRetainedAttr>() !=
185	Overridden->hasAttr<NSReturnsRetainedAttr>())) {
186	Diag(NewMethod->getLocation(),
187	getLangOpts().ObjCAutoRefCount
188	? diag::err_nsreturns_retained_attribute_mismatch
189	: diag::warn_nsreturns_retained_attribute_mismatch)
190	<< 1;
191	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
192	}
193	if ((NewMethod->hasAttr<NSReturnsNotRetainedAttr>() !=
194	Overridden->hasAttr<NSReturnsNotRetainedAttr>())) {
195	Diag(NewMethod->getLocation(),
196	getLangOpts().ObjCAutoRefCount
197	? diag::err_nsreturns_retained_attribute_mismatch
198	: diag::warn_nsreturns_retained_attribute_mismatch)
199	<< 0;
200	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
201	}
202
203	ObjCMethodDecl::param_const_iterator oi = Overridden->param_begin(),
204	oe = Overridden->param_end();
205	for (ObjCMethodDecl::param_iterator ni = NewMethod->param_begin(),
206	ne = NewMethod->param_end();
207	ni != ne && oi != oe; ++ni, ++oi) {
208	const ParmVarDecl *oldDecl = (*oi);
209	ParmVarDecl *newDecl = (*ni);
210	if (newDecl->hasAttr<NSConsumedAttr>() !=
211	oldDecl->hasAttr<NSConsumedAttr>()) {
212	Diag(newDecl->getLocation(),
213	getLangOpts().ObjCAutoRefCount
214	? diag::err_nsconsumed_attribute_mismatch
215	: diag::warn_nsconsumed_attribute_mismatch);
216	Diag(oldDecl->getLocation(), diag::note_previous_decl) << "parameter";
217	}
218
219	diagnoseNoescape(NewD: newDecl, OldD: oldDecl, S&: *this);
220	}
221	}
222
223	/// Check a method declaration for compatibility with the Objective-C
224	/// ARC conventions.
225	bool Sema::CheckARCMethodDecl(ObjCMethodDecl *method) {
226	ObjCMethodFamily family = method->getMethodFamily();
227	switch (family) {
228	case OMF_None:
229	case OMF_finalize:
230	case OMF_retain:
231	case OMF_release:
232	case OMF_autorelease:
233	case OMF_retainCount:
234	case OMF_self:
235	case OMF_initialize:
236	case OMF_performSelector:
237	return false;
238
239	case OMF_dealloc:
240	if (!Context.hasSameType(method->getReturnType(), Context.VoidTy)) {
241	SourceRange ResultTypeRange = method->getReturnTypeSourceRange();
242	if (ResultTypeRange.isInvalid())
243	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
244	<< method->getReturnType()
245	<< FixItHint::CreateInsertion(method->getSelectorLoc(0), "(void)");
246	else
247	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
248	<< method->getReturnType()
249	<< FixItHint::CreateReplacement(ResultTypeRange, "void");
250	return true;
251	}
252	return false;
253
254	case OMF_init:
255	// If the method doesn't obey the init rules, don't bother annotating it.
256	if (checkInitMethod(method, receiverTypeIfCall: QualType()))
257	return true;
258
259	method->addAttr(NSConsumesSelfAttr::CreateImplicit(Context));
260
261	// Don't add a second copy of this attribute, but otherwise don't
262	// let it be suppressed.
263	if (method->hasAttr<NSReturnsRetainedAttr>())
264	return false;
265	break;
266
267	case OMF_alloc:
268	case OMF_copy:
269	case OMF_mutableCopy:
270	case OMF_new:
271	if (method->hasAttr<NSReturnsRetainedAttr>() ||
272	method->hasAttr<NSReturnsNotRetainedAttr>() ||
273	method->hasAttr<NSReturnsAutoreleasedAttr>())
274	return false;
275	break;
276	}
277
278	method->addAttr(NSReturnsRetainedAttr::CreateImplicit(Context));
279	return false;
280	}
281
282	static void DiagnoseObjCImplementedDeprecations(Sema &S, const NamedDecl *ND,
283	SourceLocation ImplLoc) {
284	if (!ND)
285	return;
286	bool IsCategory = false;
287	StringRef RealizedPlatform;
288	AvailabilityResult Availability = ND->getAvailability(
289	/*Message=*/nullptr, /*EnclosingVersion=*/VersionTuple(),
290	&RealizedPlatform);
291	if (Availability != AR_Deprecated) {
292	if (isa<ObjCMethodDecl>(Val: ND)) {
293	if (Availability != AR_Unavailable)
294	return;
295	if (RealizedPlatform.empty())
296	RealizedPlatform = S.Context.getTargetInfo().getPlatformName();
297	// Warn about implementing unavailable methods, unless the unavailable
298	// is for an app extension.
299	if (RealizedPlatform.ends_with(Suffix: "_app_extension"))
300	return;
301	S.Diag(ImplLoc, diag::warn_unavailable_def);
302	S.Diag(ND->getLocation(), diag::note_method_declared_at)
303	<< ND->getDeclName();
304	return;
305	}
306	if (const auto *CD = dyn_cast<ObjCCategoryDecl>(Val: ND)) {
307	if (!CD->getClassInterface()->isDeprecated())
308	return;
309	ND = CD->getClassInterface();
310	IsCategory = true;
311	} else
312	return;
313	}
314	S.Diag(ImplLoc, diag::warn_deprecated_def)
315	<< (isa<ObjCMethodDecl>(ND)
316	? /*Method*/ 0
317	: isa<ObjCCategoryDecl>(ND) || IsCategory ? /*Category*/ 2
318	: /*Class*/ 1);
319	if (isa<ObjCMethodDecl>(ND))
320	S.Diag(ND->getLocation(), diag::note_method_declared_at)
321	<< ND->getDeclName();
322	else
323	S.Diag(ND->getLocation(), diag::note_previous_decl)
324	<< (isa<ObjCCategoryDecl>(ND) ? "category" : "class");
325	}
326
327	/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
328	/// pool.
329	void Sema::AddAnyMethodToGlobalPool(Decl *D) {
330	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
331
332	// If we don't have a valid method decl, simply return.
333	if (!MDecl)
334	return;
335	if (MDecl->isInstanceMethod())
336	AddInstanceMethodToGlobalPool(Method: MDecl, impl: true);
337	else
338	AddFactoryMethodToGlobalPool(Method: MDecl, impl: true);
339	}
340
341	/// HasExplicitOwnershipAttr - returns true when pointer to ObjC pointer
342	/// has explicit ownership attribute; false otherwise.
343	static bool
344	HasExplicitOwnershipAttr(Sema &S, ParmVarDecl *Param) {
345	QualType T = Param->getType();
346
347	if (const PointerType *PT = T->getAs<PointerType>()) {
348	T = PT->getPointeeType();
349	} else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
350	T = RT->getPointeeType();
351	} else {
352	return true;
353	}
354
355	// If we have a lifetime qualifier, but it's local, we must have
356	// inferred it. So, it is implicit.
357	return !T.getLocalQualifiers().hasObjCLifetime();
358	}
359
360	/// ActOnStartOfObjCMethodDef - This routine sets up parameters; invisible
361	/// and user declared, in the method definition's AST.
362	void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
363	ImplicitlyRetainedSelfLocs.clear();
364	assert((getCurMethodDecl() == nullptr) && "Methodparsing confused");
365	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
366
367	PushExpressionEvaluationContext(NewContext: ExprEvalContexts.back().Context);
368
369	// If we don't have a valid method decl, simply return.
370	if (!MDecl)
371	return;
372
373	QualType ResultType = MDecl->getReturnType();
374	if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
375	!MDecl->isInvalidDecl() &&
376	RequireCompleteType(MDecl->getLocation(), ResultType,
377	diag::err_func_def_incomplete_result))
378	MDecl->setInvalidDecl();
379
380	// Allow all of Sema to see that we are entering a method definition.
381	PushDeclContext(FnBodyScope, MDecl);
382	PushFunctionScope();
383
384	// Create Decl objects for each parameter, entrring them in the scope for
385	// binding to their use.
386
387	// Insert the invisible arguments, self and _cmd!
388	MDecl->createImplicitParams(Context, ID: MDecl->getClassInterface());
389
390	PushOnScopeChains(MDecl->getSelfDecl(), FnBodyScope);
391	PushOnScopeChains(MDecl->getCmdDecl(), FnBodyScope);
392
393	// The ObjC parser requires parameter names so there's no need to check.
394	CheckParmsForFunctionDef(Parameters: MDecl->parameters(),
395	/*CheckParameterNames=*/false);
396
397	// Introduce all of the other parameters into this scope.
398	for (auto *Param : MDecl->parameters()) {
399	if (!Param->isInvalidDecl() &&
400	getLangOpts().ObjCAutoRefCount &&
401	!HasExplicitOwnershipAttr(*this, Param))
402	Diag(Param->getLocation(), diag::warn_arc_strong_pointer_objc_pointer) <<
403	Param->getType();
404
405	if (Param->getIdentifier())
406	PushOnScopeChains(Param, FnBodyScope);
407	}
408
409	// In ARC, disallow definition of retain/release/autorelease/retainCount
410	if (getLangOpts().ObjCAutoRefCount) {
411	switch (MDecl->getMethodFamily()) {
412	case OMF_retain:
413	case OMF_retainCount:
414	case OMF_release:
415	case OMF_autorelease:
416	Diag(MDecl->getLocation(), diag::err_arc_illegal_method_def)
417	<< 0 << MDecl->getSelector();
418	break;
419
420	case OMF_None:
421	case OMF_dealloc:
422	case OMF_finalize:
423	case OMF_alloc:
424	case OMF_init:
425	case OMF_mutableCopy:
426	case OMF_copy:
427	case OMF_new:
428	case OMF_self:
429	case OMF_initialize:
430	case OMF_performSelector:
431	break;
432	}
433	}
434
435	// Warn on deprecated methods under -Wdeprecated-implementations,
436	// and prepare for warning on missing super calls.
437	if (ObjCInterfaceDecl *IC = MDecl->getClassInterface()) {
438	ObjCMethodDecl *IMD =
439	IC->lookupMethod(Sel: MDecl->getSelector(), isInstance: MDecl->isInstanceMethod());
440
441	if (IMD) {
442	ObjCImplDecl *ImplDeclOfMethodDef =
443	dyn_cast<ObjCImplDecl>(MDecl->getDeclContext());
444	ObjCContainerDecl *ContDeclOfMethodDecl =
445	dyn_cast<ObjCContainerDecl>(IMD->getDeclContext());
446	ObjCImplDecl *ImplDeclOfMethodDecl = nullptr;
447	if (ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(Val: ContDeclOfMethodDecl))
448	ImplDeclOfMethodDecl = OID->getImplementation();
449	else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(Val: ContDeclOfMethodDecl)) {
450	if (CD->IsClassExtension()) {
451	if (ObjCInterfaceDecl *OID = CD->getClassInterface())
452	ImplDeclOfMethodDecl = OID->getImplementation();
453	} else
454	ImplDeclOfMethodDecl = CD->getImplementation();
455	}
456	// No need to issue deprecated warning if deprecated mehod in class/category
457	// is being implemented in its own implementation (no overriding is involved).
458	if (!ImplDeclOfMethodDecl || ImplDeclOfMethodDecl != ImplDeclOfMethodDef)
459	DiagnoseObjCImplementedDeprecations(*this, IMD, MDecl->getLocation());
460	}
461
462	if (MDecl->getMethodFamily() == OMF_init) {
463	if (MDecl->isDesignatedInitializerForTheInterface()) {
464	getCurFunction()->ObjCIsDesignatedInit = true;
465	getCurFunction()->ObjCWarnForNoDesignatedInitChain =
466	IC->getSuperClass() != nullptr;
467	} else if (IC->hasDesignatedInitializers()) {
468	getCurFunction()->ObjCIsSecondaryInit = true;
469	getCurFunction()->ObjCWarnForNoInitDelegation = true;
470	}
471	}
472
473	// If this is "dealloc" or "finalize", set some bit here.
474	// Then in ActOnSuperMessage() (SemaExprObjC), set it back to false.
475	// Finally, in ActOnFinishFunctionBody() (SemaDecl), warn if flag is set.
476	// Only do this if the current class actually has a superclass.
477	if (const ObjCInterfaceDecl *SuperClass = IC->getSuperClass()) {
478	ObjCMethodFamily Family = MDecl->getMethodFamily();
479	if (Family == OMF_dealloc) {
480	if (!(getLangOpts().ObjCAutoRefCount ||
481	getLangOpts().getGC() == LangOptions::GCOnly))
482	getCurFunction()->ObjCShouldCallSuper = true;
483
484	} else if (Family == OMF_finalize) {
485	if (Context.getLangOpts().getGC() != LangOptions::NonGC)
486	getCurFunction()->ObjCShouldCallSuper = true;
487
488	} else {
489	const ObjCMethodDecl *SuperMethod =
490	SuperClass->lookupMethod(Sel: MDecl->getSelector(),
491	isInstance: MDecl->isInstanceMethod());
492	getCurFunction()->ObjCShouldCallSuper =
493	(SuperMethod && SuperMethod->hasAttr<ObjCRequiresSuperAttr>());
494	}
495	}
496	}
497
498	// Some function attributes (like OptimizeNoneAttr) need actions before
499	// parsing body started.
500	applyFunctionAttributesBeforeParsingBody(FD: D);
501	}
502
503	namespace {
504
505	// Callback to only accept typo corrections that are Objective-C classes.
506	// If an ObjCInterfaceDecl* is given to the constructor, then the validation
507	// function will reject corrections to that class.
508	class ObjCInterfaceValidatorCCC final : public CorrectionCandidateCallback {
509	public:
510	ObjCInterfaceValidatorCCC() : CurrentIDecl(nullptr) {}
511	explicit ObjCInterfaceValidatorCCC(ObjCInterfaceDecl *IDecl)
512	: CurrentIDecl(IDecl) {}
513
514	bool ValidateCandidate(const TypoCorrection &candidate) override {
515	ObjCInterfaceDecl *ID = candidate.getCorrectionDeclAs<ObjCInterfaceDecl>();
516	return ID && !declaresSameEntity(ID, CurrentIDecl);
517	}
518
519	std::unique_ptr<CorrectionCandidateCallback> clone() override {
520	return std::make_unique<ObjCInterfaceValidatorCCC>(args&: *this);
521	}
522
523	private:
524	ObjCInterfaceDecl *CurrentIDecl;
525	};
526
527	} // end anonymous namespace
528
529	static void diagnoseUseOfProtocols(Sema &TheSema,
530	ObjCContainerDecl *CD,
531	ObjCProtocolDecl *const *ProtoRefs,
532	unsigned NumProtoRefs,
533	const SourceLocation *ProtoLocs) {
534	assert(ProtoRefs);
535	// Diagnose availability in the context of the ObjC container.
536	Sema::ContextRAII SavedContext(TheSema, CD);
537	for (unsigned i = 0; i < NumProtoRefs; ++i) {
538	(void)TheSema.DiagnoseUseOfDecl(ProtoRefs[i], ProtoLocs[i],
539	/*UnknownObjCClass=*/nullptr,
540	/*ObjCPropertyAccess=*/false,
541	/*AvoidPartialAvailabilityChecks=*/true);
542	}
543	}
544
545	void Sema::
546	ActOnSuperClassOfClassInterface(Scope *S,
547	SourceLocation AtInterfaceLoc,
548	ObjCInterfaceDecl *IDecl,
549	IdentifierInfo *ClassName,
550	SourceLocation ClassLoc,
551	IdentifierInfo *SuperName,
552	SourceLocation SuperLoc,
553	ArrayRef<ParsedType> SuperTypeArgs,
554	SourceRange SuperTypeArgsRange) {
555	// Check if a different kind of symbol declared in this scope.
556	NamedDecl *PrevDecl = LookupSingleName(S: TUScope, Name: SuperName, Loc: SuperLoc,
557	NameKind: LookupOrdinaryName);
558
559	if (!PrevDecl) {
560	// Try to correct for a typo in the superclass name without correcting
561	// to the class we're defining.
562	ObjCInterfaceValidatorCCC CCC(IDecl);
563	if (TypoCorrection Corrected = CorrectTypo(
564	Typo: DeclarationNameInfo(SuperName, SuperLoc), LookupKind: LookupOrdinaryName,
565	S: TUScope, SS: nullptr, CCC, Mode: CTK_ErrorRecovery)) {
566	diagnoseTypo(Corrected, PDiag(diag::err_undef_superclass_suggest)
567	<< SuperName << ClassName);
568	PrevDecl = Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>();
569	}
570	}
571
572	if (declaresSameEntity(PrevDecl, IDecl)) {
573	Diag(SuperLoc, diag::err_recursive_superclass)
574	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
575	IDecl->setEndOfDefinitionLoc(ClassLoc);
576	} else {
577	ObjCInterfaceDecl *SuperClassDecl =
578	dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
579	QualType SuperClassType;
580
581	// Diagnose classes that inherit from deprecated classes.
582	if (SuperClassDecl) {
583	(void)DiagnoseUseOfDecl(SuperClassDecl, SuperLoc);
584	SuperClassType = Context.getObjCInterfaceType(Decl: SuperClassDecl);
585	}
586
587	if (PrevDecl && !SuperClassDecl) {
588	// The previous declaration was not a class decl. Check if we have a
589	// typedef. If we do, get the underlying class type.
590	if (const TypedefNameDecl *TDecl =
591	dyn_cast_or_null<TypedefNameDecl>(Val: PrevDecl)) {
592	QualType T = TDecl->getUnderlyingType();
593	if (T->isObjCObjectType()) {
594	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
595	SuperClassDecl = dyn_cast<ObjCInterfaceDecl>(Val: IDecl);
596	SuperClassType = Context.getTypeDeclType(TDecl);
597
598	// This handles the following case:
599	// @interface NewI @end
600	// typedef NewI DeprI __attribute__((deprecated("blah")))
601	// @interface SI : DeprI /* warn here */ @end
602	(void)DiagnoseUseOfDecl(const_cast<TypedefNameDecl*>(TDecl), SuperLoc);
603	}
604	}
605	}
606
607	// This handles the following case:
608	//
609	// typedef int SuperClass;
610	// @interface MyClass : SuperClass {} @end
611	//
612	if (!SuperClassDecl) {
613	Diag(SuperLoc, diag::err_redefinition_different_kind) << SuperName;
614	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
615	}
616	}
617
618	if (!isa_and_nonnull<TypedefNameDecl>(Val: PrevDecl)) {
619	if (!SuperClassDecl)
620	Diag(SuperLoc, diag::err_undef_superclass)
621	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
622	else if (RequireCompleteType(SuperLoc,
623	SuperClassType,
624	diag::err_forward_superclass,
625	SuperClassDecl->getDeclName(),
626	ClassName,
627	SourceRange(AtInterfaceLoc, ClassLoc))) {
628	SuperClassDecl = nullptr;
629	SuperClassType = QualType();
630	}
631	}
632
633	if (SuperClassType.isNull()) {
634	assert(!SuperClassDecl && "Failed to set SuperClassType?");
635	return;
636	}
637
638	// Handle type arguments on the superclass.
639	TypeSourceInfo *SuperClassTInfo = nullptr;
640	if (!SuperTypeArgs.empty()) {
641	TypeResult fullSuperClassType = actOnObjCTypeArgsAndProtocolQualifiers(
642	S,
643	Loc: SuperLoc,
644	BaseType: CreateParsedType(T: SuperClassType,
645	TInfo: nullptr),
646	TypeArgsLAngleLoc: SuperTypeArgsRange.getBegin(),
647	TypeArgs: SuperTypeArgs,
648	TypeArgsRAngleLoc: SuperTypeArgsRange.getEnd(),
649	ProtocolLAngleLoc: SourceLocation(),
650	Protocols: { },
651	ProtocolLocs: { },
652	ProtocolRAngleLoc: SourceLocation());
653	if (!fullSuperClassType.isUsable())
654	return;
655
656	SuperClassType = GetTypeFromParser(Ty: fullSuperClassType.get(),
657	TInfo: &SuperClassTInfo);
658	}
659
660	if (!SuperClassTInfo) {
661	SuperClassTInfo = Context.getTrivialTypeSourceInfo(T: SuperClassType,
662	Loc: SuperLoc);
663	}
664
665	IDecl->setSuperClass(SuperClassTInfo);
666	IDecl->setEndOfDefinitionLoc(SuperClassTInfo->getTypeLoc().getEndLoc());
667	}
668	}
669
670	DeclResult Sema::actOnObjCTypeParam(Scope *S,
671	ObjCTypeParamVariance variance,
672	SourceLocation varianceLoc,
673	unsigned index,
674	IdentifierInfo *paramName,
675	SourceLocation paramLoc,
676	SourceLocation colonLoc,
677	ParsedType parsedTypeBound) {
678	// If there was an explicitly-provided type bound, check it.
679	TypeSourceInfo *typeBoundInfo = nullptr;
680	if (parsedTypeBound) {
681	// The type bound can be any Objective-C pointer type.
682	QualType typeBound = GetTypeFromParser(Ty: parsedTypeBound, TInfo: &typeBoundInfo);
683	if (typeBound->isObjCObjectPointerType()) {
684	// okay
685	} else if (typeBound->isObjCObjectType()) {
686	// The user forgot the * on an Objective-C pointer type, e.g.,
687	// "T : NSView".
688	SourceLocation starLoc = getLocForEndOfToken(
689	Loc: typeBoundInfo->getTypeLoc().getEndLoc());
690	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
691	diag::err_objc_type_param_bound_missing_pointer)
692	<< typeBound << paramName
693	<< FixItHint::CreateInsertion(starLoc, " *");
694
695	// Create a new type location builder so we can update the type
696	// location information we have.
697	TypeLocBuilder builder;
698	builder.pushFullCopy(L: typeBoundInfo->getTypeLoc());
699
700	// Create the Objective-C pointer type.
701	typeBound = Context.getObjCObjectPointerType(OIT: typeBound);
702	ObjCObjectPointerTypeLoc newT
703	= builder.push<ObjCObjectPointerTypeLoc>(T: typeBound);
704	newT.setStarLoc(starLoc);
705
706	// Form the new type source information.
707	typeBoundInfo = builder.getTypeSourceInfo(Context, T: typeBound);
708	} else {
709	// Not a valid type bound.
710	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
711	diag::err_objc_type_param_bound_nonobject)
712	<< typeBound << paramName;
713
714	// Forget the bound; we'll default to id later.
715	typeBoundInfo = nullptr;
716	}
717
718	// Type bounds cannot have qualifiers (even indirectly) or explicit
719	// nullability.
720	if (typeBoundInfo) {
721	QualType typeBound = typeBoundInfo->getType();
722	TypeLoc qual = typeBoundInfo->getTypeLoc().findExplicitQualifierLoc();
723	if (qual || typeBound.hasQualifiers()) {
724	bool diagnosed = false;
725	SourceRange rangeToRemove;
726	if (qual) {
727	if (auto attr = qual.getAs<AttributedTypeLoc>()) {
728	rangeToRemove = attr.getLocalSourceRange();
729	if (attr.getTypePtr()->getImmediateNullability()) {
730	Diag(attr.getBeginLoc(),
731	diag::err_objc_type_param_bound_explicit_nullability)
732	<< paramName << typeBound
733	<< FixItHint::CreateRemoval(rangeToRemove);
734	diagnosed = true;
735	}
736	}
737	}
738
739	if (!diagnosed) {
740	Diag(qual ? qual.getBeginLoc()
741	: typeBoundInfo->getTypeLoc().getBeginLoc(),
742	diag::err_objc_type_param_bound_qualified)
743	<< paramName << typeBound
744	<< typeBound.getQualifiers().getAsString()
745	<< FixItHint::CreateRemoval(rangeToRemove);
746	}
747
748	// If the type bound has qualifiers other than CVR, we need to strip
749	// them or we'll probably assert later when trying to apply new
750	// qualifiers.
751	Qualifiers quals = typeBound.getQualifiers();
752	quals.removeCVRQualifiers();
753	if (!quals.empty()) {
754	typeBoundInfo =
755	Context.getTrivialTypeSourceInfo(T: typeBound.getUnqualifiedType());
756	}
757	}
758	}
759	}
760
761	// If there was no explicit type bound (or we removed it due to an error),
762	// use 'id' instead.
763	if (!typeBoundInfo) {
764	colonLoc = SourceLocation();
765	typeBoundInfo = Context.getTrivialTypeSourceInfo(T: Context.getObjCIdType());
766	}
767
768	// Create the type parameter.
769	return ObjCTypeParamDecl::Create(ctx&: Context, dc: CurContext, variance, varianceLoc,
770	index, nameLoc: paramLoc, name: paramName, colonLoc,
771	boundInfo: typeBoundInfo);
772	}
773
774	ObjCTypeParamList *Sema::actOnObjCTypeParamList(Scope *S,
775	SourceLocation lAngleLoc,
776	ArrayRef<Decl *> typeParamsIn,
777	SourceLocation rAngleLoc) {
778	// We know that the array only contains Objective-C type parameters.
779	ArrayRef<ObjCTypeParamDecl *>
780	typeParams(
781	reinterpret_cast<ObjCTypeParamDecl * const *>(typeParamsIn.data()),
782	typeParamsIn.size());
783
784	// Diagnose redeclarations of type parameters.
785	// We do this now because Objective-C type parameters aren't pushed into
786	// scope until later (after the instance variable block), but we want the
787	// diagnostics to occur right after we parse the type parameter list.
788	llvm::SmallDenseMap<IdentifierInfo *, ObjCTypeParamDecl *> knownParams;
789	for (auto *typeParam : typeParams) {
790	auto known = knownParams.find(typeParam->getIdentifier());
791	if (known != knownParams.end()) {
792	Diag(typeParam->getLocation(), diag::err_objc_type_param_redecl)
793	<< typeParam->getIdentifier()
794	<< SourceRange(known->second->getLocation());
795
796	typeParam->setInvalidDecl();
797	} else {
798	knownParams.insert(std::make_pair(typeParam->getIdentifier(), typeParam));
799
800	// Push the type parameter into scope.
801	PushOnScopeChains(typeParam, S, /*AddToContext=*/false);
802	}
803	}
804
805	// Create the parameter list.
806	return ObjCTypeParamList::create(ctx&: Context, lAngleLoc, typeParams, rAngleLoc);
807	}
808
809	void Sema::popObjCTypeParamList(Scope *S, ObjCTypeParamList *typeParamList) {
810	for (auto *typeParam : *typeParamList) {
811	if (!typeParam->isInvalidDecl()) {
812	S->RemoveDecl(typeParam);
813	IdResolver.RemoveDecl(typeParam);
814	}
815	}
816	}
817
818	namespace {
819	/// The context in which an Objective-C type parameter list occurs, for use
820	/// in diagnostics.
821	enum class TypeParamListContext {
822	ForwardDeclaration,
823	Definition,
824	Category,
825	Extension
826	};
827	} // end anonymous namespace
828
829	/// Check consistency between two Objective-C type parameter lists, e.g.,
830	/// between a category/extension and an \@interface or between an \@class and an
831	/// \@interface.
832	static bool checkTypeParamListConsistency(Sema &S,
833	ObjCTypeParamList *prevTypeParams,
834	ObjCTypeParamList *newTypeParams,
835	TypeParamListContext newContext) {
836	// If the sizes don't match, complain about that.
837	if (prevTypeParams->size() != newTypeParams->size()) {
838	SourceLocation diagLoc;
839	if (newTypeParams->size() > prevTypeParams->size()) {
840	diagLoc = newTypeParams->begin()[prevTypeParams->size()]->getLocation();
841	} else {
842	diagLoc = S.getLocForEndOfToken(Loc: newTypeParams->back()->getEndLoc());
843	}
844
845	S.Diag(diagLoc, diag::err_objc_type_param_arity_mismatch)
846	<< static_cast<unsigned>(newContext)
847	<< (newTypeParams->size() > prevTypeParams->size())
848	<< prevTypeParams->size()
849	<< newTypeParams->size();
850
851	return true;
852	}
853
854	// Match up the type parameters.
855	for (unsigned i = 0, n = prevTypeParams->size(); i != n; ++i) {
856	ObjCTypeParamDecl *prevTypeParam = prevTypeParams->begin()[i];
857	ObjCTypeParamDecl *newTypeParam = newTypeParams->begin()[i];
858
859	// Check for consistency of the variance.
860	if (newTypeParam->getVariance() != prevTypeParam->getVariance()) {
861	if (newTypeParam->getVariance() == ObjCTypeParamVariance::Invariant &&
862	newContext != TypeParamListContext::Definition) {
863	// When the new type parameter is invariant and is not part
864	// of the definition, just propagate the variance.
865	newTypeParam->setVariance(prevTypeParam->getVariance());
866	} else if (prevTypeParam->getVariance()
867	== ObjCTypeParamVariance::Invariant &&
868	!(isa<ObjCInterfaceDecl>(prevTypeParam->getDeclContext()) &&
869	cast<ObjCInterfaceDecl>(prevTypeParam->getDeclContext())
870	->getDefinition() == prevTypeParam->getDeclContext())) {
871	// When the old parameter is invariant and was not part of the
872	// definition, just ignore the difference because it doesn't
873	// matter.
874	} else {
875	{
876	// Diagnose the conflict and update the second declaration.
877	SourceLocation diagLoc = newTypeParam->getVarianceLoc();
878	if (diagLoc.isInvalid())
879	diagLoc = newTypeParam->getBeginLoc();
880
881	auto diag = S.Diag(diagLoc,
882	diag::err_objc_type_param_variance_conflict)
883	<< static_cast<unsigned>(newTypeParam->getVariance())
884	<< newTypeParam->getDeclName()
885	<< static_cast<unsigned>(prevTypeParam->getVariance())
886	<< prevTypeParam->getDeclName();
887	switch (prevTypeParam->getVariance()) {
888	case ObjCTypeParamVariance::Invariant:
889	diag << FixItHint::CreateRemoval(RemoveRange: newTypeParam->getVarianceLoc());
890	break;
891
892	case ObjCTypeParamVariance::Covariant:
893	case ObjCTypeParamVariance::Contravariant: {
894	StringRef newVarianceStr
895	= prevTypeParam->getVariance() == ObjCTypeParamVariance::Covariant
896	? "__covariant"
897	: "__contravariant";
898	if (newTypeParam->getVariance()
899	== ObjCTypeParamVariance::Invariant) {
900	diag << FixItHint::CreateInsertion(InsertionLoc: newTypeParam->getBeginLoc(),
901	Code: (newVarianceStr + " ").str());
902	} else {
903	diag << FixItHint::CreateReplacement(RemoveRange: newTypeParam->getVarianceLoc(),
904	Code: newVarianceStr);
905	}
906	}
907	}
908	}
909
910	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
911	<< prevTypeParam->getDeclName();
912
913	// Override the variance.
914	newTypeParam->setVariance(prevTypeParam->getVariance());
915	}
916	}
917
918	// If the bound types match, there's nothing to do.
919	if (S.Context.hasSameType(prevTypeParam->getUnderlyingType(),
920	newTypeParam->getUnderlyingType()))
921	continue;
922
923	// If the new type parameter's bound was explicit, complain about it being
924	// different from the original.
925	if (newTypeParam->hasExplicitBound()) {
926	SourceRange newBoundRange = newTypeParam->getTypeSourceInfo()
927	->getTypeLoc().getSourceRange();
928	S.Diag(newBoundRange.getBegin(), diag::err_objc_type_param_bound_conflict)
929	<< newTypeParam->getUnderlyingType()
930	<< newTypeParam->getDeclName()
931	<< prevTypeParam->hasExplicitBound()
932	<< prevTypeParam->getUnderlyingType()
933	<< (newTypeParam->getDeclName() == prevTypeParam->getDeclName())
934	<< prevTypeParam->getDeclName()
935	<< FixItHint::CreateReplacement(
936	newBoundRange,
937	prevTypeParam->getUnderlyingType().getAsString(
938	S.Context.getPrintingPolicy()));
939
940	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
941	<< prevTypeParam->getDeclName();
942
943	// Override the new type parameter's bound type with the previous type,
944	// so that it's consistent.
945	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
946	continue;
947	}
948
949	// The new type parameter got the implicit bound of 'id'. That's okay for
950	// categories and extensions (overwrite it later), but not for forward
951	// declarations and @interfaces, because those must be standalone.
952	if (newContext == TypeParamListContext::ForwardDeclaration ||
953	newContext == TypeParamListContext::Definition) {
954	// Diagnose this problem for forward declarations and definitions.
955	SourceLocation insertionLoc
956	= S.getLocForEndOfToken(Loc: newTypeParam->getLocation());
957	std::string newCode
958	= " : " + prevTypeParam->getUnderlyingType().getAsString(
959	S.Context.getPrintingPolicy());
960	S.Diag(newTypeParam->getLocation(),
961	diag::err_objc_type_param_bound_missing)
962	<< prevTypeParam->getUnderlyingType()
963	<< newTypeParam->getDeclName()
964	<< (newContext == TypeParamListContext::ForwardDeclaration)
965	<< FixItHint::CreateInsertion(insertionLoc, newCode);
966
967	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
968	<< prevTypeParam->getDeclName();
969	}
970
971	// Update the new type parameter's bound to match the previous one.
972	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
973	}
974
975	return false;
976	}
977
978	ObjCInterfaceDecl *Sema::ActOnStartClassInterface(
979	Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
980	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
981	IdentifierInfo *SuperName, SourceLocation SuperLoc,
982	ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
983	Decl *const *ProtoRefs, unsigned NumProtoRefs,
984	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
985	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
986	assert(ClassName && "Missing class identifier");
987
988	// Check for another declaration kind with the same name.
989	NamedDecl *PrevDecl =
990	LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLoc, NameKind: LookupOrdinaryName,
991	Redecl: forRedeclarationInCurContext());
992
993	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
994	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
995	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
996	}
997
998	// Create a declaration to describe this @interface.
999	ObjCInterfaceDecl* PrevIDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
1000
1001	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
1002	// A previous decl with a different name is because of
1003	// @compatibility_alias, for example:
1004	// \code
1005	// @class NewImage;
1006	// @compatibility_alias OldImage NewImage;
1007	// \endcode
1008	// A lookup for 'OldImage' will return the 'NewImage' decl.
1009	//
1010	// In such a case use the real declaration name, instead of the alias one,
1011	// otherwise we will break IdentifierResolver and redecls-chain invariants.
1012	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
1013	// has been aliased.
1014	ClassName = PrevIDecl->getIdentifier();
1015	}
1016
1017	// If there was a forward declaration with type parameters, check
1018	// for consistency.
1019	if (PrevIDecl) {
1020	if (ObjCTypeParamList *prevTypeParamList = PrevIDecl->getTypeParamList()) {
1021	if (typeParamList) {
1022	// Both have type parameter lists; check for consistency.
1023	if (checkTypeParamListConsistency(S&: *this, prevTypeParams: prevTypeParamList,
1024	newTypeParams: typeParamList,
1025	newContext: TypeParamListContext::Definition)) {
1026	typeParamList = nullptr;
1027	}
1028	} else {
1029	Diag(ClassLoc, diag::err_objc_parameterized_forward_class_first)
1030	<< ClassName;
1031	Diag(prevTypeParamList->getLAngleLoc(), diag::note_previous_decl)
1032	<< ClassName;
1033
1034	// Clone the type parameter list.
1035	SmallVector<ObjCTypeParamDecl *, 4> clonedTypeParams;
1036	for (auto *typeParam : *prevTypeParamList) {
1037	clonedTypeParams.push_back(
1038	Elt: ObjCTypeParamDecl::Create(
1039	ctx&: Context,
1040	dc: CurContext,
1041	variance: typeParam->getVariance(),
1042	varianceLoc: SourceLocation(),
1043	index: typeParam->getIndex(),
1044	nameLoc: SourceLocation(),
1045	name: typeParam->getIdentifier(),
1046	colonLoc: SourceLocation(),
1047	boundInfo: Context.getTrivialTypeSourceInfo(T: typeParam->getUnderlyingType())));
1048	}
1049
1050	typeParamList = ObjCTypeParamList::create(ctx&: Context,
1051	lAngleLoc: SourceLocation(),
1052	typeParams: clonedTypeParams,
1053	rAngleLoc: SourceLocation());
1054	}
1055	}
1056	}
1057
1058	ObjCInterfaceDecl *IDecl
1059	= ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtInterfaceLoc, Id: ClassName,
1060	typeParamList, PrevDecl: PrevIDecl, ClassLoc);
1061	if (PrevIDecl) {
1062	// Class already seen. Was it a definition?
1063	if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
1064	if (SkipBody && !hasVisibleDefinition(Def)) {
1065	SkipBody->CheckSameAsPrevious = true;
1066	SkipBody->New = IDecl;
1067	SkipBody->Previous = Def;
1068	} else {
1069	Diag(AtInterfaceLoc, diag::err_duplicate_class_def)
1070	<< PrevIDecl->getDeclName();
1071	Diag(Def->getLocation(), diag::note_previous_definition);
1072	IDecl->setInvalidDecl();
1073	}
1074	}
1075	}
1076
1077	ProcessDeclAttributeList(TUScope, IDecl, AttrList);
1078	AddPragmaAttributes(TUScope, IDecl);
1079	ProcessAPINotes(IDecl);
1080
1081	// Merge attributes from previous declarations.
1082	if (PrevIDecl)
1083	mergeDeclAttributes(IDecl, PrevIDecl);
1084
1085	PushOnScopeChains(IDecl, TUScope);
1086
1087	// Start the definition of this class. If we're in a redefinition case, there
1088	// may already be a definition, so we'll end up adding to it.
1089	if (SkipBody && SkipBody->CheckSameAsPrevious)
1090	IDecl->startDuplicateDefinitionForComparison();
1091	else if (!IDecl->hasDefinition())
1092	IDecl->startDefinition();
1093
1094	if (SuperName) {
1095	// Diagnose availability in the context of the @interface.
1096	ContextRAII SavedContext(*this, IDecl);
1097
1098	ActOnSuperClassOfClassInterface(S, AtInterfaceLoc, IDecl,
1099	ClassName, ClassLoc,
1100	SuperName, SuperLoc, SuperTypeArgs,
1101	SuperTypeArgsRange);
1102	} else { // we have a root class.
1103	IDecl->setEndOfDefinitionLoc(ClassLoc);
1104	}
1105
1106	// Check then save referenced protocols.
1107	if (NumProtoRefs) {
1108	diagnoseUseOfProtocols(*this, IDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1109	NumProtoRefs, ProtoLocs);
1110	IDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1111	Locs: ProtoLocs, C&: Context);
1112	IDecl->setEndOfDefinitionLoc(EndProtoLoc);
1113	}
1114
1115	CheckObjCDeclScope(IDecl);
1116	ActOnObjCContainerStartDefinition(IDecl);
1117	return IDecl;
1118	}
1119
1120	/// ActOnTypedefedProtocols - this action finds protocol list as part of the
1121	/// typedef'ed use for a qualified super class and adds them to the list
1122	/// of the protocols.
1123	void Sema::ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
1124	SmallVectorImpl<SourceLocation> &ProtocolLocs,
1125	IdentifierInfo *SuperName,
1126	SourceLocation SuperLoc) {
1127	if (!SuperName)
1128	return;
1129	NamedDecl* IDecl = LookupSingleName(S: TUScope, Name: SuperName, Loc: SuperLoc,
1130	NameKind: LookupOrdinaryName);
1131	if (!IDecl)
1132	return;
1133
1134	if (const TypedefNameDecl *TDecl = dyn_cast_or_null<TypedefNameDecl>(Val: IDecl)) {
1135	QualType T = TDecl->getUnderlyingType();
1136	if (T->isObjCObjectType())
1137	if (const ObjCObjectType *OPT = T->getAs<ObjCObjectType>()) {
1138	ProtocolRefs.append(OPT->qual_begin(), OPT->qual_end());
1139	// FIXME: Consider whether this should be an invalid loc since the loc
1140	// is not actually pointing to a protocol name reference but to the
1141	// typedef reference. Note that the base class name loc is also pointing
1142	// at the typedef.
1143	ProtocolLocs.append(OPT->getNumProtocols(), SuperLoc);
1144	}
1145	}
1146	}
1147
1148	/// ActOnCompatibilityAlias - this action is called after complete parsing of
1149	/// a \@compatibility_alias declaration. It sets up the alias relationships.
1150	Decl *Sema::ActOnCompatibilityAlias(SourceLocation AtLoc,
1151	IdentifierInfo *AliasName,
1152	SourceLocation AliasLocation,
1153	IdentifierInfo *ClassName,
1154	SourceLocation ClassLocation) {
1155	// Look for previous declaration of alias name
1156	NamedDecl *ADecl =
1157	LookupSingleName(S: TUScope, Name: AliasName, Loc: AliasLocation, NameKind: LookupOrdinaryName,
1158	Redecl: forRedeclarationInCurContext());
1159	if (ADecl) {
1160	Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
1161	Diag(ADecl->getLocation(), diag::note_previous_declaration);
1162	return nullptr;
1163	}
1164	// Check for class declaration
1165	NamedDecl *CDeclU =
1166	LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLocation, NameKind: LookupOrdinaryName,
1167	Redecl: forRedeclarationInCurContext());
1168	if (const TypedefNameDecl *TDecl =
1169	dyn_cast_or_null<TypedefNameDecl>(Val: CDeclU)) {
1170	QualType T = TDecl->getUnderlyingType();
1171	if (T->isObjCObjectType()) {
1172	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
1173	ClassName = IDecl->getIdentifier();
1174	CDeclU = LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLocation,
1175	NameKind: LookupOrdinaryName,
1176	Redecl: forRedeclarationInCurContext());
1177	}
1178	}
1179	}
1180	ObjCInterfaceDecl *CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: CDeclU);
1181	if (!CDecl) {
1182	Diag(ClassLocation, diag::warn_undef_interface) << ClassName;
1183	if (CDeclU)
1184	Diag(CDeclU->getLocation(), diag::note_previous_declaration);
1185	return nullptr;
1186	}
1187
1188	// Everything checked out, instantiate a new alias declaration AST.
1189	ObjCCompatibleAliasDecl *AliasDecl =
1190	ObjCCompatibleAliasDecl::Create(C&: Context, DC: CurContext, L: AtLoc, Id: AliasName, aliasedClass: CDecl);
1191
1192	if (!CheckObjCDeclScope(AliasDecl))
1193	PushOnScopeChains(AliasDecl, TUScope);
1194
1195	return AliasDecl;
1196	}
1197
1198	bool Sema::CheckForwardProtocolDeclarationForCircularDependency(
1199	IdentifierInfo *PName,
1200	SourceLocation &Ploc, SourceLocation PrevLoc,
1201	const ObjCList<ObjCProtocolDecl> &PList) {
1202
1203	bool res = false;
1204	for (ObjCList<ObjCProtocolDecl>::iterator I = PList.begin(),
1205	E = PList.end(); I != E; ++I) {
1206	if (ObjCProtocolDecl *PDecl = LookupProtocol(II: (*I)->getIdentifier(),
1207	IdLoc: Ploc)) {
1208	if (PDecl->getIdentifier() == PName) {
1209	Diag(Ploc, diag::err_protocol_has_circular_dependency);
1210	Diag(PrevLoc, diag::note_previous_definition);
1211	res = true;
1212	}
1213
1214	if (!PDecl->hasDefinition())
1215	continue;
1216
1217	if (CheckForwardProtocolDeclarationForCircularDependency(PName, Ploc,
1218	PrevLoc: PDecl->getLocation(), PList: PDecl->getReferencedProtocols()))
1219	res = true;
1220	}
1221	}
1222	return res;
1223	}
1224
1225	ObjCProtocolDecl *Sema::ActOnStartProtocolInterface(
1226	SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
1227	SourceLocation ProtocolLoc, Decl *const *ProtoRefs, unsigned NumProtoRefs,
1228	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1229	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
1230	bool err = false;
1231	// FIXME: Deal with AttrList.
1232	assert(ProtocolName && "Missing protocol identifier");
1233	ObjCProtocolDecl *PrevDecl = LookupProtocol(II: ProtocolName, IdLoc: ProtocolLoc,
1234	Redecl: forRedeclarationInCurContext());
1235	ObjCProtocolDecl *PDecl = nullptr;
1236	if (ObjCProtocolDecl *Def = PrevDecl? PrevDecl->getDefinition() : nullptr) {
1237	// Create a new protocol that is completely distinct from previous
1238	// declarations, and do not make this protocol available for name lookup.
1239	// That way, we'll end up completely ignoring the duplicate.
1240	// FIXME: Can we turn this into an error?
1241	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: ProtocolName,
1242	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1243	/*PrevDecl=*/Def);
1244
1245	if (SkipBody && !hasVisibleDefinition(Def)) {
1246	SkipBody->CheckSameAsPrevious = true;
1247	SkipBody->New = PDecl;
1248	SkipBody->Previous = Def;
1249	} else {
1250	// If we already have a definition, complain.
1251	Diag(ProtocolLoc, diag::warn_duplicate_protocol_def) << ProtocolName;
1252	Diag(Def->getLocation(), diag::note_previous_definition);
1253	}
1254
1255	// If we are using modules, add the decl to the context in order to
1256	// serialize something meaningful.
1257	if (getLangOpts().Modules)
1258	PushOnScopeChains(PDecl, TUScope);
1259	PDecl->startDuplicateDefinitionForComparison();
1260	} else {
1261	if (PrevDecl) {
1262	// Check for circular dependencies among protocol declarations. This can
1263	// only happen if this protocol was forward-declared.
1264	ObjCList<ObjCProtocolDecl> PList;
1265	PList.set(InList: (ObjCProtocolDecl *const*)ProtoRefs, Elts: NumProtoRefs, Ctx&: Context);
1266	err = CheckForwardProtocolDeclarationForCircularDependency(
1267	PName: ProtocolName, Ploc&: ProtocolLoc, PrevLoc: PrevDecl->getLocation(), PList);
1268	}
1269
1270	// Create the new declaration.
1271	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: ProtocolName,
1272	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1273	/*PrevDecl=*/PrevDecl);
1274
1275	PushOnScopeChains(PDecl, TUScope);
1276	PDecl->startDefinition();
1277	}
1278
1279	ProcessDeclAttributeList(TUScope, PDecl, AttrList);
1280	AddPragmaAttributes(TUScope, PDecl);
1281	ProcessAPINotes(PDecl);
1282
1283	// Merge attributes from previous declarations.
1284	if (PrevDecl)
1285	mergeDeclAttributes(PDecl, PrevDecl);
1286
1287	if (!err && NumProtoRefs ) {
1288	/// Check then save referenced protocols.
1289	diagnoseUseOfProtocols(*this, PDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1290	NumProtoRefs, ProtoLocs);
1291	PDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1292	Locs: ProtoLocs, C&: Context);
1293	}
1294
1295	CheckObjCDeclScope(PDecl);
1296	ActOnObjCContainerStartDefinition(PDecl);
1297	return PDecl;
1298	}
1299
1300	static bool NestedProtocolHasNoDefinition(ObjCProtocolDecl *PDecl,
1301	ObjCProtocolDecl *&UndefinedProtocol) {
1302	if (!PDecl->hasDefinition() ||
1303	!PDecl->getDefinition()->isUnconditionallyVisible()) {
1304	UndefinedProtocol = PDecl;
1305	return true;
1306	}
1307
1308	for (auto *PI : PDecl->protocols())
1309	if (NestedProtocolHasNoDefinition(PDecl: PI, UndefinedProtocol)) {
1310	UndefinedProtocol = PI;
1311	return true;
1312	}
1313	return false;
1314	}
1315
1316	/// FindProtocolDeclaration - This routine looks up protocols and
1317	/// issues an error if they are not declared. It returns list of
1318	/// protocol declarations in its 'Protocols' argument.
1319	void
1320	Sema::FindProtocolDeclaration(bool WarnOnDeclarations, bool ForObjCContainer,
1321	ArrayRef<IdentifierLocPair> ProtocolId,
1322	SmallVectorImpl<Decl *> &Protocols) {
1323	for (const IdentifierLocPair &Pair : ProtocolId) {
1324	ObjCProtocolDecl *PDecl = LookupProtocol(II: Pair.first, IdLoc: Pair.second);
1325	if (!PDecl) {
1326	DeclFilterCCC<ObjCProtocolDecl> CCC{};
1327	TypoCorrection Corrected = CorrectTypo(
1328	Typo: DeclarationNameInfo(Pair.first, Pair.second), LookupKind: LookupObjCProtocolName,
1329	S: TUScope, SS: nullptr, CCC, Mode: CTK_ErrorRecovery);
1330	if ((PDecl = Corrected.getCorrectionDeclAs<ObjCProtocolDecl>()))
1331	diagnoseTypo(Corrected, PDiag(diag::err_undeclared_protocol_suggest)
1332	<< Pair.first);
1333	}
1334
1335	if (!PDecl) {
1336	Diag(Pair.second, diag::err_undeclared_protocol) << Pair.first;
1337	continue;
1338	}
1339	// If this is a forward protocol declaration, get its definition.
1340	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
1341	PDecl = PDecl->getDefinition();
1342
1343	// For an objc container, delay protocol reference checking until after we
1344	// can set the objc decl as the availability context, otherwise check now.
1345	if (!ForObjCContainer) {
1346	(void)DiagnoseUseOfDecl(PDecl, Pair.second);
1347	}
1348
1349	// If this is a forward declaration and we are supposed to warn in this
1350	// case, do it.
1351	// FIXME: Recover nicely in the hidden case.
1352	ObjCProtocolDecl *UndefinedProtocol;
1353
1354	if (WarnOnDeclarations &&
1355	NestedProtocolHasNoDefinition(PDecl, UndefinedProtocol)) {
1356	Diag(Pair.second, diag::warn_undef_protocolref) << Pair.first;
1357	Diag(UndefinedProtocol->getLocation(), diag::note_protocol_decl_undefined)
1358	<< UndefinedProtocol;
1359	}
1360	Protocols.push_back(PDecl);
1361	}
1362	}
1363
1364	namespace {
1365	// Callback to only accept typo corrections that are either
1366	// Objective-C protocols or valid Objective-C type arguments.
1367	class ObjCTypeArgOrProtocolValidatorCCC final
1368	: public CorrectionCandidateCallback {
1369	ASTContext &Context;
1370	Sema::LookupNameKind LookupKind;
1371	public:
1372	ObjCTypeArgOrProtocolValidatorCCC(ASTContext &context,
1373	Sema::LookupNameKind lookupKind)
1374	: Context(context), LookupKind(lookupKind) { }
1375
1376	bool ValidateCandidate(const TypoCorrection &candidate) override {
1377	// If we're allowed to find protocols and we have a protocol, accept it.
1378	if (LookupKind != Sema::LookupOrdinaryName) {
1379	if (candidate.getCorrectionDeclAs<ObjCProtocolDecl>())
1380	return true;
1381	}
1382
1383	// If we're allowed to find type names and we have one, accept it.
1384	if (LookupKind != Sema::LookupObjCProtocolName) {
1385	// If we have a type declaration, we might accept this result.
1386	if (auto typeDecl = candidate.getCorrectionDeclAs<TypeDecl>()) {
1387	// If we found a tag declaration outside of C++, skip it. This
1388	// can happy because we look for any name when there is no
1389	// bias to protocol or type names.
1390	if (isa<RecordDecl>(Val: typeDecl) && !Context.getLangOpts().CPlusPlus)
1391	return false;
1392
1393	// Make sure the type is something we would accept as a type
1394	// argument.
1395	auto type = Context.getTypeDeclType(Decl: typeDecl);
1396	if (type->isObjCObjectPointerType() ||
1397	type->isBlockPointerType() ||
1398	type->isDependentType() ||
1399	type->isObjCObjectType())
1400	return true;
1401
1402	return false;
1403	}
1404
1405	// If we have an Objective-C class type, accept it; there will
1406	// be another fix to add the '*'.
1407	if (candidate.getCorrectionDeclAs<ObjCInterfaceDecl>())
1408	return true;
1409
1410	return false;
1411	}
1412
1413	return false;
1414	}
1415
1416	std::unique_ptr<CorrectionCandidateCallback> clone() override {
1417	return std::make_unique<ObjCTypeArgOrProtocolValidatorCCC>(args&: *this);
1418	}
1419	};
1420	} // end anonymous namespace
1421
1422	void Sema::DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
1423	SourceLocation ProtocolLoc,
1424	IdentifierInfo *TypeArgId,
1425	SourceLocation TypeArgLoc,
1426	bool SelectProtocolFirst) {
1427	Diag(TypeArgLoc, diag::err_objc_type_args_and_protocols)
1428	<< SelectProtocolFirst << TypeArgId << ProtocolId
1429	<< SourceRange(ProtocolLoc);
1430	}
1431
1432	void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
1433	Scope *S,
1434	ParsedType baseType,
1435	SourceLocation lAngleLoc,
1436	ArrayRef<IdentifierInfo *> identifiers,
1437	ArrayRef<SourceLocation> identifierLocs,
1438	SourceLocation rAngleLoc,
1439	SourceLocation &typeArgsLAngleLoc,
1440	SmallVectorImpl<ParsedType> &typeArgs,
1441	SourceLocation &typeArgsRAngleLoc,
1442	SourceLocation &protocolLAngleLoc,
1443	SmallVectorImpl<Decl *> &protocols,
1444	SourceLocation &protocolRAngleLoc,
1445	bool warnOnIncompleteProtocols) {
1446	// Local function that updates the declaration specifiers with
1447	// protocol information.
1448	unsigned numProtocolsResolved = 0;
1449	auto resolvedAsProtocols = [&] {
1450	assert(numProtocolsResolved == identifiers.size() && "Unresolved protocols");
1451
1452	// Determine whether the base type is a parameterized class, in
1453	// which case we want to warn about typos such as
1454	// "NSArray<NSObject>" (that should be NSArray<NSObject *>).
1455	ObjCInterfaceDecl *baseClass = nullptr;
1456	QualType base = GetTypeFromParser(Ty: baseType, TInfo: nullptr);
1457	bool allAreTypeNames = false;
1458	SourceLocation firstClassNameLoc;
1459	if (!base.isNull()) {
1460	if (const auto *objcObjectType = base->getAs<ObjCObjectType>()) {
1461	baseClass = objcObjectType->getInterface();
1462	if (baseClass) {
1463	if (auto typeParams = baseClass->getTypeParamList()) {
1464	if (typeParams->size() == numProtocolsResolved) {
1465	// Note that we should be looking for type names, too.
1466	allAreTypeNames = true;
1467	}
1468	}
1469	}
1470	}
1471	}
1472
1473	for (unsigned i = 0, n = protocols.size(); i != n; ++i) {
1474	ObjCProtocolDecl *&proto
1475	= reinterpret_cast<ObjCProtocolDecl *&>(protocols[i]);
1476	// For an objc container, delay protocol reference checking until after we
1477	// can set the objc decl as the availability context, otherwise check now.
1478	if (!warnOnIncompleteProtocols) {
1479	(void)DiagnoseUseOfDecl(proto, identifierLocs[i]);
1480	}
1481
1482	// If this is a forward protocol declaration, get its definition.
1483	if (!proto->isThisDeclarationADefinition() && proto->getDefinition())
1484	proto = proto->getDefinition();
1485
1486	// If this is a forward declaration and we are supposed to warn in this
1487	// case, do it.
1488	// FIXME: Recover nicely in the hidden case.
1489	ObjCProtocolDecl *forwardDecl = nullptr;
1490	if (warnOnIncompleteProtocols &&
1491	NestedProtocolHasNoDefinition(PDecl: proto, UndefinedProtocol&: forwardDecl)) {
1492	Diag(identifierLocs[i], diag::warn_undef_protocolref)
1493	<< proto->getDeclName();
1494	Diag(forwardDecl->getLocation(), diag::note_protocol_decl_undefined)
1495	<< forwardDecl;
1496	}
1497
1498	// If everything this far has been a type name (and we care
1499	// about such things), check whether this name refers to a type
1500	// as well.
1501	if (allAreTypeNames) {
1502	if (auto *decl = LookupSingleName(S, Name: identifiers[i], Loc: identifierLocs[i],
1503	NameKind: LookupOrdinaryName)) {
1504	if (isa<ObjCInterfaceDecl>(Val: decl)) {
1505	if (firstClassNameLoc.isInvalid())
1506	firstClassNameLoc = identifierLocs[i];
1507	} else if (!isa<TypeDecl>(Val: decl)) {
1508	// Not a type.
1509	allAreTypeNames = false;
1510	}
1511	} else {
1512	allAreTypeNames = false;
1513	}
1514	}
1515	}
1516
1517	// All of the protocols listed also have type names, and at least
1518	// one is an Objective-C class name. Check whether all of the
1519	// protocol conformances are declared by the base class itself, in
1520	// which case we warn.
1521	if (allAreTypeNames && firstClassNameLoc.isValid()) {
1522	llvm::SmallPtrSet<ObjCProtocolDecl*, 8> knownProtocols;
1523	Context.CollectInheritedProtocols(baseClass, knownProtocols);
1524	bool allProtocolsDeclared = true;
1525	for (auto *proto : protocols) {
1526	if (knownProtocols.count(Ptr: static_cast<ObjCProtocolDecl *>(proto)) == 0) {
1527	allProtocolsDeclared = false;
1528	break;
1529	}
1530	}
1531
1532	if (allProtocolsDeclared) {
1533	Diag(firstClassNameLoc, diag::warn_objc_redundant_qualified_class_type)
1534	<< baseClass->getDeclName() << SourceRange(lAngleLoc, rAngleLoc)
1535	<< FixItHint::CreateInsertion(getLocForEndOfToken(firstClassNameLoc),
1536	" *");
1537	}
1538	}
1539
1540	protocolLAngleLoc = lAngleLoc;
1541	protocolRAngleLoc = rAngleLoc;
1542	assert(protocols.size() == identifierLocs.size());
1543	};
1544
1545	// Attempt to resolve all of the identifiers as protocols.
1546	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1547	ObjCProtocolDecl *proto = LookupProtocol(II: identifiers[i], IdLoc: identifierLocs[i]);
1548	protocols.push_back(proto);
1549	if (proto)
1550	++numProtocolsResolved;
1551	}
1552
1553	// If all of the names were protocols, these were protocol qualifiers.
1554	if (numProtocolsResolved == identifiers.size())
1555	return resolvedAsProtocols();
1556
1557	// Attempt to resolve all of the identifiers as type names or
1558	// Objective-C class names. The latter is technically ill-formed,
1559	// but is probably something like \c NSArray<NSView *> missing the
1560	// \c*.
1561	typedef llvm::PointerUnion<TypeDecl *, ObjCInterfaceDecl *> TypeOrClassDecl;
1562	SmallVector<TypeOrClassDecl, 4> typeDecls;
1563	unsigned numTypeDeclsResolved = 0;
1564	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1565	NamedDecl *decl = LookupSingleName(S, Name: identifiers[i], Loc: identifierLocs[i],
1566	NameKind: LookupOrdinaryName);
1567	if (!decl) {
1568	typeDecls.push_back(Elt: TypeOrClassDecl());
1569	continue;
1570	}
1571
1572	if (auto typeDecl = dyn_cast<TypeDecl>(Val: decl)) {
1573	typeDecls.push_back(Elt: typeDecl);
1574	++numTypeDeclsResolved;
1575	continue;
1576	}
1577
1578	if (auto objcClass = dyn_cast<ObjCInterfaceDecl>(Val: decl)) {
1579	typeDecls.push_back(Elt: objcClass);
1580	++numTypeDeclsResolved;
1581	continue;
1582	}
1583
1584	typeDecls.push_back(Elt: TypeOrClassDecl());
1585	}
1586
1587	AttributeFactory attrFactory;
1588
1589	// Local function that forms a reference to the given type or
1590	// Objective-C class declaration.
1591	auto resolveTypeReference = [&](TypeOrClassDecl typeDecl, SourceLocation loc)
1592	-> TypeResult {
1593	// Form declaration specifiers. They simply refer to the type.
1594	DeclSpec DS(attrFactory);
1595	const char* prevSpec; // unused
1596	unsigned diagID; // unused
1597	QualType type;
1598	if (auto *actualTypeDecl = typeDecl.dyn_cast<TypeDecl *>())
1599	type = Context.getTypeDeclType(Decl: actualTypeDecl);
1600	else
1601	type = Context.getObjCInterfaceType(Decl: typeDecl.get<ObjCInterfaceDecl *>());
1602	TypeSourceInfo *parsedTSInfo = Context.getTrivialTypeSourceInfo(T: type, Loc: loc);
1603	ParsedType parsedType = CreateParsedType(T: type, TInfo: parsedTSInfo);
1604	DS.SetTypeSpecType(T: DeclSpec::TST_typename, Loc: loc, PrevSpec&: prevSpec, DiagID&: diagID,
1605	Rep: parsedType, Policy: Context.getPrintingPolicy());
1606	// Use the identifier location for the type source range.
1607	DS.SetRangeStart(loc);
1608	DS.SetRangeEnd(loc);
1609
1610	// Form the declarator.
1611	Declarator D(DS, ParsedAttributesView::none(), DeclaratorContext::TypeName);
1612
1613	// If we have a typedef of an Objective-C class type that is missing a '*',
1614	// add the '*'.
1615	if (type->getAs<ObjCInterfaceType>()) {
1616	SourceLocation starLoc = getLocForEndOfToken(Loc: loc);
1617	D.AddTypeInfo(TI: DeclaratorChunk::getPointer(/*TypeQuals=*/0, Loc: starLoc,
1618	ConstQualLoc: SourceLocation(),
1619	VolatileQualLoc: SourceLocation(),
1620	RestrictQualLoc: SourceLocation(),
1621	AtomicQualLoc: SourceLocation(),
1622	UnalignedQualLoc: SourceLocation()),
1623	EndLoc: starLoc);
1624
1625	// Diagnose the missing '*'.
1626	Diag(loc, diag::err_objc_type_arg_missing_star)
1627	<< type
1628	<< FixItHint::CreateInsertion(starLoc, " *");
1629	}
1630
1631	// Convert this to a type.
1632	return ActOnTypeName(D);
1633	};
1634
1635	// Local function that updates the declaration specifiers with
1636	// type argument information.
1637	auto resolvedAsTypeDecls = [&] {
1638	// We did not resolve these as protocols.
1639	protocols.clear();
1640
1641	assert(numTypeDeclsResolved == identifiers.size() && "Unresolved type decl");
1642	// Map type declarations to type arguments.
1643	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1644	// Map type reference to a type.
1645	TypeResult type = resolveTypeReference(typeDecls[i], identifierLocs[i]);
1646	if (!type.isUsable()) {
1647	typeArgs.clear();
1648	return;
1649	}
1650
1651	typeArgs.push_back(Elt: type.get());
1652	}
1653
1654	typeArgsLAngleLoc = lAngleLoc;
1655	typeArgsRAngleLoc = rAngleLoc;
1656	};
1657
1658	// If all of the identifiers can be resolved as type names or
1659	// Objective-C class names, we have type arguments.
1660	if (numTypeDeclsResolved == identifiers.size())
1661	return resolvedAsTypeDecls();
1662
1663	// Error recovery: some names weren't found, or we have a mix of
1664	// type and protocol names. Go resolve all of the unresolved names
1665	// and complain if we can't find a consistent answer.
1666	LookupNameKind lookupKind = LookupAnyName;
1667	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1668	// If we already have a protocol or type. Check whether it is the
1669	// right thing.
1670	if (protocols[i] || typeDecls[i]) {
1671	// If we haven't figured out whether we want types or protocols
1672	// yet, try to figure it out from this name.
1673	if (lookupKind == LookupAnyName) {
1674	// If this name refers to both a protocol and a type (e.g., \c
1675	// NSObject), don't conclude anything yet.
1676	if (protocols[i] && typeDecls[i])
1677	continue;
1678
1679	// Otherwise, let this name decide whether we'll be correcting
1680	// toward types or protocols.
1681	lookupKind = protocols[i] ? LookupObjCProtocolName
1682	: LookupOrdinaryName;
1683	continue;
1684	}
1685
1686	// If we want protocols and we have a protocol, there's nothing
1687	// more to do.
1688	if (lookupKind == LookupObjCProtocolName && protocols[i])
1689	continue;
1690
1691	// If we want types and we have a type declaration, there's
1692	// nothing more to do.
1693	if (lookupKind == LookupOrdinaryName && typeDecls[i])
1694	continue;
1695
1696	// We have a conflict: some names refer to protocols and others
1697	// refer to types.
1698	DiagnoseTypeArgsAndProtocols(ProtocolId: identifiers[0], ProtocolLoc: identifierLocs[0],
1699	TypeArgId: identifiers[i], TypeArgLoc: identifierLocs[i],
1700	SelectProtocolFirst: protocols[i] != nullptr);
1701
1702	protocols.clear();
1703	typeArgs.clear();
1704	return;
1705	}
1706
1707	// Perform typo correction on the name.
1708	ObjCTypeArgOrProtocolValidatorCCC CCC(Context, lookupKind);
1709	TypoCorrection corrected =
1710	CorrectTypo(Typo: DeclarationNameInfo(identifiers[i], identifierLocs[i]),
1711	LookupKind: lookupKind, S, SS: nullptr, CCC, Mode: CTK_ErrorRecovery);
1712	if (corrected) {
1713	// Did we find a protocol?
1714	if (auto proto = corrected.getCorrectionDeclAs<ObjCProtocolDecl>()) {
1715	diagnoseTypo(corrected,
1716	PDiag(diag::err_undeclared_protocol_suggest)
1717	<< identifiers[i]);
1718	lookupKind = LookupObjCProtocolName;
1719	protocols[i] = proto;
1720	++numProtocolsResolved;
1721	continue;
1722	}
1723
1724	// Did we find a type?
1725	if (auto typeDecl = corrected.getCorrectionDeclAs<TypeDecl>()) {
1726	diagnoseTypo(corrected,
1727	PDiag(diag::err_unknown_typename_suggest)
1728	<< identifiers[i]);
1729	lookupKind = LookupOrdinaryName;
1730	typeDecls[i] = typeDecl;
1731	++numTypeDeclsResolved;
1732	continue;
1733	}
1734
1735	// Did we find an Objective-C class?
1736	if (auto objcClass = corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
1737	diagnoseTypo(corrected,
1738	PDiag(diag::err_unknown_type_or_class_name_suggest)
1739	<< identifiers[i] << true);
1740	lookupKind = LookupOrdinaryName;
1741	typeDecls[i] = objcClass;
1742	++numTypeDeclsResolved;
1743	continue;
1744	}
1745	}
1746
1747	// We couldn't find anything.
1748	Diag(identifierLocs[i],
1749	(lookupKind == LookupAnyName ? diag::err_objc_type_arg_missing
1750	: lookupKind == LookupObjCProtocolName ? diag::err_undeclared_protocol
1751	: diag::err_unknown_typename))
1752	<< identifiers[i];
1753	protocols.clear();
1754	typeArgs.clear();
1755	return;
1756	}
1757
1758	// If all of the names were (corrected to) protocols, these were
1759	// protocol qualifiers.
1760	if (numProtocolsResolved == identifiers.size())
1761	return resolvedAsProtocols();
1762
1763	// Otherwise, all of the names were (corrected to) types.
1764	assert(numTypeDeclsResolved == identifiers.size() && "Not all types?");
1765	return resolvedAsTypeDecls();
1766	}
1767
1768	/// DiagnoseClassExtensionDupMethods - Check for duplicate declaration of
1769	/// a class method in its extension.
1770	///
1771	void Sema::DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
1772	ObjCInterfaceDecl *ID) {
1773	if (!ID)
1774	return; // Possibly due to previous error
1775
1776	llvm::DenseMap<Selector, const ObjCMethodDecl*> MethodMap;
1777	for (auto *MD : ID->methods())
1778	MethodMap[MD->getSelector()] = MD;
1779
1780	if (MethodMap.empty())
1781	return;
1782	for (const auto *Method : CAT->methods()) {
1783	const ObjCMethodDecl *&PrevMethod = MethodMap[Method->getSelector()];
1784	if (PrevMethod &&
1785	(PrevMethod->isInstanceMethod() == Method->isInstanceMethod()) &&
1786	!MatchTwoMethodDeclarations(Method, PrevMethod)) {
1787	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
1788	<< Method->getDeclName();
1789	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
1790	}
1791	}
1792	}
1793
1794	/// ActOnForwardProtocolDeclaration - Handle \@protocol foo;
1795	Sema::DeclGroupPtrTy
1796	Sema::ActOnForwardProtocolDeclaration(SourceLocation AtProtocolLoc,
1797	ArrayRef<IdentifierLocPair> IdentList,
1798	const ParsedAttributesView &attrList) {
1799	SmallVector<Decl *, 8> DeclsInGroup;
1800	for (const IdentifierLocPair &IdentPair : IdentList) {
1801	IdentifierInfo *Ident = IdentPair.first;
1802	ObjCProtocolDecl *PrevDecl = LookupProtocol(II: Ident, IdLoc: IdentPair.second,
1803	Redecl: forRedeclarationInCurContext());
1804	ObjCProtocolDecl *PDecl
1805	= ObjCProtocolDecl::Create(C&: Context, DC: CurContext, Id: Ident,
1806	nameLoc: IdentPair.second, atStartLoc: AtProtocolLoc,
1807	PrevDecl);
1808
1809	PushOnScopeChains(PDecl, TUScope);
1810	CheckObjCDeclScope(PDecl);
1811
1812	ProcessDeclAttributeList(TUScope, PDecl, attrList);
1813	AddPragmaAttributes(TUScope, PDecl);
1814
1815	if (PrevDecl)
1816	mergeDeclAttributes(PDecl, PrevDecl);
1817
1818	DeclsInGroup.push_back(PDecl);
1819	}
1820
1821	return BuildDeclaratorGroup(Group: DeclsInGroup);
1822	}
1823
1824	ObjCCategoryDecl *Sema::ActOnStartCategoryInterface(
1825	SourceLocation AtInterfaceLoc, const IdentifierInfo *ClassName,
1826	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
1827	const IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
1828	Decl *const *ProtoRefs, unsigned NumProtoRefs,
1829	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1830	const ParsedAttributesView &AttrList) {
1831	ObjCCategoryDecl *CDecl;
1832	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1833
1834	/// Check that class of this category is already completely declared.
1835
1836	if (!IDecl
1837	|| RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1838	diag::err_category_forward_interface,
1839	CategoryName == nullptr)) {
1840	// Create an invalid ObjCCategoryDecl to serve as context for
1841	// the enclosing method declarations. We mark the decl invalid
1842	// to make it clear that this isn't a valid AST.
1843	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtInterfaceLoc,
1844	ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc, Id: CategoryName,
1845	IDecl, typeParamList);
1846	CDecl->setInvalidDecl();
1847	CurContext->addDecl(CDecl);
1848
1849	if (!IDecl)
1850	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1851	ActOnObjCContainerStartDefinition(CDecl);
1852	return CDecl;
1853	}
1854
1855	if (!CategoryName && IDecl->getImplementation()) {
1856	Diag(ClassLoc, diag::err_class_extension_after_impl) << ClassName;
1857	Diag(IDecl->getImplementation()->getLocation(),
1858	diag::note_implementation_declared);
1859	}
1860
1861	if (CategoryName) {
1862	/// Check for duplicate interface declaration for this category
1863	if (ObjCCategoryDecl *Previous
1864	= IDecl->FindCategoryDeclaration(CategoryId: CategoryName)) {
1865	// Class extensions can be declared multiple times, categories cannot.
1866	Diag(CategoryLoc, diag::warn_dup_category_def)
1867	<< ClassName << CategoryName;
1868	Diag(Previous->getLocation(), diag::note_previous_definition);
1869	}
1870	}
1871
1872	// If we have a type parameter list, check it.
1873	if (typeParamList) {
1874	if (auto prevTypeParamList = IDecl->getTypeParamList()) {
1875	if (checkTypeParamListConsistency(S&: *this, prevTypeParams: prevTypeParamList, newTypeParams: typeParamList,
1876	newContext: CategoryName
1877	? TypeParamListContext::Category
1878	: TypeParamListContext::Extension))
1879	typeParamList = nullptr;
1880	} else {
1881	Diag(typeParamList->getLAngleLoc(),
1882	diag::err_objc_parameterized_category_nonclass)
1883	<< (CategoryName != nullptr)
1884	<< ClassName
1885	<< typeParamList->getSourceRange();
1886
1887	typeParamList = nullptr;
1888	}
1889	}
1890
1891	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtInterfaceLoc,
1892	ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc, Id: CategoryName, IDecl,
1893	typeParamList);
1894	// FIXME: PushOnScopeChains?
1895	CurContext->addDecl(CDecl);
1896
1897	// Process the attributes before looking at protocols to ensure that the
1898	// availability attribute is attached to the category to provide availability
1899	// checking for protocol uses.
1900	ProcessDeclAttributeList(TUScope, CDecl, AttrList);
1901	AddPragmaAttributes(TUScope, CDecl);
1902
1903	if (NumProtoRefs) {
1904	diagnoseUseOfProtocols(*this, CDecl, (ObjCProtocolDecl*const*)ProtoRefs,
1905	NumProtoRefs, ProtoLocs);
1906	CDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1907	Locs: ProtoLocs, C&: Context);
1908	// Protocols in the class extension belong to the class.
1909	if (CDecl->IsClassExtension())
1910	IDecl->mergeClassExtensionProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs,
1911	Num: NumProtoRefs, C&: Context);
1912	}
1913
1914	CheckObjCDeclScope(CDecl);
1915	ActOnObjCContainerStartDefinition(CDecl);
1916	return CDecl;
1917	}
1918
1919	/// ActOnStartCategoryImplementation - Perform semantic checks on the
1920	/// category implementation declaration and build an ObjCCategoryImplDecl
1921	/// object.
1922	ObjCCategoryImplDecl *Sema::ActOnStartCategoryImplementation(
1923	SourceLocation AtCatImplLoc, const IdentifierInfo *ClassName,
1924	SourceLocation ClassLoc, const IdentifierInfo *CatName,
1925	SourceLocation CatLoc, const ParsedAttributesView &Attrs) {
1926	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1927	ObjCCategoryDecl *CatIDecl = nullptr;
1928	if (IDecl && IDecl->hasDefinition()) {
1929	CatIDecl = IDecl->FindCategoryDeclaration(CategoryId: CatName);
1930	if (!CatIDecl) {
1931	// Category @implementation with no corresponding @interface.
1932	// Create and install one.
1933	CatIDecl = ObjCCategoryDecl::Create(C&: Context, DC: CurContext, AtLoc: AtCatImplLoc,
1934	ClassNameLoc: ClassLoc, CategoryNameLoc: CatLoc,
1935	Id: CatName, IDecl,
1936	/*typeParamList=*/nullptr);
1937	CatIDecl->setImplicit();
1938	}
1939	}
1940
1941	ObjCCategoryImplDecl *CDecl =
1942	ObjCCategoryImplDecl::Create(C&: Context, DC: CurContext, Id: CatName, classInterface: IDecl,
1943	nameLoc: ClassLoc, atStartLoc: AtCatImplLoc, CategoryNameLoc: CatLoc);
1944	/// Check that class of this category is already completely declared.
1945	if (!IDecl) {
1946	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1947	CDecl->setInvalidDecl();
1948	} else if (RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1949	diag::err_undef_interface)) {
1950	CDecl->setInvalidDecl();
1951	}
1952
1953	ProcessDeclAttributeList(TUScope, CDecl, Attrs);
1954	AddPragmaAttributes(TUScope, CDecl);
1955
1956	// FIXME: PushOnScopeChains?
1957	CurContext->addDecl(CDecl);
1958
1959	// If the interface has the objc_runtime_visible attribute, we
1960	// cannot implement a category for it.
1961	if (IDecl && IDecl->hasAttr<ObjCRuntimeVisibleAttr>()) {
1962	Diag(ClassLoc, diag::err_objc_runtime_visible_category)
1963	<< IDecl->getDeclName();
1964	}
1965
1966	/// Check that CatName, category name, is not used in another implementation.
1967	if (CatIDecl) {
1968	if (CatIDecl->getImplementation()) {
1969	Diag(ClassLoc, diag::err_dup_implementation_category) << ClassName
1970	<< CatName;
1971	Diag(CatIDecl->getImplementation()->getLocation(),
1972	diag::note_previous_definition);
1973	CDecl->setInvalidDecl();
1974	} else {
1975	CatIDecl->setImplementation(CDecl);
1976	// Warn on implementating category of deprecated class under
1977	// -Wdeprecated-implementations flag.
1978	DiagnoseObjCImplementedDeprecations(*this, CatIDecl,
1979	CDecl->getLocation());
1980	}
1981	}
1982
1983	CheckObjCDeclScope(CDecl);
1984	ActOnObjCContainerStartDefinition(CDecl);
1985	return CDecl;
1986	}
1987
1988	ObjCImplementationDecl *Sema::ActOnStartClassImplementation(
1989	SourceLocation AtClassImplLoc, const IdentifierInfo *ClassName,
1990	SourceLocation ClassLoc, const IdentifierInfo *SuperClassname,
1991	SourceLocation SuperClassLoc, const ParsedAttributesView &Attrs) {
1992	ObjCInterfaceDecl *IDecl = nullptr;
1993	// Check for another declaration kind with the same name.
1994	NamedDecl *PrevDecl
1995	= LookupSingleName(S: TUScope, Name: ClassName, Loc: ClassLoc, NameKind: LookupOrdinaryName,
1996	Redecl: forRedeclarationInCurContext());
1997	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
1998	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
1999	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2000	} else if ((IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl))) {
2001	// FIXME: This will produce an error if the definition of the interface has
2002	// been imported from a module but is not visible.
2003	RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
2004	diag::warn_undef_interface);
2005	} else {
2006	// We did not find anything with the name ClassName; try to correct for
2007	// typos in the class name.
2008	ObjCInterfaceValidatorCCC CCC{};
2009	TypoCorrection Corrected =
2010	CorrectTypo(Typo: DeclarationNameInfo(ClassName, ClassLoc),
2011	LookupKind: LookupOrdinaryName, S: TUScope, SS: nullptr, CCC, Mode: CTK_NonError);
2012	if (Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2013	// Suggest the (potentially) correct interface name. Don't provide a
2014	// code-modification hint or use the typo name for recovery, because
2015	// this is just a warning. The program may actually be correct.
2016	diagnoseTypo(Corrected,
2017	PDiag(diag::warn_undef_interface_suggest) << ClassName,
2018	/*ErrorRecovery*/false);
2019	} else {
2020	Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
2021	}
2022	}
2023
2024	// Check that super class name is valid class name
2025	ObjCInterfaceDecl *SDecl = nullptr;
2026	if (SuperClassname) {
2027	// Check if a different kind of symbol declared in this scope.
2028	PrevDecl = LookupSingleName(S: TUScope, Name: SuperClassname, Loc: SuperClassLoc,
2029	NameKind: LookupOrdinaryName);
2030	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
2031	Diag(SuperClassLoc, diag::err_redefinition_different_kind)
2032	<< SuperClassname;
2033	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2034	} else {
2035	SDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
2036	if (SDecl && !SDecl->hasDefinition())
2037	SDecl = nullptr;
2038	if (!SDecl)
2039	Diag(SuperClassLoc, diag::err_undef_superclass)
2040	<< SuperClassname << ClassName;
2041	else if (IDecl && !declaresSameEntity(IDecl->getSuperClass(), SDecl)) {
2042	// This implementation and its interface do not have the same
2043	// super class.
2044	Diag(SuperClassLoc, diag::err_conflicting_super_class)
2045	<< SDecl->getDeclName();
2046	Diag(SDecl->getLocation(), diag::note_previous_definition);
2047	}
2048	}
2049	}
2050
2051	if (!IDecl) {
2052	// Legacy case of @implementation with no corresponding @interface.
2053	// Build, chain & install the interface decl into the identifier.
2054
2055	// FIXME: Do we support attributes on the @implementation? If so we should
2056	// copy them over.
2057	IDecl = ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtClassImplLoc,
2058	Id: ClassName, /*typeParamList=*/nullptr,
2059	/*PrevDecl=*/nullptr, ClassLoc,
2060	isInternal: true);
2061	AddPragmaAttributes(TUScope, IDecl);
2062	IDecl->startDefinition();
2063	if (SDecl) {
2064	IDecl->setSuperClass(Context.getTrivialTypeSourceInfo(
2065	T: Context.getObjCInterfaceType(Decl: SDecl),
2066	Loc: SuperClassLoc));
2067	IDecl->setEndOfDefinitionLoc(SuperClassLoc);
2068	} else {
2069	IDecl->setEndOfDefinitionLoc(ClassLoc);
2070	}
2071
2072	PushOnScopeChains(IDecl, TUScope);
2073	} else {
2074	// Mark the interface as being completed, even if it was just as
2075	// @class ....;
2076	// declaration; the user cannot reopen it.
2077	if (!IDecl->hasDefinition())
2078	IDecl->startDefinition();
2079	}
2080
2081	ObjCImplementationDecl* IMPDecl =
2082	ObjCImplementationDecl::Create(C&: Context, DC: CurContext, classInterface: IDecl, superDecl: SDecl,
2083	nameLoc: ClassLoc, atStartLoc: AtClassImplLoc, superLoc: SuperClassLoc);
2084
2085	ProcessDeclAttributeList(TUScope, IMPDecl, Attrs);
2086	AddPragmaAttributes(TUScope, IMPDecl);
2087
2088	if (CheckObjCDeclScope(IMPDecl)) {
2089	ActOnObjCContainerStartDefinition(IMPDecl);
2090	return IMPDecl;
2091	}
2092
2093	// Check that there is no duplicate implementation of this class.
2094	if (IDecl->getImplementation()) {
2095	// FIXME: Don't leak everything!
2096	Diag(ClassLoc, diag::err_dup_implementation_class) << ClassName;
2097	Diag(IDecl->getImplementation()->getLocation(),
2098	diag::note_previous_definition);
2099	IMPDecl->setInvalidDecl();
2100	} else { // add it to the list.
2101	IDecl->setImplementation(IMPDecl);
2102	PushOnScopeChains(IMPDecl, TUScope);
2103	// Warn on implementating deprecated class under
2104	// -Wdeprecated-implementations flag.
2105	DiagnoseObjCImplementedDeprecations(*this, IDecl, IMPDecl->getLocation());
2106	}
2107
2108	// If the superclass has the objc_runtime_visible attribute, we
2109	// cannot implement a subclass of it.
2110	if (IDecl->getSuperClass() &&
2111	IDecl->getSuperClass()->hasAttr<ObjCRuntimeVisibleAttr>()) {
2112	Diag(ClassLoc, diag::err_objc_runtime_visible_subclass)
2113	<< IDecl->getDeclName()
2114	<< IDecl->getSuperClass()->getDeclName();
2115	}
2116
2117	ActOnObjCContainerStartDefinition(IMPDecl);
2118	return IMPDecl;
2119	}
2120
2121	Sema::DeclGroupPtrTy
2122	Sema::ActOnFinishObjCImplementation(Decl *ObjCImpDecl, ArrayRef<Decl *> Decls) {
2123	SmallVector<Decl *, 64> DeclsInGroup;
2124	DeclsInGroup.reserve(N: Decls.size() + 1);
2125
2126	for (unsigned i = 0, e = Decls.size(); i != e; ++i) {
2127	Decl *Dcl = Decls[i];
2128	if (!Dcl)
2129	continue;
2130	if (Dcl->getDeclContext()->isFileContext())
2131	Dcl->setTopLevelDeclInObjCContainer();
2132	DeclsInGroup.push_back(Elt: Dcl);
2133	}
2134
2135	DeclsInGroup.push_back(Elt: ObjCImpDecl);
2136
2137	return BuildDeclaratorGroup(Group: DeclsInGroup);
2138	}
2139
2140	void Sema::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
2141	ObjCIvarDecl **ivars, unsigned numIvars,
2142	SourceLocation RBrace) {
2143	assert(ImpDecl && "missing implementation decl");
2144	ObjCInterfaceDecl* IDecl = ImpDecl->getClassInterface();
2145	if (!IDecl)
2146	return;
2147	/// Check case of non-existing \@interface decl.
2148	/// (legacy objective-c \@implementation decl without an \@interface decl).
2149	/// Add implementations's ivar to the synthesize class's ivar list.
2150	if (IDecl->isImplicitInterfaceDecl()) {
2151	IDecl->setEndOfDefinitionLoc(RBrace);
2152	// Add ivar's to class's DeclContext.
2153	for (unsigned i = 0, e = numIvars; i != e; ++i) {
2154	ivars[i]->setLexicalDeclContext(ImpDecl);
2155	// In a 'fragile' runtime the ivar was added to the implicit
2156	// ObjCInterfaceDecl while in a 'non-fragile' runtime the ivar is
2157	// only in the ObjCImplementationDecl. In the non-fragile case the ivar
2158	// therefore also needs to be propagated to the ObjCInterfaceDecl.
2159	if (!LangOpts.ObjCRuntime.isFragile())
2160	IDecl->makeDeclVisibleInContext(ivars[i]);
2161	ImpDecl->addDecl(ivars[i]);
2162	}
2163
2164	return;
2165	}
2166	// If implementation has empty ivar list, just return.
2167	if (numIvars == 0)
2168	return;
2169
2170	assert(ivars && "missing @implementation ivars");
2171	if (LangOpts.ObjCRuntime.isNonFragile()) {
2172	if (ImpDecl->getSuperClass())
2173	Diag(ImpDecl->getLocation(), diag::warn_on_superclass_use);
2174	for (unsigned i = 0; i < numIvars; i++) {
2175	ObjCIvarDecl* ImplIvar = ivars[i];
2176	if (const ObjCIvarDecl *ClsIvar =
2177	IDecl->getIvarDecl(Id: ImplIvar->getIdentifier())) {
2178	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2179	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2180	continue;
2181	}
2182	// Check class extensions (unnamed categories) for duplicate ivars.
2183	for (const auto *CDecl : IDecl->visible_extensions()) {
2184	if (const ObjCIvarDecl *ClsExtIvar =
2185	CDecl->getIvarDecl(ImplIvar->getIdentifier())) {
2186	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2187	Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
2188	continue;
2189	}
2190	}
2191	// Instance ivar to Implementation's DeclContext.
2192	ImplIvar->setLexicalDeclContext(ImpDecl);
2193	IDecl->makeDeclVisibleInContext(ImplIvar);
2194	ImpDecl->addDecl(ImplIvar);
2195	}
2196	return;
2197	}
2198	// Check interface's Ivar list against those in the implementation.
2199	// names and types must match.
2200	//
2201	unsigned j = 0;
2202	ObjCInterfaceDecl::ivar_iterator
2203	IVI = IDecl->ivar_begin(), IVE = IDecl->ivar_end();
2204	for (; numIvars > 0 && IVI != IVE; ++IVI) {
2205	ObjCIvarDecl* ImplIvar = ivars[j++];
2206	ObjCIvarDecl* ClsIvar = *IVI;
2207	assert (ImplIvar && "missing implementation ivar");
2208	assert (ClsIvar && "missing class ivar");
2209
2210	// First, make sure the types match.
2211	if (!Context.hasSameType(ImplIvar->getType(), ClsIvar->getType())) {
2212	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_type)
2213	<< ImplIvar->getIdentifier()
2214	<< ImplIvar->getType() << ClsIvar->getType();
2215	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2216	} else if (ImplIvar->isBitField() && ClsIvar->isBitField() &&
2217	ImplIvar->getBitWidthValue(Context) !=
2218	ClsIvar->getBitWidthValue(Context)) {
2219	Diag(ImplIvar->getBitWidth()->getBeginLoc(),
2220	diag::err_conflicting_ivar_bitwidth)
2221	<< ImplIvar->getIdentifier();
2222	Diag(ClsIvar->getBitWidth()->getBeginLoc(),
2223	diag::note_previous_definition);
2224	}
2225	// Make sure the names are identical.
2226	if (ImplIvar->getIdentifier() != ClsIvar->getIdentifier()) {
2227	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_name)
2228	<< ImplIvar->getIdentifier() << ClsIvar->getIdentifier();
2229	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2230	}
2231	--numIvars;
2232	}
2233
2234	if (numIvars > 0)
2235	Diag(ivars[j]->getLocation(), diag::err_inconsistent_ivar_count);
2236	else if (IVI != IVE)
2237	Diag(IVI->getLocation(), diag::err_inconsistent_ivar_count);
2238	}
2239
2240	static bool shouldWarnUndefinedMethod(const ObjCMethodDecl *M) {
2241	// No point warning no definition of method which is 'unavailable'.
2242	return M->getAvailability() != AR_Unavailable;
2243	}
2244
2245	static void WarnUndefinedMethod(Sema &S, ObjCImplDecl *Impl,
2246	ObjCMethodDecl *method, bool &IncompleteImpl,
2247	unsigned DiagID,
2248	NamedDecl *NeededFor = nullptr) {
2249	if (!shouldWarnUndefinedMethod(M: method))
2250	return;
2251
2252	// FIXME: For now ignore 'IncompleteImpl'.
2253	// Previously we grouped all unimplemented methods under a single
2254	// warning, but some users strongly voiced that they would prefer
2255	// separate warnings. We will give that approach a try, as that
2256	// matches what we do with protocols.
2257	{
2258	const Sema::SemaDiagnosticBuilder &B = S.Diag(Impl->getLocation(), DiagID);
2259	B << method;
2260	if (NeededFor)
2261	B << NeededFor;
2262
2263	// Add an empty definition at the end of the @implementation.
2264	std::string FixItStr;
2265	llvm::raw_string_ostream Out(FixItStr);
2266	method->print(Out, Impl->getASTContext().getPrintingPolicy());
2267	Out << " {\n}\n\n";
2268
2269	SourceLocation Loc = Impl->getAtEndRange().getBegin();
2270	B << FixItHint::CreateInsertion(InsertionLoc: Loc, Code: FixItStr);
2271	}
2272
2273	// Issue a note to the original declaration.
2274	SourceLocation MethodLoc = method->getBeginLoc();
2275	if (MethodLoc.isValid())
2276	S.Diag(MethodLoc, diag::note_method_declared_at) << method;
2277	}
2278
2279	/// Determines if type B can be substituted for type A. Returns true if we can
2280	/// guarantee that anything that the user will do to an object of type A can
2281	/// also be done to an object of type B. This is trivially true if the two
2282	/// types are the same, or if B is a subclass of A. It becomes more complex
2283	/// in cases where protocols are involved.
2284	///
2285	/// Object types in Objective-C describe the minimum requirements for an
2286	/// object, rather than providing a complete description of a type. For
2287	/// example, if A is a subclass of B, then B* may refer to an instance of A.
2288	/// The principle of substitutability means that we may use an instance of A
2289	/// anywhere that we may use an instance of B - it will implement all of the
2290	/// ivars of B and all of the methods of B.
2291	///
2292	/// This substitutability is important when type checking methods, because
2293	/// the implementation may have stricter type definitions than the interface.
2294	/// The interface specifies minimum requirements, but the implementation may
2295	/// have more accurate ones. For example, a method may privately accept
2296	/// instances of B, but only publish that it accepts instances of A. Any
2297	/// object passed to it will be type checked against B, and so will implicitly
2298	/// by a valid A*. Similarly, a method may return a subclass of the class that
2299	/// it is declared as returning.
2300	///
2301	/// This is most important when considering subclassing. A method in a
2302	/// subclass must accept any object as an argument that its superclass's
2303	/// implementation accepts. It may, however, accept a more general type
2304	/// without breaking substitutability (i.e. you can still use the subclass
2305	/// anywhere that you can use the superclass, but not vice versa). The
2306	/// converse requirement applies to return types: the return type for a
2307	/// subclass method must be a valid object of the kind that the superclass
2308	/// advertises, but it may be specified more accurately. This avoids the need
2309	/// for explicit down-casting by callers.
2310	///
2311	/// Note: This is a stricter requirement than for assignment.
2312	static bool isObjCTypeSubstitutable(ASTContext &Context,
2313	const ObjCObjectPointerType *A,
2314	const ObjCObjectPointerType *B,
2315	bool rejectId) {
2316	// Reject a protocol-unqualified id.
2317	if (rejectId && B->isObjCIdType()) return false;
2318
2319	// If B is a qualified id, then A must also be a qualified id and it must
2320	// implement all of the protocols in B. It may not be a qualified class.
2321	// For example, MyClass<A> can be assigned to id<A>, but MyClass<A> is a
2322	// stricter definition so it is not substitutable for id<A>.
2323	if (B->isObjCQualifiedIdType()) {
2324	return A->isObjCQualifiedIdType() &&
2325	Context.ObjCQualifiedIdTypesAreCompatible(LHS: A, RHS: B, ForCompare: false);
2326	}
2327
2328	/*
2329	// id is a special type that bypasses type checking completely. We want a
2330	// warning when it is used in one place but not another.
2331	if (C.isObjCIdType(A) || C.isObjCIdType(B)) return false;
2332
2333
2334	// If B is a qualified id, then A must also be a qualified id (which it isn't
2335	// if we've got this far)
2336	if (B->isObjCQualifiedIdType()) return false;
2337	*/
2338
2339	// Now we know that A and B are (potentially-qualified) class types. The
2340	// normal rules for assignment apply.
2341	return Context.canAssignObjCInterfaces(LHSOPT: A, RHSOPT: B);
2342	}
2343
2344	static SourceRange getTypeRange(TypeSourceInfo *TSI) {
2345	return (TSI ? TSI->getTypeLoc().getSourceRange() : SourceRange());
2346	}
2347
2348	/// Determine whether two set of Objective-C declaration qualifiers conflict.
2349	static bool objcModifiersConflict(Decl::ObjCDeclQualifier x,
2350	Decl::ObjCDeclQualifier y) {
2351	return (x & ~Decl::OBJC_TQ_CSNullability) !=
2352	(y & ~Decl::OBJC_TQ_CSNullability);
2353	}
2354
2355	static bool CheckMethodOverrideReturn(Sema &S,
2356	ObjCMethodDecl *MethodImpl,
2357	ObjCMethodDecl *MethodDecl,
2358	bool IsProtocolMethodDecl,
2359	bool IsOverridingMode,
2360	bool Warn) {
2361	if (IsProtocolMethodDecl &&
2362	objcModifiersConflict(x: MethodDecl->getObjCDeclQualifier(),
2363	y: MethodImpl->getObjCDeclQualifier())) {
2364	if (Warn) {
2365	S.Diag(MethodImpl->getLocation(),
2366	(IsOverridingMode
2367	? diag::warn_conflicting_overriding_ret_type_modifiers
2368	: diag::warn_conflicting_ret_type_modifiers))
2369	<< MethodImpl->getDeclName()
2370	<< MethodImpl->getReturnTypeSourceRange();
2371	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration)
2372	<< MethodDecl->getReturnTypeSourceRange();
2373	}
2374	else
2375	return false;
2376	}
2377	if (Warn && IsOverridingMode &&
2378	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2379	!S.Context.hasSameNullabilityTypeQualifier(SubT: MethodImpl->getReturnType(),
2380	SuperT: MethodDecl->getReturnType(),
2381	IsParam: false)) {
2382	auto nullabilityMethodImpl = *MethodImpl->getReturnType()->getNullability();
2383	auto nullabilityMethodDecl = *MethodDecl->getReturnType()->getNullability();
2384	S.Diag(MethodImpl->getLocation(),
2385	diag::warn_conflicting_nullability_attr_overriding_ret_types)
2386	<< DiagNullabilityKind(nullabilityMethodImpl,
2387	((MethodImpl->getObjCDeclQualifier() &
2388	Decl::OBJC_TQ_CSNullability) != 0))
2389	<< DiagNullabilityKind(nullabilityMethodDecl,
2390	((MethodDecl->getObjCDeclQualifier() &
2391	Decl::OBJC_TQ_CSNullability) != 0));
2392	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2393	}
2394
2395	if (S.Context.hasSameUnqualifiedType(T1: MethodImpl->getReturnType(),
2396	T2: MethodDecl->getReturnType()))
2397	return true;
2398	if (!Warn)
2399	return false;
2400
2401	unsigned DiagID =
2402	IsOverridingMode ? diag::warn_conflicting_overriding_ret_types
2403	: diag::warn_conflicting_ret_types;
2404
2405	// Mismatches between ObjC pointers go into a different warning
2406	// category, and sometimes they're even completely explicitly allowed.
2407	if (const ObjCObjectPointerType *ImplPtrTy =
2408	MethodImpl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2409	if (const ObjCObjectPointerType *IfacePtrTy =
2410	MethodDecl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2411	// Allow non-matching return types as long as they don't violate
2412	// the principle of substitutability. Specifically, we permit
2413	// return types that are subclasses of the declared return type,
2414	// or that are more-qualified versions of the declared type.
2415	if (isObjCTypeSubstitutable(Context&: S.Context, A: IfacePtrTy, B: ImplPtrTy, rejectId: false))
2416	return false;
2417
2418	DiagID =
2419	IsOverridingMode ? diag::warn_non_covariant_overriding_ret_types
2420	: diag::warn_non_covariant_ret_types;
2421	}
2422	}
2423
2424	S.Diag(MethodImpl->getLocation(), DiagID)
2425	<< MethodImpl->getDeclName() << MethodDecl->getReturnType()
2426	<< MethodImpl->getReturnType()
2427	<< MethodImpl->getReturnTypeSourceRange();
2428	S.Diag(MethodDecl->getLocation(), IsOverridingMode
2429	? diag::note_previous_declaration
2430	: diag::note_previous_definition)
2431	<< MethodDecl->getReturnTypeSourceRange();
2432	return false;
2433	}
2434
2435	static bool CheckMethodOverrideParam(Sema &S,
2436	ObjCMethodDecl *MethodImpl,
2437	ObjCMethodDecl *MethodDecl,
2438	ParmVarDecl *ImplVar,
2439	ParmVarDecl *IfaceVar,
2440	bool IsProtocolMethodDecl,
2441	bool IsOverridingMode,
2442	bool Warn) {
2443	if (IsProtocolMethodDecl &&
2444	objcModifiersConflict(x: ImplVar->getObjCDeclQualifier(),
2445	y: IfaceVar->getObjCDeclQualifier())) {
2446	if (Warn) {
2447	if (IsOverridingMode)
2448	S.Diag(ImplVar->getLocation(),
2449	diag::warn_conflicting_overriding_param_modifiers)
2450	<< getTypeRange(ImplVar->getTypeSourceInfo())
2451	<< MethodImpl->getDeclName();
2452	else S.Diag(ImplVar->getLocation(),
2453	diag::warn_conflicting_param_modifiers)
2454	<< getTypeRange(ImplVar->getTypeSourceInfo())
2455	<< MethodImpl->getDeclName();
2456	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration)
2457	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2458	}
2459	else
2460	return false;
2461	}
2462
2463	QualType ImplTy = ImplVar->getType();
2464	QualType IfaceTy = IfaceVar->getType();
2465	if (Warn && IsOverridingMode &&
2466	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2467	!S.Context.hasSameNullabilityTypeQualifier(SubT: ImplTy, SuperT: IfaceTy, IsParam: true)) {
2468	S.Diag(ImplVar->getLocation(),
2469	diag::warn_conflicting_nullability_attr_overriding_param_types)
2470	<< DiagNullabilityKind(*ImplTy->getNullability(),
2471	((ImplVar->getObjCDeclQualifier() &
2472	Decl::OBJC_TQ_CSNullability) != 0))
2473	<< DiagNullabilityKind(*IfaceTy->getNullability(),
2474	((IfaceVar->getObjCDeclQualifier() &
2475	Decl::OBJC_TQ_CSNullability) != 0));
2476	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration);
2477	}
2478	if (S.Context.hasSameUnqualifiedType(T1: ImplTy, T2: IfaceTy))
2479	return true;
2480
2481	if (!Warn)
2482	return false;
2483	unsigned DiagID =
2484	IsOverridingMode ? diag::warn_conflicting_overriding_param_types
2485	: diag::warn_conflicting_param_types;
2486
2487	// Mismatches between ObjC pointers go into a different warning
2488	// category, and sometimes they're even completely explicitly allowed..
2489	if (const ObjCObjectPointerType *ImplPtrTy =
2490	ImplTy->getAs<ObjCObjectPointerType>()) {
2491	if (const ObjCObjectPointerType *IfacePtrTy =
2492	IfaceTy->getAs<ObjCObjectPointerType>()) {
2493	// Allow non-matching argument types as long as they don't
2494	// violate the principle of substitutability. Specifically, the
2495	// implementation must accept any objects that the superclass
2496	// accepts, however it may also accept others.
2497	if (isObjCTypeSubstitutable(Context&: S.Context, A: ImplPtrTy, B: IfacePtrTy, rejectId: true))
2498	return false;
2499
2500	DiagID =
2501	IsOverridingMode ? diag::warn_non_contravariant_overriding_param_types
2502	: diag::warn_non_contravariant_param_types;
2503	}
2504	}
2505
2506	S.Diag(ImplVar->getLocation(), DiagID)
2507	<< getTypeRange(ImplVar->getTypeSourceInfo())
2508	<< MethodImpl->getDeclName() << IfaceTy << ImplTy;
2509	S.Diag(IfaceVar->getLocation(),
2510	(IsOverridingMode ? diag::note_previous_declaration
2511	: diag::note_previous_definition))
2512	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2513	return false;
2514	}
2515
2516	/// In ARC, check whether the conventional meanings of the two methods
2517	/// match. If they don't, it's a hard error.
2518	static bool checkMethodFamilyMismatch(Sema &S, ObjCMethodDecl *impl,
2519	ObjCMethodDecl *decl) {
2520	ObjCMethodFamily implFamily = impl->getMethodFamily();
2521	ObjCMethodFamily declFamily = decl->getMethodFamily();
2522	if (implFamily == declFamily) return false;
2523
2524	// Since conventions are sorted by selector, the only possibility is
2525	// that the types differ enough to cause one selector or the other
2526	// to fall out of the family.
2527	assert(implFamily == OMF_None || declFamily == OMF_None);
2528
2529	// No further diagnostics required on invalid declarations.
2530	if (impl->isInvalidDecl() || decl->isInvalidDecl()) return true;
2531
2532	const ObjCMethodDecl *unmatched = impl;
2533	ObjCMethodFamily family = declFamily;
2534	unsigned errorID = diag::err_arc_lost_method_convention;
2535	unsigned noteID = diag::note_arc_lost_method_convention;
2536	if (declFamily == OMF_None) {
2537	unmatched = decl;
2538	family = implFamily;
2539	errorID = diag::err_arc_gained_method_convention;
2540	noteID = diag::note_arc_gained_method_convention;
2541	}
2542
2543	// Indexes into a %select clause in the diagnostic.
2544	enum FamilySelector {
2545	F_alloc, F_copy, F_mutableCopy = F_copy, F_init, F_new
2546	};
2547	FamilySelector familySelector = FamilySelector();
2548
2549	switch (family) {
2550	case OMF_None: llvm_unreachable("logic error, no method convention");
2551	case OMF_retain:
2552	case OMF_release:
2553	case OMF_autorelease:
2554	case OMF_dealloc:
2555	case OMF_finalize:
2556	case OMF_retainCount:
2557	case OMF_self:
2558	case OMF_initialize:
2559	case OMF_performSelector:
2560	// Mismatches for these methods don't change ownership
2561	// conventions, so we don't care.
2562	return false;
2563
2564	case OMF_init: familySelector = F_init; break;
2565	case OMF_alloc: familySelector = F_alloc; break;
2566	case OMF_copy: familySelector = F_copy; break;
2567	case OMF_mutableCopy: familySelector = F_mutableCopy; break;
2568	case OMF_new: familySelector = F_new; break;
2569	}
2570
2571	enum ReasonSelector { R_NonObjectReturn, R_UnrelatedReturn };
2572	ReasonSelector reasonSelector;
2573
2574	// The only reason these methods don't fall within their families is
2575	// due to unusual result types.
2576	if (unmatched->getReturnType()->isObjCObjectPointerType()) {
2577	reasonSelector = R_UnrelatedReturn;
2578	} else {
2579	reasonSelector = R_NonObjectReturn;
2580	}
2581
2582	S.Diag(impl->getLocation(), errorID) << int(familySelector) << int(reasonSelector);
2583	S.Diag(decl->getLocation(), noteID) << int(familySelector) << int(reasonSelector);
2584
2585	return true;
2586	}
2587
2588	void Sema::WarnConflictingTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2589	ObjCMethodDecl *MethodDecl,
2590	bool IsProtocolMethodDecl) {
2591	if (getLangOpts().ObjCAutoRefCount &&
2592	checkMethodFamilyMismatch(S&: *this, impl: ImpMethodDecl, decl: MethodDecl))
2593	return;
2594
2595	CheckMethodOverrideReturn(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2596	IsProtocolMethodDecl, IsOverridingMode: false,
2597	Warn: true);
2598
2599	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2600	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2601	EF = MethodDecl->param_end();
2602	IM != EM && IF != EF; ++IM, ++IF) {
2603	CheckMethodOverrideParam(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl, ImplVar: *IM, IfaceVar: *IF,
2604	IsProtocolMethodDecl, IsOverridingMode: false, Warn: true);
2605	}
2606
2607	if (ImpMethodDecl->isVariadic() != MethodDecl->isVariadic()) {
2608	Diag(ImpMethodDecl->getLocation(),
2609	diag::warn_conflicting_variadic);
2610	Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2611	}
2612	}
2613
2614	void Sema::CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
2615	ObjCMethodDecl *Overridden,
2616	bool IsProtocolMethodDecl) {
2617
2618	CheckMethodOverrideReturn(S&: *this, MethodImpl: Method, MethodDecl: Overridden,
2619	IsProtocolMethodDecl, IsOverridingMode: true,
2620	Warn: true);
2621
2622	for (ObjCMethodDecl::param_iterator IM = Method->param_begin(),
2623	IF = Overridden->param_begin(), EM = Method->param_end(),
2624	EF = Overridden->param_end();
2625	IM != EM && IF != EF; ++IM, ++IF) {
2626	CheckMethodOverrideParam(S&: *this, MethodImpl: Method, MethodDecl: Overridden, ImplVar: *IM, IfaceVar: *IF,
2627	IsProtocolMethodDecl, IsOverridingMode: true, Warn: true);
2628	}
2629
2630	if (Method->isVariadic() != Overridden->isVariadic()) {
2631	Diag(Method->getLocation(),
2632	diag::warn_conflicting_overriding_variadic);
2633	Diag(Overridden->getLocation(), diag::note_previous_declaration);
2634	}
2635	}
2636
2637	/// WarnExactTypedMethods - This routine issues a warning if method
2638	/// implementation declaration matches exactly that of its declaration.
2639	void Sema::WarnExactTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2640	ObjCMethodDecl *MethodDecl,
2641	bool IsProtocolMethodDecl) {
2642	// don't issue warning when protocol method is optional because primary
2643	// class is not required to implement it and it is safe for protocol
2644	// to implement it.
2645	if (MethodDecl->getImplementationControl() ==
2646	ObjCImplementationControl::Optional)
2647	return;
2648	// don't issue warning when primary class's method is
2649	// deprecated/unavailable.
2650	if (MethodDecl->hasAttr<UnavailableAttr>() ||
2651	MethodDecl->hasAttr<DeprecatedAttr>())
2652	return;
2653
2654	bool match = CheckMethodOverrideReturn(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2655	IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2656	if (match)
2657	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2658	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2659	EF = MethodDecl->param_end();
2660	IM != EM && IF != EF; ++IM, ++IF) {
2661	match = CheckMethodOverrideParam(S&: *this, MethodImpl: ImpMethodDecl, MethodDecl,
2662	ImplVar: *IM, IfaceVar: *IF,
2663	IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2664	if (!match)
2665	break;
2666	}
2667	if (match)
2668	match = (ImpMethodDecl->isVariadic() == MethodDecl->isVariadic());
2669	if (match)
2670	match = !(MethodDecl->isClassMethod() &&
2671	MethodDecl->getSelector() == GetNullarySelector(name: "load", Ctx&: Context));
2672
2673	if (match) {
2674	Diag(ImpMethodDecl->getLocation(),
2675	diag::warn_category_method_impl_match);
2676	Diag(MethodDecl->getLocation(), diag::note_method_declared_at)
2677	<< MethodDecl->getDeclName();
2678	}
2679	}
2680
2681	/// FIXME: Type hierarchies in Objective-C can be deep. We could most likely
2682	/// improve the efficiency of selector lookups and type checking by associating
2683	/// with each protocol / interface / category the flattened instance tables. If
2684	/// we used an immutable set to keep the table then it wouldn't add significant
2685	/// memory cost and it would be handy for lookups.
2686
2687	typedef llvm::DenseSet<IdentifierInfo*> ProtocolNameSet;
2688	typedef std::unique_ptr<ProtocolNameSet> LazyProtocolNameSet;
2689
2690	static void findProtocolsWithExplicitImpls(const ObjCProtocolDecl *PDecl,
2691	ProtocolNameSet &PNS) {
2692	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2693	PNS.insert(PDecl->getIdentifier());
2694	for (const auto *PI : PDecl->protocols())
2695	findProtocolsWithExplicitImpls(PDecl: PI, PNS);
2696	}
2697
2698	/// Recursively populates a set with all conformed protocols in a class
2699	/// hierarchy that have the 'objc_protocol_requires_explicit_implementation'
2700	/// attribute.
2701	static void findProtocolsWithExplicitImpls(const ObjCInterfaceDecl *Super,
2702	ProtocolNameSet &PNS) {
2703	if (!Super)
2704	return;
2705
2706	for (const auto *I : Super->all_referenced_protocols())
2707	findProtocolsWithExplicitImpls(PDecl: I, PNS);
2708
2709	findProtocolsWithExplicitImpls(Super: Super->getSuperClass(), PNS);
2710	}
2711
2712	/// CheckProtocolMethodDefs - This routine checks unimplemented methods
2713	/// Declared in protocol, and those referenced by it.
2714	static void CheckProtocolMethodDefs(
2715	Sema &S, ObjCImplDecl *Impl, ObjCProtocolDecl *PDecl, bool &IncompleteImpl,
2716	const Sema::SelectorSet &InsMap, const Sema::SelectorSet &ClsMap,
2717	ObjCContainerDecl *CDecl, LazyProtocolNameSet &ProtocolsExplictImpl) {
2718	ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: CDecl);
2719	ObjCInterfaceDecl *IDecl = C ? C->getClassInterface()
2720	: dyn_cast<ObjCInterfaceDecl>(Val: CDecl);
2721	assert (IDecl && "CheckProtocolMethodDefs - IDecl is null");
2722
2723	ObjCInterfaceDecl *Super = IDecl->getSuperClass();
2724	ObjCInterfaceDecl *NSIDecl = nullptr;
2725
2726	// If this protocol is marked 'objc_protocol_requires_explicit_implementation'
2727	// then we should check if any class in the super class hierarchy also
2728	// conforms to this protocol, either directly or via protocol inheritance.
2729	// If so, we can skip checking this protocol completely because we
2730	// know that a parent class already satisfies this protocol.
2731	//
2732	// Note: we could generalize this logic for all protocols, and merely
2733	// add the limit on looking at the super class chain for just
2734	// specially marked protocols. This may be a good optimization. This
2735	// change is restricted to 'objc_protocol_requires_explicit_implementation'
2736	// protocols for now for controlled evaluation.
2737	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>()) {
2738	if (!ProtocolsExplictImpl) {
2739	ProtocolsExplictImpl.reset(p: new ProtocolNameSet);
2740	findProtocolsWithExplicitImpls(Super, PNS&: *ProtocolsExplictImpl);
2741	}
2742	if (ProtocolsExplictImpl->contains(V: PDecl->getIdentifier()))
2743	return;
2744
2745	// If no super class conforms to the protocol, we should not search
2746	// for methods in the super class to implicitly satisfy the protocol.
2747	Super = nullptr;
2748	}
2749
2750	if (S.getLangOpts().ObjCRuntime.isNeXTFamily()) {
2751	// check to see if class implements forwardInvocation method and objects
2752	// of this class are derived from 'NSProxy' so that to forward requests
2753	// from one object to another.
2754	// Under such conditions, which means that every method possible is
2755	// implemented in the class, we should not issue "Method definition not
2756	// found" warnings.
2757	// FIXME: Use a general GetUnarySelector method for this.
2758	const IdentifierInfo *II = &S.Context.Idents.get(Name: "forwardInvocation");
2759	Selector fISelector = S.Context.Selectors.getSelector(NumArgs: 1, IIV: &II);
2760	if (InsMap.count(Ptr: fISelector))
2761	// Is IDecl derived from 'NSProxy'? If so, no instance methods
2762	// need be implemented in the implementation.
2763	NSIDecl = IDecl->lookupInheritedClass(ICName: &S.Context.Idents.get(Name: "NSProxy"));
2764	}
2765
2766	// If this is a forward protocol declaration, get its definition.
2767	if (!PDecl->isThisDeclarationADefinition() &&
2768	PDecl->getDefinition())
2769	PDecl = PDecl->getDefinition();
2770
2771	// If a method lookup fails locally we still need to look and see if
2772	// the method was implemented by a base class or an inherited
2773	// protocol. This lookup is slow, but occurs rarely in correct code
2774	// and otherwise would terminate in a warning.
2775
2776	// check unimplemented instance methods.
2777	if (!NSIDecl)
2778	for (auto *method : PDecl->instance_methods()) {
2779	if (method->getImplementationControl() !=
2780	ObjCImplementationControl::Optional &&
2781	!method->isPropertyAccessor() &&
2782	!InsMap.count(method->getSelector()) &&
2783	(!Super || !Super->lookupMethod(
2784	method->getSelector(), true /* instance */,
2785	false /* shallowCategory */, true /* followsSuper */,
2786	nullptr /* category */))) {
2787	// If a method is not implemented in the category implementation but
2788	// has been declared in its primary class, superclass,
2789	// or in one of their protocols, no need to issue the warning.
2790	// This is because method will be implemented in the primary class
2791	// or one of its super class implementation.
2792
2793	// Ugly, but necessary. Method declared in protocol might have
2794	// have been synthesized due to a property declared in the class which
2795	// uses the protocol.
2796	if (ObjCMethodDecl *MethodInClass = IDecl->lookupMethod(
2797	method->getSelector(), true /* instance */,
2798	true /* shallowCategoryLookup */, false /* followSuper */))
2799	if (C || MethodInClass->isPropertyAccessor())
2800	continue;
2801	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2802	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2803	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2804	}
2805	}
2806	}
2807	// check unimplemented class methods
2808	for (auto *method : PDecl->class_methods()) {
2809	if (method->getImplementationControl() !=
2810	ObjCImplementationControl::Optional &&
2811	!ClsMap.count(method->getSelector()) &&
2812	(!Super || !Super->lookupMethod(
2813	method->getSelector(), false /* class method */,
2814	false /* shallowCategoryLookup */,
2815	true /* followSuper */, nullptr /* category */))) {
2816	// See above comment for instance method lookups.
2817	if (C && IDecl->lookupMethod(method->getSelector(),
2818	false /* class */,
2819	true /* shallowCategoryLookup */,
2820	false /* followSuper */))
2821	continue;
2822
2823	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2824	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2825	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2826	}
2827	}
2828	}
2829	// Check on this protocols's referenced protocols, recursively.
2830	for (auto *PI : PDecl->protocols())
2831	CheckProtocolMethodDefs(S, Impl, PDecl: PI, IncompleteImpl, InsMap, ClsMap, CDecl,
2832	ProtocolsExplictImpl);
2833	}
2834
2835	/// MatchAllMethodDeclarations - Check methods declared in interface
2836	/// or protocol against those declared in their implementations.
2837	///
2838	void Sema::MatchAllMethodDeclarations(const SelectorSet &InsMap,
2839	const SelectorSet &ClsMap,
2840	SelectorSet &InsMapSeen,
2841	SelectorSet &ClsMapSeen,
2842	ObjCImplDecl* IMPDecl,
2843	ObjCContainerDecl* CDecl,
2844	bool &IncompleteImpl,
2845	bool ImmediateClass,
2846	bool WarnCategoryMethodImpl) {
2847	// Check and see if instance methods in class interface have been
2848	// implemented in the implementation class. If so, their types match.
2849	for (auto *I : CDecl->instance_methods()) {
2850	if (!InsMapSeen.insert(Ptr: I->getSelector()).second)
2851	continue;
2852	if (!I->isPropertyAccessor() &&
2853	!InsMap.count(Ptr: I->getSelector())) {
2854	if (ImmediateClass)
2855	WarnUndefinedMethod(*this, IMPDecl, I, IncompleteImpl,
2856	diag::warn_undef_method_impl);
2857	continue;
2858	} else {
2859	ObjCMethodDecl *ImpMethodDecl =
2860	IMPDecl->getInstanceMethod(I->getSelector());
2861	assert(CDecl->getInstanceMethod(I->getSelector(), true/*AllowHidden*/) &&
2862	"Expected to find the method through lookup as well");
2863	// ImpMethodDecl may be null as in a @dynamic property.
2864	if (ImpMethodDecl) {
2865	// Skip property accessor function stubs.
2866	if (ImpMethodDecl->isSynthesizedAccessorStub())
2867	continue;
2868	if (!WarnCategoryMethodImpl)
2869	WarnConflictingTypedMethods(ImpMethodDecl, MethodDecl: I,
2870	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2871	else if (!I->isPropertyAccessor())
2872	WarnExactTypedMethods(ImpMethodDecl, MethodDecl: I, IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2873	}
2874	}
2875	}
2876
2877	// Check and see if class methods in class interface have been
2878	// implemented in the implementation class. If so, their types match.
2879	for (auto *I : CDecl->class_methods()) {
2880	if (!ClsMapSeen.insert(Ptr: I->getSelector()).second)
2881	continue;
2882	if (!I->isPropertyAccessor() &&
2883	!ClsMap.count(Ptr: I->getSelector())) {
2884	if (ImmediateClass)
2885	WarnUndefinedMethod(*this, IMPDecl, I, IncompleteImpl,
2886	diag::warn_undef_method_impl);
2887	} else {
2888	ObjCMethodDecl *ImpMethodDecl =
2889	IMPDecl->getClassMethod(I->getSelector());
2890	assert(CDecl->getClassMethod(I->getSelector(), true/*AllowHidden*/) &&
2891	"Expected to find the method through lookup as well");
2892	// ImpMethodDecl may be null as in a @dynamic property.
2893	if (ImpMethodDecl) {
2894	// Skip property accessor function stubs.
2895	if (ImpMethodDecl->isSynthesizedAccessorStub())
2896	continue;
2897	if (!WarnCategoryMethodImpl)
2898	WarnConflictingTypedMethods(ImpMethodDecl, MethodDecl: I,
2899	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2900	else if (!I->isPropertyAccessor())
2901	WarnExactTypedMethods(ImpMethodDecl, MethodDecl: I, IsProtocolMethodDecl: isa<ObjCProtocolDecl>(Val: CDecl));
2902	}
2903	}
2904	}
2905
2906	if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl> (Val: CDecl)) {
2907	// Also, check for methods declared in protocols inherited by
2908	// this protocol.
2909	for (auto *PI : PD->protocols())
2910	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2911	IMPDecl, PI, IncompleteImpl, false,
2912	WarnCategoryMethodImpl);
2913	}
2914
2915	if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (Val: CDecl)) {
2916	// when checking that methods in implementation match their declaration,
2917	// i.e. when WarnCategoryMethodImpl is false, check declarations in class
2918	// extension; as well as those in categories.
2919	if (!WarnCategoryMethodImpl) {
2920	for (auto *Cat : I->visible_categories())
2921	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2922	IMPDecl, Cat, IncompleteImpl,
2923	ImmediateClass && Cat->IsClassExtension(),
2924	WarnCategoryMethodImpl);
2925	} else {
2926	// Also methods in class extensions need be looked at next.
2927	for (auto *Ext : I->visible_extensions())
2928	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2929	IMPDecl, Ext, IncompleteImpl, false,
2930	WarnCategoryMethodImpl);
2931	}
2932
2933	// Check for any implementation of a methods declared in protocol.
2934	for (auto *PI : I->all_referenced_protocols())
2935	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2936	IMPDecl, PI, IncompleteImpl, false,
2937	WarnCategoryMethodImpl);
2938
2939	// FIXME. For now, we are not checking for exact match of methods
2940	// in category implementation and its primary class's super class.
2941	if (!WarnCategoryMethodImpl && I->getSuperClass())
2942	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2943	IMPDecl,
2944	I->getSuperClass(), IncompleteImpl, false);
2945	}
2946	}
2947
2948	/// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
2949	/// category matches with those implemented in its primary class and
2950	/// warns each time an exact match is found.
2951	void Sema::CheckCategoryVsClassMethodMatches(
2952	ObjCCategoryImplDecl *CatIMPDecl) {
2953	// Get category's primary class.
2954	ObjCCategoryDecl *CatDecl = CatIMPDecl->getCategoryDecl();
2955	if (!CatDecl)
2956	return;
2957	ObjCInterfaceDecl *IDecl = CatDecl->getClassInterface();
2958	if (!IDecl)
2959	return;
2960	ObjCInterfaceDecl *SuperIDecl = IDecl->getSuperClass();
2961	SelectorSet InsMap, ClsMap;
2962
2963	for (const auto *I : CatIMPDecl->instance_methods()) {
2964	Selector Sel = I->getSelector();
2965	// When checking for methods implemented in the category, skip over
2966	// those declared in category class's super class. This is because
2967	// the super class must implement the method.
2968	if (SuperIDecl && SuperIDecl->lookupMethod(Sel, true))
2969	continue;
2970	InsMap.insert(Sel);
2971	}
2972
2973	for (const auto *I : CatIMPDecl->class_methods()) {
2974	Selector Sel = I->getSelector();
2975	if (SuperIDecl && SuperIDecl->lookupMethod(Sel, false))
2976	continue;
2977	ClsMap.insert(Sel);
2978	}
2979	if (InsMap.empty() && ClsMap.empty())
2980	return;
2981
2982	SelectorSet InsMapSeen, ClsMapSeen;
2983	bool IncompleteImpl = false;
2984	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
2985	CatIMPDecl, IDecl,
2986	IncompleteImpl, false,
2987	true /*WarnCategoryMethodImpl*/);
2988	}
2989
2990	void Sema::ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
2991	ObjCContainerDecl* CDecl,
2992	bool IncompleteImpl) {
2993	SelectorSet InsMap;
2994	// Check and see if instance methods in class interface have been
2995	// implemented in the implementation class.
2996	for (const auto *I : IMPDecl->instance_methods())
2997	InsMap.insert(I->getSelector());
2998
2999	// Add the selectors for getters/setters of @dynamic properties.
3000	for (const auto *PImpl : IMPDecl->property_impls()) {
3001	// We only care about @dynamic implementations.
3002	if (PImpl->getPropertyImplementation() != ObjCPropertyImplDecl::Dynamic)
3003	continue;
3004
3005	const auto *P = PImpl->getPropertyDecl();
3006	if (!P) continue;
3007
3008	InsMap.insert(Ptr: P->getGetterName());
3009	if (!P->getSetterName().isNull())
3010	InsMap.insert(Ptr: P->getSetterName());
3011	}
3012
3013	// Check and see if properties declared in the interface have either 1)
3014	// an implementation or 2) there is a @synthesize/@dynamic implementation
3015	// of the property in the @implementation.
3016	if (const ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(Val: CDecl)) {
3017	bool SynthesizeProperties = LangOpts.ObjCDefaultSynthProperties &&
3018	LangOpts.ObjCRuntime.isNonFragile() &&
3019	!IDecl->isObjCRequiresPropertyDefs();
3020	DiagnoseUnimplementedProperties(S, IMPDecl, CDecl, SynthesizeProperties);
3021	}
3022
3023	// Diagnose null-resettable synthesized setters.
3024	diagnoseNullResettableSynthesizedSetters(impDecl: IMPDecl);
3025
3026	SelectorSet ClsMap;
3027	for (const auto *I : IMPDecl->class_methods())
3028	ClsMap.insert(I->getSelector());
3029
3030	// Check for type conflict of methods declared in a class/protocol and
3031	// its implementation; if any.
3032	SelectorSet InsMapSeen, ClsMapSeen;
3033	MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
3034	IMPDecl, CDecl,
3035	IncompleteImpl, ImmediateClass: true);
3036
3037	// check all methods implemented in category against those declared
3038	// in its primary class.
3039	if (ObjCCategoryImplDecl *CatDecl =
3040	dyn_cast<ObjCCategoryImplDecl>(Val: IMPDecl))
3041	CheckCategoryVsClassMethodMatches(CatIMPDecl: CatDecl);
3042
3043	// Check the protocol list for unimplemented methods in the @implementation
3044	// class.
3045	// Check and see if class methods in class interface have been
3046	// implemented in the implementation class.
3047
3048	LazyProtocolNameSet ExplicitImplProtocols;
3049
3050	if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (Val: CDecl)) {
3051	for (auto *PI : I->all_referenced_protocols())
3052	CheckProtocolMethodDefs(*this, IMPDecl, PI, IncompleteImpl, InsMap,
3053	ClsMap, I, ExplicitImplProtocols);
3054	} else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: CDecl)) {
3055	// For extended class, unimplemented methods in its protocols will
3056	// be reported in the primary class.
3057	if (!C->IsClassExtension()) {
3058	for (auto *P : C->protocols())
3059	CheckProtocolMethodDefs(S&: *this, Impl: IMPDecl, PDecl: P, IncompleteImpl, InsMap,
3060	ClsMap, CDecl, ProtocolsExplictImpl&: ExplicitImplProtocols);
3061	DiagnoseUnimplementedProperties(S, IMPDecl, CDecl,
3062	/*SynthesizeProperties=*/false);
3063	}
3064	} else
3065	llvm_unreachable("invalid ObjCContainerDecl type.");
3066	}
3067
3068	Sema::DeclGroupPtrTy
3069	Sema::ActOnForwardClassDeclaration(SourceLocation AtClassLoc,
3070	IdentifierInfo **IdentList,
3071	SourceLocation *IdentLocs,
3072	ArrayRef<ObjCTypeParamList *> TypeParamLists,
3073	unsigned NumElts) {
3074	SmallVector<Decl *, 8> DeclsInGroup;
3075	for (unsigned i = 0; i != NumElts; ++i) {
3076	// Check for another declaration kind with the same name.
3077	NamedDecl *PrevDecl
3078	= LookupSingleName(S: TUScope, Name: IdentList[i], Loc: IdentLocs[i],
3079	NameKind: LookupOrdinaryName, Redecl: forRedeclarationInCurContext());
3080	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
3081	// GCC apparently allows the following idiom:
3082	//
3083	// typedef NSObject < XCElementTogglerP > XCElementToggler;
3084	// @class XCElementToggler;
3085	//
3086	// Here we have chosen to ignore the forward class declaration
3087	// with a warning. Since this is the implied behavior.
3088	TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(Val: PrevDecl);
3089	if (!TDD || !TDD->getUnderlyingType()->isObjCObjectType()) {
3090	Diag(AtClassLoc, diag::err_redefinition_different_kind) << IdentList[i];
3091	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3092	} else {
3093	// a forward class declaration matching a typedef name of a class refers
3094	// to the underlying class. Just ignore the forward class with a warning
3095	// as this will force the intended behavior which is to lookup the
3096	// typedef name.
3097	if (isa<ObjCObjectType>(Val: TDD->getUnderlyingType())) {
3098	Diag(AtClassLoc, diag::warn_forward_class_redefinition)
3099	<< IdentList[i];
3100	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3101	continue;
3102	}
3103	}
3104	}
3105
3106	// Create a declaration to describe this forward declaration.
3107	ObjCInterfaceDecl *PrevIDecl
3108	= dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
3109
3110	IdentifierInfo *ClassName = IdentList[i];
3111	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
3112	// A previous decl with a different name is because of
3113	// @compatibility_alias, for example:
3114	// \code
3115	// @class NewImage;
3116	// @compatibility_alias OldImage NewImage;
3117	// \endcode
3118	// A lookup for 'OldImage' will return the 'NewImage' decl.
3119	//
3120	// In such a case use the real declaration name, instead of the alias one,
3121	// otherwise we will break IdentifierResolver and redecls-chain invariants.
3122	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
3123	// has been aliased.
3124	ClassName = PrevIDecl->getIdentifier();
3125	}
3126
3127	// If this forward declaration has type parameters, compare them with the
3128	// type parameters of the previous declaration.
3129	ObjCTypeParamList *TypeParams = TypeParamLists[i];
3130	if (PrevIDecl && TypeParams) {
3131	if (ObjCTypeParamList *PrevTypeParams = PrevIDecl->getTypeParamList()) {
3132	// Check for consistency with the previous declaration.
3133	if (checkTypeParamListConsistency(
3134	S&: *this, prevTypeParams: PrevTypeParams, newTypeParams: TypeParams,
3135	newContext: TypeParamListContext::ForwardDeclaration)) {
3136	TypeParams = nullptr;
3137	}
3138	} else if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
3139	// The @interface does not have type parameters. Complain.
3140	Diag(IdentLocs[i], diag::err_objc_parameterized_forward_class)
3141	<< ClassName
3142	<< TypeParams->getSourceRange();
3143	Diag(Def->getLocation(), diag::note_defined_here)
3144	<< ClassName;
3145
3146	TypeParams = nullptr;
3147	}
3148	}
3149
3150	ObjCInterfaceDecl *IDecl
3151	= ObjCInterfaceDecl::Create(C: Context, DC: CurContext, atLoc: AtClassLoc,
3152	Id: ClassName, typeParamList: TypeParams, PrevDecl: PrevIDecl,
3153	ClassLoc: IdentLocs[i]);
3154	IDecl->setAtEndRange(IdentLocs[i]);
3155
3156	if (PrevIDecl)
3157	mergeDeclAttributes(IDecl, PrevIDecl);
3158
3159	PushOnScopeChains(IDecl, TUScope);
3160	CheckObjCDeclScope(IDecl);
3161	DeclsInGroup.push_back(IDecl);
3162	}
3163
3164	return BuildDeclaratorGroup(Group: DeclsInGroup);
3165	}
3166
3167	static bool tryMatchRecordTypes(ASTContext &Context,
3168	Sema::MethodMatchStrategy strategy,
3169	const Type *left, const Type *right);
3170
3171	static bool matchTypes(ASTContext &Context, Sema::MethodMatchStrategy strategy,
3172	QualType leftQT, QualType rightQT) {
3173	const Type *left =
3174	Context.getCanonicalType(T: leftQT).getUnqualifiedType().getTypePtr();
3175	const Type *right =
3176	Context.getCanonicalType(T: rightQT).getUnqualifiedType().getTypePtr();
3177
3178	if (left == right) return true;
3179
3180	// If we're doing a strict match, the types have to match exactly.
3181	if (strategy == Sema::MMS_strict) return false;
3182
3183	if (left->isIncompleteType() || right->isIncompleteType()) return false;
3184
3185	// Otherwise, use this absurdly complicated algorithm to try to
3186	// validate the basic, low-level compatibility of the two types.
3187
3188	// As a minimum, require the sizes and alignments to match.
3189	TypeInfo LeftTI = Context.getTypeInfo(T: left);
3190	TypeInfo RightTI = Context.getTypeInfo(T: right);
3191	if (LeftTI.Width != RightTI.Width)
3192	return false;
3193
3194	if (LeftTI.Align != RightTI.Align)
3195	return false;
3196
3197	// Consider all the kinds of non-dependent canonical types:
3198	// - functions and arrays aren't possible as return and parameter types
3199
3200	// - vector types of equal size can be arbitrarily mixed
3201	if (isa<VectorType>(Val: left)) return isa<VectorType>(Val: right);
3202	if (isa<VectorType>(Val: right)) return false;
3203
3204	// - references should only match references of identical type
3205	// - structs, unions, and Objective-C objects must match more-or-less
3206	// exactly
3207	// - everything else should be a scalar
3208	if (!left->isScalarType() || !right->isScalarType())
3209	return tryMatchRecordTypes(Context, strategy, left, right);
3210
3211	// Make scalars agree in kind, except count bools as chars, and group
3212	// all non-member pointers together.
3213	Type::ScalarTypeKind leftSK = left->getScalarTypeKind();
3214	Type::ScalarTypeKind rightSK = right->getScalarTypeKind();
3215	if (leftSK == Type::STK_Bool) leftSK = Type::STK_Integral;
3216	if (rightSK == Type::STK_Bool) rightSK = Type::STK_Integral;
3217	if (leftSK == Type::STK_CPointer || leftSK == Type::STK_BlockPointer)
3218	leftSK = Type::STK_ObjCObjectPointer;
3219	if (rightSK == Type::STK_CPointer || rightSK == Type::STK_BlockPointer)
3220	rightSK = Type::STK_ObjCObjectPointer;
3221
3222	// Note that data member pointers and function member pointers don't
3223	// intermix because of the size differences.
3224
3225	return (leftSK == rightSK);
3226	}
3227
3228	static bool tryMatchRecordTypes(ASTContext &Context,
3229	Sema::MethodMatchStrategy strategy,
3230	const Type *lt, const Type *rt) {
3231	assert(lt && rt && lt != rt);
3232
3233	if (!isa<RecordType>(Val: lt) || !isa<RecordType>(Val: rt)) return false;
3234	RecordDecl *left = cast<RecordType>(Val: lt)->getDecl();
3235	RecordDecl *right = cast<RecordType>(Val: rt)->getDecl();
3236
3237	// Require union-hood to match.
3238	if (left->isUnion() != right->isUnion()) return false;
3239
3240	// Require an exact match if either is non-POD.
3241	if ((isa<CXXRecordDecl>(Val: left) && !cast<CXXRecordDecl>(Val: left)->isPOD()) ||
3242	(isa<CXXRecordDecl>(Val: right) && !cast<CXXRecordDecl>(Val: right)->isPOD()))
3243	return false;
3244
3245	// Require size and alignment to match.
3246	TypeInfo LeftTI = Context.getTypeInfo(T: lt);
3247	TypeInfo RightTI = Context.getTypeInfo(T: rt);
3248	if (LeftTI.Width != RightTI.Width)
3249	return false;
3250
3251	if (LeftTI.Align != RightTI.Align)
3252	return false;
3253
3254	// Require fields to match.
3255	RecordDecl::field_iterator li = left->field_begin(), le = left->field_end();
3256	RecordDecl::field_iterator ri = right->field_begin(), re = right->field_end();
3257	for (; li != le && ri != re; ++li, ++ri) {
3258	if (!matchTypes(Context, strategy, li->getType(), ri->getType()))
3259	return false;
3260	}
3261	return (li == le && ri == re);
3262	}
3263
3264	/// MatchTwoMethodDeclarations - Checks that two methods have matching type and
3265	/// returns true, or false, accordingly.
3266	/// TODO: Handle protocol list; such as id<p1,p2> in type comparisons
3267	bool Sema::MatchTwoMethodDeclarations(const ObjCMethodDecl *left,
3268	const ObjCMethodDecl *right,
3269	MethodMatchStrategy strategy) {
3270	if (!matchTypes(Context, strategy, leftQT: left->getReturnType(),
3271	rightQT: right->getReturnType()))
3272	return false;
3273
3274	// If either is hidden, it is not considered to match.
3275	if (!left->isUnconditionallyVisible() || !right->isUnconditionallyVisible())
3276	return false;
3277
3278	if (left->isDirectMethod() != right->isDirectMethod())
3279	return false;
3280
3281	if (getLangOpts().ObjCAutoRefCount &&
3282	(left->hasAttr<NSReturnsRetainedAttr>()
3283	!= right->hasAttr<NSReturnsRetainedAttr>() ||
3284	left->hasAttr<NSConsumesSelfAttr>()
3285	!= right->hasAttr<NSConsumesSelfAttr>()))
3286	return false;
3287
3288	ObjCMethodDecl::param_const_iterator
3289	li = left->param_begin(), le = left->param_end(), ri = right->param_begin(),
3290	re = right->param_end();
3291
3292	for (; li != le && ri != re; ++li, ++ri) {
3293	assert(ri != right->param_end() && "Param mismatch");
3294	const ParmVarDecl *lparm = *li, *rparm = *ri;
3295
3296	if (!matchTypes(Context, strategy, lparm->getType(), rparm->getType()))
3297	return false;
3298
3299	if (getLangOpts().ObjCAutoRefCount &&
3300	lparm->hasAttr<NSConsumedAttr>() != rparm->hasAttr<NSConsumedAttr>())
3301	return false;
3302	}
3303	return true;
3304	}
3305
3306	static bool isMethodContextSameForKindofLookup(ObjCMethodDecl *Method,
3307	ObjCMethodDecl *MethodInList) {
3308	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3309	auto *MethodInListProtocol =
3310	dyn_cast<ObjCProtocolDecl>(MethodInList->getDeclContext());
3311	// If this method belongs to a protocol but the method in list does not, or
3312	// vice versa, we say the context is not the same.
3313	if ((MethodProtocol && !MethodInListProtocol) ||
3314	(!MethodProtocol && MethodInListProtocol))
3315	return false;
3316
3317	if (MethodProtocol && MethodInListProtocol)
3318	return true;
3319
3320	ObjCInterfaceDecl *MethodInterface = Method->getClassInterface();
3321	ObjCInterfaceDecl *MethodInListInterface =
3322	MethodInList->getClassInterface();
3323	return MethodInterface == MethodInListInterface;
3324	}
3325
3326	void Sema::addMethodToGlobalList(ObjCMethodList *List,
3327	ObjCMethodDecl *Method) {
3328	// Record at the head of the list whether there were 0, 1, or >= 2 methods
3329	// inside categories.
3330	if (ObjCCategoryDecl *CD =
3331	dyn_cast<ObjCCategoryDecl>(Method->getDeclContext()))
3332	if (!CD->IsClassExtension() && List->getBits() < 2)
3333	List->setBits(List->getBits() + 1);
3334
3335	// If the list is empty, make it a singleton list.
3336	if (List->getMethod() == nullptr) {
3337	List->setMethod(Method);
3338	List->setNext(nullptr);
3339	return;
3340	}
3341
3342	// We've seen a method with this name, see if we have already seen this type
3343	// signature.
3344	ObjCMethodList *Previous = List;
3345	ObjCMethodList *ListWithSameDeclaration = nullptr;
3346	for (; List; Previous = List, List = List->getNext()) {
3347	// If we are building a module, keep all of the methods.
3348	if (getLangOpts().isCompilingModule())
3349	continue;
3350
3351	bool SameDeclaration = MatchTwoMethodDeclarations(left: Method,
3352	right: List->getMethod());
3353	// Looking for method with a type bound requires the correct context exists.
3354	// We need to insert a method into the list if the context is different.
3355	// If the method's declaration matches the list
3356	// a> the method belongs to a different context: we need to insert it, in
3357	// order to emit the availability message, we need to prioritize over
3358	// availability among the methods with the same declaration.
3359	// b> the method belongs to the same context: there is no need to insert a
3360	// new entry.
3361	// If the method's declaration does not match the list, we insert it to the
3362	// end.
3363	if (!SameDeclaration ||
3364	!isMethodContextSameForKindofLookup(Method, MethodInList: List->getMethod())) {
3365	// Even if two method types do not match, we would like to say
3366	// there is more than one declaration so unavailability/deprecated
3367	// warning is not too noisy.
3368	if (!Method->isDefined())
3369	List->setHasMoreThanOneDecl(true);
3370
3371	// For methods with the same declaration, the one that is deprecated
3372	// should be put in the front for better diagnostics.
3373	if (Method->isDeprecated() && SameDeclaration &&
3374	!ListWithSameDeclaration && !List->getMethod()->isDeprecated())
3375	ListWithSameDeclaration = List;
3376
3377	if (Method->isUnavailable() && SameDeclaration &&
3378	!ListWithSameDeclaration &&
3379	List->getMethod()->getAvailability() < AR_Deprecated)
3380	ListWithSameDeclaration = List;
3381	continue;
3382	}
3383
3384	ObjCMethodDecl *PrevObjCMethod = List->getMethod();
3385
3386	// Propagate the 'defined' bit.
3387	if (Method->isDefined())
3388	PrevObjCMethod->setDefined(true);
3389	else {
3390	// Objective-C doesn't allow an @interface for a class after its
3391	// @implementation. So if Method is not defined and there already is
3392	// an entry for this type signature, Method has to be for a different
3393	// class than PrevObjCMethod.
3394	List->setHasMoreThanOneDecl(true);
3395	}
3396
3397	// If a method is deprecated, push it in the global pool.
3398	// This is used for better diagnostics.
3399	if (Method->isDeprecated()) {
3400	if (!PrevObjCMethod->isDeprecated())
3401	List->setMethod(Method);
3402	}
3403	// If the new method is unavailable, push it into global pool
3404	// unless previous one is deprecated.
3405	if (Method->isUnavailable()) {
3406	if (PrevObjCMethod->getAvailability() < AR_Deprecated)
3407	List->setMethod(Method);
3408	}
3409
3410	return;
3411	}
3412
3413	// We have a new signature for an existing method - add it.
3414	// This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
3415	ObjCMethodList *Mem = BumpAlloc.Allocate<ObjCMethodList>();
3416
3417	// We insert it right before ListWithSameDeclaration.
3418	if (ListWithSameDeclaration) {
3419	auto *List = new (Mem) ObjCMethodList(*ListWithSameDeclaration);
3420	// FIXME: should we clear the other bits in ListWithSameDeclaration?
3421	ListWithSameDeclaration->setMethod(Method);
3422	ListWithSameDeclaration->setNext(List);
3423	return;
3424	}
3425
3426	Previous->setNext(new (Mem) ObjCMethodList(Method));
3427	}
3428
3429	/// Read the contents of the method pool for a given selector from
3430	/// external storage.
3431	void Sema::ReadMethodPool(Selector Sel) {
3432	assert(ExternalSource && "We need an external AST source");
3433	ExternalSource->ReadMethodPool(Sel);
3434	}
3435
3436	void Sema::updateOutOfDateSelector(Selector Sel) {
3437	if (!ExternalSource)
3438	return;
3439	ExternalSource->updateOutOfDateSelector(Sel);
3440	}
3441
3442	void Sema::AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl,
3443	bool instance) {
3444	// Ignore methods of invalid containers.
3445	if (cast<Decl>(Method->getDeclContext())->isInvalidDecl())
3446	return;
3447
3448	if (ExternalSource)
3449	ReadMethodPool(Sel: Method->getSelector());
3450
3451	GlobalMethodPool::iterator Pos = MethodPool.find(Sel: Method->getSelector());
3452	if (Pos == MethodPool.end())
3453	Pos = MethodPool
3454	.insert(Val: std::make_pair(x: Method->getSelector(),
3455	y: GlobalMethodPool::Lists()))
3456	.first;
3457
3458	Method->setDefined(impl);
3459
3460	ObjCMethodList &Entry = instance ? Pos->second.first : Pos->second.second;
3461	addMethodToGlobalList(List: &Entry, Method);
3462	}
3463
3464	/// Determines if this is an "acceptable" loose mismatch in the global
3465	/// method pool. This exists mostly as a hack to get around certain
3466	/// global mismatches which we can't afford to make warnings / errors.
3467	/// Really, what we want is a way to take a method out of the global
3468	/// method pool.
3469	static bool isAcceptableMethodMismatch(ObjCMethodDecl *chosen,
3470	ObjCMethodDecl *other) {
3471	if (!chosen->isInstanceMethod())
3472	return false;
3473
3474	if (chosen->isDirectMethod() != other->isDirectMethod())
3475	return false;
3476
3477	Selector sel = chosen->getSelector();
3478	if (!sel.isUnarySelector() || sel.getNameForSlot(argIndex: 0) != "length")
3479	return false;
3480
3481	// Don't complain about mismatches for -length if the method we
3482	// chose has an integral result type.
3483	return (chosen->getReturnType()->isIntegerType());
3484	}
3485
3486	/// Return true if the given method is wthin the type bound.
3487	static bool FilterMethodsByTypeBound(ObjCMethodDecl *Method,
3488	const ObjCObjectType *TypeBound) {
3489	if (!TypeBound)
3490	return true;
3491
3492	if (TypeBound->isObjCId())
3493	// FIXME: should we handle the case of bounding to id<A, B> differently?
3494	return true;
3495
3496	auto *BoundInterface = TypeBound->getInterface();
3497	assert(BoundInterface && "unexpected object type!");
3498
3499	// Check if the Method belongs to a protocol. We should allow any method
3500	// defined in any protocol, because any subclass could adopt the protocol.
3501	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3502	if (MethodProtocol) {
3503	return true;
3504	}
3505
3506	// If the Method belongs to a class, check if it belongs to the class
3507	// hierarchy of the class bound.
3508	if (ObjCInterfaceDecl *MethodInterface = Method->getClassInterface()) {
3509	// We allow methods declared within classes that are part of the hierarchy
3510	// of the class bound (superclass of, subclass of, or the same as the class
3511	// bound).
3512	return MethodInterface == BoundInterface ||
3513	MethodInterface->isSuperClassOf(I: BoundInterface) ||
3514	BoundInterface->isSuperClassOf(I: MethodInterface);
3515	}
3516	llvm_unreachable("unknown method context");
3517	}
3518
3519	/// We first select the type of the method: Instance or Factory, then collect
3520	/// all methods with that type.
3521	bool Sema::CollectMultipleMethodsInGlobalPool(
3522	Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods,
3523	bool InstanceFirst, bool CheckTheOther,
3524	const ObjCObjectType *TypeBound) {
3525	if (ExternalSource)
3526	ReadMethodPool(Sel);
3527
3528	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3529	if (Pos == MethodPool.end())
3530	return false;
3531
3532	// Gather the non-hidden methods.
3533	ObjCMethodList &MethList = InstanceFirst ? Pos->second.first :
3534	Pos->second.second;
3535	for (ObjCMethodList *M = &MethList; M; M = M->getNext())
3536	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3537	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3538	Methods.push_back(Elt: M->getMethod());
3539	}
3540
3541	// Return if we find any method with the desired kind.
3542	if (!Methods.empty())
3543	return Methods.size() > 1;
3544
3545	if (!CheckTheOther)
3546	return false;
3547
3548	// Gather the other kind.
3549	ObjCMethodList &MethList2 = InstanceFirst ? Pos->second.second :
3550	Pos->second.first;
3551	for (ObjCMethodList *M = &MethList2; M; M = M->getNext())
3552	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3553	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3554	Methods.push_back(Elt: M->getMethod());
3555	}
3556
3557	return Methods.size() > 1;
3558	}
3559
3560	bool Sema::AreMultipleMethodsInGlobalPool(
3561	Selector Sel, ObjCMethodDecl *BestMethod, SourceRange R,
3562	bool receiverIdOrClass, SmallVectorImpl<ObjCMethodDecl *> &Methods) {
3563	// Diagnose finding more than one method in global pool.
3564	SmallVector<ObjCMethodDecl *, 4> FilteredMethods;
3565	FilteredMethods.push_back(Elt: BestMethod);
3566
3567	for (auto *M : Methods)
3568	if (M != BestMethod && !M->hasAttr<UnavailableAttr>())
3569	FilteredMethods.push_back(Elt: M);
3570
3571	if (FilteredMethods.size() > 1)
3572	DiagnoseMultipleMethodInGlobalPool(Methods&: FilteredMethods, Sel, R,
3573	receiverIdOrClass);
3574
3575	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3576	// Test for no method in the pool which should not trigger any warning by
3577	// caller.
3578	if (Pos == MethodPool.end())
3579	return true;
3580	ObjCMethodList &MethList =
3581	BestMethod->isInstanceMethod() ? Pos->second.first : Pos->second.second;
3582	return MethList.hasMoreThanOneDecl();
3583	}
3584
3585	ObjCMethodDecl *Sema::LookupMethodInGlobalPool(Selector Sel, SourceRange R,
3586	bool receiverIdOrClass,
3587	bool instance) {
3588	if (ExternalSource)
3589	ReadMethodPool(Sel);
3590
3591	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3592	if (Pos == MethodPool.end())
3593	return nullptr;
3594
3595	// Gather the non-hidden methods.
3596	ObjCMethodList &MethList = instance ? Pos->second.first : Pos->second.second;
3597	SmallVector<ObjCMethodDecl *, 4> Methods;
3598	for (ObjCMethodList *M = &MethList; M; M = M->getNext()) {
3599	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible())
3600	return M->getMethod();
3601	}
3602	return nullptr;
3603	}
3604
3605	void Sema::DiagnoseMultipleMethodInGlobalPool(SmallVectorImpl<ObjCMethodDecl*> &Methods,
3606	Selector Sel, SourceRange R,
3607	bool receiverIdOrClass) {
3608	// We found multiple methods, so we may have to complain.
3609	bool issueDiagnostic = false, issueError = false;
3610
3611	// We support a warning which complains about *any* difference in
3612	// method signature.
3613	bool strictSelectorMatch =
3614	receiverIdOrClass &&
3615	!Diags.isIgnored(diag::warn_strict_multiple_method_decl, R.getBegin());
3616	if (strictSelectorMatch) {
3617	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3618	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_strict)) {
3619	issueDiagnostic = true;
3620	break;
3621	}
3622	}
3623	}
3624
3625	// If we didn't see any strict differences, we won't see any loose
3626	// differences. In ARC, however, we also need to check for loose
3627	// mismatches, because most of them are errors.
3628	if (!strictSelectorMatch ||
3629	(issueDiagnostic && getLangOpts().ObjCAutoRefCount))
3630	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3631	// This checks if the methods differ in type mismatch.
3632	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_loose) &&
3633	!isAcceptableMethodMismatch(chosen: Methods[0], other: Methods[I])) {
3634	issueDiagnostic = true;
3635	if (getLangOpts().ObjCAutoRefCount)
3636	issueError = true;
3637	break;
3638	}
3639	}
3640
3641	if (issueDiagnostic) {
3642	if (issueError)
3643	Diag(R.getBegin(), diag::err_arc_multiple_method_decl) << Sel << R;
3644	else if (strictSelectorMatch)
3645	Diag(R.getBegin(), diag::warn_strict_multiple_method_decl) << Sel << R;
3646	else
3647	Diag(R.getBegin(), diag::warn_multiple_method_decl) << Sel << R;
3648
3649	Diag(Methods[0]->getBeginLoc(),
3650	issueError ? diag::note_possibility : diag::note_using)
3651	<< Methods[0]->getSourceRange();
3652	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3653	Diag(Methods[I]->getBeginLoc(), diag::note_also_found)
3654	<< Methods[I]->getSourceRange();
3655	}
3656	}
3657	}
3658
3659	ObjCMethodDecl *Sema::LookupImplementedMethodInGlobalPool(Selector Sel) {
3660	GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
3661	if (Pos == MethodPool.end())
3662	return nullptr;
3663
3664	GlobalMethodPool::Lists &Methods = Pos->second;
3665	for (const ObjCMethodList *Method = &Methods.first; Method;
3666	Method = Method->getNext())
3667	if (Method->getMethod() &&
3668	(Method->getMethod()->isDefined() ||
3669	Method->getMethod()->isPropertyAccessor()))
3670	return Method->getMethod();
3671
3672	for (const ObjCMethodList *Method = &Methods.second; Method;
3673	Method = Method->getNext())
3674	if (Method->getMethod() &&
3675	(Method->getMethod()->isDefined() ||
3676	Method->getMethod()->isPropertyAccessor()))
3677	return Method->getMethod();
3678	return nullptr;
3679	}
3680
3681	static void
3682	HelperSelectorsForTypoCorrection(
3683	SmallVectorImpl<const ObjCMethodDecl *> &BestMethod,
3684	StringRef Typo, const ObjCMethodDecl * Method) {
3685	const unsigned MaxEditDistance = 1;
3686	unsigned BestEditDistance = MaxEditDistance + 1;
3687	std::string MethodName = Method->getSelector().getAsString();
3688
3689	unsigned MinPossibleEditDistance = abs(x: (int)MethodName.size() - (int)Typo.size());
3690	if (MinPossibleEditDistance > 0 &&
3691	Typo.size() / MinPossibleEditDistance < 1)
3692	return;
3693	unsigned EditDistance = Typo.edit_distance(Other: MethodName, AllowReplacements: true, MaxEditDistance);
3694	if (EditDistance > MaxEditDistance)
3695	return;
3696	if (EditDistance == BestEditDistance)
3697	BestMethod.push_back(Elt: Method);
3698	else if (EditDistance < BestEditDistance) {
3699	BestMethod.clear();
3700	BestMethod.push_back(Elt: Method);
3701	}
3702	}
3703
3704	static bool HelperIsMethodInObjCType(Sema &S, Selector Sel,
3705	QualType ObjectType) {
3706	if (ObjectType.isNull())
3707	return true;
3708	if (S.LookupMethodInObjectType(Sel, Ty: ObjectType, IsInstance: true/*Instance method*/))
3709	return true;
3710	return S.LookupMethodInObjectType(Sel, Ty: ObjectType, IsInstance: false/*Class method*/) !=
3711	nullptr;
3712	}
3713
3714	const ObjCMethodDecl *
3715	Sema::SelectorsForTypoCorrection(Selector Sel,
3716	QualType ObjectType) {
3717	unsigned NumArgs = Sel.getNumArgs();
3718	SmallVector<const ObjCMethodDecl *, 8> Methods;
3719	bool ObjectIsId = true, ObjectIsClass = true;
3720	if (ObjectType.isNull())
3721	ObjectIsId = ObjectIsClass = false;
3722	else if (!ObjectType->isObjCObjectPointerType())
3723	return nullptr;
3724	else if (const ObjCObjectPointerType *ObjCPtr =
3725	ObjectType->getAsObjCInterfacePointerType()) {
3726	ObjectType = QualType(ObjCPtr->getInterfaceType(), 0);
3727	ObjectIsId = ObjectIsClass = false;
3728	}
3729	else if (ObjectType->isObjCIdType() || ObjectType->isObjCQualifiedIdType())
3730	ObjectIsClass = false;
3731	else if (ObjectType->isObjCClassType() || ObjectType->isObjCQualifiedClassType())
3732	ObjectIsId = false;
3733	else
3734	return nullptr;
3735
3736	for (GlobalMethodPool::iterator b = MethodPool.begin(),
3737	e = MethodPool.end(); b != e; b++) {
3738	// instance methods
3739	for (ObjCMethodList *M = &b->second.first; M; M=M->getNext())
3740	if (M->getMethod() &&
3741	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3742	(M->getMethod()->getSelector() != Sel)) {
3743	if (ObjectIsId)
3744	Methods.push_back(Elt: M->getMethod());
3745	else if (!ObjectIsClass &&
3746	HelperIsMethodInObjCType(S&: *this, Sel: M->getMethod()->getSelector(),
3747	ObjectType))
3748	Methods.push_back(Elt: M->getMethod());
3749	}
3750	// class methods
3751	for (ObjCMethodList *M = &b->second.second; M; M=M->getNext())
3752	if (M->getMethod() &&
3753	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3754	(M->getMethod()->getSelector() != Sel)) {
3755	if (ObjectIsClass)
3756	Methods.push_back(Elt: M->getMethod());
3757	else if (!ObjectIsId &&
3758	HelperIsMethodInObjCType(S&: *this, Sel: M->getMethod()->getSelector(),
3759	ObjectType))
3760	Methods.push_back(Elt: M->getMethod());
3761	}
3762	}
3763
3764	SmallVector<const ObjCMethodDecl *, 8> SelectedMethods;
3765	for (unsigned i = 0, e = Methods.size(); i < e; i++) {
3766	HelperSelectorsForTypoCorrection(BestMethod&: SelectedMethods,
3767	Typo: Sel.getAsString(), Method: Methods[i]);
3768	}
3769	return (SelectedMethods.size() == 1) ? SelectedMethods[0] : nullptr;
3770	}
3771
3772	/// DiagnoseDuplicateIvars -
3773	/// Check for duplicate ivars in the entire class at the start of
3774	/// \@implementation. This becomes necessary because class extension can
3775	/// add ivars to a class in random order which will not be known until
3776	/// class's \@implementation is seen.
3777	void Sema::DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID,
3778	ObjCInterfaceDecl *SID) {
3779	for (auto *Ivar : ID->ivars()) {
3780	if (Ivar->isInvalidDecl())
3781	continue;
3782	if (IdentifierInfo *II = Ivar->getIdentifier()) {
3783	ObjCIvarDecl* prevIvar = SID->lookupInstanceVariable(IVarName: II);
3784	if (prevIvar) {
3785	Diag(Ivar->getLocation(), diag::err_duplicate_member) << II;
3786	Diag(prevIvar->getLocation(), diag::note_previous_declaration);
3787	Ivar->setInvalidDecl();
3788	}
3789	}
3790	}
3791	}
3792
3793	/// Diagnose attempts to define ARC-__weak ivars when __weak is disabled.
3794	static void DiagnoseWeakIvars(Sema &S, ObjCImplementationDecl *ID) {
3795	if (S.getLangOpts().ObjCWeak) return;
3796
3797	for (auto ivar = ID->getClassInterface()->all_declared_ivar_begin();
3798	ivar; ivar = ivar->getNextIvar()) {
3799	if (ivar->isInvalidDecl()) continue;
3800	if (ivar->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
3801	if (S.getLangOpts().ObjCWeakRuntime) {
3802	S.Diag(ivar->getLocation(), diag::err_arc_weak_disabled);
3803	} else {
3804	S.Diag(ivar->getLocation(), diag::err_arc_weak_no_runtime);
3805	}
3806	}
3807	}
3808	}
3809
3810	/// Diagnose attempts to use flexible array member with retainable object type.
3811	static void DiagnoseRetainableFlexibleArrayMember(Sema &S,
3812	ObjCInterfaceDecl *ID) {
3813	if (!S.getLangOpts().ObjCAutoRefCount)
3814	return;
3815
3816	for (auto ivar = ID->all_declared_ivar_begin(); ivar;
3817	ivar = ivar->getNextIvar()) {
3818	if (ivar->isInvalidDecl())
3819	continue;
3820	QualType IvarTy = ivar->getType();
3821	if (IvarTy->isIncompleteArrayType() &&
3822	(IvarTy.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) &&
3823	IvarTy->isObjCLifetimeType()) {
3824	S.Diag(ivar->getLocation(), diag::err_flexible_array_arc_retainable);
3825	ivar->setInvalidDecl();
3826	}
3827	}
3828	}
3829
3830	Sema::ObjCContainerKind Sema::getObjCContainerKind() const {
3831	switch (CurContext->getDeclKind()) {
3832	case Decl::ObjCInterface:
3833	return Sema::OCK_Interface;
3834	case Decl::ObjCProtocol:
3835	return Sema::OCK_Protocol;
3836	case Decl::ObjCCategory:
3837	if (cast<ObjCCategoryDecl>(Val: CurContext)->IsClassExtension())
3838	return Sema::OCK_ClassExtension;
3839	return Sema::OCK_Category;
3840	case Decl::ObjCImplementation:
3841	return Sema::OCK_Implementation;
3842	case Decl::ObjCCategoryImpl:
3843	return Sema::OCK_CategoryImplementation;
3844
3845	default:
3846	return Sema::OCK_None;
3847	}
3848	}
3849
3850	static bool IsVariableSizedType(QualType T) {
3851	if (T->isIncompleteArrayType())
3852	return true;
3853	const auto *RecordTy = T->getAs<RecordType>();
3854	return (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember());
3855	}
3856
3857	static void DiagnoseVariableSizedIvars(Sema &S, ObjCContainerDecl *OCD) {
3858	ObjCInterfaceDecl *IntfDecl = nullptr;
3859	ObjCInterfaceDecl::ivar_range Ivars = llvm::make_range(
3860	x: ObjCInterfaceDecl::ivar_iterator(), y: ObjCInterfaceDecl::ivar_iterator());
3861	if ((IntfDecl = dyn_cast<ObjCInterfaceDecl>(Val: OCD))) {
3862	Ivars = IntfDecl->ivars();
3863	} else if (auto *ImplDecl = dyn_cast<ObjCImplementationDecl>(Val: OCD)) {
3864	IntfDecl = ImplDecl->getClassInterface();
3865	Ivars = ImplDecl->ivars();
3866	} else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Val: OCD)) {
3867	if (CategoryDecl->IsClassExtension()) {
3868	IntfDecl = CategoryDecl->getClassInterface();
3869	Ivars = CategoryDecl->ivars();
3870	}
3871	}
3872
3873	// Check if variable sized ivar is in interface and visible to subclasses.
3874	if (!isa<ObjCInterfaceDecl>(Val: OCD)) {
3875	for (auto *ivar : Ivars) {
3876	if (!ivar->isInvalidDecl() && IsVariableSizedType(ivar->getType())) {
3877	S.Diag(ivar->getLocation(), diag::warn_variable_sized_ivar_visibility)
3878	<< ivar->getDeclName() << ivar->getType();
3879	}
3880	}
3881	}
3882
3883	// Subsequent checks require interface decl.
3884	if (!IntfDecl)
3885	return;
3886
3887	// Check if variable sized ivar is followed by another ivar.
3888	for (ObjCIvarDecl *ivar = IntfDecl->all_declared_ivar_begin(); ivar;
3889	ivar = ivar->getNextIvar()) {
3890	if (ivar->isInvalidDecl() || !ivar->getNextIvar())
3891	continue;
3892	QualType IvarTy = ivar->getType();
3893	bool IsInvalidIvar = false;
3894	if (IvarTy->isIncompleteArrayType()) {
3895	S.Diag(ivar->getLocation(), diag::err_flexible_array_not_at_end)
3896	<< ivar->getDeclName() << IvarTy
3897	<< llvm::to_underlying(TagTypeKind::Class); // Use "class" for Obj-C.
3898	IsInvalidIvar = true;
3899	} else if (const RecordType *RecordTy = IvarTy->getAs<RecordType>()) {
3900	if (RecordTy->getDecl()->hasFlexibleArrayMember()) {
3901	S.Diag(ivar->getLocation(),
3902	diag::err_objc_variable_sized_type_not_at_end)
3903	<< ivar->getDeclName() << IvarTy;
3904	IsInvalidIvar = true;
3905	}
3906	}
3907	if (IsInvalidIvar) {
3908	S.Diag(ivar->getNextIvar()->getLocation(),
3909	diag::note_next_ivar_declaration)
3910	<< ivar->getNextIvar()->getSynthesize();
3911	ivar->setInvalidDecl();
3912	}
3913	}
3914
3915	// Check if ObjC container adds ivars after variable sized ivar in superclass.
3916	// Perform the check only if OCD is the first container to declare ivars to
3917	// avoid multiple warnings for the same ivar.
3918	ObjCIvarDecl *FirstIvar =
3919	(Ivars.begin() == Ivars.end()) ? nullptr : *Ivars.begin();
3920	if (FirstIvar && (FirstIvar == IntfDecl->all_declared_ivar_begin())) {
3921	const ObjCInterfaceDecl *SuperClass = IntfDecl->getSuperClass();
3922	while (SuperClass && SuperClass->ivar_empty())
3923	SuperClass = SuperClass->getSuperClass();
3924	if (SuperClass) {
3925	auto IvarIter = SuperClass->ivar_begin();
3926	std::advance(i&: IvarIter, n: SuperClass->ivar_size() - 1);
3927	const ObjCIvarDecl *LastIvar = *IvarIter;
3928	if (IsVariableSizedType(LastIvar->getType())) {
3929	S.Diag(FirstIvar->getLocation(),
3930	diag::warn_superclass_variable_sized_type_not_at_end)
3931	<< FirstIvar->getDeclName() << LastIvar->getDeclName()
3932	<< LastIvar->getType() << SuperClass->getDeclName();
3933	S.Diag(LastIvar->getLocation(), diag::note_entity_declared_at)
3934	<< LastIvar->getDeclName();
3935	}
3936	}
3937	}
3938	}
3939
3940	static void DiagnoseCategoryDirectMembersProtocolConformance(
3941	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl);
3942
3943	static void DiagnoseCategoryDirectMembersProtocolConformance(
3944	Sema &S, ObjCCategoryDecl *CDecl,
3945	const llvm::iterator_range<ObjCProtocolList::iterator> &Protocols) {
3946	for (auto *PI : Protocols)
3947	DiagnoseCategoryDirectMembersProtocolConformance(S, PDecl: PI, CDecl);
3948	}
3949
3950	static void DiagnoseCategoryDirectMembersProtocolConformance(
3951	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl) {
3952	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
3953	PDecl = PDecl->getDefinition();
3954
3955	llvm::SmallVector<const Decl *, 4> DirectMembers;
3956	const auto *IDecl = CDecl->getClassInterface();
3957	for (auto *MD : PDecl->methods()) {
3958	if (!MD->isPropertyAccessor()) {
3959	if (const auto *CMD =
3960	IDecl->getMethod(MD->getSelector(), MD->isInstanceMethod())) {
3961	if (CMD->isDirectMethod())
3962	DirectMembers.push_back(CMD);
3963	}
3964	}
3965	}
3966	for (auto *PD : PDecl->properties()) {
3967	if (const auto *CPD = IDecl->FindPropertyVisibleInPrimaryClass(
3968	PD->getIdentifier(),
3969	PD->isClassProperty()
3970	? ObjCPropertyQueryKind::OBJC_PR_query_class
3971	: ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
3972	if (CPD->isDirectProperty())
3973	DirectMembers.push_back(CPD);
3974	}
3975	}
3976	if (!DirectMembers.empty()) {
3977	S.Diag(CDecl->getLocation(), diag::err_objc_direct_protocol_conformance)
3978	<< CDecl->IsClassExtension() << CDecl << PDecl << IDecl;
3979	for (const auto *MD : DirectMembers)
3980	S.Diag(MD->getLocation(), diag::note_direct_member_here);
3981	return;
3982	}
3983
3984	// Check on this protocols's referenced protocols, recursively.
3985	DiagnoseCategoryDirectMembersProtocolConformance(S, CDecl,
3986	Protocols: PDecl->protocols());
3987	}
3988
3989	// Note: For class/category implementations, allMethods is always null.
3990	Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd, ArrayRef<Decl *> allMethods,
3991	ArrayRef<DeclGroupPtrTy> allTUVars) {
3992	if (getObjCContainerKind() == Sema::OCK_None)
3993	return nullptr;
3994
3995	assert(AtEnd.isValid() && "Invalid location for '@end'");
3996
3997	auto *OCD = cast<ObjCContainerDecl>(Val: CurContext);
3998	Decl *ClassDecl = OCD;
3999
4000	bool isInterfaceDeclKind =
4001	isa<ObjCInterfaceDecl>(Val: ClassDecl) || isa<ObjCCategoryDecl>(Val: ClassDecl)
4002	|| isa<ObjCProtocolDecl>(Val: ClassDecl);
4003	bool checkIdenticalMethods = isa<ObjCImplementationDecl>(Val: ClassDecl);
4004
4005	// Make synthesized accessor stub functions visible.
4006	// ActOnPropertyImplDecl() creates them as not visible in case
4007	// they are overridden by an explicit method that is encountered
4008	// later.
4009	if (auto *OID = dyn_cast<ObjCImplementationDecl>(Val: CurContext)) {
4010	for (auto *PropImpl : OID->property_impls()) {
4011	if (auto *Getter = PropImpl->getGetterMethodDecl())
4012	if (Getter->isSynthesizedAccessorStub())
4013	OID->addDecl(Getter);
4014	if (auto *Setter = PropImpl->getSetterMethodDecl())
4015	if (Setter->isSynthesizedAccessorStub())
4016	OID->addDecl(Setter);
4017	}
4018	}
4019
4020	// FIXME: Remove these and use the ObjCContainerDecl/DeclContext.
4021	llvm::DenseMap<Selector, const ObjCMethodDecl*> InsMap;
4022	llvm::DenseMap<Selector, const ObjCMethodDecl*> ClsMap;
4023
4024	for (unsigned i = 0, e = allMethods.size(); i != e; i++ ) {
4025	ObjCMethodDecl *Method =
4026	cast_or_null<ObjCMethodDecl>(Val: allMethods[i]);
4027
4028	if (!Method) continue; // Already issued a diagnostic.
4029	if (Method->isInstanceMethod()) {
4030	/// Check for instance method of the same name with incompatible types
4031	const ObjCMethodDecl *&PrevMethod = InsMap[Method->getSelector()];
4032	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4033	: false;
4034	if ((isInterfaceDeclKind && PrevMethod && !match)
4035	|| (checkIdenticalMethods && match)) {
4036	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4037	<< Method->getDeclName();
4038	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4039	Method->setInvalidDecl();
4040	} else {
4041	if (PrevMethod) {
4042	Method->setAsRedeclaration(PrevMethod);
4043	if (!Context.getSourceManager().isInSystemHeader(
4044	Method->getLocation()))
4045	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4046	<< Method->getDeclName();
4047	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4048	}
4049	InsMap[Method->getSelector()] = Method;
4050	/// The following allows us to typecheck messages to "id".
4051	AddInstanceMethodToGlobalPool(Method);
4052	}
4053	} else {
4054	/// Check for class method of the same name with incompatible types
4055	const ObjCMethodDecl *&PrevMethod = ClsMap[Method->getSelector()];
4056	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4057	: false;
4058	if ((isInterfaceDeclKind && PrevMethod && !match)
4059	|| (checkIdenticalMethods && match)) {
4060	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4061	<< Method->getDeclName();
4062	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4063	Method->setInvalidDecl();
4064	} else {
4065	if (PrevMethod) {
4066	Method->setAsRedeclaration(PrevMethod);
4067	if (!Context.getSourceManager().isInSystemHeader(
4068	Method->getLocation()))
4069	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4070	<< Method->getDeclName();
4071	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4072	}
4073	ClsMap[Method->getSelector()] = Method;
4074	AddFactoryMethodToGlobalPool(Method);
4075	}
4076	}
4077	}
4078	if (isa<ObjCInterfaceDecl>(Val: ClassDecl)) {
4079	// Nothing to do here.
4080	} else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl)) {
4081	// Categories are used to extend the class by declaring new methods.
4082	// By the same token, they are also used to add new properties. No
4083	// need to compare the added property to those in the class.
4084
4085	if (C->IsClassExtension()) {
4086	ObjCInterfaceDecl *CCPrimary = C->getClassInterface();
4087	DiagnoseClassExtensionDupMethods(CAT: C, ID: CCPrimary);
4088	}
4089
4090	DiagnoseCategoryDirectMembersProtocolConformance(S&: *this, CDecl: C, Protocols: C->protocols());
4091	}
4092	if (ObjCContainerDecl *CDecl = dyn_cast<ObjCContainerDecl>(Val: ClassDecl)) {
4093	if (CDecl->getIdentifier())
4094	// ProcessPropertyDecl is responsible for diagnosing conflicts with any
4095	// user-defined setter/getter. It also synthesizes setter/getter methods
4096	// and adds them to the DeclContext and global method pools.
4097	for (auto *I : CDecl->properties())
4098	ProcessPropertyDecl(I);
4099	CDecl->setAtEndRange(AtEnd);
4100	}
4101	if (ObjCImplementationDecl *IC=dyn_cast<ObjCImplementationDecl>(Val: ClassDecl)) {
4102	IC->setAtEndRange(AtEnd);
4103	if (ObjCInterfaceDecl* IDecl = IC->getClassInterface()) {
4104	// Any property declared in a class extension might have user
4105	// declared setter or getter in current class extension or one
4106	// of the other class extensions. Mark them as synthesized as
4107	// property will be synthesized when property with same name is
4108	// seen in the @implementation.
4109	for (const auto *Ext : IDecl->visible_extensions()) {
4110	for (const auto *Property : Ext->instance_properties()) {
4111	// Skip over properties declared @dynamic
4112	if (const ObjCPropertyImplDecl *PIDecl
4113	= IC->FindPropertyImplDecl(Property->getIdentifier(),
4114	Property->getQueryKind()))
4115	if (PIDecl->getPropertyImplementation()
4116	== ObjCPropertyImplDecl::Dynamic)
4117	continue;
4118
4119	for (const auto *Ext : IDecl->visible_extensions()) {
4120	if (ObjCMethodDecl *GetterMethod =
4121	Ext->getInstanceMethod(Property->getGetterName()))
4122	GetterMethod->setPropertyAccessor(true);
4123	if (!Property->isReadOnly())
4124	if (ObjCMethodDecl *SetterMethod
4125	= Ext->getInstanceMethod(Property->getSetterName()))
4126	SetterMethod->setPropertyAccessor(true);
4127	}
4128	}
4129	}
4130	ImplMethodsVsClassMethods(S, IC, IDecl);
4131	AtomicPropertySetterGetterRules(IC, IDecl);
4132	DiagnoseOwningPropertyGetterSynthesis(D: IC);
4133	DiagnoseUnusedBackingIvarInAccessor(S, ImplD: IC);
4134	if (IDecl->hasDesignatedInitializers())
4135	DiagnoseMissingDesignatedInitOverrides(ImplD: IC, IFD: IDecl);
4136	DiagnoseWeakIvars(S&: *this, ID: IC);
4137	DiagnoseRetainableFlexibleArrayMember(S&: *this, ID: IDecl);
4138
4139	bool HasRootClassAttr = IDecl->hasAttr<ObjCRootClassAttr>();
4140	if (IDecl->getSuperClass() == nullptr) {
4141	// This class has no superclass, so check that it has been marked with
4142	// __attribute((objc_root_class)).
4143	if (!HasRootClassAttr) {
4144	SourceLocation DeclLoc(IDecl->getLocation());
4145	SourceLocation SuperClassLoc(getLocForEndOfToken(Loc: DeclLoc));
4146	Diag(DeclLoc, diag::warn_objc_root_class_missing)
4147	<< IDecl->getIdentifier();
4148	// See if NSObject is in the current scope, and if it is, suggest
4149	// adding " : NSObject " to the class declaration.
4150	NamedDecl *IF = LookupSingleName(S: TUScope,
4151	Name: NSAPIObj->getNSClassId(K: NSAPI::ClassId_NSObject),
4152	Loc: DeclLoc, NameKind: LookupOrdinaryName);
4153	ObjCInterfaceDecl *NSObjectDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: IF);
4154	if (NSObjectDecl && NSObjectDecl->getDefinition()) {
4155	Diag(SuperClassLoc, diag::note_objc_needs_superclass)
4156	<< FixItHint::CreateInsertion(SuperClassLoc, " : NSObject ");
4157	} else {
4158	Diag(SuperClassLoc, diag::note_objc_needs_superclass);
4159	}
4160	}
4161	} else if (HasRootClassAttr) {
4162	// Complain that only root classes may have this attribute.
4163	Diag(IDecl->getLocation(), diag::err_objc_root_class_subclass);
4164	}
4165
4166	if (const ObjCInterfaceDecl *Super = IDecl->getSuperClass()) {
4167	// An interface can subclass another interface with a
4168	// objc_subclassing_restricted attribute when it has that attribute as
4169	// well (because of interfaces imported from Swift). Therefore we have
4170	// to check if we can subclass in the implementation as well.
4171	if (IDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4172	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4173	Diag(IC->getLocation(), diag::err_restricted_superclass_mismatch);
4174	Diag(Super->getLocation(), diag::note_class_declared);
4175	}
4176	}
4177
4178	if (IDecl->hasAttr<ObjCClassStubAttr>())
4179	Diag(IC->getLocation(), diag::err_implementation_of_class_stub);
4180
4181	if (LangOpts.ObjCRuntime.isNonFragile()) {
4182	while (IDecl->getSuperClass()) {
4183	DiagnoseDuplicateIvars(ID: IDecl, SID: IDecl->getSuperClass());
4184	IDecl = IDecl->getSuperClass();
4185	}
4186	}
4187	}
4188	SetIvarInitializers(IC);
4189	} else if (ObjCCategoryImplDecl* CatImplClass =
4190	dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl)) {
4191	CatImplClass->setAtEndRange(AtEnd);
4192
4193	// Find category interface decl and then check that all methods declared
4194	// in this interface are implemented in the category @implementation.
4195	if (ObjCInterfaceDecl* IDecl = CatImplClass->getClassInterface()) {
4196	if (ObjCCategoryDecl *Cat
4197	= IDecl->FindCategoryDeclaration(CategoryId: CatImplClass->getIdentifier())) {
4198	ImplMethodsVsClassMethods(S, CatImplClass, Cat);
4199	}
4200	}
4201	} else if (const auto *IntfDecl = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
4202	if (const ObjCInterfaceDecl *Super = IntfDecl->getSuperClass()) {
4203	if (!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4204	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4205	Diag(IntfDecl->getLocation(), diag::err_restricted_superclass_mismatch);
4206	Diag(Super->getLocation(), diag::note_class_declared);
4207	}
4208	}
4209
4210	if (IntfDecl->hasAttr<ObjCClassStubAttr>() &&
4211	!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>())
4212	Diag(IntfDecl->getLocation(), diag::err_class_stub_subclassing_mismatch);
4213	}
4214	DiagnoseVariableSizedIvars(S&: *this, OCD);
4215	if (isInterfaceDeclKind) {
4216	// Reject invalid vardecls.
4217	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4218	DeclGroupRef DG = allTUVars[i].get();
4219	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4220	if (VarDecl *VDecl = dyn_cast<VarDecl>(Val: *I)) {
4221	if (!VDecl->hasExternalStorage())
4222	Diag(VDecl->getLocation(), diag::err_objc_var_decl_inclass);
4223	}
4224	}
4225	}
4226	ActOnObjCContainerFinishDefinition();
4227
4228	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4229	DeclGroupRef DG = allTUVars[i].get();
4230	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4231	(*I)->setTopLevelDeclInObjCContainer();
4232	Consumer.HandleTopLevelDeclInObjCContainer(D: DG);
4233	}
4234
4235	ActOnDocumentableDecl(D: ClassDecl);
4236	return ClassDecl;
4237	}
4238
4239	/// CvtQTToAstBitMask - utility routine to produce an AST bitmask for
4240	/// objective-c's type qualifier from the parser version of the same info.
4241	static Decl::ObjCDeclQualifier
4242	CvtQTToAstBitMask(ObjCDeclSpec::ObjCDeclQualifier PQTVal) {
4243	return (Decl::ObjCDeclQualifier) (unsigned) PQTVal;
4244	}
4245
4246	/// Check whether the declared result type of the given Objective-C
4247	/// method declaration is compatible with the method's class.
4248	///
4249	static Sema::ResultTypeCompatibilityKind
4250	CheckRelatedResultTypeCompatibility(Sema &S, ObjCMethodDecl *Method,
4251	ObjCInterfaceDecl *CurrentClass) {
4252	QualType ResultType = Method->getReturnType();
4253
4254	// If an Objective-C method inherits its related result type, then its
4255	// declared result type must be compatible with its own class type. The
4256	// declared result type is compatible if:
4257	if (const ObjCObjectPointerType *ResultObjectType
4258	= ResultType->getAs<ObjCObjectPointerType>()) {
4259	// - it is id or qualified id, or
4260	if (ResultObjectType->isObjCIdType() ||
4261	ResultObjectType->isObjCQualifiedIdType())
4262	return Sema::RTC_Compatible;
4263
4264	if (CurrentClass) {
4265	if (ObjCInterfaceDecl *ResultClass
4266	= ResultObjectType->getInterfaceDecl()) {
4267	// - it is the same as the method's class type, or
4268	if (declaresSameEntity(CurrentClass, ResultClass))
4269	return Sema::RTC_Compatible;
4270
4271	// - it is a superclass of the method's class type
4272	if (ResultClass->isSuperClassOf(I: CurrentClass))
4273	return Sema::RTC_Compatible;
4274	}
4275	} else {
4276	// Any Objective-C pointer type might be acceptable for a protocol
4277	// method; we just don't know.
4278	return Sema::RTC_Unknown;
4279	}
4280	}
4281
4282	return Sema::RTC_Incompatible;
4283	}
4284
4285	namespace {
4286	/// A helper class for searching for methods which a particular method
4287	/// overrides.
4288	class OverrideSearch {
4289	public:
4290	const ObjCMethodDecl *Method;
4291	llvm::SmallSetVector<ObjCMethodDecl*, 4> Overridden;
4292	bool Recursive;
4293
4294	public:
4295	OverrideSearch(Sema &S, const ObjCMethodDecl *method) : Method(method) {
4296	Selector selector = method->getSelector();
4297
4298	// Bypass this search if we've never seen an instance/class method
4299	// with this selector before.
4300	Sema::GlobalMethodPool::iterator it = S.MethodPool.find(Sel: selector);
4301	if (it == S.MethodPool.end()) {
4302	if (!S.getExternalSource()) return;
4303	S.ReadMethodPool(Sel: selector);
4304
4305	it = S.MethodPool.find(Sel: selector);
4306	if (it == S.MethodPool.end())
4307	return;
4308	}
4309	const ObjCMethodList &list =
4310	method->isInstanceMethod() ? it->second.first : it->second.second;
4311	if (!list.getMethod()) return;
4312
4313	const ObjCContainerDecl *container
4314	= cast<ObjCContainerDecl>(method->getDeclContext());
4315
4316	// Prevent the search from reaching this container again. This is
4317	// important with categories, which override methods from the
4318	// interface and each other.
4319	if (const ObjCCategoryDecl *Category =
4320	dyn_cast<ObjCCategoryDecl>(container)) {
4321	searchFromContainer(container);
4322	if (const ObjCInterfaceDecl *Interface = Category->getClassInterface())
4323	searchFromContainer(Interface);
4324	} else {
4325	searchFromContainer(container);
4326	}
4327	}
4328
4329	typedef decltype(Overridden)::iterator iterator;
4330	iterator begin() const { return Overridden.begin(); }
4331	iterator end() const { return Overridden.end(); }
4332
4333	private:
4334	void searchFromContainer(const ObjCContainerDecl *container) {
4335	if (container->isInvalidDecl()) return;
4336
4337	switch (container->getDeclKind()) {
4338	#define OBJCCONTAINER(type, base) \
4339	case Decl::type: \
4340	searchFrom(cast<type##Decl>(container)); \
4341	break;
4342	#define ABSTRACT_DECL(expansion)
4343	#define DECL(type, base) \
4344	case Decl::type:
4345	#include "clang/AST/DeclNodes.inc"
4346	llvm_unreachable("not an ObjC container!");
4347	}
4348	}
4349
4350	void searchFrom(const ObjCProtocolDecl *protocol) {
4351	if (!protocol->hasDefinition())
4352	return;
4353
4354	// A method in a protocol declaration overrides declarations from
4355	// referenced ("parent") protocols.
4356	search(protocols: protocol->getReferencedProtocols());
4357	}
4358
4359	void searchFrom(const ObjCCategoryDecl *category) {
4360	// A method in a category declaration overrides declarations from
4361	// the main class and from protocols the category references.
4362	// The main class is handled in the constructor.
4363	search(protocols: category->getReferencedProtocols());
4364	}
4365
4366	void searchFrom(const ObjCCategoryImplDecl *impl) {
4367	// A method in a category definition that has a category
4368	// declaration overrides declarations from the category
4369	// declaration.
4370	if (ObjCCategoryDecl *category = impl->getCategoryDecl()) {
4371	search(category);
4372	if (ObjCInterfaceDecl *Interface = category->getClassInterface())
4373	search(Interface);
4374
4375	// Otherwise it overrides declarations from the class.
4376	} else if (const auto *Interface = impl->getClassInterface()) {
4377	search(Interface);
4378	}
4379	}
4380
4381	void searchFrom(const ObjCInterfaceDecl *iface) {
4382	// A method in a class declaration overrides declarations from
4383	if (!iface->hasDefinition())
4384	return;
4385
4386	// - categories,
4387	for (auto *Cat : iface->known_categories())
4388	search(Cat);
4389
4390	// - the super class, and
4391	if (ObjCInterfaceDecl *super = iface->getSuperClass())
4392	search(super);
4393
4394	// - any referenced protocols.
4395	search(protocols: iface->getReferencedProtocols());
4396	}
4397
4398	void searchFrom(const ObjCImplementationDecl *impl) {
4399	// A method in a class implementation overrides declarations from
4400	// the class interface.
4401	if (const auto *Interface = impl->getClassInterface())
4402	search(Interface);
4403	}
4404
4405	void search(const ObjCProtocolList &protocols) {
4406	for (const auto *Proto : protocols)
4407	search(Proto);
4408	}
4409
4410	void search(const ObjCContainerDecl *container) {
4411	// Check for a method in this container which matches this selector.
4412	ObjCMethodDecl *meth = container->getMethod(Sel: Method->getSelector(),
4413	isInstance: Method->isInstanceMethod(),
4414	/*AllowHidden=*/true);
4415
4416	// If we find one, record it and bail out.
4417	if (meth) {
4418	Overridden.insert(X: meth);
4419	return;
4420	}
4421
4422	// Otherwise, search for methods that a hypothetical method here
4423	// would have overridden.
4424
4425	// Note that we're now in a recursive case.
4426	Recursive = true;
4427
4428	searchFromContainer(container);
4429	}
4430	};
4431	} // end anonymous namespace
4432
4433	void Sema::CheckObjCMethodDirectOverrides(ObjCMethodDecl *method,
4434	ObjCMethodDecl *overridden) {
4435	if (overridden->isDirectMethod()) {
4436	const auto *attr = overridden->getAttr<ObjCDirectAttr>();
4437	Diag(method->getLocation(), diag::err_objc_override_direct_method);
4438	Diag(attr->getLocation(), diag::note_previous_declaration);
4439	} else if (method->isDirectMethod()) {
4440	const auto *attr = method->getAttr<ObjCDirectAttr>();
4441	Diag(attr->getLocation(), diag::err_objc_direct_on_override)
4442	<< isa<ObjCProtocolDecl>(overridden->getDeclContext());
4443	Diag(overridden->getLocation(), diag::note_previous_declaration);
4444	}
4445	}
4446
4447	void Sema::CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
4448	ObjCInterfaceDecl *CurrentClass,
4449	ResultTypeCompatibilityKind RTC) {
4450	if (!ObjCMethod)
4451	return;
4452	auto IsMethodInCurrentClass = [CurrentClass](const ObjCMethodDecl *M) {
4453	// Checking canonical decl works across modules.
4454	return M->getClassInterface()->getCanonicalDecl() ==
4455	CurrentClass->getCanonicalDecl();
4456	};
4457	// Search for overridden methods and merge information down from them.
4458	OverrideSearch overrides(*this, ObjCMethod);
4459	// Keep track if the method overrides any method in the class's base classes,
4460	// its protocols, or its categories' protocols; we will keep that info
4461	// in the ObjCMethodDecl.
4462	// For this info, a method in an implementation is not considered as
4463	// overriding the same method in the interface or its categories.
4464	bool hasOverriddenMethodsInBaseOrProtocol = false;
4465	for (ObjCMethodDecl *overridden : overrides) {
4466	if (!hasOverriddenMethodsInBaseOrProtocol) {
4467	if (isa<ObjCProtocolDecl>(overridden->getDeclContext()) ||
4468	!IsMethodInCurrentClass(overridden) || overridden->isOverriding()) {
4469	CheckObjCMethodDirectOverrides(method: ObjCMethod, overridden);
4470	hasOverriddenMethodsInBaseOrProtocol = true;
4471	} else if (isa<ObjCImplDecl>(ObjCMethod->getDeclContext())) {
4472	// OverrideSearch will return as "overridden" the same method in the
4473	// interface. For hasOverriddenMethodsInBaseOrProtocol, we need to
4474	// check whether a category of a base class introduced a method with the
4475	// same selector, after the interface method declaration.
4476	// To avoid unnecessary lookups in the majority of cases, we use the
4477	// extra info bits in GlobalMethodPool to check whether there were any
4478	// category methods with this selector.
4479	GlobalMethodPool::iterator It =
4480	MethodPool.find(Sel: ObjCMethod->getSelector());
4481	if (It != MethodPool.end()) {
4482	ObjCMethodList &List =
4483	ObjCMethod->isInstanceMethod()? It->second.first: It->second.second;
4484	unsigned CategCount = List.getBits();
4485	if (CategCount > 0) {
4486	// If the method is in a category we'll do lookup if there were at
4487	// least 2 category methods recorded, otherwise only one will do.
4488	if (CategCount > 1 ||
4489	!isa<ObjCCategoryImplDecl>(overridden->getDeclContext())) {
4490	OverrideSearch overrides(*this, overridden);
4491	for (ObjCMethodDecl *SuperOverridden : overrides) {
4492	if (isa<ObjCProtocolDecl>(SuperOverridden->getDeclContext()) ||
4493	!IsMethodInCurrentClass(SuperOverridden)) {
4494	CheckObjCMethodDirectOverrides(method: ObjCMethod, overridden: SuperOverridden);
4495	hasOverriddenMethodsInBaseOrProtocol = true;
4496	overridden->setOverriding(true);
4497	break;
4498	}
4499	}
4500	}
4501	}
4502	}
4503	}
4504	}
4505
4506	// Propagate down the 'related result type' bit from overridden methods.
4507	if (RTC != Sema::RTC_Incompatible && overridden->hasRelatedResultType())
4508	ObjCMethod->setRelatedResultType();
4509
4510	// Then merge the declarations.
4511	mergeObjCMethodDecls(New: ObjCMethod, Old: overridden);
4512
4513	if (ObjCMethod->isImplicit() && overridden->isImplicit())
4514	continue; // Conflicting properties are detected elsewhere.
4515
4516	// Check for overriding methods
4517	if (isa<ObjCInterfaceDecl>(ObjCMethod->getDeclContext()) ||
4518	isa<ObjCImplementationDecl>(ObjCMethod->getDeclContext()))
4519	CheckConflictingOverridingMethod(Method: ObjCMethod, Overridden: overridden,
4520	IsProtocolMethodDecl: isa<ObjCProtocolDecl>(overridden->getDeclContext()));
4521
4522	if (CurrentClass && overridden->getDeclContext() != CurrentClass &&
4523	isa<ObjCInterfaceDecl>(overridden->getDeclContext()) &&
4524	!overridden->isImplicit() /* not meant for properties */) {
4525	ObjCMethodDecl::param_iterator ParamI = ObjCMethod->param_begin(),
4526	E = ObjCMethod->param_end();
4527	ObjCMethodDecl::param_iterator PrevI = overridden->param_begin(),
4528	PrevE = overridden->param_end();
4529	for (; ParamI != E && PrevI != PrevE; ++ParamI, ++PrevI) {
4530	assert(PrevI != overridden->param_end() && "Param mismatch");
4531	QualType T1 = Context.getCanonicalType((*ParamI)->getType());
4532	QualType T2 = Context.getCanonicalType((*PrevI)->getType());
4533	// If type of argument of method in this class does not match its
4534	// respective argument type in the super class method, issue warning;
4535	if (!Context.typesAreCompatible(T1, T2)) {
4536	Diag((*ParamI)->getLocation(), diag::ext_typecheck_base_super)
4537	<< T1 << T2;
4538	Diag(overridden->getLocation(), diag::note_previous_declaration);
4539	break;
4540	}
4541	}
4542	}
4543	}
4544
4545	ObjCMethod->setOverriding(hasOverriddenMethodsInBaseOrProtocol);
4546	}
4547
4548	/// Merge type nullability from for a redeclaration of the same entity,
4549	/// producing the updated type of the redeclared entity.
4550	static QualType mergeTypeNullabilityForRedecl(Sema &S, SourceLocation loc,
4551	QualType type,
4552	bool usesCSKeyword,
4553	SourceLocation prevLoc,
4554	QualType prevType,
4555	bool prevUsesCSKeyword) {
4556	// Determine the nullability of both types.
4557	auto nullability = type->getNullability();
4558	auto prevNullability = prevType->getNullability();
4559
4560	// Easy case: both have nullability.
4561	if (nullability.has_value() == prevNullability.has_value()) {
4562	// Neither has nullability; continue.
4563	if (!nullability)
4564	return type;
4565
4566	// The nullabilities are equivalent; do nothing.
4567	if (*nullability == *prevNullability)
4568	return type;
4569
4570	// Complain about mismatched nullability.
4571	S.Diag(loc, diag::err_nullability_conflicting)
4572	<< DiagNullabilityKind(*nullability, usesCSKeyword)
4573	<< DiagNullabilityKind(*prevNullability, prevUsesCSKeyword);
4574	return type;
4575	}
4576
4577	// If it's the redeclaration that has nullability, don't change anything.
4578	if (nullability)
4579	return type;
4580
4581	// Otherwise, provide the result with the same nullability.
4582	return S.Context.getAttributedType(
4583	attrKind: AttributedType::getNullabilityAttrKind(kind: *prevNullability),
4584	modifiedType: type, equivalentType: type);
4585	}
4586
4587	/// Merge information from the declaration of a method in the \@interface
4588	/// (or a category/extension) into the corresponding method in the
4589	/// @implementation (for a class or category).
4590	static void mergeInterfaceMethodToImpl(Sema &S,
4591	ObjCMethodDecl *method,
4592	ObjCMethodDecl *prevMethod) {
4593	// Merge the objc_requires_super attribute.
4594	if (prevMethod->hasAttr<ObjCRequiresSuperAttr>() &&
4595	!method->hasAttr<ObjCRequiresSuperAttr>()) {
4596	// merge the attribute into implementation.
4597	method->addAttr(
4598	ObjCRequiresSuperAttr::CreateImplicit(S.Context,
4599	method->getLocation()));
4600	}
4601
4602	// Merge nullability of the result type.
4603	QualType newReturnType
4604	= mergeTypeNullabilityForRedecl(
4605	S, loc: method->getReturnTypeSourceRange().getBegin(),
4606	type: method->getReturnType(),
4607	usesCSKeyword: method->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4608	prevLoc: prevMethod->getReturnTypeSourceRange().getBegin(),
4609	prevType: prevMethod->getReturnType(),
4610	prevUsesCSKeyword: prevMethod->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4611	method->setReturnType(newReturnType);
4612
4613	// Handle each of the parameters.
4614	unsigned numParams = method->param_size();
4615	unsigned numPrevParams = prevMethod->param_size();
4616	for (unsigned i = 0, n = std::min(a: numParams, b: numPrevParams); i != n; ++i) {
4617	ParmVarDecl *param = method->param_begin()[i];
4618	ParmVarDecl *prevParam = prevMethod->param_begin()[i];
4619
4620	// Merge nullability.
4621	QualType newParamType
4622	= mergeTypeNullabilityForRedecl(
4623	S, param->getLocation(), param->getType(),
4624	param->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4625	prevParam->getLocation(), prevParam->getType(),
4626	prevParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4627	param->setType(newParamType);
4628	}
4629	}
4630
4631	/// Verify that the method parameters/return value have types that are supported
4632	/// by the x86 target.
4633	static void checkObjCMethodX86VectorTypes(Sema &SemaRef,
4634	const ObjCMethodDecl *Method) {
4635	assert(SemaRef.getASTContext().getTargetInfo().getTriple().getArch() ==
4636	llvm::Triple::x86 &&
4637	"x86-specific check invoked for a different target");
4638	SourceLocation Loc;
4639	QualType T;
4640	for (const ParmVarDecl *P : Method->parameters()) {
4641	if (P->getType()->isVectorType()) {
4642	Loc = P->getBeginLoc();
4643	T = P->getType();
4644	break;
4645	}
4646	}
4647	if (Loc.isInvalid()) {
4648	if (Method->getReturnType()->isVectorType()) {
4649	Loc = Method->getReturnTypeSourceRange().getBegin();
4650	T = Method->getReturnType();
4651	} else
4652	return;
4653	}
4654
4655	// Vector parameters/return values are not supported by objc_msgSend on x86 in
4656	// iOS < 9 and macOS < 10.11.
4657	const auto &Triple = SemaRef.getASTContext().getTargetInfo().getTriple();
4658	VersionTuple AcceptedInVersion;
4659	if (Triple.getOS() == llvm::Triple::IOS)
4660	AcceptedInVersion = VersionTuple(/*Major=*/9);
4661	else if (Triple.isMacOSX())
4662	AcceptedInVersion = VersionTuple(/*Major=*/10, /*Minor=*/11);
4663	else
4664	return;
4665	if (SemaRef.getASTContext().getTargetInfo().getPlatformMinVersion() >=
4666	AcceptedInVersion)
4667	return;
4668	SemaRef.Diag(Loc, diag::err_objc_method_unsupported_param_ret_type)
4669	<< T << (Method->getReturnType()->isVectorType() ? /*return value*/ 1
4670	: /*parameter*/ 0)
4671	<< (Triple.isMacOSX() ? "macOS 10.11" : "iOS 9");
4672	}
4673
4674	static void mergeObjCDirectMembers(Sema &S, Decl *CD, ObjCMethodDecl *Method) {
4675	if (!Method->isDirectMethod() && !Method->hasAttr<UnavailableAttr>() &&
4676	CD->hasAttr<ObjCDirectMembersAttr>()) {
4677	Method->addAttr(
4678	ObjCDirectAttr::CreateImplicit(S.Context, Method->getLocation()));
4679	}
4680	}
4681
4682	static void checkObjCDirectMethodClashes(Sema &S, ObjCInterfaceDecl *IDecl,
4683	ObjCMethodDecl *Method,
4684	ObjCImplDecl *ImpDecl = nullptr) {
4685	auto Sel = Method->getSelector();
4686	bool isInstance = Method->isInstanceMethod();
4687	bool diagnosed = false;
4688
4689	auto diagClash = [&](const ObjCMethodDecl *IMD) {
4690	if (diagnosed || IMD->isImplicit())
4691	return;
4692	if (Method->isDirectMethod() || IMD->isDirectMethod()) {
4693	S.Diag(Method->getLocation(), diag::err_objc_direct_duplicate_decl)
4694	<< Method->isDirectMethod() << /* method */ 0 << IMD->isDirectMethod()
4695	<< Method->getDeclName();
4696	S.Diag(IMD->getLocation(), diag::note_previous_declaration);
4697	diagnosed = true;
4698	}
4699	};
4700
4701	// Look for any other declaration of this method anywhere we can see in this
4702	// compilation unit.
4703	//
4704	// We do not use IDecl->lookupMethod() because we have specific needs:
4705	//
4706	// - we absolutely do not need to walk protocols, because
4707	// diag::err_objc_direct_on_protocol has already been emitted
4708	// during parsing if there's a conflict,
4709	//
4710	// - when we do not find a match in a given @interface container,
4711	// we need to attempt looking it up in the @implementation block if the
4712	// translation unit sees it to find more clashes.
4713
4714	if (auto *IMD = IDecl->getMethod(Sel, isInstance))
4715	diagClash(IMD);
4716	else if (auto *Impl = IDecl->getImplementation())
4717	if (Impl != ImpDecl)
4718	if (auto *IMD = IDecl->getImplementation()->getMethod(Sel, isInstance))
4719	diagClash(IMD);
4720
4721	for (const auto *Cat : IDecl->visible_categories())
4722	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4723	diagClash(IMD);
4724	else if (auto CatImpl = Cat->getImplementation())
4725	if (CatImpl != ImpDecl)
4726	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4727	diagClash(IMD);
4728	}
4729
4730	Decl *Sema::ActOnMethodDeclaration(
4731	Scope *S, SourceLocation MethodLoc, SourceLocation EndLoc,
4732	tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
4733	ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
4734	// optional arguments. The number of types/arguments is obtained
4735	// from the Sel.getNumArgs().
4736	ObjCArgInfo *ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
4737	unsigned CNumArgs, // c-style args
4738	const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodDeclKind,
4739	bool isVariadic, bool MethodDefinition) {
4740	// Make sure we can establish a context for the method.
4741	if (!CurContext->isObjCContainer()) {
4742	Diag(MethodLoc, diag::err_missing_method_context);
4743	return nullptr;
4744	}
4745
4746	Decl *ClassDecl = cast<ObjCContainerDecl>(Val: CurContext);
4747	QualType resultDeclType;
4748
4749	bool HasRelatedResultType = false;
4750	TypeSourceInfo *ReturnTInfo = nullptr;
4751	if (ReturnType) {
4752	resultDeclType = GetTypeFromParser(Ty: ReturnType, TInfo: &ReturnTInfo);
4753
4754	if (CheckFunctionReturnType(T: resultDeclType, Loc: MethodLoc))
4755	return nullptr;
4756
4757	QualType bareResultType = resultDeclType;
4758	(void)AttributedType::stripOuterNullability(T&: bareResultType);
4759	HasRelatedResultType = (bareResultType == Context.getObjCInstanceType());
4760	} else { // get the type for "id".
4761	resultDeclType = Context.getObjCIdType();
4762	Diag(MethodLoc, diag::warn_missing_method_return_type)
4763	<< FixItHint::CreateInsertion(SelectorLocs.front(), "(id)");
4764	}
4765
4766	ObjCMethodDecl *ObjCMethod = ObjCMethodDecl::Create(
4767	C&: Context, beginLoc: MethodLoc, endLoc: EndLoc, SelInfo: Sel, T: resultDeclType, ReturnTInfo, contextDecl: CurContext,
4768	isInstance: MethodType == tok::minus, isVariadic,
4769	/*isPropertyAccessor=*/false, /*isSynthesizedAccessorStub=*/false,
4770	/*isImplicitlyDeclared=*/false, /*isDefined=*/false,
4771	impControl: MethodDeclKind == tok::objc_optional
4772	? ObjCImplementationControl::Optional
4773	: ObjCImplementationControl::Required,
4774	HasRelatedResultType);
4775
4776	SmallVector<ParmVarDecl*, 16> Params;
4777
4778	for (unsigned i = 0, e = Sel.getNumArgs(); i != e; ++i) {
4779	QualType ArgType;
4780	TypeSourceInfo *DI;
4781
4782	if (!ArgInfo[i].Type) {
4783	ArgType = Context.getObjCIdType();
4784	DI = nullptr;
4785	} else {
4786	ArgType = GetTypeFromParser(Ty: ArgInfo[i].Type, TInfo: &DI);
4787	}
4788
4789	LookupResult R(*this, ArgInfo[i].Name, ArgInfo[i].NameLoc,
4790	LookupOrdinaryName, forRedeclarationInCurContext());
4791	LookupName(R, S);
4792	if (R.isSingleResult()) {
4793	NamedDecl *PrevDecl = R.getFoundDecl();
4794	if (S->isDeclScope(PrevDecl)) {
4795	Diag(ArgInfo[i].NameLoc,
4796	(MethodDefinition ? diag::warn_method_param_redefinition
4797	: diag::warn_method_param_declaration))
4798	<< ArgInfo[i].Name;
4799	Diag(PrevDecl->getLocation(),
4800	diag::note_previous_declaration);
4801	}
4802	}
4803
4804	SourceLocation StartLoc = DI
4805	? DI->getTypeLoc().getBeginLoc()
4806	: ArgInfo[i].NameLoc;
4807
4808	ParmVarDecl* Param = CheckParameter(ObjCMethod, StartLoc,
4809	ArgInfo[i].NameLoc, ArgInfo[i].Name,
4810	ArgType, DI, SC_None);
4811
4812	Param->setObjCMethodScopeInfo(i);
4813
4814	Param->setObjCDeclQualifier(
4815	CvtQTToAstBitMask(PQTVal: ArgInfo[i].DeclSpec.getObjCDeclQualifier()));
4816
4817	// Apply the attributes to the parameter.
4818	ProcessDeclAttributeList(TUScope, Param, ArgInfo[i].ArgAttrs);
4819	AddPragmaAttributes(TUScope, Param);
4820	ProcessAPINotes(Param);
4821
4822	if (Param->hasAttr<BlocksAttr>()) {
4823	Diag(Param->getLocation(), diag::err_block_on_nonlocal);
4824	Param->setInvalidDecl();
4825	}
4826	S->AddDecl(Param);
4827	IdResolver.AddDecl(Param);
4828
4829	Params.push_back(Elt: Param);
4830	}
4831
4832	for (unsigned i = 0, e = CNumArgs; i != e; ++i) {
4833	ParmVarDecl *Param = cast<ParmVarDecl>(Val: CParamInfo[i].Param);
4834	QualType ArgType = Param->getType();
4835	if (ArgType.isNull())
4836	ArgType = Context.getObjCIdType();
4837	else
4838	// Perform the default array/function conversions (C99 6.7.5.3p[7,8]).
4839	ArgType = Context.getAdjustedParameterType(T: ArgType);
4840
4841	Param->setDeclContext(ObjCMethod);
4842	Params.push_back(Elt: Param);
4843	}
4844
4845	ObjCMethod->setMethodParams(C&: Context, Params, SelLocs: SelectorLocs);
4846	ObjCMethod->setObjCDeclQualifier(
4847	CvtQTToAstBitMask(PQTVal: ReturnQT.getObjCDeclQualifier()));
4848
4849	ProcessDeclAttributeList(TUScope, ObjCMethod, AttrList);
4850	AddPragmaAttributes(TUScope, ObjCMethod);
4851	ProcessAPINotes(ObjCMethod);
4852
4853	// Add the method now.
4854	const ObjCMethodDecl *PrevMethod = nullptr;
4855	if (ObjCImplDecl *ImpDecl = dyn_cast<ObjCImplDecl>(Val: ClassDecl)) {
4856	if (MethodType == tok::minus) {
4857	PrevMethod = ImpDecl->getInstanceMethod(Sel);
4858	ImpDecl->addInstanceMethod(method: ObjCMethod);
4859	} else {
4860	PrevMethod = ImpDecl->getClassMethod(Sel);
4861	ImpDecl->addClassMethod(method: ObjCMethod);
4862	}
4863
4864	// If this method overrides a previous @synthesize declaration,
4865	// register it with the property. Linear search through all
4866	// properties here, because the autosynthesized stub hasn't been
4867	// made visible yet, so it can be overridden by a later
4868	// user-specified implementation.
4869	for (ObjCPropertyImplDecl *PropertyImpl : ImpDecl->property_impls()) {
4870	if (auto *Setter = PropertyImpl->getSetterMethodDecl())
4871	if (Setter->getSelector() == Sel &&
4872	Setter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4873	assert(Setter->isSynthesizedAccessorStub() && "autosynth stub expected");
4874	PropertyImpl->setSetterMethodDecl(ObjCMethod);
4875	}
4876	if (auto *Getter = PropertyImpl->getGetterMethodDecl())
4877	if (Getter->getSelector() == Sel &&
4878	Getter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4879	assert(Getter->isSynthesizedAccessorStub() && "autosynth stub expected");
4880	PropertyImpl->setGetterMethodDecl(ObjCMethod);
4881	break;
4882	}
4883	}
4884
4885	// A method is either tagged direct explicitly, or inherits it from its
4886	// canonical declaration.
4887	//
4888	// We have to do the merge upfront and not in mergeInterfaceMethodToImpl()
4889	// because IDecl->lookupMethod() returns more possible matches than just
4890	// the canonical declaration.
4891	if (!ObjCMethod->isDirectMethod()) {
4892	const ObjCMethodDecl *CanonicalMD = ObjCMethod->getCanonicalDecl();
4893	if (CanonicalMD->isDirectMethod()) {
4894	const auto *attr = CanonicalMD->getAttr<ObjCDirectAttr>();
4895	ObjCMethod->addAttr(
4896	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4897	}
4898	}
4899
4900	// Merge information from the @interface declaration into the
4901	// @implementation.
4902	if (ObjCInterfaceDecl *IDecl = ImpDecl->getClassInterface()) {
4903	if (auto *IMD = IDecl->lookupMethod(ObjCMethod->getSelector(),
4904	ObjCMethod->isInstanceMethod())) {
4905	mergeInterfaceMethodToImpl(*this, ObjCMethod, IMD);
4906
4907	// The Idecl->lookupMethod() above will find declarations for ObjCMethod
4908	// in one of these places:
4909	//
4910	// (1) the canonical declaration in an @interface container paired
4911	// with the ImplDecl,
4912	// (2) non canonical declarations in @interface not paired with the
4913	// ImplDecl for the same Class,
4914	// (3) any superclass container.
4915	//
4916	// Direct methods only allow for canonical declarations in the matching
4917	// container (case 1).
4918	//
4919	// Direct methods overriding a superclass declaration (case 3) is
4920	// handled during overrides checks in CheckObjCMethodOverrides().
4921	//
4922	// We deal with same-class container mismatches (Case 2) here.
4923	if (IDecl == IMD->getClassInterface()) {
4924	auto diagContainerMismatch = [&] {
4925	int decl = 0, impl = 0;
4926
4927	if (auto *Cat = dyn_cast<ObjCCategoryDecl>(IMD->getDeclContext()))
4928	decl = Cat->IsClassExtension() ? 1 : 2;
4929
4930	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl))
4931	impl = 1 + (decl != 0);
4932
4933	Diag(ObjCMethod->getLocation(),
4934	diag::err_objc_direct_impl_decl_mismatch)
4935	<< decl << impl;
4936	Diag(IMD->getLocation(), diag::note_previous_declaration);
4937	};
4938
4939	if (ObjCMethod->isDirectMethod()) {
4940	const auto *attr = ObjCMethod->getAttr<ObjCDirectAttr>();
4941	if (ObjCMethod->getCanonicalDecl() != IMD) {
4942	diagContainerMismatch();
4943	} else if (!IMD->isDirectMethod()) {
4944	Diag(attr->getLocation(), diag::err_objc_direct_missing_on_decl);
4945	Diag(IMD->getLocation(), diag::note_previous_declaration);
4946	}
4947	} else if (IMD->isDirectMethod()) {
4948	const auto *attr = IMD->getAttr<ObjCDirectAttr>();
4949	if (ObjCMethod->getCanonicalDecl() != IMD) {
4950	diagContainerMismatch();
4951	} else {
4952	ObjCMethod->addAttr(
4953	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4954	}
4955	}
4956	}
4957
4958	// Warn about defining -dealloc in a category.
4959	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl) && IMD->isOverriding() &&
4960	ObjCMethod->getSelector().getMethodFamily() == OMF_dealloc) {
4961	Diag(ObjCMethod->getLocation(), diag::warn_dealloc_in_category)
4962	<< ObjCMethod->getDeclName();
4963	}
4964	} else {
4965	mergeObjCDirectMembers(S&: *this, CD: ClassDecl, Method: ObjCMethod);
4966	checkObjCDirectMethodClashes(S&: *this, IDecl, Method: ObjCMethod, ImpDecl);
4967	}
4968
4969	// Warn if a method declared in a protocol to which a category or
4970	// extension conforms is non-escaping and the implementation's method is
4971	// escaping.
4972	for (auto *C : IDecl->visible_categories())
4973	for (auto &P : C->protocols())
4974	if (auto *IMD = P->lookupMethod(ObjCMethod->getSelector(),
4975	ObjCMethod->isInstanceMethod())) {
4976	assert(ObjCMethod->parameters().size() ==
4977	IMD->parameters().size() &&
4978	"Methods have different number of parameters");
4979	auto OI = IMD->param_begin(), OE = IMD->param_end();
4980	auto NI = ObjCMethod->param_begin();
4981	for (; OI != OE; ++OI, ++NI)
4982	diagnoseNoescape(*NI, *OI, C, P, *this);
4983	}
4984	}
4985	} else {
4986	if (!isa<ObjCProtocolDecl>(Val: ClassDecl)) {
4987	mergeObjCDirectMembers(S&: *this, CD: ClassDecl, Method: ObjCMethod);
4988
4989	ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
4990	if (!IDecl)
4991	IDecl = cast<ObjCCategoryDecl>(Val: ClassDecl)->getClassInterface();
4992	// For valid code, we should always know the primary interface
4993	// declaration by now, however for invalid code we'll keep parsing
4994	// but we won't find the primary interface and IDecl will be nil.
4995	if (IDecl)
4996	checkObjCDirectMethodClashes(S&: *this, IDecl, Method: ObjCMethod);
4997	}
4998
4999	cast<DeclContext>(Val: ClassDecl)->addDecl(ObjCMethod);
5000	}
5001
5002	if (PrevMethod) {
5003	// You can never have two method definitions with the same name.
5004	Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
5005	<< ObjCMethod->getDeclName();
5006	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
5007	ObjCMethod->setInvalidDecl();
5008	return ObjCMethod;
5009	}
5010
5011	// If this Objective-C method does not have a related result type, but we
5012	// are allowed to infer related result types, try to do so based on the
5013	// method family.
5014	ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
5015	if (!CurrentClass) {
5016	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl))
5017	CurrentClass = Cat->getClassInterface();
5018	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: ClassDecl))
5019	CurrentClass = Impl->getClassInterface();
5020	else if (ObjCCategoryImplDecl *CatImpl
5021	= dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl))
5022	CurrentClass = CatImpl->getClassInterface();
5023	}
5024
5025	ResultTypeCompatibilityKind RTC
5026	= CheckRelatedResultTypeCompatibility(S&: *this, Method: ObjCMethod, CurrentClass);
5027
5028	CheckObjCMethodOverrides(ObjCMethod, CurrentClass, RTC);
5029
5030	bool ARCError = false;
5031	if (getLangOpts().ObjCAutoRefCount)
5032	ARCError = CheckARCMethodDecl(method: ObjCMethod);
5033
5034	// Infer the related result type when possible.
5035	if (!ARCError && RTC == Sema::RTC_Compatible &&
5036	!ObjCMethod->hasRelatedResultType() &&
5037	LangOpts.ObjCInferRelatedResultType) {
5038	bool InferRelatedResultType = false;
5039	switch (ObjCMethod->getMethodFamily()) {
5040	case OMF_None:
5041	case OMF_copy:
5042	case OMF_dealloc:
5043	case OMF_finalize:
5044	case OMF_mutableCopy:
5045	case OMF_release:
5046	case OMF_retainCount:
5047	case OMF_initialize:
5048	case OMF_performSelector:
5049	break;
5050
5051	case OMF_alloc:
5052	case OMF_new:
5053	InferRelatedResultType = ObjCMethod->isClassMethod();
5054	break;
5055
5056	case OMF_init:
5057	case OMF_autorelease:
5058	case OMF_retain:
5059	case OMF_self:
5060	InferRelatedResultType = ObjCMethod->isInstanceMethod();
5061	break;
5062	}
5063
5064	if (InferRelatedResultType &&
5065	!ObjCMethod->getReturnType()->isObjCIndependentClassType())
5066	ObjCMethod->setRelatedResultType();
5067	}
5068
5069	if (MethodDefinition &&
5070	Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
5071	checkObjCMethodX86VectorTypes(SemaRef&: *this, Method: ObjCMethod);
5072
5073	// + load method cannot have availability attributes. It get called on
5074	// startup, so it has to have the availability of the deployment target.
5075	if (const auto *attr = ObjCMethod->getAttr<AvailabilityAttr>()) {
5076	if (ObjCMethod->isClassMethod() &&
5077	ObjCMethod->getSelector().getAsString() == "load") {
5078	Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
5079	<< 0;
5080	ObjCMethod->dropAttr<AvailabilityAttr>();
5081	}
5082	}
5083
5084	// Insert the invisible arguments, self and _cmd!
5085	ObjCMethod->createImplicitParams(Context, ID: ObjCMethod->getClassInterface());
5086
5087	ActOnDocumentableDecl(ObjCMethod);
5088
5089	return ObjCMethod;
5090	}
5091
5092	bool Sema::CheckObjCDeclScope(Decl *D) {
5093	// Following is also an error. But it is caused by a missing @end
5094	// and diagnostic is issued elsewhere.
5095	if (isa<ObjCContainerDecl>(Val: CurContext->getRedeclContext()))
5096	return false;
5097
5098	// If we switched context to translation unit while we are still lexically in
5099	// an objc container, it means the parser missed emitting an error.
5100	if (isa<TranslationUnitDecl>(Val: getCurLexicalContext()->getRedeclContext()))
5101	return false;
5102
5103	Diag(D->getLocation(), diag::err_objc_decls_may_only_appear_in_global_scope);
5104	D->setInvalidDecl();
5105
5106	return true;
5107	}
5108
5109	/// Called whenever \@defs(ClassName) is encountered in the source. Inserts the
5110	/// instance variables of ClassName into Decls.
5111	void Sema::ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
5112	const IdentifierInfo *ClassName,
5113	SmallVectorImpl<Decl *> &Decls) {
5114	// Check that ClassName is a valid class
5115	ObjCInterfaceDecl *Class = getObjCInterfaceDecl(Id&: ClassName, IdLoc: DeclStart);
5116	if (!Class) {
5117	Diag(DeclStart, diag::err_undef_interface) << ClassName;
5118	return;
5119	}
5120	if (LangOpts.ObjCRuntime.isNonFragile()) {
5121	Diag(DeclStart, diag::err_atdef_nonfragile_interface);
5122	return;
5123	}
5124
5125	// Collect the instance variables
5126	SmallVector<const ObjCIvarDecl*, 32> Ivars;
5127	Context.DeepCollectObjCIvars(OI: Class, leafClass: true, Ivars);
5128	// For each ivar, create a fresh ObjCAtDefsFieldDecl.
5129	for (unsigned i = 0; i < Ivars.size(); i++) {
5130	const FieldDecl* ID = Ivars[i];
5131	RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD);
5132	Decl *FD = ObjCAtDefsFieldDecl::Create(C&: Context, DC: Record,
5133	/*FIXME: StartL=*/StartLoc: ID->getLocation(),
5134	IdLoc: ID->getLocation(),
5135	Id: ID->getIdentifier(), T: ID->getType(),
5136	BW: ID->getBitWidth());
5137	Decls.push_back(Elt: FD);
5138	}
5139
5140	// Introduce all of these fields into the appropriate scope.
5141	for (SmallVectorImpl<Decl*>::iterator D = Decls.begin();
5142	D != Decls.end(); ++D) {
5143	FieldDecl *FD = cast<FieldDecl>(Val: *D);
5144	if (getLangOpts().CPlusPlus)
5145	PushOnScopeChains(FD, S);
5146	else if (RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD))
5147	Record->addDecl(FD);
5148	}
5149	}
5150
5151	/// Build a type-check a new Objective-C exception variable declaration.
5152	VarDecl *Sema::BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType T,
5153	SourceLocation StartLoc,
5154	SourceLocation IdLoc,
5155	const IdentifierInfo *Id, bool Invalid) {
5156	// ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
5157	// duration shall not be qualified by an address-space qualifier."
5158	// Since all parameters have automatic store duration, they can not have
5159	// an address space.
5160	if (T.getAddressSpace() != LangAS::Default) {
5161	Diag(IdLoc, diag::err_arg_with_address_space);
5162	Invalid = true;
5163	}
5164
5165	// An @catch parameter must be an unqualified object pointer type;
5166	// FIXME: Recover from "NSObject foo" by inserting the * in "NSObject *foo"?
5167	if (Invalid) {
5168	// Don't do any further checking.
5169	} else if (T->isDependentType()) {
5170	// Okay: we don't know what this type will instantiate to.
5171	} else if (T->isObjCQualifiedIdType()) {
5172	Invalid = true;
5173	Diag(IdLoc, diag::err_illegal_qualifiers_on_catch_parm);
5174	} else if (T->isObjCIdType()) {
5175	// Okay: we don't know what this type will instantiate to.
5176	} else if (!T->isObjCObjectPointerType()) {
5177	Invalid = true;
5178	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5179	} else if (!T->castAs<ObjCObjectPointerType>()->getInterfaceType()) {
5180	Invalid = true;
5181	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5182	}
5183
5184	VarDecl *New = VarDecl::Create(C&: Context, DC: CurContext, StartLoc, IdLoc, Id,
5185	T, TInfo, S: SC_None);
5186	New->setExceptionVariable(true);
5187
5188	// In ARC, infer 'retaining' for variables of retainable type.
5189	if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(New))
5190	Invalid = true;
5191
5192	if (Invalid)
5193	New->setInvalidDecl();
5194	return New;
5195	}
5196
5197	Decl *Sema::ActOnObjCExceptionDecl(Scope *S, Declarator &D) {
5198	const DeclSpec &DS = D.getDeclSpec();
5199
5200	// We allow the "register" storage class on exception variables because
5201	// GCC did, but we drop it completely. Any other storage class is an error.
5202	if (DS.getStorageClassSpec() == DeclSpec::SCS_register) {
5203	Diag(DS.getStorageClassSpecLoc(), diag::warn_register_objc_catch_parm)
5204	<< FixItHint::CreateRemoval(SourceRange(DS.getStorageClassSpecLoc()));
5205	} else if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
5206	Diag(DS.getStorageClassSpecLoc(), diag::err_storage_spec_on_catch_parm)
5207	<< DeclSpec::getSpecifierName(SCS);
5208	}
5209	if (DS.isInlineSpecified())
5210	Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
5211	<< getLangOpts().CPlusPlus17;
5212	if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
5213	Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
5214	diag::err_invalid_thread)
5215	<< DeclSpec::getSpecifierName(TSCS);
5216	D.getMutableDeclSpec().ClearStorageClassSpecs();
5217
5218	DiagnoseFunctionSpecifiers(DS: D.getDeclSpec());
5219
5220	// Check that there are no default arguments inside the type of this
5221	// exception object (C++ only).
5222	if (getLangOpts().CPlusPlus)
5223	CheckExtraCXXDefaultArguments(D);
5224
5225	TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
5226	QualType ExceptionType = TInfo->getType();
5227
5228	VarDecl *New = BuildObjCExceptionDecl(TInfo, T: ExceptionType,
5229	StartLoc: D.getSourceRange().getBegin(),
5230	IdLoc: D.getIdentifierLoc(),
5231	Id: D.getIdentifier(),
5232	Invalid: D.isInvalidType());
5233
5234	// Parameter declarators cannot be qualified (C++ [dcl.meaning]p1).
5235	if (D.getCXXScopeSpec().isSet()) {
5236	Diag(D.getIdentifierLoc(), diag::err_qualified_objc_catch_parm)
5237	<< D.getCXXScopeSpec().getRange();
5238	New->setInvalidDecl();
5239	}
5240
5241	// Add the parameter declaration into this scope.
5242	S->AddDecl(New);
5243	if (D.getIdentifier())
5244	IdResolver.AddDecl(New);
5245
5246	ProcessDeclAttributes(S, New, D);
5247
5248	if (New->hasAttr<BlocksAttr>())
5249	Diag(New->getLocation(), diag::err_block_on_nonlocal);
5250	return New;
5251	}
5252
5253	/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
5254	/// initialization.
5255	void Sema::CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
5256	SmallVectorImpl<ObjCIvarDecl*> &Ivars) {
5257	for (ObjCIvarDecl *Iv = OI->all_declared_ivar_begin(); Iv;
5258	Iv= Iv->getNextIvar()) {
5259	QualType QT = Context.getBaseElementType(Iv->getType());
5260	if (QT->isRecordType())
5261	Ivars.push_back(Elt: Iv);
5262	}
5263	}
5264
5265	void Sema::DiagnoseUseOfUnimplementedSelectors() {
5266	// Load referenced selectors from the external source.
5267	if (ExternalSource) {
5268	SmallVector<std::pair<Selector, SourceLocation>, 4> Sels;
5269	ExternalSource->ReadReferencedSelectors(Sels);
5270	for (unsigned I = 0, N = Sels.size(); I != N; ++I)
5271	ReferencedSelectors[Sels[I].first] = Sels[I].second;
5272	}
5273
5274	// Warning will be issued only when selector table is
5275	// generated (which means there is at lease one implementation
5276	// in the TU). This is to match gcc's behavior.
5277	if (ReferencedSelectors.empty() ||
5278	!Context.AnyObjCImplementation())
5279	return;
5280	for (auto &SelectorAndLocation : ReferencedSelectors) {
5281	Selector Sel = SelectorAndLocation.first;
5282	SourceLocation Loc = SelectorAndLocation.second;
5283	if (!LookupImplementedMethodInGlobalPool(Sel))
5284	Diag(Loc, diag::warn_unimplemented_selector) << Sel;
5285	}
5286	}
5287
5288	ObjCIvarDecl *
5289	Sema::GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
5290	const ObjCPropertyDecl *&PDecl) const {
5291	if (Method->isClassMethod())
5292	return nullptr;
5293	const ObjCInterfaceDecl *IDecl = Method->getClassInterface();
5294	if (!IDecl)
5295	return nullptr;
5296	Method = IDecl->lookupMethod(Sel: Method->getSelector(), /*isInstance=*/true,
5297	/*shallowCategoryLookup=*/false,
5298	/*followSuper=*/false);
5299	if (!Method || !Method->isPropertyAccessor())
5300	return nullptr;
5301	if ((PDecl = Method->findPropertyDecl()))
5302	if (ObjCIvarDecl *IV = PDecl->getPropertyIvarDecl()) {
5303	// property backing ivar must belong to property's class
5304	// or be a private ivar in class's implementation.
5305	// FIXME. fix the const-ness issue.
5306	IV = const_cast<ObjCInterfaceDecl *>(IDecl)->lookupInstanceVariable(
5307	IV->getIdentifier());
5308	return IV;
5309	}
5310	return nullptr;
5311	}
5312
5313	namespace {
5314	/// Used by Sema::DiagnoseUnusedBackingIvarInAccessor to check if a property
5315	/// accessor references the backing ivar.
5316	class UnusedBackingIvarChecker :
5317	public RecursiveASTVisitor<UnusedBackingIvarChecker> {
5318	public:
5319	Sema &S;
5320	const ObjCMethodDecl *Method;
5321	const ObjCIvarDecl *IvarD;
5322	bool AccessedIvar;
5323	bool InvokedSelfMethod;
5324
5325	UnusedBackingIvarChecker(Sema &S, const ObjCMethodDecl *Method,
5326	const ObjCIvarDecl *IvarD)
5327	: S(S), Method(Method), IvarD(IvarD),
5328	AccessedIvar(false), InvokedSelfMethod(false) {
5329	assert(IvarD);
5330	}
5331
5332	bool VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
5333	if (E->getDecl() == IvarD) {
5334	AccessedIvar = true;
5335	return false;
5336	}
5337	return true;
5338	}
5339
5340	bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
5341	if (E->getReceiverKind() == ObjCMessageExpr::Instance &&
5342	S.isSelfExpr(RExpr: E->getInstanceReceiver(), Method)) {
5343	InvokedSelfMethod = true;
5344	}
5345	return true;
5346	}
5347	};
5348	} // end anonymous namespace
5349
5350	void Sema::DiagnoseUnusedBackingIvarInAccessor(Scope *S,
5351	const ObjCImplementationDecl *ImplD) {
5352	if (S->hasUnrecoverableErrorOccurred())
5353	return;
5354
5355	for (const auto *CurMethod : ImplD->instance_methods()) {
5356	unsigned DIAG = diag::warn_unused_property_backing_ivar;
5357	SourceLocation Loc = CurMethod->getLocation();
5358	if (Diags.isIgnored(DIAG, Loc))
5359	continue;
5360
5361	const ObjCPropertyDecl *PDecl;
5362	const ObjCIvarDecl *IV = GetIvarBackingPropertyAccessor(CurMethod, PDecl);
5363	if (!IV)
5364	continue;
5365
5366	if (CurMethod->isSynthesizedAccessorStub())
5367	continue;
5368
5369	UnusedBackingIvarChecker Checker(*this, CurMethod, IV);
5370	Checker.TraverseStmt(CurMethod->getBody());
5371	if (Checker.AccessedIvar)
5372	continue;
5373
5374	// Do not issue this warning if backing ivar is used somewhere and accessor
5375	// implementation makes a self call. This is to prevent false positive in
5376	// cases where the ivar is accessed by another method that the accessor
5377	// delegates to.
5378	if (!IV->isReferenced() || !Checker.InvokedSelfMethod) {
5379	Diag(Loc, DIAG) << IV;
5380	Diag(PDecl->getLocation(), diag::note_property_declare);
5381	}
5382	}
5383	}
5384