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/DynamicRecursiveASTVisitor.h"
19	#include "clang/AST/Expr.h"
20	#include "clang/AST/ExprObjC.h"
21	#include "clang/Basic/SourceManager.h"
22	#include "clang/Basic/TargetInfo.h"
23	#include "clang/Sema/DeclSpec.h"
24	#include "clang/Sema/DelayedDiagnostic.h"
25	#include "clang/Sema/Initialization.h"
26	#include "clang/Sema/Lookup.h"
27	#include "clang/Sema/Scope.h"
28	#include "clang/Sema/ScopeInfo.h"
29	#include "clang/Sema/SemaObjC.h"
30	#include "llvm/ADT/DenseMap.h"
31	#include "llvm/ADT/DenseSet.h"
32
33	using namespace clang;
34
35	/// Check whether the given method, which must be in the 'init'
36	/// family, is a valid member of that family.
37	///
38	/// \param receiverTypeIfCall - if null, check this as if declaring it;
39	/// if non-null, check this as if making a call to it with the given
40	/// receiver type
41	///
42	/// \return true to indicate that there was an error and appropriate
43	/// actions were taken
44	bool SemaObjC::checkInitMethod(ObjCMethodDecl *method,
45	QualType receiverTypeIfCall) {
46	ASTContext &Context = getASTContext();
47	if (method->isInvalidDecl()) return true;
48
49	// This castAs is safe: methods that don't return an object
50	// pointer won't be inferred as inits and will reject an explicit
51	// objc_method_family(init).
52
53	// We ignore protocols here. Should we? What about Class?
54
55	const ObjCObjectType *result =
56	method->getReturnType()->castAs<ObjCObjectPointerType>()->getObjectType();
57
58	if (result->isObjCId()) {
59	return false;
60	} else if (result->isObjCClass()) {
61	// fall through: always an error
62	} else {
63	ObjCInterfaceDecl *resultClass = result->getInterface();
64	assert(resultClass && "unexpected object type!");
65
66	// It's okay for the result type to still be a forward declaration
67	// if we're checking an interface declaration.
68	if (!resultClass->hasDefinition()) {
69	if (receiverTypeIfCall.isNull() &&
70	!isa<ObjCImplementationDecl>(method->getDeclContext()))
71	return false;
72
73	// Otherwise, we try to compare class types.
74	} else {
75	// If this method was declared in a protocol, we can't check
76	// anything unless we have a receiver type that's an interface.
77	const ObjCInterfaceDecl *receiverClass = nullptr;
78	if (isa<ObjCProtocolDecl>(method->getDeclContext())) {
79	if (receiverTypeIfCall.isNull())
80	return false;
81
82	receiverClass = receiverTypeIfCall->castAs<ObjCObjectPointerType>()
83	->getInterfaceDecl();
84
85	// This can be null for calls to e.g. id<Foo>.
86	if (!receiverClass) return false;
87	} else {
88	receiverClass = method->getClassInterface();
89	assert(receiverClass && "method not associated with a class!");
90	}
91
92	// If either class is a subclass of the other, it's fine.
93	if (receiverClass->isSuperClassOf(I: resultClass) ||
94	resultClass->isSuperClassOf(I: receiverClass))
95	return false;
96	}
97	}
98
99	SourceLocation loc = method->getLocation();
100
101	// If we're in a system header, and this is not a call, just make
102	// the method unusable.
103	if (receiverTypeIfCall.isNull() &&
104	SemaRef.getSourceManager().isInSystemHeader(Loc: loc)) {
105	method->addAttr(UnavailableAttr::CreateImplicit(Context, "",
106	UnavailableAttr::IR_ARCInitReturnsUnrelated, loc));
107	return true;
108	}
109
110	// Otherwise, it's an error.
111	Diag(loc, diag::err_arc_init_method_unrelated_result_type);
112	method->setInvalidDecl();
113	return true;
114	}
115
116	/// Issue a warning if the parameter of the overridden method is non-escaping
117	/// but the parameter of the overriding method is not.
118	static bool diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
119	Sema &S) {
120	if (OldD->hasAttr<NoEscapeAttr>() && !NewD->hasAttr<NoEscapeAttr>()) {
121	S.Diag(NewD->getLocation(), diag::warn_overriding_method_missing_noescape);
122	S.Diag(OldD->getLocation(), diag::note_overridden_marked_noescape);
123	return false;
124	}
125
126	return true;
127	}
128
129	/// Produce additional diagnostics if a category conforms to a protocol that
130	/// defines a method taking a non-escaping parameter.
131	static void diagnoseNoescape(const ParmVarDecl *NewD, const ParmVarDecl *OldD,
132	const ObjCCategoryDecl *CD,
133	const ObjCProtocolDecl *PD, Sema &S) {
134	if (!diagnoseNoescape(NewD, OldD, S))
135	S.Diag(CD->getLocation(), diag::note_cat_conform_to_noescape_prot)
136	<< CD->IsClassExtension() << PD
137	<< cast<ObjCMethodDecl>(NewD->getDeclContext());
138	}
139
140	void SemaObjC::CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
141	const ObjCMethodDecl *Overridden) {
142	ASTContext &Context = getASTContext();
143	if (Overridden->hasRelatedResultType() &&
144	!NewMethod->hasRelatedResultType()) {
145	// This can only happen when the method follows a naming convention that
146	// implies a related result type, and the original (overridden) method has
147	// a suitable return type, but the new (overriding) method does not have
148	// a suitable return type.
149	QualType ResultType = NewMethod->getReturnType();
150	SourceRange ResultTypeRange = NewMethod->getReturnTypeSourceRange();
151
152	// Figure out which class this method is part of, if any.
153	ObjCInterfaceDecl *CurrentClass
154	= dyn_cast<ObjCInterfaceDecl>(NewMethod->getDeclContext());
155	if (!CurrentClass) {
156	DeclContext *DC = NewMethod->getDeclContext();
157	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: DC))
158	CurrentClass = Cat->getClassInterface();
159	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: DC))
160	CurrentClass = Impl->getClassInterface();
161	else if (ObjCCategoryImplDecl *CatImpl
162	= dyn_cast<ObjCCategoryImplDecl>(Val: DC))
163	CurrentClass = CatImpl->getClassInterface();
164	}
165
166	if (CurrentClass) {
167	Diag(NewMethod->getLocation(),
168	diag::warn_related_result_type_compatibility_class)
169	<< Context.getObjCInterfaceType(CurrentClass)
170	<< ResultType
171	<< ResultTypeRange;
172	} else {
173	Diag(NewMethod->getLocation(),
174	diag::warn_related_result_type_compatibility_protocol)
175	<< ResultType
176	<< ResultTypeRange;
177	}
178
179	if (ObjCMethodFamily Family = Overridden->getMethodFamily())
180	Diag(Overridden->getLocation(),
181	diag::note_related_result_type_family)
182	<< /*overridden method*/ 0
183	<< Family;
184	else
185	Diag(Overridden->getLocation(),
186	diag::note_related_result_type_overridden);
187	}
188
189	if ((NewMethod->hasAttr<NSReturnsRetainedAttr>() !=
190	Overridden->hasAttr<NSReturnsRetainedAttr>())) {
191	Diag(NewMethod->getLocation(),
192	getLangOpts().ObjCAutoRefCount
193	? diag::err_nsreturns_retained_attribute_mismatch
194	: diag::warn_nsreturns_retained_attribute_mismatch)
195	<< 1;
196	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
197	}
198	if ((NewMethod->hasAttr<NSReturnsNotRetainedAttr>() !=
199	Overridden->hasAttr<NSReturnsNotRetainedAttr>())) {
200	Diag(NewMethod->getLocation(),
201	getLangOpts().ObjCAutoRefCount
202	? diag::err_nsreturns_retained_attribute_mismatch
203	: diag::warn_nsreturns_retained_attribute_mismatch)
204	<< 0;
205	Diag(Overridden->getLocation(), diag::note_previous_decl) << "method";
206	}
207
208	ObjCMethodDecl::param_const_iterator oi = Overridden->param_begin(),
209	oe = Overridden->param_end();
210	for (ObjCMethodDecl::param_iterator ni = NewMethod->param_begin(),
211	ne = NewMethod->param_end();
212	ni != ne && oi != oe; ++ni, ++oi) {
213	const ParmVarDecl *oldDecl = (*oi);
214	ParmVarDecl *newDecl = (*ni);
215	if (newDecl->hasAttr<NSConsumedAttr>() !=
216	oldDecl->hasAttr<NSConsumedAttr>()) {
217	Diag(newDecl->getLocation(),
218	getLangOpts().ObjCAutoRefCount
219	? diag::err_nsconsumed_attribute_mismatch
220	: diag::warn_nsconsumed_attribute_mismatch);
221	Diag(oldDecl->getLocation(), diag::note_previous_decl) << "parameter";
222	}
223
224	diagnoseNoescape(NewD: newDecl, OldD: oldDecl, S&: SemaRef);
225	}
226	}
227
228	/// Check a method declaration for compatibility with the Objective-C
229	/// ARC conventions.
230	bool SemaObjC::CheckARCMethodDecl(ObjCMethodDecl *method) {
231	ASTContext &Context = getASTContext();
232	ObjCMethodFamily family = method->getMethodFamily();
233	switch (family) {
234	case OMF_None:
235	case OMF_finalize:
236	case OMF_retain:
237	case OMF_release:
238	case OMF_autorelease:
239	case OMF_retainCount:
240	case OMF_self:
241	case OMF_initialize:
242	case OMF_performSelector:
243	return false;
244
245	case OMF_dealloc:
246	if (!Context.hasSameType(method->getReturnType(), Context.VoidTy)) {
247	SourceRange ResultTypeRange = method->getReturnTypeSourceRange();
248	if (ResultTypeRange.isInvalid())
249	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
250	<< method->getReturnType()
251	<< FixItHint::CreateInsertion(method->getSelectorLoc(0), "(void)");
252	else
253	Diag(method->getLocation(), diag::err_dealloc_bad_result_type)
254	<< method->getReturnType()
255	<< FixItHint::CreateReplacement(ResultTypeRange, "void");
256	return true;
257	}
258	return false;
259
260	case OMF_init:
261	// If the method doesn't obey the init rules, don't bother annotating it.
262	if (checkInitMethod(method, receiverTypeIfCall: QualType()))
263	return true;
264
265	method->addAttr(NSConsumesSelfAttr::CreateImplicit(Context));
266
267	// Don't add a second copy of this attribute, but otherwise don't
268	// let it be suppressed.
269	if (method->hasAttr<NSReturnsRetainedAttr>())
270	return false;
271	break;
272
273	case OMF_alloc:
274	case OMF_copy:
275	case OMF_mutableCopy:
276	case OMF_new:
277	if (method->hasAttr<NSReturnsRetainedAttr>() ||
278	method->hasAttr<NSReturnsNotRetainedAttr>() ||
279	method->hasAttr<NSReturnsAutoreleasedAttr>())
280	return false;
281	break;
282	}
283
284	method->addAttr(NSReturnsRetainedAttr::CreateImplicit(Context));
285	return false;
286	}
287
288	static void DiagnoseObjCImplementedDeprecations(Sema &S, const NamedDecl *ND,
289	SourceLocation ImplLoc) {
290	if (!ND)
291	return;
292	bool IsCategory = false;
293	StringRef RealizedPlatform;
294	AvailabilityResult Availability = ND->getAvailability(
295	/*Message=*/nullptr, /*EnclosingVersion=*/VersionTuple(),
296	&RealizedPlatform);
297	if (Availability != AR_Deprecated) {
298	if (isa<ObjCMethodDecl>(Val: ND)) {
299	if (Availability != AR_Unavailable)
300	return;
301	if (RealizedPlatform.empty())
302	RealizedPlatform = S.Context.getTargetInfo().getPlatformName();
303	// Warn about implementing unavailable methods, unless the unavailable
304	// is for an app extension.
305	if (RealizedPlatform.ends_with(Suffix: "_app_extension"))
306	return;
307	S.Diag(ImplLoc, diag::warn_unavailable_def);
308	S.Diag(ND->getLocation(), diag::note_method_declared_at)
309	<< ND->getDeclName();
310	return;
311	}
312	if (const auto *CD = dyn_cast<ObjCCategoryDecl>(Val: ND)) {
313	if (!CD->getClassInterface()->isDeprecated())
314	return;
315	ND = CD->getClassInterface();
316	IsCategory = true;
317	} else
318	return;
319	}
320	S.Diag(ImplLoc, diag::warn_deprecated_def)
321	<< (isa<ObjCMethodDecl>(ND)
322	? /*Method*/ 0
323	: isa<ObjCCategoryDecl>(ND) || IsCategory ? /*Category*/ 2
324	: /*Class*/ 1);
325	if (isa<ObjCMethodDecl>(ND))
326	S.Diag(ND->getLocation(), diag::note_method_declared_at)
327	<< ND->getDeclName();
328	else
329	S.Diag(ND->getLocation(), diag::note_previous_decl)
330	<< (isa<ObjCCategoryDecl>(ND) ? "category" : "class");
331	}
332
333	/// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
334	/// pool.
335	void SemaObjC::AddAnyMethodToGlobalPool(Decl *D) {
336	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
337
338	// If we don't have a valid method decl, simply return.
339	if (!MDecl)
340	return;
341	if (MDecl->isInstanceMethod())
342	AddInstanceMethodToGlobalPool(Method: MDecl, impl: true);
343	else
344	AddFactoryMethodToGlobalPool(Method: MDecl, impl: true);
345	}
346
347	/// HasExplicitOwnershipAttr - returns true when pointer to ObjC pointer
348	/// has explicit ownership attribute; false otherwise.
349	static bool
350	HasExplicitOwnershipAttr(Sema &S, ParmVarDecl *Param) {
351	QualType T = Param->getType();
352
353	if (const PointerType *PT = T->getAs<PointerType>()) {
354	T = PT->getPointeeType();
355	} else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
356	T = RT->getPointeeType();
357	} else {
358	return true;
359	}
360
361	// If we have a lifetime qualifier, but it's local, we must have
362	// inferred it. So, it is implicit.
363	return !T.getLocalQualifiers().hasObjCLifetime();
364	}
365
366	/// ActOnStartOfObjCMethodDef - This routine sets up parameters; invisible
367	/// and user declared, in the method definition's AST.
368	void SemaObjC::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
369	ASTContext &Context = getASTContext();
370	SemaRef.ImplicitlyRetainedSelfLocs.clear();
371	assert((SemaRef.getCurMethodDecl() == nullptr) && "Methodparsing confused");
372	ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(Val: D);
373
374	SemaRef.PushExpressionEvaluationContext(
375	NewContext: SemaRef.ExprEvalContexts.back().Context);
376
377	// If we don't have a valid method decl, simply return.
378	if (!MDecl)
379	return;
380
381	QualType ResultType = MDecl->getReturnType();
382	if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
383	!MDecl->isInvalidDecl() &&
384	SemaRef.RequireCompleteType(MDecl->getLocation(), ResultType,
385	diag::err_func_def_incomplete_result))
386	MDecl->setInvalidDecl();
387
388	// Allow all of Sema to see that we are entering a method definition.
389	SemaRef.PushDeclContext(FnBodyScope, MDecl);
390	SemaRef.PushFunctionScope();
391
392	// Create Decl objects for each parameter, entrring them in the scope for
393	// binding to their use.
394
395	// Insert the invisible arguments, self and _cmd!
396	MDecl->createImplicitParams(Context, ID: MDecl->getClassInterface());
397
398	SemaRef.PushOnScopeChains(MDecl->getSelfDecl(), FnBodyScope);
399	SemaRef.PushOnScopeChains(MDecl->getCmdDecl(), FnBodyScope);
400
401	// The ObjC parser requires parameter names so there's no need to check.
402	SemaRef.CheckParmsForFunctionDef(Parameters: MDecl->parameters(),
403	/*CheckParameterNames=*/false);
404
405	// Introduce all of the other parameters into this scope.
406	for (auto *Param : MDecl->parameters()) {
407	if (!Param->isInvalidDecl() && getLangOpts().ObjCAutoRefCount &&
408	!HasExplicitOwnershipAttr(SemaRef, Param))
409	Diag(Param->getLocation(), diag::warn_arc_strong_pointer_objc_pointer) <<
410	Param->getType();
411
412	if (Param->getIdentifier())
413	SemaRef.PushOnScopeChains(Param, FnBodyScope);
414	}
415
416	// In ARC, disallow definition of retain/release/autorelease/retainCount
417	if (getLangOpts().ObjCAutoRefCount) {
418	switch (MDecl->getMethodFamily()) {
419	case OMF_retain:
420	case OMF_retainCount:
421	case OMF_release:
422	case OMF_autorelease:
423	Diag(MDecl->getLocation(), diag::err_arc_illegal_method_def)
424	<< 0 << MDecl->getSelector();
425	break;
426
427	case OMF_None:
428	case OMF_dealloc:
429	case OMF_finalize:
430	case OMF_alloc:
431	case OMF_init:
432	case OMF_mutableCopy:
433	case OMF_copy:
434	case OMF_new:
435	case OMF_self:
436	case OMF_initialize:
437	case OMF_performSelector:
438	break;
439	}
440	}
441
442	// Warn on deprecated methods under -Wdeprecated-implementations,
443	// and prepare for warning on missing super calls.
444	if (ObjCInterfaceDecl *IC = MDecl->getClassInterface()) {
445	ObjCMethodDecl *IMD =
446	IC->lookupMethod(Sel: MDecl->getSelector(), isInstance: MDecl->isInstanceMethod());
447
448	if (IMD) {
449	ObjCImplDecl *ImplDeclOfMethodDef =
450	dyn_cast<ObjCImplDecl>(MDecl->getDeclContext());
451	ObjCContainerDecl *ContDeclOfMethodDecl =
452	dyn_cast<ObjCContainerDecl>(IMD->getDeclContext());
453	ObjCImplDecl *ImplDeclOfMethodDecl = nullptr;
454	if (ObjCInterfaceDecl *OID = dyn_cast<ObjCInterfaceDecl>(Val: ContDeclOfMethodDecl))
455	ImplDeclOfMethodDecl = OID->getImplementation();
456	else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(Val: ContDeclOfMethodDecl)) {
457	if (CD->IsClassExtension()) {
458	if (ObjCInterfaceDecl *OID = CD->getClassInterface())
459	ImplDeclOfMethodDecl = OID->getImplementation();
460	} else
461	ImplDeclOfMethodDecl = CD->getImplementation();
462	}
463	// No need to issue deprecated warning if deprecated mehod in class/category
464	// is being implemented in its own implementation (no overriding is involved).
465	if (!ImplDeclOfMethodDecl || ImplDeclOfMethodDecl != ImplDeclOfMethodDef)
466	DiagnoseObjCImplementedDeprecations(SemaRef, IMD, MDecl->getLocation());
467	}
468
469	if (MDecl->getMethodFamily() == OMF_init) {
470	if (MDecl->isDesignatedInitializerForTheInterface()) {
471	SemaRef.getCurFunction()->ObjCIsDesignatedInit = true;
472	SemaRef.getCurFunction()->ObjCWarnForNoDesignatedInitChain =
473	IC->getSuperClass() != nullptr;
474	} else if (IC->hasDesignatedInitializers()) {
475	SemaRef.getCurFunction()->ObjCIsSecondaryInit = true;
476	SemaRef.getCurFunction()->ObjCWarnForNoInitDelegation = true;
477	}
478	}
479
480	// If this is "dealloc" or "finalize", set some bit here.
481	// Then in ActOnSuperMessage() (SemaExprObjC), set it back to false.
482	// Finally, in ActOnFinishFunctionBody() (SemaDecl), warn if flag is set.
483	// Only do this if the current class actually has a superclass.
484	if (const ObjCInterfaceDecl *SuperClass = IC->getSuperClass()) {
485	ObjCMethodFamily Family = MDecl->getMethodFamily();
486	if (Family == OMF_dealloc) {
487	if (!(getLangOpts().ObjCAutoRefCount ||
488	getLangOpts().getGC() == LangOptions::GCOnly))
489	SemaRef.getCurFunction()->ObjCShouldCallSuper = true;
490
491	} else if (Family == OMF_finalize) {
492	if (Context.getLangOpts().getGC() != LangOptions::NonGC)
493	SemaRef.getCurFunction()->ObjCShouldCallSuper = true;
494
495	} else {
496	const ObjCMethodDecl *SuperMethod =
497	SuperClass->lookupMethod(Sel: MDecl->getSelector(),
498	isInstance: MDecl->isInstanceMethod());
499	SemaRef.getCurFunction()->ObjCShouldCallSuper =
500	(SuperMethod && SuperMethod->hasAttr<ObjCRequiresSuperAttr>());
501	}
502	}
503	}
504
505	// Some function attributes (like OptimizeNoneAttr) need actions before
506	// parsing body started.
507	SemaRef.applyFunctionAttributesBeforeParsingBody(FD: D);
508	}
509
510	namespace {
511
512	// Callback to only accept typo corrections that are Objective-C classes.
513	// If an ObjCInterfaceDecl* is given to the constructor, then the validation
514	// function will reject corrections to that class.
515	class ObjCInterfaceValidatorCCC final : public CorrectionCandidateCallback {
516	public:
517	ObjCInterfaceValidatorCCC() : CurrentIDecl(nullptr) {}
518	explicit ObjCInterfaceValidatorCCC(ObjCInterfaceDecl *IDecl)
519	: CurrentIDecl(IDecl) {}
520
521	bool ValidateCandidate(const TypoCorrection &candidate) override {
522	ObjCInterfaceDecl *ID = candidate.getCorrectionDeclAs<ObjCInterfaceDecl>();
523	return ID && !declaresSameEntity(ID, CurrentIDecl);
524	}
525
526	std::unique_ptr<CorrectionCandidateCallback> clone() override {
527	return std::make_unique<ObjCInterfaceValidatorCCC>(args&: *this);
528	}
529
530	private:
531	ObjCInterfaceDecl *CurrentIDecl;
532	};
533
534	} // end anonymous namespace
535
536	static void diagnoseUseOfProtocols(Sema &TheSema,
537	ObjCContainerDecl *CD,
538	ObjCProtocolDecl *const *ProtoRefs,
539	unsigned NumProtoRefs,
540	const SourceLocation *ProtoLocs) {
541	assert(ProtoRefs);
542	// Diagnose availability in the context of the ObjC container.
543	Sema::ContextRAII SavedContext(TheSema, CD);
544	for (unsigned i = 0; i < NumProtoRefs; ++i) {
545	(void)TheSema.DiagnoseUseOfDecl(ProtoRefs[i], ProtoLocs[i],
546	/*UnknownObjCClass=*/nullptr,
547	/*ObjCPropertyAccess=*/false,
548	/*AvoidPartialAvailabilityChecks=*/true);
549	}
550	}
551
552	void SemaObjC::ActOnSuperClassOfClassInterface(
553	Scope *S, SourceLocation AtInterfaceLoc, ObjCInterfaceDecl *IDecl,
554	IdentifierInfo *ClassName, SourceLocation ClassLoc,
555	IdentifierInfo *SuperName, SourceLocation SuperLoc,
556	ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange) {
557	ASTContext &Context = getASTContext();
558	// Check if a different kind of symbol declared in this scope.
559	NamedDecl *PrevDecl = SemaRef.LookupSingleName(
560	S: SemaRef.TUScope, Name: SuperName, Loc: SuperLoc, NameKind: Sema::LookupOrdinaryName);
561
562	if (!PrevDecl) {
563	// Try to correct for a typo in the superclass name without correcting
564	// to the class we're defining.
565	ObjCInterfaceValidatorCCC CCC(IDecl);
566	if (TypoCorrection Corrected = SemaRef.CorrectTypo(
567	Typo: DeclarationNameInfo(SuperName, SuperLoc), LookupKind: Sema::LookupOrdinaryName,
568	S: SemaRef.TUScope, SS: nullptr, CCC, Mode: CorrectTypoKind::ErrorRecovery)) {
569	SemaRef.diagnoseTypo(Corrected, PDiag(diag::err_undef_superclass_suggest)
570	<< SuperName << ClassName);
571	PrevDecl = Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>();
572	}
573	}
574
575	if (declaresSameEntity(PrevDecl, IDecl)) {
576	Diag(SuperLoc, diag::err_recursive_superclass)
577	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
578	IDecl->setEndOfDefinitionLoc(ClassLoc);
579	} else {
580	ObjCInterfaceDecl *SuperClassDecl =
581	dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
582	QualType SuperClassType;
583
584	// Diagnose classes that inherit from deprecated classes.
585	if (SuperClassDecl) {
586	(void)SemaRef.DiagnoseUseOfDecl(SuperClassDecl, SuperLoc);
587	SuperClassType = Context.getObjCInterfaceType(Decl: SuperClassDecl);
588	}
589
590	if (PrevDecl && !SuperClassDecl) {
591	// The previous declaration was not a class decl. Check if we have a
592	// typedef. If we do, get the underlying class type.
593	if (const TypedefNameDecl *TDecl =
594	dyn_cast_or_null<TypedefNameDecl>(Val: PrevDecl)) {
595	QualType T = TDecl->getUnderlyingType();
596	if (T->isObjCObjectType()) {
597	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
598	SuperClassDecl = dyn_cast<ObjCInterfaceDecl>(Val: IDecl);
599	SuperClassType = Context.getTypeDeclType(TDecl);
600
601	// This handles the following case:
602	// @interface NewI @end
603	// typedef NewI DeprI __attribute__((deprecated("blah")))
604	// @interface SI : DeprI /* warn here */ @end
605	(void)SemaRef.DiagnoseUseOfDecl(
606	const_cast<TypedefNameDecl *>(TDecl), SuperLoc);
607	}
608	}
609	}
610
611	// This handles the following case:
612	//
613	// typedef int SuperClass;
614	// @interface MyClass : SuperClass {} @end
615	//
616	if (!SuperClassDecl) {
617	Diag(SuperLoc, diag::err_redefinition_different_kind) << SuperName;
618	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
619	}
620	}
621
622	if (!isa_and_nonnull<TypedefNameDecl>(Val: PrevDecl)) {
623	if (!SuperClassDecl)
624	Diag(SuperLoc, diag::err_undef_superclass)
625	<< SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
626	else if (SemaRef.RequireCompleteType(
627	SuperLoc, SuperClassType, diag::err_forward_superclass,
628	SuperClassDecl->getDeclName(), ClassName,
629	SourceRange(AtInterfaceLoc, ClassLoc))) {
630	SuperClassDecl = nullptr;
631	SuperClassType = QualType();
632	}
633	}
634
635	if (SuperClassType.isNull()) {
636	assert(!SuperClassDecl && "Failed to set SuperClassType?");
637	return;
638	}
639
640	// Handle type arguments on the superclass.
641	TypeSourceInfo *SuperClassTInfo = nullptr;
642	if (!SuperTypeArgs.empty()) {
643	TypeResult fullSuperClassType = actOnObjCTypeArgsAndProtocolQualifiers(
644	S, Loc: SuperLoc, BaseType: SemaRef.CreateParsedType(T: SuperClassType, TInfo: nullptr),
645	TypeArgsLAngleLoc: SuperTypeArgsRange.getBegin(), TypeArgs: SuperTypeArgs,
646	TypeArgsRAngleLoc: SuperTypeArgsRange.getEnd(), ProtocolLAngleLoc: SourceLocation(), Protocols: {}, ProtocolLocs: {},
647	ProtocolRAngleLoc: SourceLocation());
648	if (!fullSuperClassType.isUsable())
649	return;
650
651	SuperClassType =
652	SemaRef.GetTypeFromParser(Ty: fullSuperClassType.get(), TInfo: &SuperClassTInfo);
653	}
654
655	if (!SuperClassTInfo) {
656	SuperClassTInfo = Context.getTrivialTypeSourceInfo(T: SuperClassType,
657	Loc: SuperLoc);
658	}
659
660	IDecl->setSuperClass(SuperClassTInfo);
661	IDecl->setEndOfDefinitionLoc(SuperClassTInfo->getTypeLoc().getEndLoc());
662	getASTContext().addObjCSubClass(IDecl->getSuperClass(), IDecl);
663	}
664	}
665
666	DeclResult SemaObjC::actOnObjCTypeParam(
667	Scope *S, ObjCTypeParamVariance variance, SourceLocation varianceLoc,
668	unsigned index, IdentifierInfo *paramName, SourceLocation paramLoc,
669	SourceLocation colonLoc, ParsedType parsedTypeBound) {
670	ASTContext &Context = getASTContext();
671	// If there was an explicitly-provided type bound, check it.
672	TypeSourceInfo *typeBoundInfo = nullptr;
673	if (parsedTypeBound) {
674	// The type bound can be any Objective-C pointer type.
675	QualType typeBound =
676	SemaRef.GetTypeFromParser(Ty: parsedTypeBound, TInfo: &typeBoundInfo);
677	if (typeBound->isObjCObjectPointerType()) {
678	// okay
679	} else if (typeBound->isObjCObjectType()) {
680	// The user forgot the * on an Objective-C pointer type, e.g.,
681	// "T : NSView".
682	SourceLocation starLoc =
683	SemaRef.getLocForEndOfToken(Loc: typeBoundInfo->getTypeLoc().getEndLoc());
684	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
685	diag::err_objc_type_param_bound_missing_pointer)
686	<< typeBound << paramName
687	<< FixItHint::CreateInsertion(starLoc, " *");
688
689	// Create a new type location builder so we can update the type
690	// location information we have.
691	TypeLocBuilder builder;
692	builder.pushFullCopy(L: typeBoundInfo->getTypeLoc());
693
694	// Create the Objective-C pointer type.
695	typeBound = Context.getObjCObjectPointerType(OIT: typeBound);
696	ObjCObjectPointerTypeLoc newT
697	= builder.push<ObjCObjectPointerTypeLoc>(T: typeBound);
698	newT.setStarLoc(starLoc);
699
700	// Form the new type source information.
701	typeBoundInfo = builder.getTypeSourceInfo(Context, T: typeBound);
702	} else {
703	// Not a valid type bound.
704	Diag(typeBoundInfo->getTypeLoc().getBeginLoc(),
705	diag::err_objc_type_param_bound_nonobject)
706	<< typeBound << paramName;
707
708	// Forget the bound; we'll default to id later.
709	typeBoundInfo = nullptr;
710	}
711
712	// Type bounds cannot have qualifiers (even indirectly) or explicit
713	// nullability.
714	if (typeBoundInfo) {
715	QualType typeBound = typeBoundInfo->getType();
716	TypeLoc qual = typeBoundInfo->getTypeLoc().findExplicitQualifierLoc();
717	if (qual || typeBound.hasQualifiers()) {
718	bool diagnosed = false;
719	SourceRange rangeToRemove;
720	if (qual) {
721	if (auto attr = qual.getAs<AttributedTypeLoc>()) {
722	rangeToRemove = attr.getLocalSourceRange();
723	if (attr.getTypePtr()->getImmediateNullability()) {
724	Diag(attr.getBeginLoc(),
725	diag::err_objc_type_param_bound_explicit_nullability)
726	<< paramName << typeBound
727	<< FixItHint::CreateRemoval(rangeToRemove);
728	diagnosed = true;
729	}
730	}
731	}
732
733	if (!diagnosed) {
734	Diag(qual ? qual.getBeginLoc()
735	: typeBoundInfo->getTypeLoc().getBeginLoc(),
736	diag::err_objc_type_param_bound_qualified)
737	<< paramName << typeBound
738	<< typeBound.getQualifiers().getAsString()
739	<< FixItHint::CreateRemoval(rangeToRemove);
740	}
741
742	// If the type bound has qualifiers other than CVR, we need to strip
743	// them or we'll probably assert later when trying to apply new
744	// qualifiers.
745	Qualifiers quals = typeBound.getQualifiers();
746	quals.removeCVRQualifiers();
747	if (!quals.empty()) {
748	typeBoundInfo =
749	Context.getTrivialTypeSourceInfo(T: typeBound.getUnqualifiedType());
750	}
751	}
752	}
753	}
754
755	// If there was no explicit type bound (or we removed it due to an error),
756	// use 'id' instead.
757	if (!typeBoundInfo) {
758	colonLoc = SourceLocation();
759	typeBoundInfo = Context.getTrivialTypeSourceInfo(T: Context.getObjCIdType());
760	}
761
762	// Create the type parameter.
763	return ObjCTypeParamDecl::Create(ctx&: Context, dc: SemaRef.CurContext, variance,
764	varianceLoc, index, nameLoc: paramLoc, name: paramName,
765	colonLoc, boundInfo: typeBoundInfo);
766	}
767
768	ObjCTypeParamList *
769	SemaObjC::actOnObjCTypeParamList(Scope *S, SourceLocation lAngleLoc,
770	ArrayRef<Decl *> typeParamsIn,
771	SourceLocation rAngleLoc) {
772	ASTContext &Context = getASTContext();
773	// We know that the array only contains Objective-C type parameters.
774	ArrayRef<ObjCTypeParamDecl *>
775	typeParams(
776	reinterpret_cast<ObjCTypeParamDecl * const *>(typeParamsIn.data()),
777	typeParamsIn.size());
778
779	// Diagnose redeclarations of type parameters.
780	// We do this now because Objective-C type parameters aren't pushed into
781	// scope until later (after the instance variable block), but we want the
782	// diagnostics to occur right after we parse the type parameter list.
783	llvm::SmallDenseMap<IdentifierInfo *, ObjCTypeParamDecl *> knownParams;
784	for (auto *typeParam : typeParams) {
785	auto known = knownParams.find(typeParam->getIdentifier());
786	if (known != knownParams.end()) {
787	Diag(typeParam->getLocation(), diag::err_objc_type_param_redecl)
788	<< typeParam->getIdentifier()
789	<< SourceRange(known->second->getLocation());
790
791	typeParam->setInvalidDecl();
792	} else {
793	knownParams.insert(std::make_pair(typeParam->getIdentifier(), typeParam));
794
795	// Push the type parameter into scope.
796	SemaRef.PushOnScopeChains(typeParam, S, /*AddToContext=*/false);
797	}
798	}
799
800	// Create the parameter list.
801	return ObjCTypeParamList::create(ctx&: Context, lAngleLoc, typeParams, rAngleLoc);
802	}
803
804	void SemaObjC::popObjCTypeParamList(Scope *S,
805	ObjCTypeParamList *typeParamList) {
806	for (auto *typeParam : *typeParamList) {
807	if (!typeParam->isInvalidDecl()) {
808	S->RemoveDecl(typeParam);
809	SemaRef.IdResolver.RemoveDecl(typeParam);
810	}
811	}
812	}
813
814	namespace {
815	/// The context in which an Objective-C type parameter list occurs, for use
816	/// in diagnostics.
817	enum class TypeParamListContext {
818	ForwardDeclaration,
819	Definition,
820	Category,
821	Extension
822	};
823	} // end anonymous namespace
824
825	/// Check consistency between two Objective-C type parameter lists, e.g.,
826	/// between a category/extension and an \@interface or between an \@class and an
827	/// \@interface.
828	static bool checkTypeParamListConsistency(Sema &S,
829	ObjCTypeParamList *prevTypeParams,
830	ObjCTypeParamList *newTypeParams,
831	TypeParamListContext newContext) {
832	// If the sizes don't match, complain about that.
833	if (prevTypeParams->size() != newTypeParams->size()) {
834	SourceLocation diagLoc;
835	if (newTypeParams->size() > prevTypeParams->size()) {
836	diagLoc = newTypeParams->begin()[prevTypeParams->size()]->getLocation();
837	} else {
838	diagLoc = S.getLocForEndOfToken(Loc: newTypeParams->back()->getEndLoc());
839	}
840
841	S.Diag(diagLoc, diag::err_objc_type_param_arity_mismatch)
842	<< static_cast<unsigned>(newContext)
843	<< (newTypeParams->size() > prevTypeParams->size())
844	<< prevTypeParams->size()
845	<< newTypeParams->size();
846
847	return true;
848	}
849
850	// Match up the type parameters.
851	for (unsigned i = 0, n = prevTypeParams->size(); i != n; ++i) {
852	ObjCTypeParamDecl *prevTypeParam = prevTypeParams->begin()[i];
853	ObjCTypeParamDecl *newTypeParam = newTypeParams->begin()[i];
854
855	// Check for consistency of the variance.
856	if (newTypeParam->getVariance() != prevTypeParam->getVariance()) {
857	if (newTypeParam->getVariance() == ObjCTypeParamVariance::Invariant &&
858	newContext != TypeParamListContext::Definition) {
859	// When the new type parameter is invariant and is not part
860	// of the definition, just propagate the variance.
861	newTypeParam->setVariance(prevTypeParam->getVariance());
862	} else if (prevTypeParam->getVariance()
863	== ObjCTypeParamVariance::Invariant &&
864	!(isa<ObjCInterfaceDecl>(prevTypeParam->getDeclContext()) &&
865	cast<ObjCInterfaceDecl>(prevTypeParam->getDeclContext())
866	->getDefinition() == prevTypeParam->getDeclContext())) {
867	// When the old parameter is invariant and was not part of the
868	// definition, just ignore the difference because it doesn't
869	// matter.
870	} else {
871	{
872	// Diagnose the conflict and update the second declaration.
873	SourceLocation diagLoc = newTypeParam->getVarianceLoc();
874	if (diagLoc.isInvalid())
875	diagLoc = newTypeParam->getBeginLoc();
876
877	auto diag = S.Diag(diagLoc,
878	diag::err_objc_type_param_variance_conflict)
879	<< static_cast<unsigned>(newTypeParam->getVariance())
880	<< newTypeParam->getDeclName()
881	<< static_cast<unsigned>(prevTypeParam->getVariance())
882	<< prevTypeParam->getDeclName();
883	switch (prevTypeParam->getVariance()) {
884	case ObjCTypeParamVariance::Invariant:
885	diag << FixItHint::CreateRemoval(RemoveRange: newTypeParam->getVarianceLoc());
886	break;
887
888	case ObjCTypeParamVariance::Covariant:
889	case ObjCTypeParamVariance::Contravariant: {
890	StringRef newVarianceStr
891	= prevTypeParam->getVariance() == ObjCTypeParamVariance::Covariant
892	? "__covariant"
893	: "__contravariant";
894	if (newTypeParam->getVariance()
895	== ObjCTypeParamVariance::Invariant) {
896	diag << FixItHint::CreateInsertion(InsertionLoc: newTypeParam->getBeginLoc(),
897	Code: (newVarianceStr + " ").str());
898	} else {
899	diag << FixItHint::CreateReplacement(RemoveRange: newTypeParam->getVarianceLoc(),
900	Code: newVarianceStr);
901	}
902	}
903	}
904	}
905
906	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
907	<< prevTypeParam->getDeclName();
908
909	// Override the variance.
910	newTypeParam->setVariance(prevTypeParam->getVariance());
911	}
912	}
913
914	// If the bound types match, there's nothing to do.
915	if (S.Context.hasSameType(prevTypeParam->getUnderlyingType(),
916	newTypeParam->getUnderlyingType()))
917	continue;
918
919	// If the new type parameter's bound was explicit, complain about it being
920	// different from the original.
921	if (newTypeParam->hasExplicitBound()) {
922	SourceRange newBoundRange = newTypeParam->getTypeSourceInfo()
923	->getTypeLoc().getSourceRange();
924	S.Diag(newBoundRange.getBegin(), diag::err_objc_type_param_bound_conflict)
925	<< newTypeParam->getUnderlyingType()
926	<< newTypeParam->getDeclName()
927	<< prevTypeParam->hasExplicitBound()
928	<< prevTypeParam->getUnderlyingType()
929	<< (newTypeParam->getDeclName() == prevTypeParam->getDeclName())
930	<< prevTypeParam->getDeclName()
931	<< FixItHint::CreateReplacement(
932	newBoundRange,
933	prevTypeParam->getUnderlyingType().getAsString(
934	S.Context.getPrintingPolicy()));
935
936	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
937	<< prevTypeParam->getDeclName();
938
939	// Override the new type parameter's bound type with the previous type,
940	// so that it's consistent.
941	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
942	continue;
943	}
944
945	// The new type parameter got the implicit bound of 'id'. That's okay for
946	// categories and extensions (overwrite it later), but not for forward
947	// declarations and @interfaces, because those must be standalone.
948	if (newContext == TypeParamListContext::ForwardDeclaration ||
949	newContext == TypeParamListContext::Definition) {
950	// Diagnose this problem for forward declarations and definitions.
951	SourceLocation insertionLoc
952	= S.getLocForEndOfToken(Loc: newTypeParam->getLocation());
953	std::string newCode
954	= " : " + prevTypeParam->getUnderlyingType().getAsString(
955	S.Context.getPrintingPolicy());
956	S.Diag(newTypeParam->getLocation(),
957	diag::err_objc_type_param_bound_missing)
958	<< prevTypeParam->getUnderlyingType()
959	<< newTypeParam->getDeclName()
960	<< (newContext == TypeParamListContext::ForwardDeclaration)
961	<< FixItHint::CreateInsertion(insertionLoc, newCode);
962
963	S.Diag(prevTypeParam->getLocation(), diag::note_objc_type_param_here)
964	<< prevTypeParam->getDeclName();
965	}
966
967	// Update the new type parameter's bound to match the previous one.
968	S.Context.adjustObjCTypeParamBoundType(Orig: prevTypeParam, New: newTypeParam);
969	}
970
971	return false;
972	}
973
974	ObjCInterfaceDecl *SemaObjC::ActOnStartClassInterface(
975	Scope *S, SourceLocation AtInterfaceLoc, IdentifierInfo *ClassName,
976	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
977	IdentifierInfo *SuperName, SourceLocation SuperLoc,
978	ArrayRef<ParsedType> SuperTypeArgs, SourceRange SuperTypeArgsRange,
979	Decl *const *ProtoRefs, unsigned NumProtoRefs,
980	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
981	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
982	assert(ClassName && "Missing class identifier");
983
984	ASTContext &Context = getASTContext();
985	// Check for another declaration kind with the same name.
986	NamedDecl *PrevDecl = SemaRef.LookupSingleName(
987	S: SemaRef.TUScope, Name: ClassName, Loc: ClassLoc, NameKind: Sema::LookupOrdinaryName,
988	Redecl: SemaRef.forRedeclarationInCurContext());
989
990	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
991	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
992	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
993	}
994
995	// Create a declaration to describe this @interface.
996	ObjCInterfaceDecl* PrevIDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
997
998	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
999	// A previous decl with a different name is because of
1000	// @compatibility_alias, for example:
1001	// \code
1002	// @class NewImage;
1003	// @compatibility_alias OldImage NewImage;
1004	// \endcode
1005	// A lookup for 'OldImage' will return the 'NewImage' decl.
1006	//
1007	// In such a case use the real declaration name, instead of the alias one,
1008	// otherwise we will break IdentifierResolver and redecls-chain invariants.
1009	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
1010	// has been aliased.
1011	ClassName = PrevIDecl->getIdentifier();
1012	}
1013
1014	// If there was a forward declaration with type parameters, check
1015	// for consistency.
1016	if (PrevIDecl) {
1017	if (ObjCTypeParamList *prevTypeParamList = PrevIDecl->getTypeParamList()) {
1018	if (typeParamList) {
1019	// Both have type parameter lists; check for consistency.
1020	if (checkTypeParamListConsistency(S&: SemaRef, prevTypeParams: prevTypeParamList,
1021	newTypeParams: typeParamList,
1022	newContext: TypeParamListContext::Definition)) {
1023	typeParamList = nullptr;
1024	}
1025	} else {
1026	Diag(ClassLoc, diag::err_objc_parameterized_forward_class_first)
1027	<< ClassName;
1028	Diag(prevTypeParamList->getLAngleLoc(), diag::note_previous_decl)
1029	<< ClassName;
1030
1031	// Clone the type parameter list.
1032	SmallVector<ObjCTypeParamDecl *, 4> clonedTypeParams;
1033	for (auto *typeParam : *prevTypeParamList) {
1034	clonedTypeParams.push_back(Elt: ObjCTypeParamDecl::Create(
1035	ctx&: Context, dc: SemaRef.CurContext, variance: typeParam->getVariance(),
1036	varianceLoc: SourceLocation(), index: typeParam->getIndex(), nameLoc: SourceLocation(),
1037	name: typeParam->getIdentifier(), colonLoc: SourceLocation(),
1038	boundInfo: Context.getTrivialTypeSourceInfo(
1039	T: typeParam->getUnderlyingType())));
1040	}
1041
1042	typeParamList = ObjCTypeParamList::create(ctx&: Context,
1043	lAngleLoc: SourceLocation(),
1044	typeParams: clonedTypeParams,
1045	rAngleLoc: SourceLocation());
1046	}
1047	}
1048	}
1049
1050	ObjCInterfaceDecl *IDecl =
1051	ObjCInterfaceDecl::Create(C: Context, DC: SemaRef.CurContext, atLoc: AtInterfaceLoc,
1052	Id: ClassName, typeParamList, PrevDecl: PrevIDecl, ClassLoc);
1053	if (PrevIDecl) {
1054	// Class already seen. Was it a definition?
1055	if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
1056	if (SkipBody && !SemaRef.hasVisibleDefinition(Def)) {
1057	SkipBody->CheckSameAsPrevious = true;
1058	SkipBody->New = IDecl;
1059	SkipBody->Previous = Def;
1060	} else {
1061	Diag(AtInterfaceLoc, diag::err_duplicate_class_def)
1062	<< PrevIDecl->getDeclName();
1063	Diag(Def->getLocation(), diag::note_previous_definition);
1064	IDecl->setInvalidDecl();
1065	}
1066	}
1067	}
1068
1069	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, IDecl, AttrList);
1070	SemaRef.AddPragmaAttributes(SemaRef.TUScope, IDecl);
1071	SemaRef.ProcessAPINotes(IDecl);
1072
1073	// Merge attributes from previous declarations.
1074	if (PrevIDecl)
1075	SemaRef.mergeDeclAttributes(IDecl, PrevIDecl);
1076
1077	SemaRef.PushOnScopeChains(IDecl, SemaRef.TUScope);
1078
1079	// Start the definition of this class. If we're in a redefinition case, there
1080	// may already be a definition, so we'll end up adding to it.
1081	if (SkipBody && SkipBody->CheckSameAsPrevious)
1082	IDecl->startDuplicateDefinitionForComparison();
1083	else if (!IDecl->hasDefinition())
1084	IDecl->startDefinition();
1085
1086	if (SuperName) {
1087	// Diagnose availability in the context of the @interface.
1088	Sema::ContextRAII SavedContext(SemaRef, IDecl);
1089
1090	ActOnSuperClassOfClassInterface(S, AtInterfaceLoc, IDecl,
1091	ClassName, ClassLoc,
1092	SuperName, SuperLoc, SuperTypeArgs,
1093	SuperTypeArgsRange);
1094	} else { // we have a root class.
1095	IDecl->setEndOfDefinitionLoc(ClassLoc);
1096	}
1097
1098	// Check then save referenced protocols.
1099	if (NumProtoRefs) {
1100	diagnoseUseOfProtocols(SemaRef, IDecl, (ObjCProtocolDecl *const *)ProtoRefs,
1101	NumProtoRefs, ProtoLocs);
1102	IDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1103	Locs: ProtoLocs, C&: Context);
1104	IDecl->setEndOfDefinitionLoc(EndProtoLoc);
1105	}
1106
1107	CheckObjCDeclScope(IDecl);
1108	ActOnObjCContainerStartDefinition(IDecl);
1109	return IDecl;
1110	}
1111
1112	/// ActOnTypedefedProtocols - this action finds protocol list as part of the
1113	/// typedef'ed use for a qualified super class and adds them to the list
1114	/// of the protocols.
1115	void SemaObjC::ActOnTypedefedProtocols(
1116	SmallVectorImpl<Decl *> &ProtocolRefs,
1117	SmallVectorImpl<SourceLocation> &ProtocolLocs, IdentifierInfo *SuperName,
1118	SourceLocation SuperLoc) {
1119	if (!SuperName)
1120	return;
1121	NamedDecl *IDecl = SemaRef.LookupSingleName(
1122	S: SemaRef.TUScope, Name: SuperName, Loc: SuperLoc, NameKind: Sema::LookupOrdinaryName);
1123	if (!IDecl)
1124	return;
1125
1126	if (const TypedefNameDecl *TDecl = dyn_cast_or_null<TypedefNameDecl>(Val: IDecl)) {
1127	QualType T = TDecl->getUnderlyingType();
1128	if (T->isObjCObjectType())
1129	if (const ObjCObjectType *OPT = T->getAs<ObjCObjectType>()) {
1130	ProtocolRefs.append(OPT->qual_begin(), OPT->qual_end());
1131	// FIXME: Consider whether this should be an invalid loc since the loc
1132	// is not actually pointing to a protocol name reference but to the
1133	// typedef reference. Note that the base class name loc is also pointing
1134	// at the typedef.
1135	ProtocolLocs.append(OPT->getNumProtocols(), SuperLoc);
1136	}
1137	}
1138	}
1139
1140	/// ActOnCompatibilityAlias - this action is called after complete parsing of
1141	/// a \@compatibility_alias declaration. It sets up the alias relationships.
1142	Decl *SemaObjC::ActOnCompatibilityAlias(SourceLocation AtLoc,
1143	IdentifierInfo *AliasName,
1144	SourceLocation AliasLocation,
1145	IdentifierInfo *ClassName,
1146	SourceLocation ClassLocation) {
1147	ASTContext &Context = getASTContext();
1148	// Look for previous declaration of alias name
1149	NamedDecl *ADecl = SemaRef.LookupSingleName(
1150	S: SemaRef.TUScope, Name: AliasName, Loc: AliasLocation, NameKind: Sema::LookupOrdinaryName,
1151	Redecl: SemaRef.forRedeclarationInCurContext());
1152	if (ADecl) {
1153	Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
1154	Diag(ADecl->getLocation(), diag::note_previous_declaration);
1155	return nullptr;
1156	}
1157	// Check for class declaration
1158	NamedDecl *CDeclU = SemaRef.LookupSingleName(
1159	S: SemaRef.TUScope, Name: ClassName, Loc: ClassLocation, NameKind: Sema::LookupOrdinaryName,
1160	Redecl: SemaRef.forRedeclarationInCurContext());
1161	if (const TypedefNameDecl *TDecl =
1162	dyn_cast_or_null<TypedefNameDecl>(Val: CDeclU)) {
1163	QualType T = TDecl->getUnderlyingType();
1164	if (T->isObjCObjectType()) {
1165	if (NamedDecl *IDecl = T->castAs<ObjCObjectType>()->getInterface()) {
1166	ClassName = IDecl->getIdentifier();
1167	CDeclU = SemaRef.LookupSingleName(
1168	S: SemaRef.TUScope, Name: ClassName, Loc: ClassLocation, NameKind: Sema::LookupOrdinaryName,
1169	Redecl: SemaRef.forRedeclarationInCurContext());
1170	}
1171	}
1172	}
1173	ObjCInterfaceDecl *CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: CDeclU);
1174	if (!CDecl) {
1175	Diag(ClassLocation, diag::warn_undef_interface) << ClassName;
1176	if (CDeclU)
1177	Diag(CDeclU->getLocation(), diag::note_previous_declaration);
1178	return nullptr;
1179	}
1180
1181	// Everything checked out, instantiate a new alias declaration AST.
1182	ObjCCompatibleAliasDecl *AliasDecl = ObjCCompatibleAliasDecl::Create(
1183	C&: Context, DC: SemaRef.CurContext, L: AtLoc, Id: AliasName, aliasedClass: CDecl);
1184
1185	if (!CheckObjCDeclScope(AliasDecl))
1186	SemaRef.PushOnScopeChains(AliasDecl, SemaRef.TUScope);
1187
1188	return AliasDecl;
1189	}
1190
1191	bool SemaObjC::CheckForwardProtocolDeclarationForCircularDependency(
1192	IdentifierInfo *PName, SourceLocation &Ploc, SourceLocation PrevLoc,
1193	const ObjCList<ObjCProtocolDecl> &PList) {
1194
1195	bool res = false;
1196	for (ObjCList<ObjCProtocolDecl>::iterator I = PList.begin(),
1197	E = PList.end(); I != E; ++I) {
1198	if (ObjCProtocolDecl *PDecl = LookupProtocol(II: (*I)->getIdentifier(), IdLoc: Ploc)) {
1199	if (PDecl->getIdentifier() == PName) {
1200	Diag(Ploc, diag::err_protocol_has_circular_dependency);
1201	Diag(PrevLoc, diag::note_previous_definition);
1202	res = true;
1203	}
1204
1205	if (!PDecl->hasDefinition())
1206	continue;
1207
1208	if (CheckForwardProtocolDeclarationForCircularDependency(PName, Ploc,
1209	PrevLoc: PDecl->getLocation(), PList: PDecl->getReferencedProtocols()))
1210	res = true;
1211	}
1212	}
1213	return res;
1214	}
1215
1216	ObjCProtocolDecl *SemaObjC::ActOnStartProtocolInterface(
1217	SourceLocation AtProtoInterfaceLoc, IdentifierInfo *ProtocolName,
1218	SourceLocation ProtocolLoc, Decl *const *ProtoRefs, unsigned NumProtoRefs,
1219	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1220	const ParsedAttributesView &AttrList, SkipBodyInfo *SkipBody) {
1221	ASTContext &Context = getASTContext();
1222	bool err = false;
1223	// FIXME: Deal with AttrList.
1224	assert(ProtocolName && "Missing protocol identifier");
1225	ObjCProtocolDecl *PrevDecl = LookupProtocol(
1226	II: ProtocolName, IdLoc: ProtocolLoc, Redecl: SemaRef.forRedeclarationInCurContext());
1227	ObjCProtocolDecl *PDecl = nullptr;
1228	if (ObjCProtocolDecl *Def = PrevDecl? PrevDecl->getDefinition() : nullptr) {
1229	// Create a new protocol that is completely distinct from previous
1230	// declarations, and do not make this protocol available for name lookup.
1231	// That way, we'll end up completely ignoring the duplicate.
1232	// FIXME: Can we turn this into an error?
1233	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: SemaRef.CurContext, Id: ProtocolName,
1234	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1235	/*PrevDecl=*/Def);
1236
1237	if (SkipBody && !SemaRef.hasVisibleDefinition(Def)) {
1238	SkipBody->CheckSameAsPrevious = true;
1239	SkipBody->New = PDecl;
1240	SkipBody->Previous = Def;
1241	} else {
1242	// If we already have a definition, complain.
1243	Diag(ProtocolLoc, diag::warn_duplicate_protocol_def) << ProtocolName;
1244	Diag(Def->getLocation(), diag::note_previous_definition);
1245	}
1246
1247	// If we are using modules, add the decl to the context in order to
1248	// serialize something meaningful.
1249	if (getLangOpts().Modules)
1250	SemaRef.PushOnScopeChains(PDecl, SemaRef.TUScope);
1251	PDecl->startDuplicateDefinitionForComparison();
1252	} else {
1253	if (PrevDecl) {
1254	// Check for circular dependencies among protocol declarations. This can
1255	// only happen if this protocol was forward-declared.
1256	ObjCList<ObjCProtocolDecl> PList;
1257	PList.set(InList: (ObjCProtocolDecl *const*)ProtoRefs, Elts: NumProtoRefs, Ctx&: Context);
1258	err = CheckForwardProtocolDeclarationForCircularDependency(
1259	PName: ProtocolName, Ploc&: ProtocolLoc, PrevLoc: PrevDecl->getLocation(), PList);
1260	}
1261
1262	// Create the new declaration.
1263	PDecl = ObjCProtocolDecl::Create(C&: Context, DC: SemaRef.CurContext, Id: ProtocolName,
1264	nameLoc: ProtocolLoc, atStartLoc: AtProtoInterfaceLoc,
1265	/*PrevDecl=*/PrevDecl);
1266
1267	SemaRef.PushOnScopeChains(PDecl, SemaRef.TUScope);
1268	PDecl->startDefinition();
1269	}
1270
1271	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, PDecl, AttrList);
1272	SemaRef.AddPragmaAttributes(SemaRef.TUScope, PDecl);
1273	SemaRef.ProcessAPINotes(PDecl);
1274
1275	// Merge attributes from previous declarations.
1276	if (PrevDecl)
1277	SemaRef.mergeDeclAttributes(PDecl, PrevDecl);
1278
1279	if (!err && NumProtoRefs ) {
1280	/// Check then save referenced protocols.
1281	diagnoseUseOfProtocols(SemaRef, PDecl, (ObjCProtocolDecl *const *)ProtoRefs,
1282	NumProtoRefs, ProtoLocs);
1283	PDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1284	Locs: ProtoLocs, C&: Context);
1285	}
1286
1287	CheckObjCDeclScope(PDecl);
1288	ActOnObjCContainerStartDefinition(PDecl);
1289	return PDecl;
1290	}
1291
1292	static bool NestedProtocolHasNoDefinition(ObjCProtocolDecl *PDecl,
1293	ObjCProtocolDecl *&UndefinedProtocol) {
1294	if (!PDecl->hasDefinition() ||
1295	!PDecl->getDefinition()->isUnconditionallyVisible()) {
1296	UndefinedProtocol = PDecl;
1297	return true;
1298	}
1299
1300	for (auto *PI : PDecl->protocols())
1301	if (NestedProtocolHasNoDefinition(PDecl: PI, UndefinedProtocol)) {
1302	UndefinedProtocol = PI;
1303	return true;
1304	}
1305	return false;
1306	}
1307
1308	/// FindProtocolDeclaration - This routine looks up protocols and
1309	/// issues an error if they are not declared. It returns list of
1310	/// protocol declarations in its 'Protocols' argument.
1311	void SemaObjC::FindProtocolDeclaration(bool WarnOnDeclarations,
1312	bool ForObjCContainer,
1313	ArrayRef<IdentifierLoc> ProtocolId,
1314	SmallVectorImpl<Decl *> &Protocols) {
1315	for (const IdentifierLoc &Pair : ProtocolId) {
1316	ObjCProtocolDecl *PDecl =
1317	LookupProtocol(II: Pair.getIdentifierInfo(), IdLoc: Pair.getLoc());
1318	if (!PDecl) {
1319	DeclFilterCCC<ObjCProtocolDecl> CCC{};
1320	TypoCorrection Corrected = SemaRef.CorrectTypo(
1321	Typo: DeclarationNameInfo(Pair.getIdentifierInfo(), Pair.getLoc()),
1322	LookupKind: Sema::LookupObjCProtocolName, S: SemaRef.TUScope, SS: nullptr, CCC,
1323	Mode: CorrectTypoKind::ErrorRecovery);
1324	if ((PDecl = Corrected.getCorrectionDeclAs<ObjCProtocolDecl>()))
1325	SemaRef.diagnoseTypo(Corrected,
1326	PDiag(diag::err_undeclared_protocol_suggest)
1327	<< Pair.getIdentifierInfo());
1328	}
1329
1330	if (!PDecl) {
1331	Diag(Pair.getLoc(), diag::err_undeclared_protocol)
1332	<< Pair.getIdentifierInfo();
1333	continue;
1334	}
1335	// If this is a forward protocol declaration, get its definition.
1336	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
1337	PDecl = PDecl->getDefinition();
1338
1339	// For an objc container, delay protocol reference checking until after we
1340	// can set the objc decl as the availability context, otherwise check now.
1341	if (!ForObjCContainer) {
1342	(void)SemaRef.DiagnoseUseOfDecl(PDecl, Pair.getLoc());
1343	}
1344
1345	// If this is a forward declaration and we are supposed to warn in this
1346	// case, do it.
1347	// FIXME: Recover nicely in the hidden case.
1348	ObjCProtocolDecl *UndefinedProtocol;
1349
1350	if (WarnOnDeclarations &&
1351	NestedProtocolHasNoDefinition(PDecl, UndefinedProtocol)) {
1352	Diag(Pair.getLoc(), diag::warn_undef_protocolref)
1353	<< Pair.getIdentifierInfo();
1354	Diag(UndefinedProtocol->getLocation(), diag::note_protocol_decl_undefined)
1355	<< UndefinedProtocol;
1356	}
1357	Protocols.push_back(PDecl);
1358	}
1359	}
1360
1361	namespace {
1362	// Callback to only accept typo corrections that are either
1363	// Objective-C protocols or valid Objective-C type arguments.
1364	class ObjCTypeArgOrProtocolValidatorCCC final
1365	: public CorrectionCandidateCallback {
1366	ASTContext &Context;
1367	Sema::LookupNameKind LookupKind;
1368	public:
1369	ObjCTypeArgOrProtocolValidatorCCC(ASTContext &context,
1370	Sema::LookupNameKind lookupKind)
1371	: Context(context), LookupKind(lookupKind) { }
1372
1373	bool ValidateCandidate(const TypoCorrection &candidate) override {
1374	// If we're allowed to find protocols and we have a protocol, accept it.
1375	if (LookupKind != Sema::LookupOrdinaryName) {
1376	if (candidate.getCorrectionDeclAs<ObjCProtocolDecl>())
1377	return true;
1378	}
1379
1380	// If we're allowed to find type names and we have one, accept it.
1381	if (LookupKind != Sema::LookupObjCProtocolName) {
1382	// If we have a type declaration, we might accept this result.
1383	if (auto typeDecl = candidate.getCorrectionDeclAs<TypeDecl>()) {
1384	// If we found a tag declaration outside of C++, skip it. This
1385	// can happy because we look for any name when there is no
1386	// bias to protocol or type names.
1387	if (isa<RecordDecl>(Val: typeDecl) && !Context.getLangOpts().CPlusPlus)
1388	return false;
1389
1390	// Make sure the type is something we would accept as a type
1391	// argument.
1392	auto type = Context.getTypeDeclType(Decl: typeDecl);
1393	if (type->isObjCObjectPointerType() ||
1394	type->isBlockPointerType() ||
1395	type->isDependentType() ||
1396	type->isObjCObjectType())
1397	return true;
1398
1399	return false;
1400	}
1401
1402	// If we have an Objective-C class type, accept it; there will
1403	// be another fix to add the '*'.
1404	if (candidate.getCorrectionDeclAs<ObjCInterfaceDecl>())
1405	return true;
1406
1407	return false;
1408	}
1409
1410	return false;
1411	}
1412
1413	std::unique_ptr<CorrectionCandidateCallback> clone() override {
1414	return std::make_unique<ObjCTypeArgOrProtocolValidatorCCC>(args&: *this);
1415	}
1416	};
1417	} // end anonymous namespace
1418
1419	void SemaObjC::DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
1420	SourceLocation ProtocolLoc,
1421	IdentifierInfo *TypeArgId,
1422	SourceLocation TypeArgLoc,
1423	bool SelectProtocolFirst) {
1424	Diag(TypeArgLoc, diag::err_objc_type_args_and_protocols)
1425	<< SelectProtocolFirst << TypeArgId << ProtocolId
1426	<< SourceRange(ProtocolLoc);
1427	}
1428
1429	void SemaObjC::actOnObjCTypeArgsOrProtocolQualifiers(
1430	Scope *S, ParsedType baseType, SourceLocation lAngleLoc,
1431	ArrayRef<IdentifierInfo *> identifiers,
1432	ArrayRef<SourceLocation> identifierLocs, SourceLocation rAngleLoc,
1433	SourceLocation &typeArgsLAngleLoc, SmallVectorImpl<ParsedType> &typeArgs,
1434	SourceLocation &typeArgsRAngleLoc, SourceLocation &protocolLAngleLoc,
1435	SmallVectorImpl<Decl *> &protocols, SourceLocation &protocolRAngleLoc,
1436	bool warnOnIncompleteProtocols) {
1437	ASTContext &Context = getASTContext();
1438	// Local function that updates the declaration specifiers with
1439	// protocol information.
1440	unsigned numProtocolsResolved = 0;
1441	auto resolvedAsProtocols = [&] {
1442	assert(numProtocolsResolved == identifiers.size() && "Unresolved protocols");
1443
1444	// Determine whether the base type is a parameterized class, in
1445	// which case we want to warn about typos such as
1446	// "NSArray<NSObject>" (that should be NSArray<NSObject *>).
1447	ObjCInterfaceDecl *baseClass = nullptr;
1448	QualType base = SemaRef.GetTypeFromParser(Ty: baseType, TInfo: nullptr);
1449	bool allAreTypeNames = false;
1450	SourceLocation firstClassNameLoc;
1451	if (!base.isNull()) {
1452	if (const auto *objcObjectType = base->getAs<ObjCObjectType>()) {
1453	baseClass = objcObjectType->getInterface();
1454	if (baseClass) {
1455	if (auto typeParams = baseClass->getTypeParamList()) {
1456	if (typeParams->size() == numProtocolsResolved) {
1457	// Note that we should be looking for type names, too.
1458	allAreTypeNames = true;
1459	}
1460	}
1461	}
1462	}
1463	}
1464
1465	for (unsigned i = 0, n = protocols.size(); i != n; ++i) {
1466	ObjCProtocolDecl *&proto
1467	= reinterpret_cast<ObjCProtocolDecl *&>(protocols[i]);
1468	// For an objc container, delay protocol reference checking until after we
1469	// can set the objc decl as the availability context, otherwise check now.
1470	if (!warnOnIncompleteProtocols) {
1471	(void)SemaRef.DiagnoseUseOfDecl(proto, identifierLocs[i]);
1472	}
1473
1474	// If this is a forward protocol declaration, get its definition.
1475	if (!proto->isThisDeclarationADefinition() && proto->getDefinition())
1476	proto = proto->getDefinition();
1477
1478	// If this is a forward declaration and we are supposed to warn in this
1479	// case, do it.
1480	// FIXME: Recover nicely in the hidden case.
1481	ObjCProtocolDecl *forwardDecl = nullptr;
1482	if (warnOnIncompleteProtocols &&
1483	NestedProtocolHasNoDefinition(PDecl: proto, UndefinedProtocol&: forwardDecl)) {
1484	Diag(identifierLocs[i], diag::warn_undef_protocolref)
1485	<< proto->getDeclName();
1486	Diag(forwardDecl->getLocation(), diag::note_protocol_decl_undefined)
1487	<< forwardDecl;
1488	}
1489
1490	// If everything this far has been a type name (and we care
1491	// about such things), check whether this name refers to a type
1492	// as well.
1493	if (allAreTypeNames) {
1494	if (auto *decl =
1495	SemaRef.LookupSingleName(S, Name: identifiers[i], Loc: identifierLocs[i],
1496	NameKind: Sema::LookupOrdinaryName)) {
1497	if (isa<ObjCInterfaceDecl>(Val: decl)) {
1498	if (firstClassNameLoc.isInvalid())
1499	firstClassNameLoc = identifierLocs[i];
1500	} else if (!isa<TypeDecl>(Val: decl)) {
1501	// Not a type.
1502	allAreTypeNames = false;
1503	}
1504	} else {
1505	allAreTypeNames = false;
1506	}
1507	}
1508	}
1509
1510	// All of the protocols listed also have type names, and at least
1511	// one is an Objective-C class name. Check whether all of the
1512	// protocol conformances are declared by the base class itself, in
1513	// which case we warn.
1514	if (allAreTypeNames && firstClassNameLoc.isValid()) {
1515	llvm::SmallPtrSet<ObjCProtocolDecl*, 8> knownProtocols;
1516	Context.CollectInheritedProtocols(baseClass, knownProtocols);
1517	bool allProtocolsDeclared = true;
1518	for (auto *proto : protocols) {
1519	if (knownProtocols.count(Ptr: static_cast<ObjCProtocolDecl *>(proto)) == 0) {
1520	allProtocolsDeclared = false;
1521	break;
1522	}
1523	}
1524
1525	if (allProtocolsDeclared) {
1526	Diag(firstClassNameLoc, diag::warn_objc_redundant_qualified_class_type)
1527	<< baseClass->getDeclName() << SourceRange(lAngleLoc, rAngleLoc)
1528	<< FixItHint::CreateInsertion(
1529	SemaRef.getLocForEndOfToken(firstClassNameLoc), " *");
1530	}
1531	}
1532
1533	protocolLAngleLoc = lAngleLoc;
1534	protocolRAngleLoc = rAngleLoc;
1535	assert(protocols.size() == identifierLocs.size());
1536	};
1537
1538	// Attempt to resolve all of the identifiers as protocols.
1539	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1540	ObjCProtocolDecl *proto = LookupProtocol(II: identifiers[i], IdLoc: identifierLocs[i]);
1541	protocols.push_back(proto);
1542	if (proto)
1543	++numProtocolsResolved;
1544	}
1545
1546	// If all of the names were protocols, these were protocol qualifiers.
1547	if (numProtocolsResolved == identifiers.size())
1548	return resolvedAsProtocols();
1549
1550	// Attempt to resolve all of the identifiers as type names or
1551	// Objective-C class names. The latter is technically ill-formed,
1552	// but is probably something like \c NSArray<NSView *> missing the
1553	// \c*.
1554	typedef llvm::PointerUnion<TypeDecl *, ObjCInterfaceDecl *> TypeOrClassDecl;
1555	SmallVector<TypeOrClassDecl, 4> typeDecls;
1556	unsigned numTypeDeclsResolved = 0;
1557	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1558	NamedDecl *decl = SemaRef.LookupSingleName(
1559	S, Name: identifiers[i], Loc: identifierLocs[i], NameKind: Sema::LookupOrdinaryName);
1560	if (!decl) {
1561	typeDecls.push_back(Elt: TypeOrClassDecl());
1562	continue;
1563	}
1564
1565	if (auto typeDecl = dyn_cast<TypeDecl>(Val: decl)) {
1566	typeDecls.push_back(Elt: typeDecl);
1567	++numTypeDeclsResolved;
1568	continue;
1569	}
1570
1571	if (auto objcClass = dyn_cast<ObjCInterfaceDecl>(Val: decl)) {
1572	typeDecls.push_back(Elt: objcClass);
1573	++numTypeDeclsResolved;
1574	continue;
1575	}
1576
1577	typeDecls.push_back(Elt: TypeOrClassDecl());
1578	}
1579
1580	AttributeFactory attrFactory;
1581
1582	// Local function that forms a reference to the given type or
1583	// Objective-C class declaration.
1584	auto resolveTypeReference = [&](TypeOrClassDecl typeDecl, SourceLocation loc)
1585	-> TypeResult {
1586	// Form declaration specifiers. They simply refer to the type.
1587	DeclSpec DS(attrFactory);
1588	const char* prevSpec; // unused
1589	unsigned diagID; // unused
1590	QualType type;
1591	if (auto *actualTypeDecl = dyn_cast<TypeDecl *>(Val&: typeDecl))
1592	type = Context.getTypeDeclType(Decl: actualTypeDecl);
1593	else
1594	type = Context.getObjCInterfaceType(Decl: cast<ObjCInterfaceDecl *>(Val&: typeDecl));
1595	TypeSourceInfo *parsedTSInfo = Context.getTrivialTypeSourceInfo(T: type, Loc: loc);
1596	ParsedType parsedType = SemaRef.CreateParsedType(T: type, TInfo: parsedTSInfo);
1597	DS.SetTypeSpecType(T: DeclSpec::TST_typename, Loc: loc, PrevSpec&: prevSpec, DiagID&: diagID,
1598	Rep: parsedType, Policy: Context.getPrintingPolicy());
1599	// Use the identifier location for the type source range.
1600	DS.SetRangeStart(loc);
1601	DS.SetRangeEnd(loc);
1602
1603	// Form the declarator.
1604	Declarator D(DS, ParsedAttributesView::none(), DeclaratorContext::TypeName);
1605
1606	// If we have a typedef of an Objective-C class type that is missing a '*',
1607	// add the '*'.
1608	if (type->getAs<ObjCInterfaceType>()) {
1609	SourceLocation starLoc = SemaRef.getLocForEndOfToken(Loc: loc);
1610	D.AddTypeInfo(TI: DeclaratorChunk::getPointer(/*TypeQuals=*/0, Loc: starLoc,
1611	ConstQualLoc: SourceLocation(),
1612	VolatileQualLoc: SourceLocation(),
1613	RestrictQualLoc: SourceLocation(),
1614	AtomicQualLoc: SourceLocation(),
1615	UnalignedQualLoc: SourceLocation()),
1616	EndLoc: starLoc);
1617
1618	// Diagnose the missing '*'.
1619	Diag(loc, diag::err_objc_type_arg_missing_star)
1620	<< type
1621	<< FixItHint::CreateInsertion(starLoc, " *");
1622	}
1623
1624	// Convert this to a type.
1625	return SemaRef.ActOnTypeName(D);
1626	};
1627
1628	// Local function that updates the declaration specifiers with
1629	// type argument information.
1630	auto resolvedAsTypeDecls = [&] {
1631	// We did not resolve these as protocols.
1632	protocols.clear();
1633
1634	assert(numTypeDeclsResolved == identifiers.size() && "Unresolved type decl");
1635	// Map type declarations to type arguments.
1636	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1637	// Map type reference to a type.
1638	TypeResult type = resolveTypeReference(typeDecls[i], identifierLocs[i]);
1639	if (!type.isUsable()) {
1640	typeArgs.clear();
1641	return;
1642	}
1643
1644	typeArgs.push_back(Elt: type.get());
1645	}
1646
1647	typeArgsLAngleLoc = lAngleLoc;
1648	typeArgsRAngleLoc = rAngleLoc;
1649	};
1650
1651	// If all of the identifiers can be resolved as type names or
1652	// Objective-C class names, we have type arguments.
1653	if (numTypeDeclsResolved == identifiers.size())
1654	return resolvedAsTypeDecls();
1655
1656	// Error recovery: some names weren't found, or we have a mix of
1657	// type and protocol names. Go resolve all of the unresolved names
1658	// and complain if we can't find a consistent answer.
1659	Sema::LookupNameKind lookupKind = Sema::LookupAnyName;
1660	for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
1661	// If we already have a protocol or type. Check whether it is the
1662	// right thing.
1663	if (protocols[i] || typeDecls[i]) {
1664	// If we haven't figured out whether we want types or protocols
1665	// yet, try to figure it out from this name.
1666	if (lookupKind == Sema::LookupAnyName) {
1667	// If this name refers to both a protocol and a type (e.g., \c
1668	// NSObject), don't conclude anything yet.
1669	if (protocols[i] && typeDecls[i])
1670	continue;
1671
1672	// Otherwise, let this name decide whether we'll be correcting
1673	// toward types or protocols.
1674	lookupKind = protocols[i] ? Sema::LookupObjCProtocolName
1675	: Sema::LookupOrdinaryName;
1676	continue;
1677	}
1678
1679	// If we want protocols and we have a protocol, there's nothing
1680	// more to do.
1681	if (lookupKind == Sema::LookupObjCProtocolName && protocols[i])
1682	continue;
1683
1684	// If we want types and we have a type declaration, there's
1685	// nothing more to do.
1686	if (lookupKind == Sema::LookupOrdinaryName && typeDecls[i])
1687	continue;
1688
1689	// We have a conflict: some names refer to protocols and others
1690	// refer to types.
1691	DiagnoseTypeArgsAndProtocols(ProtocolId: identifiers[0], ProtocolLoc: identifierLocs[0],
1692	TypeArgId: identifiers[i], TypeArgLoc: identifierLocs[i],
1693	SelectProtocolFirst: protocols[i] != nullptr);
1694
1695	protocols.clear();
1696	typeArgs.clear();
1697	return;
1698	}
1699
1700	// Perform typo correction on the name.
1701	ObjCTypeArgOrProtocolValidatorCCC CCC(Context, lookupKind);
1702	TypoCorrection corrected = SemaRef.CorrectTypo(
1703	Typo: DeclarationNameInfo(identifiers[i], identifierLocs[i]), LookupKind: lookupKind, S,
1704	SS: nullptr, CCC, Mode: CorrectTypoKind::ErrorRecovery);
1705	if (corrected) {
1706	// Did we find a protocol?
1707	if (auto proto = corrected.getCorrectionDeclAs<ObjCProtocolDecl>()) {
1708	SemaRef.diagnoseTypo(corrected,
1709	PDiag(diag::err_undeclared_protocol_suggest)
1710	<< identifiers[i]);
1711	lookupKind = Sema::LookupObjCProtocolName;
1712	protocols[i] = proto;
1713	++numProtocolsResolved;
1714	continue;
1715	}
1716
1717	// Did we find a type?
1718	if (auto typeDecl = corrected.getCorrectionDeclAs<TypeDecl>()) {
1719	SemaRef.diagnoseTypo(corrected,
1720	PDiag(diag::err_unknown_typename_suggest)
1721	<< identifiers[i]);
1722	lookupKind = Sema::LookupOrdinaryName;
1723	typeDecls[i] = typeDecl;
1724	++numTypeDeclsResolved;
1725	continue;
1726	}
1727
1728	// Did we find an Objective-C class?
1729	if (auto objcClass = corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
1730	SemaRef.diagnoseTypo(corrected,
1731	PDiag(diag::err_unknown_type_or_class_name_suggest)
1732	<< identifiers[i] << true);
1733	lookupKind = Sema::LookupOrdinaryName;
1734	typeDecls[i] = objcClass;
1735	++numTypeDeclsResolved;
1736	continue;
1737	}
1738	}
1739
1740	// We couldn't find anything.
1741	Diag(identifierLocs[i],
1742	(lookupKind == Sema::LookupAnyName ? diag::err_objc_type_arg_missing
1743	: lookupKind == Sema::LookupObjCProtocolName
1744	? diag::err_undeclared_protocol
1745	: diag::err_unknown_typename))
1746	<< identifiers[i];
1747	protocols.clear();
1748	typeArgs.clear();
1749	return;
1750	}
1751
1752	// If all of the names were (corrected to) protocols, these were
1753	// protocol qualifiers.
1754	if (numProtocolsResolved == identifiers.size())
1755	return resolvedAsProtocols();
1756
1757	// Otherwise, all of the names were (corrected to) types.
1758	assert(numTypeDeclsResolved == identifiers.size() && "Not all types?");
1759	return resolvedAsTypeDecls();
1760	}
1761
1762	/// DiagnoseClassExtensionDupMethods - Check for duplicate declaration of
1763	/// a class method in its extension.
1764	///
1765	void SemaObjC::DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
1766	ObjCInterfaceDecl *ID) {
1767	if (!ID)
1768	return; // Possibly due to previous error
1769
1770	llvm::DenseMap<Selector, const ObjCMethodDecl*> MethodMap;
1771	for (auto *MD : ID->methods())
1772	MethodMap[MD->getSelector()] = MD;
1773
1774	if (MethodMap.empty())
1775	return;
1776	for (const auto *Method : CAT->methods()) {
1777	const ObjCMethodDecl *&PrevMethod = MethodMap[Method->getSelector()];
1778	if (PrevMethod &&
1779	(PrevMethod->isInstanceMethod() == Method->isInstanceMethod()) &&
1780	!MatchTwoMethodDeclarations(Method, PrevMethod)) {
1781	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
1782	<< Method->getDeclName();
1783	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
1784	}
1785	}
1786	}
1787
1788	/// ActOnForwardProtocolDeclaration - Handle \@protocol foo;
1789	SemaObjC::DeclGroupPtrTy SemaObjC::ActOnForwardProtocolDeclaration(
1790	SourceLocation AtProtocolLoc, ArrayRef<IdentifierLoc> IdentList,
1791	const ParsedAttributesView &attrList) {
1792	ASTContext &Context = getASTContext();
1793	SmallVector<Decl *, 8> DeclsInGroup;
1794	for (const IdentifierLoc &IdentPair : IdentList) {
1795	IdentifierInfo *Ident = IdentPair.getIdentifierInfo();
1796	ObjCProtocolDecl *PrevDecl = LookupProtocol(
1797	II: Ident, IdLoc: IdentPair.getLoc(), Redecl: SemaRef.forRedeclarationInCurContext());
1798	ObjCProtocolDecl *PDecl =
1799	ObjCProtocolDecl::Create(C&: Context, DC: SemaRef.CurContext, Id: Ident,
1800	nameLoc: IdentPair.getLoc(), atStartLoc: AtProtocolLoc, PrevDecl);
1801
1802	SemaRef.PushOnScopeChains(PDecl, SemaRef.TUScope);
1803	CheckObjCDeclScope(PDecl);
1804
1805	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, PDecl, attrList);
1806	SemaRef.AddPragmaAttributes(SemaRef.TUScope, PDecl);
1807
1808	if (PrevDecl)
1809	SemaRef.mergeDeclAttributes(PDecl, PrevDecl);
1810
1811	DeclsInGroup.push_back(PDecl);
1812	}
1813
1814	return SemaRef.BuildDeclaratorGroup(Group: DeclsInGroup);
1815	}
1816
1817	ObjCCategoryDecl *SemaObjC::ActOnStartCategoryInterface(
1818	SourceLocation AtInterfaceLoc, const IdentifierInfo *ClassName,
1819	SourceLocation ClassLoc, ObjCTypeParamList *typeParamList,
1820	const IdentifierInfo *CategoryName, SourceLocation CategoryLoc,
1821	Decl *const *ProtoRefs, unsigned NumProtoRefs,
1822	const SourceLocation *ProtoLocs, SourceLocation EndProtoLoc,
1823	const ParsedAttributesView &AttrList) {
1824	ASTContext &Context = getASTContext();
1825	ObjCCategoryDecl *CDecl;
1826	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1827
1828	/// Check that class of this category is already completely declared.
1829
1830	if (!IDecl ||
1831	SemaRef.RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
1832	diag::err_category_forward_interface,
1833	CategoryName == nullptr)) {
1834	// Create an invalid ObjCCategoryDecl to serve as context for
1835	// the enclosing method declarations. We mark the decl invalid
1836	// to make it clear that this isn't a valid AST.
1837	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: SemaRef.CurContext,
1838	AtLoc: AtInterfaceLoc, ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc,
1839	Id: CategoryName, IDecl, typeParamList);
1840	CDecl->setInvalidDecl();
1841	SemaRef.CurContext->addDecl(CDecl);
1842
1843	if (!IDecl)
1844	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1845	ActOnObjCContainerStartDefinition(CDecl);
1846	return CDecl;
1847	}
1848
1849	if (!CategoryName && IDecl->getImplementation()) {
1850	Diag(ClassLoc, diag::err_class_extension_after_impl) << ClassName;
1851	Diag(IDecl->getImplementation()->getLocation(),
1852	diag::note_implementation_declared);
1853	}
1854
1855	if (CategoryName) {
1856	/// Check for duplicate interface declaration for this category
1857	if (ObjCCategoryDecl *Previous
1858	= IDecl->FindCategoryDeclaration(CategoryId: CategoryName)) {
1859	// Class extensions can be declared multiple times, categories cannot.
1860	Diag(CategoryLoc, diag::warn_dup_category_def)
1861	<< ClassName << CategoryName;
1862	Diag(Previous->getLocation(), diag::note_previous_definition);
1863	}
1864	}
1865
1866	// If we have a type parameter list, check it.
1867	if (typeParamList) {
1868	if (auto prevTypeParamList = IDecl->getTypeParamList()) {
1869	if (checkTypeParamListConsistency(
1870	S&: SemaRef, prevTypeParams: prevTypeParamList, newTypeParams: typeParamList,
1871	newContext: CategoryName ? TypeParamListContext::Category
1872	: TypeParamListContext::Extension))
1873	typeParamList = nullptr;
1874	} else {
1875	Diag(typeParamList->getLAngleLoc(),
1876	diag::err_objc_parameterized_category_nonclass)
1877	<< (CategoryName != nullptr)
1878	<< ClassName
1879	<< typeParamList->getSourceRange();
1880
1881	typeParamList = nullptr;
1882	}
1883	}
1884
1885	CDecl = ObjCCategoryDecl::Create(C&: Context, DC: SemaRef.CurContext, AtLoc: AtInterfaceLoc,
1886	ClassNameLoc: ClassLoc, CategoryNameLoc: CategoryLoc, Id: CategoryName, IDecl,
1887	typeParamList);
1888	// FIXME: PushOnScopeChains?
1889	SemaRef.CurContext->addDecl(CDecl);
1890
1891	// Process the attributes before looking at protocols to ensure that the
1892	// availability attribute is attached to the category to provide availability
1893	// checking for protocol uses.
1894	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, CDecl, AttrList);
1895	SemaRef.AddPragmaAttributes(SemaRef.TUScope, CDecl);
1896
1897	if (NumProtoRefs) {
1898	diagnoseUseOfProtocols(SemaRef, CDecl, (ObjCProtocolDecl *const *)ProtoRefs,
1899	NumProtoRefs, ProtoLocs);
1900	CDecl->setProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs, Num: NumProtoRefs,
1901	Locs: ProtoLocs, C&: Context);
1902	// Protocols in the class extension belong to the class.
1903	if (CDecl->IsClassExtension())
1904	IDecl->mergeClassExtensionProtocolList(List: (ObjCProtocolDecl*const*)ProtoRefs,
1905	Num: NumProtoRefs, C&: Context);
1906	}
1907
1908	CheckObjCDeclScope(CDecl);
1909	ActOnObjCContainerStartDefinition(CDecl);
1910	return CDecl;
1911	}
1912
1913	/// ActOnStartCategoryImplementation - Perform semantic checks on the
1914	/// category implementation declaration and build an ObjCCategoryImplDecl
1915	/// object.
1916	ObjCCategoryImplDecl *SemaObjC::ActOnStartCategoryImplementation(
1917	SourceLocation AtCatImplLoc, const IdentifierInfo *ClassName,
1918	SourceLocation ClassLoc, const IdentifierInfo *CatName,
1919	SourceLocation CatLoc, const ParsedAttributesView &Attrs) {
1920	ASTContext &Context = getASTContext();
1921	ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(Id&: ClassName, IdLoc: ClassLoc, TypoCorrection: true);
1922	ObjCCategoryDecl *CatIDecl = nullptr;
1923	if (IDecl && IDecl->hasDefinition()) {
1924	CatIDecl = IDecl->FindCategoryDeclaration(CategoryId: CatName);
1925	if (!CatIDecl) {
1926	// Category @implementation with no corresponding @interface.
1927	// Create and install one.
1928	CatIDecl =
1929	ObjCCategoryDecl::Create(C&: Context, DC: SemaRef.CurContext, AtLoc: AtCatImplLoc,
1930	ClassNameLoc: ClassLoc, CategoryNameLoc: CatLoc, Id: CatName, IDecl,
1931	/*typeParamList=*/nullptr);
1932	CatIDecl->setImplicit();
1933	}
1934	}
1935
1936	ObjCCategoryImplDecl *CDecl =
1937	ObjCCategoryImplDecl::Create(C&: Context, DC: SemaRef.CurContext, Id: CatName, classInterface: IDecl,
1938	nameLoc: ClassLoc, atStartLoc: AtCatImplLoc, CategoryNameLoc: CatLoc);
1939	/// Check that class of this category is already completely declared.
1940	if (!IDecl) {
1941	Diag(ClassLoc, diag::err_undef_interface) << ClassName;
1942	CDecl->setInvalidDecl();
1943	} else if (SemaRef.RequireCompleteType(ClassLoc,
1944	Context.getObjCInterfaceType(IDecl),
1945	diag::err_undef_interface)) {
1946	CDecl->setInvalidDecl();
1947	}
1948
1949	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, CDecl, Attrs);
1950	SemaRef.AddPragmaAttributes(SemaRef.TUScope, CDecl);
1951
1952	// FIXME: PushOnScopeChains?
1953	SemaRef.CurContext->addDecl(CDecl);
1954
1955	// If the interface has the objc_runtime_visible attribute, we
1956	// cannot implement a category for it.
1957	if (IDecl && IDecl->hasAttr<ObjCRuntimeVisibleAttr>()) {
1958	Diag(ClassLoc, diag::err_objc_runtime_visible_category)
1959	<< IDecl->getDeclName();
1960	}
1961
1962	/// Check that CatName, category name, is not used in another implementation.
1963	if (CatIDecl) {
1964	if (CatIDecl->getImplementation()) {
1965	Diag(ClassLoc, diag::err_dup_implementation_category) << ClassName
1966	<< CatName;
1967	Diag(CatIDecl->getImplementation()->getLocation(),
1968	diag::note_previous_definition);
1969	CDecl->setInvalidDecl();
1970	} else {
1971	CatIDecl->setImplementation(CDecl);
1972	// Warn on implementating category of deprecated class under
1973	// -Wdeprecated-implementations flag.
1974	DiagnoseObjCImplementedDeprecations(SemaRef, CatIDecl,
1975	CDecl->getLocation());
1976	}
1977	}
1978
1979	CheckObjCDeclScope(CDecl);
1980	ActOnObjCContainerStartDefinition(CDecl);
1981	return CDecl;
1982	}
1983
1984	ObjCImplementationDecl *SemaObjC::ActOnStartClassImplementation(
1985	SourceLocation AtClassImplLoc, const IdentifierInfo *ClassName,
1986	SourceLocation ClassLoc, const IdentifierInfo *SuperClassname,
1987	SourceLocation SuperClassLoc, const ParsedAttributesView &Attrs) {
1988	ASTContext &Context = getASTContext();
1989	ObjCInterfaceDecl *IDecl = nullptr;
1990	// Check for another declaration kind with the same name.
1991	NamedDecl *PrevDecl = SemaRef.LookupSingleName(
1992	S: SemaRef.TUScope, Name: ClassName, Loc: ClassLoc, NameKind: Sema::LookupOrdinaryName,
1993	Redecl: SemaRef.forRedeclarationInCurContext());
1994	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
1995	Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
1996	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1997	} else if ((IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl))) {
1998	// FIXME: This will produce an error if the definition of the interface has
1999	// been imported from a module but is not visible.
2000	SemaRef.RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
2001	diag::warn_undef_interface);
2002	} else {
2003	// We did not find anything with the name ClassName; try to correct for
2004	// typos in the class name.
2005	ObjCInterfaceValidatorCCC CCC{};
2006	TypoCorrection Corrected = SemaRef.CorrectTypo(
2007	Typo: DeclarationNameInfo(ClassName, ClassLoc), LookupKind: Sema::LookupOrdinaryName,
2008	S: SemaRef.TUScope, SS: nullptr, CCC, Mode: CorrectTypoKind::NonError);
2009	if (Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
2010	// Suggest the (potentially) correct interface name. Don't provide a
2011	// code-modification hint or use the typo name for recovery, because
2012	// this is just a warning. The program may actually be correct.
2013	SemaRef.diagnoseTypo(
2014	Corrected, PDiag(diag::warn_undef_interface_suggest) << ClassName,
2015	/*ErrorRecovery*/ false);
2016	} else {
2017	Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
2018	}
2019	}
2020
2021	// Check that super class name is valid class name
2022	ObjCInterfaceDecl *SDecl = nullptr;
2023	if (SuperClassname) {
2024	// Check if a different kind of symbol declared in this scope.
2025	PrevDecl =
2026	SemaRef.LookupSingleName(S: SemaRef.TUScope, Name: SuperClassname, Loc: SuperClassLoc,
2027	NameKind: Sema::LookupOrdinaryName);
2028	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
2029	Diag(SuperClassLoc, diag::err_redefinition_different_kind)
2030	<< SuperClassname;
2031	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2032	} else {
2033	SDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
2034	if (SDecl && !SDecl->hasDefinition())
2035	SDecl = nullptr;
2036	if (!SDecl)
2037	Diag(SuperClassLoc, diag::err_undef_superclass)
2038	<< SuperClassname << ClassName;
2039	else if (IDecl && !declaresSameEntity(IDecl->getSuperClass(), SDecl)) {
2040	// This implementation and its interface do not have the same
2041	// super class.
2042	Diag(SuperClassLoc, diag::err_conflicting_super_class)
2043	<< SDecl->getDeclName();
2044	Diag(SDecl->getLocation(), diag::note_previous_definition);
2045	}
2046	}
2047	}
2048
2049	if (!IDecl) {
2050	// Legacy case of @implementation with no corresponding @interface.
2051	// Build, chain & install the interface decl into the identifier.
2052
2053	// FIXME: Do we support attributes on the @implementation? If so we should
2054	// copy them over.
2055	IDecl =
2056	ObjCInterfaceDecl::Create(C: Context, DC: SemaRef.CurContext, atLoc: AtClassImplLoc,
2057	Id: ClassName, /*typeParamList=*/nullptr,
2058	/*PrevDecl=*/nullptr, ClassLoc, isInternal: true);
2059	SemaRef.AddPragmaAttributes(SemaRef.TUScope, IDecl);
2060	IDecl->startDefinition();
2061	if (SDecl) {
2062	IDecl->setSuperClass(Context.getTrivialTypeSourceInfo(
2063	T: Context.getObjCInterfaceType(Decl: SDecl),
2064	Loc: SuperClassLoc));
2065	IDecl->setEndOfDefinitionLoc(SuperClassLoc);
2066	} else {
2067	IDecl->setEndOfDefinitionLoc(ClassLoc);
2068	}
2069
2070	SemaRef.PushOnScopeChains(IDecl, SemaRef.TUScope);
2071	} else {
2072	// Mark the interface as being completed, even if it was just as
2073	// @class ....;
2074	// declaration; the user cannot reopen it.
2075	if (!IDecl->hasDefinition())
2076	IDecl->startDefinition();
2077	}
2078
2079	ObjCImplementationDecl *IMPDecl =
2080	ObjCImplementationDecl::Create(C&: Context, DC: SemaRef.CurContext, classInterface: IDecl, superDecl: SDecl,
2081	nameLoc: ClassLoc, atStartLoc: AtClassImplLoc, superLoc: SuperClassLoc);
2082
2083	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, IMPDecl, Attrs);
2084	SemaRef.AddPragmaAttributes(SemaRef.TUScope, IMPDecl);
2085
2086	if (CheckObjCDeclScope(IMPDecl)) {
2087	ActOnObjCContainerStartDefinition(IMPDecl);
2088	return IMPDecl;
2089	}
2090
2091	// Check that there is no duplicate implementation of this class.
2092	if (IDecl->getImplementation()) {
2093	// FIXME: Don't leak everything!
2094	Diag(ClassLoc, diag::err_dup_implementation_class) << ClassName;
2095	Diag(IDecl->getImplementation()->getLocation(),
2096	diag::note_previous_definition);
2097	IMPDecl->setInvalidDecl();
2098	} else { // add it to the list.
2099	IDecl->setImplementation(IMPDecl);
2100	SemaRef.PushOnScopeChains(IMPDecl, SemaRef.TUScope);
2101	// Warn on implementating deprecated class under
2102	// -Wdeprecated-implementations flag.
2103	DiagnoseObjCImplementedDeprecations(SemaRef, IDecl, IMPDecl->getLocation());
2104	}
2105
2106	// If the superclass has the objc_runtime_visible attribute, we
2107	// cannot implement a subclass of it.
2108	if (IDecl->getSuperClass() &&
2109	IDecl->getSuperClass()->hasAttr<ObjCRuntimeVisibleAttr>()) {
2110	Diag(ClassLoc, diag::err_objc_runtime_visible_subclass)
2111	<< IDecl->getDeclName()
2112	<< IDecl->getSuperClass()->getDeclName();
2113	}
2114
2115	ActOnObjCContainerStartDefinition(IMPDecl);
2116	return IMPDecl;
2117	}
2118
2119	SemaObjC::DeclGroupPtrTy
2120	SemaObjC::ActOnFinishObjCImplementation(Decl *ObjCImpDecl,
2121	ArrayRef<Decl *> Decls) {
2122	SmallVector<Decl *, 64> DeclsInGroup;
2123	DeclsInGroup.reserve(N: Decls.size() + 1);
2124
2125	for (unsigned i = 0, e = Decls.size(); i != e; ++i) {
2126	Decl *Dcl = Decls[i];
2127	if (!Dcl)
2128	continue;
2129	if (Dcl->getDeclContext()->isFileContext())
2130	Dcl->setTopLevelDeclInObjCContainer();
2131	DeclsInGroup.push_back(Elt: Dcl);
2132	}
2133
2134	DeclsInGroup.push_back(Elt: ObjCImpDecl);
2135
2136	// Reset the cached layout if there are any ivars added to
2137	// the implementation.
2138	if (auto *ImplD = dyn_cast<ObjCImplementationDecl>(Val: ObjCImpDecl))
2139	if (!ImplD->ivar_empty())
2140	getASTContext().ResetObjCLayout(ImplD->getClassInterface());
2141
2142	return SemaRef.BuildDeclaratorGroup(Group: DeclsInGroup);
2143	}
2144
2145	void SemaObjC::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
2146	ObjCIvarDecl **ivars, unsigned numIvars,
2147	SourceLocation RBrace) {
2148	assert(ImpDecl && "missing implementation decl");
2149	ASTContext &Context = getASTContext();
2150	ObjCInterfaceDecl* IDecl = ImpDecl->getClassInterface();
2151	if (!IDecl)
2152	return;
2153	/// Check case of non-existing \@interface decl.
2154	/// (legacy objective-c \@implementation decl without an \@interface decl).
2155	/// Add implementations's ivar to the synthesize class's ivar list.
2156	if (IDecl->isImplicitInterfaceDecl()) {
2157	IDecl->setEndOfDefinitionLoc(RBrace);
2158	// Add ivar's to class's DeclContext.
2159	for (unsigned i = 0, e = numIvars; i != e; ++i) {
2160	ivars[i]->setLexicalDeclContext(ImpDecl);
2161	// In a 'fragile' runtime the ivar was added to the implicit
2162	// ObjCInterfaceDecl while in a 'non-fragile' runtime the ivar is
2163	// only in the ObjCImplementationDecl. In the non-fragile case the ivar
2164	// therefore also needs to be propagated to the ObjCInterfaceDecl.
2165	if (!getLangOpts().ObjCRuntime.isFragile())
2166	IDecl->makeDeclVisibleInContext(ivars[i]);
2167	ImpDecl->addDecl(ivars[i]);
2168	}
2169
2170	return;
2171	}
2172	// If implementation has empty ivar list, just return.
2173	if (numIvars == 0)
2174	return;
2175
2176	assert(ivars && "missing @implementation ivars");
2177	if (getLangOpts().ObjCRuntime.isNonFragile()) {
2178	if (ImpDecl->getSuperClass())
2179	Diag(ImpDecl->getLocation(), diag::warn_on_superclass_use);
2180	for (unsigned i = 0; i < numIvars; i++) {
2181	ObjCIvarDecl* ImplIvar = ivars[i];
2182	if (const ObjCIvarDecl *ClsIvar =
2183	IDecl->getIvarDecl(Id: ImplIvar->getIdentifier())) {
2184	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2185	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2186	continue;
2187	}
2188	// Check class extensions (unnamed categories) for duplicate ivars.
2189	for (const auto *CDecl : IDecl->visible_extensions()) {
2190	if (const ObjCIvarDecl *ClsExtIvar =
2191	CDecl->getIvarDecl(ImplIvar->getIdentifier())) {
2192	Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration);
2193	Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
2194	continue;
2195	}
2196	}
2197	// Instance ivar to Implementation's DeclContext.
2198	ImplIvar->setLexicalDeclContext(ImpDecl);
2199	IDecl->makeDeclVisibleInContext(ImplIvar);
2200	ImpDecl->addDecl(ImplIvar);
2201	}
2202	return;
2203	}
2204	// Check interface's Ivar list against those in the implementation.
2205	// names and types must match.
2206	//
2207	unsigned j = 0;
2208	ObjCInterfaceDecl::ivar_iterator
2209	IVI = IDecl->ivar_begin(), IVE = IDecl->ivar_end();
2210	for (; numIvars > 0 && IVI != IVE; ++IVI) {
2211	ObjCIvarDecl* ImplIvar = ivars[j++];
2212	ObjCIvarDecl* ClsIvar = *IVI;
2213	assert (ImplIvar && "missing implementation ivar");
2214	assert (ClsIvar && "missing class ivar");
2215
2216	// First, make sure the types match.
2217	if (!Context.hasSameType(ImplIvar->getType(), ClsIvar->getType())) {
2218	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_type)
2219	<< ImplIvar->getIdentifier()
2220	<< ImplIvar->getType() << ClsIvar->getType();
2221	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2222	} else if (ImplIvar->isBitField() && ClsIvar->isBitField() &&
2223	ImplIvar->getBitWidthValue() != ClsIvar->getBitWidthValue()) {
2224	Diag(ImplIvar->getBitWidth()->getBeginLoc(),
2225	diag::err_conflicting_ivar_bitwidth)
2226	<< ImplIvar->getIdentifier();
2227	Diag(ClsIvar->getBitWidth()->getBeginLoc(),
2228	diag::note_previous_definition);
2229	}
2230	// Make sure the names are identical.
2231	if (ImplIvar->getIdentifier() != ClsIvar->getIdentifier()) {
2232	Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_name)
2233	<< ImplIvar->getIdentifier() << ClsIvar->getIdentifier();
2234	Diag(ClsIvar->getLocation(), diag::note_previous_definition);
2235	}
2236	--numIvars;
2237	}
2238
2239	if (numIvars > 0)
2240	Diag(ivars[j]->getLocation(), diag::err_inconsistent_ivar_count);
2241	else if (IVI != IVE)
2242	Diag(IVI->getLocation(), diag::err_inconsistent_ivar_count);
2243	}
2244
2245	static bool shouldWarnUndefinedMethod(const ObjCMethodDecl *M) {
2246	// No point warning no definition of method which is 'unavailable'.
2247	return M->getAvailability() != AR_Unavailable;
2248	}
2249
2250	static void WarnUndefinedMethod(Sema &S, ObjCImplDecl *Impl,
2251	ObjCMethodDecl *method, bool &IncompleteImpl,
2252	unsigned DiagID,
2253	NamedDecl *NeededFor = nullptr) {
2254	if (!shouldWarnUndefinedMethod(M: method))
2255	return;
2256
2257	// FIXME: For now ignore 'IncompleteImpl'.
2258	// Previously we grouped all unimplemented methods under a single
2259	// warning, but some users strongly voiced that they would prefer
2260	// separate warnings. We will give that approach a try, as that
2261	// matches what we do with protocols.
2262	{
2263	const SemaBase::SemaDiagnosticBuilder &B =
2264	S.Diag(Impl->getLocation(), DiagID);
2265	B << method;
2266	if (NeededFor)
2267	B << NeededFor;
2268
2269	// Add an empty definition at the end of the @implementation.
2270	std::string FixItStr;
2271	llvm::raw_string_ostream Out(FixItStr);
2272	method->print(Out, Impl->getASTContext().getPrintingPolicy());
2273	Out << " {\n}\n\n";
2274
2275	SourceLocation Loc = Impl->getAtEndRange().getBegin();
2276	B << FixItHint::CreateInsertion(InsertionLoc: Loc, Code: FixItStr);
2277	}
2278
2279	// Issue a note to the original declaration.
2280	SourceLocation MethodLoc = method->getBeginLoc();
2281	if (MethodLoc.isValid())
2282	S.Diag(MethodLoc, diag::note_method_declared_at) << method;
2283	}
2284
2285	/// Determines if type B can be substituted for type A. Returns true if we can
2286	/// guarantee that anything that the user will do to an object of type A can
2287	/// also be done to an object of type B. This is trivially true if the two
2288	/// types are the same, or if B is a subclass of A. It becomes more complex
2289	/// in cases where protocols are involved.
2290	///
2291	/// Object types in Objective-C describe the minimum requirements for an
2292	/// object, rather than providing a complete description of a type. For
2293	/// example, if A is a subclass of B, then B* may refer to an instance of A.
2294	/// The principle of substitutability means that we may use an instance of A
2295	/// anywhere that we may use an instance of B - it will implement all of the
2296	/// ivars of B and all of the methods of B.
2297	///
2298	/// This substitutability is important when type checking methods, because
2299	/// the implementation may have stricter type definitions than the interface.
2300	/// The interface specifies minimum requirements, but the implementation may
2301	/// have more accurate ones. For example, a method may privately accept
2302	/// instances of B, but only publish that it accepts instances of A. Any
2303	/// object passed to it will be type checked against B, and so will implicitly
2304	/// by a valid A*. Similarly, a method may return a subclass of the class that
2305	/// it is declared as returning.
2306	///
2307	/// This is most important when considering subclassing. A method in a
2308	/// subclass must accept any object as an argument that its superclass's
2309	/// implementation accepts. It may, however, accept a more general type
2310	/// without breaking substitutability (i.e. you can still use the subclass
2311	/// anywhere that you can use the superclass, but not vice versa). The
2312	/// converse requirement applies to return types: the return type for a
2313	/// subclass method must be a valid object of the kind that the superclass
2314	/// advertises, but it may be specified more accurately. This avoids the need
2315	/// for explicit down-casting by callers.
2316	///
2317	/// Note: This is a stricter requirement than for assignment.
2318	static bool isObjCTypeSubstitutable(ASTContext &Context,
2319	const ObjCObjectPointerType *A,
2320	const ObjCObjectPointerType *B,
2321	bool rejectId) {
2322	// Reject a protocol-unqualified id.
2323	if (rejectId && B->isObjCIdType()) return false;
2324
2325	// If B is a qualified id, then A must also be a qualified id and it must
2326	// implement all of the protocols in B. It may not be a qualified class.
2327	// For example, MyClass<A> can be assigned to id<A>, but MyClass<A> is a
2328	// stricter definition so it is not substitutable for id<A>.
2329	if (B->isObjCQualifiedIdType()) {
2330	return A->isObjCQualifiedIdType() &&
2331	Context.ObjCQualifiedIdTypesAreCompatible(LHS: A, RHS: B, ForCompare: false);
2332	}
2333
2334	/*
2335	// id is a special type that bypasses type checking completely. We want a
2336	// warning when it is used in one place but not another.
2337	if (C.isObjCIdType(A) || C.isObjCIdType(B)) return false;
2338
2339
2340	// If B is a qualified id, then A must also be a qualified id (which it isn't
2341	// if we've got this far)
2342	if (B->isObjCQualifiedIdType()) return false;
2343	*/
2344
2345	// Now we know that A and B are (potentially-qualified) class types. The
2346	// normal rules for assignment apply.
2347	return Context.canAssignObjCInterfaces(LHSOPT: A, RHSOPT: B);
2348	}
2349
2350	static SourceRange getTypeRange(TypeSourceInfo *TSI) {
2351	return (TSI ? TSI->getTypeLoc().getSourceRange() : SourceRange());
2352	}
2353
2354	/// Determine whether two set of Objective-C declaration qualifiers conflict.
2355	static bool objcModifiersConflict(Decl::ObjCDeclQualifier x,
2356	Decl::ObjCDeclQualifier y) {
2357	return (x & ~Decl::OBJC_TQ_CSNullability) !=
2358	(y & ~Decl::OBJC_TQ_CSNullability);
2359	}
2360
2361	static bool CheckMethodOverrideReturn(Sema &S,
2362	ObjCMethodDecl *MethodImpl,
2363	ObjCMethodDecl *MethodDecl,
2364	bool IsProtocolMethodDecl,
2365	bool IsOverridingMode,
2366	bool Warn) {
2367	if (IsProtocolMethodDecl &&
2368	objcModifiersConflict(x: MethodDecl->getObjCDeclQualifier(),
2369	y: MethodImpl->getObjCDeclQualifier())) {
2370	if (Warn) {
2371	S.Diag(MethodImpl->getLocation(),
2372	(IsOverridingMode
2373	? diag::warn_conflicting_overriding_ret_type_modifiers
2374	: diag::warn_conflicting_ret_type_modifiers))
2375	<< MethodImpl->getDeclName()
2376	<< MethodImpl->getReturnTypeSourceRange();
2377	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration)
2378	<< MethodDecl->getReturnTypeSourceRange();
2379	}
2380	else
2381	return false;
2382	}
2383	if (Warn && IsOverridingMode &&
2384	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2385	!S.Context.hasSameNullabilityTypeQualifier(SubT: MethodImpl->getReturnType(),
2386	SuperT: MethodDecl->getReturnType(),
2387	IsParam: false)) {
2388	auto nullabilityMethodImpl = *MethodImpl->getReturnType()->getNullability();
2389	auto nullabilityMethodDecl = *MethodDecl->getReturnType()->getNullability();
2390	S.Diag(MethodImpl->getLocation(),
2391	diag::warn_conflicting_nullability_attr_overriding_ret_types)
2392	<< DiagNullabilityKind(nullabilityMethodImpl,
2393	((MethodImpl->getObjCDeclQualifier() &
2394	Decl::OBJC_TQ_CSNullability) != 0))
2395	<< DiagNullabilityKind(nullabilityMethodDecl,
2396	((MethodDecl->getObjCDeclQualifier() &
2397	Decl::OBJC_TQ_CSNullability) != 0));
2398	S.Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2399	}
2400
2401	if (S.Context.hasSameUnqualifiedType(T1: MethodImpl->getReturnType(),
2402	T2: MethodDecl->getReturnType()))
2403	return true;
2404	if (!Warn)
2405	return false;
2406
2407	unsigned DiagID =
2408	IsOverridingMode ? diag::warn_conflicting_overriding_ret_types
2409	: diag::warn_conflicting_ret_types;
2410
2411	// Mismatches between ObjC pointers go into a different warning
2412	// category, and sometimes they're even completely explicitly allowed.
2413	if (const ObjCObjectPointerType *ImplPtrTy =
2414	MethodImpl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2415	if (const ObjCObjectPointerType *IfacePtrTy =
2416	MethodDecl->getReturnType()->getAs<ObjCObjectPointerType>()) {
2417	// Allow non-matching return types as long as they don't violate
2418	// the principle of substitutability. Specifically, we permit
2419	// return types that are subclasses of the declared return type,
2420	// or that are more-qualified versions of the declared type.
2421	if (isObjCTypeSubstitutable(Context&: S.Context, A: IfacePtrTy, B: ImplPtrTy, rejectId: false))
2422	return false;
2423
2424	DiagID =
2425	IsOverridingMode ? diag::warn_non_covariant_overriding_ret_types
2426	: diag::warn_non_covariant_ret_types;
2427	}
2428	}
2429
2430	S.Diag(MethodImpl->getLocation(), DiagID)
2431	<< MethodImpl->getDeclName() << MethodDecl->getReturnType()
2432	<< MethodImpl->getReturnType()
2433	<< MethodImpl->getReturnTypeSourceRange();
2434	S.Diag(MethodDecl->getLocation(), IsOverridingMode
2435	? diag::note_previous_declaration
2436	: diag::note_previous_definition)
2437	<< MethodDecl->getReturnTypeSourceRange();
2438	return false;
2439	}
2440
2441	static bool CheckMethodOverrideParam(Sema &S,
2442	ObjCMethodDecl *MethodImpl,
2443	ObjCMethodDecl *MethodDecl,
2444	ParmVarDecl *ImplVar,
2445	ParmVarDecl *IfaceVar,
2446	bool IsProtocolMethodDecl,
2447	bool IsOverridingMode,
2448	bool Warn) {
2449	if (IsProtocolMethodDecl &&
2450	objcModifiersConflict(x: ImplVar->getObjCDeclQualifier(),
2451	y: IfaceVar->getObjCDeclQualifier())) {
2452	if (Warn) {
2453	if (IsOverridingMode)
2454	S.Diag(ImplVar->getLocation(),
2455	diag::warn_conflicting_overriding_param_modifiers)
2456	<< getTypeRange(ImplVar->getTypeSourceInfo())
2457	<< MethodImpl->getDeclName();
2458	else S.Diag(ImplVar->getLocation(),
2459	diag::warn_conflicting_param_modifiers)
2460	<< getTypeRange(ImplVar->getTypeSourceInfo())
2461	<< MethodImpl->getDeclName();
2462	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration)
2463	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2464	}
2465	else
2466	return false;
2467	}
2468
2469	QualType ImplTy = ImplVar->getType();
2470	QualType IfaceTy = IfaceVar->getType();
2471	if (Warn && IsOverridingMode &&
2472	!isa<ObjCImplementationDecl>(MethodImpl->getDeclContext()) &&
2473	!S.Context.hasSameNullabilityTypeQualifier(SubT: ImplTy, SuperT: IfaceTy, IsParam: true)) {
2474	S.Diag(ImplVar->getLocation(),
2475	diag::warn_conflicting_nullability_attr_overriding_param_types)
2476	<< DiagNullabilityKind(*ImplTy->getNullability(),
2477	((ImplVar->getObjCDeclQualifier() &
2478	Decl::OBJC_TQ_CSNullability) != 0))
2479	<< DiagNullabilityKind(*IfaceTy->getNullability(),
2480	((IfaceVar->getObjCDeclQualifier() &
2481	Decl::OBJC_TQ_CSNullability) != 0));
2482	S.Diag(IfaceVar->getLocation(), diag::note_previous_declaration);
2483	}
2484	if (S.Context.hasSameUnqualifiedType(T1: ImplTy, T2: IfaceTy))
2485	return true;
2486
2487	if (!Warn)
2488	return false;
2489	unsigned DiagID =
2490	IsOverridingMode ? diag::warn_conflicting_overriding_param_types
2491	: diag::warn_conflicting_param_types;
2492
2493	// Mismatches between ObjC pointers go into a different warning
2494	// category, and sometimes they're even completely explicitly allowed..
2495	if (const ObjCObjectPointerType *ImplPtrTy =
2496	ImplTy->getAs<ObjCObjectPointerType>()) {
2497	if (const ObjCObjectPointerType *IfacePtrTy =
2498	IfaceTy->getAs<ObjCObjectPointerType>()) {
2499	// Allow non-matching argument types as long as they don't
2500	// violate the principle of substitutability. Specifically, the
2501	// implementation must accept any objects that the superclass
2502	// accepts, however it may also accept others.
2503	if (isObjCTypeSubstitutable(Context&: S.Context, A: ImplPtrTy, B: IfacePtrTy, rejectId: true))
2504	return false;
2505
2506	DiagID =
2507	IsOverridingMode ? diag::warn_non_contravariant_overriding_param_types
2508	: diag::warn_non_contravariant_param_types;
2509	}
2510	}
2511
2512	S.Diag(ImplVar->getLocation(), DiagID)
2513	<< getTypeRange(ImplVar->getTypeSourceInfo())
2514	<< MethodImpl->getDeclName() << IfaceTy << ImplTy;
2515	S.Diag(IfaceVar->getLocation(),
2516	(IsOverridingMode ? diag::note_previous_declaration
2517	: diag::note_previous_definition))
2518	<< getTypeRange(IfaceVar->getTypeSourceInfo());
2519	return false;
2520	}
2521
2522	/// In ARC, check whether the conventional meanings of the two methods
2523	/// match. If they don't, it's a hard error.
2524	static bool checkMethodFamilyMismatch(Sema &S, ObjCMethodDecl *impl,
2525	ObjCMethodDecl *decl) {
2526	ObjCMethodFamily implFamily = impl->getMethodFamily();
2527	ObjCMethodFamily declFamily = decl->getMethodFamily();
2528	if (implFamily == declFamily) return false;
2529
2530	// Since conventions are sorted by selector, the only possibility is
2531	// that the types differ enough to cause one selector or the other
2532	// to fall out of the family.
2533	assert(implFamily == OMF_None || declFamily == OMF_None);
2534
2535	// No further diagnostics required on invalid declarations.
2536	if (impl->isInvalidDecl() || decl->isInvalidDecl()) return true;
2537
2538	const ObjCMethodDecl *unmatched = impl;
2539	ObjCMethodFamily family = declFamily;
2540	unsigned errorID = diag::err_arc_lost_method_convention;
2541	unsigned noteID = diag::note_arc_lost_method_convention;
2542	if (declFamily == OMF_None) {
2543	unmatched = decl;
2544	family = implFamily;
2545	errorID = diag::err_arc_gained_method_convention;
2546	noteID = diag::note_arc_gained_method_convention;
2547	}
2548
2549	// Indexes into a %select clause in the diagnostic.
2550	enum FamilySelector {
2551	F_alloc, F_copy, F_mutableCopy = F_copy, F_init, F_new
2552	};
2553	FamilySelector familySelector = FamilySelector();
2554
2555	switch (family) {
2556	case OMF_None: llvm_unreachable("logic error, no method convention");
2557	case OMF_retain:
2558	case OMF_release:
2559	case OMF_autorelease:
2560	case OMF_dealloc:
2561	case OMF_finalize:
2562	case OMF_retainCount:
2563	case OMF_self:
2564	case OMF_initialize:
2565	case OMF_performSelector:
2566	// Mismatches for these methods don't change ownership
2567	// conventions, so we don't care.
2568	return false;
2569
2570	case OMF_init: familySelector = F_init; break;
2571	case OMF_alloc: familySelector = F_alloc; break;
2572	case OMF_copy: familySelector = F_copy; break;
2573	case OMF_mutableCopy: familySelector = F_mutableCopy; break;
2574	case OMF_new: familySelector = F_new; break;
2575	}
2576
2577	enum ReasonSelector { R_NonObjectReturn, R_UnrelatedReturn };
2578	ReasonSelector reasonSelector;
2579
2580	// The only reason these methods don't fall within their families is
2581	// due to unusual result types.
2582	if (unmatched->getReturnType()->isObjCObjectPointerType()) {
2583	reasonSelector = R_UnrelatedReturn;
2584	} else {
2585	reasonSelector = R_NonObjectReturn;
2586	}
2587
2588	S.Diag(impl->getLocation(), errorID) << int(familySelector) << int(reasonSelector);
2589	S.Diag(decl->getLocation(), noteID) << int(familySelector) << int(reasonSelector);
2590
2591	return true;
2592	}
2593
2594	void SemaObjC::WarnConflictingTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2595	ObjCMethodDecl *MethodDecl,
2596	bool IsProtocolMethodDecl) {
2597	if (getLangOpts().ObjCAutoRefCount &&
2598	checkMethodFamilyMismatch(S&: SemaRef, impl: ImpMethodDecl, decl: MethodDecl))
2599	return;
2600
2601	CheckMethodOverrideReturn(S&: SemaRef, MethodImpl: ImpMethodDecl, MethodDecl,
2602	IsProtocolMethodDecl, IsOverridingMode: false, Warn: true);
2603
2604	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2605	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2606	EF = MethodDecl->param_end();
2607	IM != EM && IF != EF; ++IM, ++IF) {
2608	CheckMethodOverrideParam(S&: SemaRef, MethodImpl: ImpMethodDecl, MethodDecl, ImplVar: *IM, IfaceVar: *IF,
2609	IsProtocolMethodDecl, IsOverridingMode: false, Warn: true);
2610	}
2611
2612	if (ImpMethodDecl->isVariadic() != MethodDecl->isVariadic()) {
2613	Diag(ImpMethodDecl->getLocation(),
2614	diag::warn_conflicting_variadic);
2615	Diag(MethodDecl->getLocation(), diag::note_previous_declaration);
2616	}
2617	}
2618
2619	void SemaObjC::CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
2620	ObjCMethodDecl *Overridden,
2621	bool IsProtocolMethodDecl) {
2622
2623	CheckMethodOverrideReturn(S&: SemaRef, MethodImpl: Method, MethodDecl: Overridden, IsProtocolMethodDecl,
2624	IsOverridingMode: true, Warn: true);
2625
2626	for (ObjCMethodDecl::param_iterator IM = Method->param_begin(),
2627	IF = Overridden->param_begin(), EM = Method->param_end(),
2628	EF = Overridden->param_end();
2629	IM != EM && IF != EF; ++IM, ++IF) {
2630	CheckMethodOverrideParam(S&: SemaRef, MethodImpl: Method, MethodDecl: Overridden, ImplVar: *IM, IfaceVar: *IF,
2631	IsProtocolMethodDecl, IsOverridingMode: true, Warn: true);
2632	}
2633
2634	if (Method->isVariadic() != Overridden->isVariadic()) {
2635	Diag(Method->getLocation(),
2636	diag::warn_conflicting_overriding_variadic);
2637	Diag(Overridden->getLocation(), diag::note_previous_declaration);
2638	}
2639	}
2640
2641	/// WarnExactTypedMethods - This routine issues a warning if method
2642	/// implementation declaration matches exactly that of its declaration.
2643	void SemaObjC::WarnExactTypedMethods(ObjCMethodDecl *ImpMethodDecl,
2644	ObjCMethodDecl *MethodDecl,
2645	bool IsProtocolMethodDecl) {
2646	ASTContext &Context = getASTContext();
2647	// don't issue warning when protocol method is optional because primary
2648	// class is not required to implement it and it is safe for protocol
2649	// to implement it.
2650	if (MethodDecl->getImplementationControl() ==
2651	ObjCImplementationControl::Optional)
2652	return;
2653	// don't issue warning when primary class's method is
2654	// deprecated/unavailable.
2655	if (MethodDecl->hasAttr<UnavailableAttr>() ||
2656	MethodDecl->hasAttr<DeprecatedAttr>())
2657	return;
2658
2659	bool match = CheckMethodOverrideReturn(S&: SemaRef, MethodImpl: ImpMethodDecl, MethodDecl,
2660	IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2661	if (match)
2662	for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
2663	IF = MethodDecl->param_begin(), EM = ImpMethodDecl->param_end(),
2664	EF = MethodDecl->param_end();
2665	IM != EM && IF != EF; ++IM, ++IF) {
2666	match = CheckMethodOverrideParam(S&: SemaRef, MethodImpl: ImpMethodDecl, MethodDecl, ImplVar: *IM,
2667	IfaceVar: *IF, IsProtocolMethodDecl, IsOverridingMode: false, Warn: false);
2668	if (!match)
2669	break;
2670	}
2671	if (match)
2672	match = (ImpMethodDecl->isVariadic() == MethodDecl->isVariadic());
2673	if (match)
2674	match = !(MethodDecl->isClassMethod() &&
2675	MethodDecl->getSelector() == GetNullarySelector(name: "load", Ctx&: Context));
2676
2677	if (match) {
2678	Diag(ImpMethodDecl->getLocation(),
2679	diag::warn_category_method_impl_match);
2680	Diag(MethodDecl->getLocation(), diag::note_method_declared_at)
2681	<< MethodDecl->getDeclName();
2682	}
2683	}
2684
2685	/// FIXME: Type hierarchies in Objective-C can be deep. We could most likely
2686	/// improve the efficiency of selector lookups and type checking by associating
2687	/// with each protocol / interface / category the flattened instance tables. If
2688	/// we used an immutable set to keep the table then it wouldn't add significant
2689	/// memory cost and it would be handy for lookups.
2690
2691	typedef llvm::DenseSet<IdentifierInfo*> ProtocolNameSet;
2692	typedef std::unique_ptr<ProtocolNameSet> LazyProtocolNameSet;
2693
2694	static void findProtocolsWithExplicitImpls(const ObjCProtocolDecl *PDecl,
2695	ProtocolNameSet &PNS) {
2696	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2697	PNS.insert(PDecl->getIdentifier());
2698	for (const auto *PI : PDecl->protocols())
2699	findProtocolsWithExplicitImpls(PDecl: PI, PNS);
2700	}
2701
2702	/// Recursively populates a set with all conformed protocols in a class
2703	/// hierarchy that have the 'objc_protocol_requires_explicit_implementation'
2704	/// attribute.
2705	static void findProtocolsWithExplicitImpls(const ObjCInterfaceDecl *Super,
2706	ProtocolNameSet &PNS) {
2707	if (!Super)
2708	return;
2709
2710	for (const auto *I : Super->all_referenced_protocols())
2711	findProtocolsWithExplicitImpls(PDecl: I, PNS);
2712
2713	findProtocolsWithExplicitImpls(Super: Super->getSuperClass(), PNS);
2714	}
2715
2716	/// CheckProtocolMethodDefs - This routine checks unimplemented methods
2717	/// Declared in protocol, and those referenced by it.
2718	static void CheckProtocolMethodDefs(
2719	Sema &S, ObjCImplDecl *Impl, ObjCProtocolDecl *PDecl, bool &IncompleteImpl,
2720	const SemaObjC::SelectorSet &InsMap, const SemaObjC::SelectorSet &ClsMap,
2721	ObjCContainerDecl *CDecl, LazyProtocolNameSet &ProtocolsExplictImpl) {
2722	ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: CDecl);
2723	ObjCInterfaceDecl *IDecl = C ? C->getClassInterface()
2724	: dyn_cast<ObjCInterfaceDecl>(Val: CDecl);
2725	assert (IDecl && "CheckProtocolMethodDefs - IDecl is null");
2726
2727	ObjCInterfaceDecl *Super = IDecl->getSuperClass();
2728	ObjCInterfaceDecl *NSIDecl = nullptr;
2729
2730	// If this protocol is marked 'objc_protocol_requires_explicit_implementation'
2731	// then we should check if any class in the super class hierarchy also
2732	// conforms to this protocol, either directly or via protocol inheritance.
2733	// If so, we can skip checking this protocol completely because we
2734	// know that a parent class already satisfies this protocol.
2735	//
2736	// Note: we could generalize this logic for all protocols, and merely
2737	// add the limit on looking at the super class chain for just
2738	// specially marked protocols. This may be a good optimization. This
2739	// change is restricted to 'objc_protocol_requires_explicit_implementation'
2740	// protocols for now for controlled evaluation.
2741	if (PDecl->hasAttr<ObjCExplicitProtocolImplAttr>()) {
2742	if (!ProtocolsExplictImpl) {
2743	ProtocolsExplictImpl.reset(p: new ProtocolNameSet);
2744	findProtocolsWithExplicitImpls(Super, PNS&: *ProtocolsExplictImpl);
2745	}
2746	if (ProtocolsExplictImpl->contains(V: PDecl->getIdentifier()))
2747	return;
2748
2749	// If no super class conforms to the protocol, we should not search
2750	// for methods in the super class to implicitly satisfy the protocol.
2751	Super = nullptr;
2752	}
2753
2754	if (S.getLangOpts().ObjCRuntime.isNeXTFamily()) {
2755	// check to see if class implements forwardInvocation method and objects
2756	// of this class are derived from 'NSProxy' so that to forward requests
2757	// from one object to another.
2758	// Under such conditions, which means that every method possible is
2759	// implemented in the class, we should not issue "Method definition not
2760	// found" warnings.
2761	// FIXME: Use a general GetUnarySelector method for this.
2762	const IdentifierInfo *II = &S.Context.Idents.get(Name: "forwardInvocation");
2763	Selector fISelector = S.Context.Selectors.getSelector(NumArgs: 1, IIV: &II);
2764	if (InsMap.count(Ptr: fISelector))
2765	// Is IDecl derived from 'NSProxy'? If so, no instance methods
2766	// need be implemented in the implementation.
2767	NSIDecl = IDecl->lookupInheritedClass(ICName: &S.Context.Idents.get(Name: "NSProxy"));
2768	}
2769
2770	// If this is a forward protocol declaration, get its definition.
2771	if (!PDecl->isThisDeclarationADefinition() &&
2772	PDecl->getDefinition())
2773	PDecl = PDecl->getDefinition();
2774
2775	// If a method lookup fails locally we still need to look and see if
2776	// the method was implemented by a base class or an inherited
2777	// protocol. This lookup is slow, but occurs rarely in correct code
2778	// and otherwise would terminate in a warning.
2779
2780	// check unimplemented instance methods.
2781	if (!NSIDecl)
2782	for (auto *method : PDecl->instance_methods()) {
2783	if (method->getImplementationControl() !=
2784	ObjCImplementationControl::Optional &&
2785	!method->isPropertyAccessor() &&
2786	!InsMap.count(method->getSelector()) &&
2787	(!Super || !Super->lookupMethod(
2788	method->getSelector(), true /* instance */,
2789	false /* shallowCategory */, true /* followsSuper */,
2790	nullptr /* category */))) {
2791	// If a method is not implemented in the category implementation but
2792	// has been declared in its primary class, superclass,
2793	// or in one of their protocols, no need to issue the warning.
2794	// This is because method will be implemented in the primary class
2795	// or one of its super class implementation.
2796
2797	// Ugly, but necessary. Method declared in protocol might have
2798	// have been synthesized due to a property declared in the class which
2799	// uses the protocol.
2800	if (ObjCMethodDecl *MethodInClass = IDecl->lookupMethod(
2801	method->getSelector(), true /* instance */,
2802	true /* shallowCategoryLookup */, false /* followSuper */))
2803	if (C || MethodInClass->isPropertyAccessor())
2804	continue;
2805	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2806	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2807	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2808	}
2809	}
2810	}
2811	// check unimplemented class methods
2812	for (auto *method : PDecl->class_methods()) {
2813	if (method->getImplementationControl() !=
2814	ObjCImplementationControl::Optional &&
2815	!ClsMap.count(method->getSelector()) &&
2816	(!Super || !Super->lookupMethod(
2817	method->getSelector(), false /* class method */,
2818	false /* shallowCategoryLookup */,
2819	true /* followSuper */, nullptr /* category */))) {
2820	// See above comment for instance method lookups.
2821	if (C && IDecl->lookupMethod(method->getSelector(),
2822	false /* class */,
2823	true /* shallowCategoryLookup */,
2824	false /* followSuper */))
2825	continue;
2826
2827	unsigned DIAG = diag::warn_unimplemented_protocol_method;
2828	if (!S.Diags.isIgnored(DIAG, Impl->getLocation())) {
2829	WarnUndefinedMethod(S, Impl, method, IncompleteImpl, DIAG, PDecl);
2830	}
2831	}
2832	}
2833	// Check on this protocols's referenced protocols, recursively.
2834	for (auto *PI : PDecl->protocols())
2835	CheckProtocolMethodDefs(S, Impl, PDecl: PI, IncompleteImpl, InsMap, ClsMap, CDecl,
2836	ProtocolsExplictImpl);
2837	}
2838
2839	/// MatchAllMethodDeclarations - Check methods declared in interface
2840	/// or protocol against those declared in their implementations.
2841	///
2842	void SemaObjC::MatchAllMethodDeclarations(
2843	const SelectorSet &InsMap, const SelectorSet &ClsMap,
2844	SelectorSet &InsMapSeen, SelectorSet &ClsMapSeen, ObjCImplDecl *IMPDecl,
2845	ObjCContainerDecl *CDecl, bool &IncompleteImpl, 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(SemaRef, 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(SemaRef, 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 SemaObjC::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 SemaObjC::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 = getLangOpts().ObjCDefaultSynthProperties &&
3018	getLangOpts().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(SemaRef, 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&: SemaRef, 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	SemaObjC::DeclGroupPtrTy SemaObjC::ActOnForwardClassDeclaration(
3069	SourceLocation AtClassLoc, IdentifierInfo **IdentList,
3070	SourceLocation *IdentLocs, ArrayRef<ObjCTypeParamList *> TypeParamLists,
3071	unsigned NumElts) {
3072	ASTContext &Context = getASTContext();
3073	SmallVector<Decl *, 8> DeclsInGroup;
3074	for (unsigned i = 0; i != NumElts; ++i) {
3075	// Check for another declaration kind with the same name.
3076	NamedDecl *PrevDecl = SemaRef.LookupSingleName(
3077	S: SemaRef.TUScope, Name: IdentList[i], Loc: IdentLocs[i], NameKind: Sema::LookupOrdinaryName,
3078	Redecl: SemaRef.forRedeclarationInCurContext());
3079	if (PrevDecl && !isa<ObjCInterfaceDecl>(Val: PrevDecl)) {
3080	// GCC apparently allows the following idiom:
3081	//
3082	// typedef NSObject < XCElementTogglerP > XCElementToggler;
3083	// @class XCElementToggler;
3084	//
3085	// Here we have chosen to ignore the forward class declaration
3086	// with a warning. Since this is the implied behavior.
3087	TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(Val: PrevDecl);
3088	if (!TDD || !TDD->getUnderlyingType()->isObjCObjectType()) {
3089	Diag(AtClassLoc, diag::err_redefinition_different_kind) << IdentList[i];
3090	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3091	} else {
3092	// a forward class declaration matching a typedef name of a class refers
3093	// to the underlying class. Just ignore the forward class with a warning
3094	// as this will force the intended behavior which is to lookup the
3095	// typedef name.
3096	if (isa<ObjCObjectType>(Val: TDD->getUnderlyingType())) {
3097	Diag(AtClassLoc, diag::warn_forward_class_redefinition)
3098	<< IdentList[i];
3099	Diag(PrevDecl->getLocation(), diag::note_previous_definition);
3100	continue;
3101	}
3102	}
3103	}
3104
3105	// Create a declaration to describe this forward declaration.
3106	ObjCInterfaceDecl *PrevIDecl
3107	= dyn_cast_or_null<ObjCInterfaceDecl>(Val: PrevDecl);
3108
3109	IdentifierInfo *ClassName = IdentList[i];
3110	if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
3111	// A previous decl with a different name is because of
3112	// @compatibility_alias, for example:
3113	// \code
3114	// @class NewImage;
3115	// @compatibility_alias OldImage NewImage;
3116	// \endcode
3117	// A lookup for 'OldImage' will return the 'NewImage' decl.
3118	//
3119	// In such a case use the real declaration name, instead of the alias one,
3120	// otherwise we will break IdentifierResolver and redecls-chain invariants.
3121	// FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
3122	// has been aliased.
3123	ClassName = PrevIDecl->getIdentifier();
3124	}
3125
3126	// If this forward declaration has type parameters, compare them with the
3127	// type parameters of the previous declaration.
3128	ObjCTypeParamList *TypeParams = TypeParamLists[i];
3129	if (PrevIDecl && TypeParams) {
3130	if (ObjCTypeParamList *PrevTypeParams = PrevIDecl->getTypeParamList()) {
3131	// Check for consistency with the previous declaration.
3132	if (checkTypeParamListConsistency(
3133	S&: SemaRef, prevTypeParams: PrevTypeParams, newTypeParams: TypeParams,
3134	newContext: TypeParamListContext::ForwardDeclaration)) {
3135	TypeParams = nullptr;
3136	}
3137	} else if (ObjCInterfaceDecl *Def = PrevIDecl->getDefinition()) {
3138	// The @interface does not have type parameters. Complain.
3139	Diag(IdentLocs[i], diag::err_objc_parameterized_forward_class)
3140	<< ClassName
3141	<< TypeParams->getSourceRange();
3142	Diag(Def->getLocation(), diag::note_defined_here)
3143	<< ClassName;
3144
3145	TypeParams = nullptr;
3146	}
3147	}
3148
3149	ObjCInterfaceDecl *IDecl = ObjCInterfaceDecl::Create(
3150	C: Context, DC: SemaRef.CurContext, atLoc: AtClassLoc, Id: ClassName, typeParamList: TypeParams,
3151	PrevDecl: PrevIDecl, ClassLoc: IdentLocs[i]);
3152	IDecl->setAtEndRange(IdentLocs[i]);
3153
3154	if (PrevIDecl)
3155	SemaRef.mergeDeclAttributes(IDecl, PrevIDecl);
3156
3157	SemaRef.PushOnScopeChains(IDecl, SemaRef.TUScope);
3158	CheckObjCDeclScope(IDecl);
3159	DeclsInGroup.push_back(IDecl);
3160	}
3161
3162	return SemaRef.BuildDeclaratorGroup(Group: DeclsInGroup);
3163	}
3164
3165	static bool tryMatchRecordTypes(ASTContext &Context,
3166	SemaObjC::MethodMatchStrategy strategy,
3167	const Type *left, const Type *right);
3168
3169	static bool matchTypes(ASTContext &Context,
3170	SemaObjC::MethodMatchStrategy strategy, QualType leftQT,
3171	QualType rightQT) {
3172	const Type *left =
3173	Context.getCanonicalType(T: leftQT).getUnqualifiedType().getTypePtr();
3174	const Type *right =
3175	Context.getCanonicalType(T: rightQT).getUnqualifiedType().getTypePtr();
3176
3177	if (left == right) return true;
3178
3179	// If we're doing a strict match, the types have to match exactly.
3180	if (strategy == SemaObjC::MMS_strict)
3181	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	SemaObjC::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 SemaObjC::MatchTwoMethodDeclarations(const ObjCMethodDecl *left,
3268	const ObjCMethodDecl *right,
3269	MethodMatchStrategy strategy) {
3270	ASTContext &Context = getASTContext();
3271	if (!matchTypes(Context, strategy, leftQT: left->getReturnType(),
3272	rightQT: right->getReturnType()))
3273	return false;
3274
3275	// If either is hidden, it is not considered to match.
3276	if (!left->isUnconditionallyVisible() || !right->isUnconditionallyVisible())
3277	return false;
3278
3279	if (left->isDirectMethod() != right->isDirectMethod())
3280	return false;
3281
3282	if (getLangOpts().ObjCAutoRefCount &&
3283	(left->hasAttr<NSReturnsRetainedAttr>()
3284	!= right->hasAttr<NSReturnsRetainedAttr>() ||
3285	left->hasAttr<NSConsumesSelfAttr>()
3286	!= right->hasAttr<NSConsumesSelfAttr>()))
3287	return false;
3288
3289	ObjCMethodDecl::param_const_iterator
3290	li = left->param_begin(), le = left->param_end(), ri = right->param_begin(),
3291	re = right->param_end();
3292
3293	for (; li != le && ri != re; ++li, ++ri) {
3294	assert(ri != right->param_end() && "Param mismatch");
3295	const ParmVarDecl *lparm = *li, *rparm = *ri;
3296
3297	if (!matchTypes(Context, strategy, lparm->getType(), rparm->getType()))
3298	return false;
3299
3300	if (getLangOpts().ObjCAutoRefCount &&
3301	lparm->hasAttr<NSConsumedAttr>() != rparm->hasAttr<NSConsumedAttr>())
3302	return false;
3303	}
3304	return true;
3305	}
3306
3307	static bool isMethodContextSameForKindofLookup(ObjCMethodDecl *Method,
3308	ObjCMethodDecl *MethodInList) {
3309	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3310	auto *MethodInListProtocol =
3311	dyn_cast<ObjCProtocolDecl>(MethodInList->getDeclContext());
3312	// If this method belongs to a protocol but the method in list does not, or
3313	// vice versa, we say the context is not the same.
3314	if ((MethodProtocol && !MethodInListProtocol) ||
3315	(!MethodProtocol && MethodInListProtocol))
3316	return false;
3317
3318	if (MethodProtocol && MethodInListProtocol)
3319	return true;
3320
3321	ObjCInterfaceDecl *MethodInterface = Method->getClassInterface();
3322	ObjCInterfaceDecl *MethodInListInterface =
3323	MethodInList->getClassInterface();
3324	return MethodInterface == MethodInListInterface;
3325	}
3326
3327	void SemaObjC::addMethodToGlobalList(ObjCMethodList *List,
3328	ObjCMethodDecl *Method) {
3329	// Record at the head of the list whether there were 0, 1, or >= 2 methods
3330	// inside categories.
3331	if (ObjCCategoryDecl *CD =
3332	dyn_cast<ObjCCategoryDecl>(Method->getDeclContext()))
3333	if (!CD->IsClassExtension() && List->getBits() < 2)
3334	List->setBits(List->getBits() + 1);
3335
3336	// If the list is empty, make it a singleton list.
3337	if (List->getMethod() == nullptr) {
3338	List->setMethod(Method);
3339	List->setNext(nullptr);
3340	return;
3341	}
3342
3343	// We've seen a method with this name, see if we have already seen this type
3344	// signature.
3345	ObjCMethodList *Previous = List;
3346	ObjCMethodList *ListWithSameDeclaration = nullptr;
3347	for (; List; Previous = List, List = List->getNext()) {
3348	// If we are building a module, keep all of the methods.
3349	if (getLangOpts().isCompilingModule())
3350	continue;
3351
3352	bool SameDeclaration = MatchTwoMethodDeclarations(left: Method,
3353	right: List->getMethod());
3354	// Looking for method with a type bound requires the correct context exists.
3355	// We need to insert a method into the list if the context is different.
3356	// If the method's declaration matches the list
3357	// a> the method belongs to a different context: we need to insert it, in
3358	// order to emit the availability message, we need to prioritize over
3359	// availability among the methods with the same declaration.
3360	// b> the method belongs to the same context: there is no need to insert a
3361	// new entry.
3362	// If the method's declaration does not match the list, we insert it to the
3363	// end.
3364	if (!SameDeclaration ||
3365	!isMethodContextSameForKindofLookup(Method, MethodInList: List->getMethod())) {
3366	// Even if two method types do not match, we would like to say
3367	// there is more than one declaration so unavailability/deprecated
3368	// warning is not too noisy.
3369	if (!Method->isDefined())
3370	List->setHasMoreThanOneDecl(true);
3371
3372	// For methods with the same declaration, the one that is deprecated
3373	// should be put in the front for better diagnostics.
3374	if (Method->isDeprecated() && SameDeclaration &&
3375	!ListWithSameDeclaration && !List->getMethod()->isDeprecated())
3376	ListWithSameDeclaration = List;
3377
3378	if (Method->isUnavailable() && SameDeclaration &&
3379	!ListWithSameDeclaration &&
3380	List->getMethod()->getAvailability() < AR_Deprecated)
3381	ListWithSameDeclaration = List;
3382	continue;
3383	}
3384
3385	ObjCMethodDecl *PrevObjCMethod = List->getMethod();
3386
3387	// Propagate the 'defined' bit.
3388	if (Method->isDefined())
3389	PrevObjCMethod->setDefined(true);
3390	else {
3391	// Objective-C doesn't allow an @interface for a class after its
3392	// @implementation. So if Method is not defined and there already is
3393	// an entry for this type signature, Method has to be for a different
3394	// class than PrevObjCMethod.
3395	List->setHasMoreThanOneDecl(true);
3396	}
3397
3398	// If a method is deprecated, push it in the global pool.
3399	// This is used for better diagnostics.
3400	if (Method->isDeprecated()) {
3401	if (!PrevObjCMethod->isDeprecated())
3402	List->setMethod(Method);
3403	}
3404	// If the new method is unavailable, push it into global pool
3405	// unless previous one is deprecated.
3406	if (Method->isUnavailable()) {
3407	if (PrevObjCMethod->getAvailability() < AR_Deprecated)
3408	List->setMethod(Method);
3409	}
3410
3411	return;
3412	}
3413
3414	// We have a new signature for an existing method - add it.
3415	// This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
3416	ObjCMethodList *Mem = SemaRef.BumpAlloc.Allocate<ObjCMethodList>();
3417
3418	// We insert it right before ListWithSameDeclaration.
3419	if (ListWithSameDeclaration) {
3420	auto *List = new (Mem) ObjCMethodList(*ListWithSameDeclaration);
3421	// FIXME: should we clear the other bits in ListWithSameDeclaration?
3422	ListWithSameDeclaration->setMethod(Method);
3423	ListWithSameDeclaration->setNext(List);
3424	return;
3425	}
3426
3427	Previous->setNext(new (Mem) ObjCMethodList(Method));
3428	}
3429
3430	/// Read the contents of the method pool for a given selector from
3431	/// external storage.
3432	void SemaObjC::ReadMethodPool(Selector Sel) {
3433	assert(SemaRef.ExternalSource && "We need an external AST source");
3434	SemaRef.ExternalSource->ReadMethodPool(Sel);
3435	}
3436
3437	void SemaObjC::updateOutOfDateSelector(Selector Sel) {
3438	if (!SemaRef.ExternalSource)
3439	return;
3440	SemaRef.ExternalSource->updateOutOfDateSelector(Sel);
3441	}
3442
3443	void SemaObjC::AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl,
3444	bool instance) {
3445	// Ignore methods of invalid containers.
3446	if (cast<Decl>(Method->getDeclContext())->isInvalidDecl())
3447	return;
3448
3449	if (SemaRef.ExternalSource)
3450	ReadMethodPool(Sel: Method->getSelector());
3451
3452	auto &Lists = MethodPool[Method->getSelector()];
3453
3454	Method->setDefined(impl);
3455
3456	ObjCMethodList &Entry = instance ? Lists.first : Lists.second;
3457	addMethodToGlobalList(List: &Entry, Method);
3458	}
3459
3460	/// Determines if this is an "acceptable" loose mismatch in the global
3461	/// method pool. This exists mostly as a hack to get around certain
3462	/// global mismatches which we can't afford to make warnings / errors.
3463	/// Really, what we want is a way to take a method out of the global
3464	/// method pool.
3465	static bool isAcceptableMethodMismatch(ObjCMethodDecl *chosen,
3466	ObjCMethodDecl *other) {
3467	if (!chosen->isInstanceMethod())
3468	return false;
3469
3470	if (chosen->isDirectMethod() != other->isDirectMethod())
3471	return false;
3472
3473	Selector sel = chosen->getSelector();
3474	if (!sel.isUnarySelector() || sel.getNameForSlot(argIndex: 0) != "length")
3475	return false;
3476
3477	// Don't complain about mismatches for -length if the method we
3478	// chose has an integral result type.
3479	return (chosen->getReturnType()->isIntegerType());
3480	}
3481
3482	/// Return true if the given method is wthin the type bound.
3483	static bool FilterMethodsByTypeBound(ObjCMethodDecl *Method,
3484	const ObjCObjectType *TypeBound) {
3485	if (!TypeBound)
3486	return true;
3487
3488	if (TypeBound->isObjCId())
3489	// FIXME: should we handle the case of bounding to id<A, B> differently?
3490	return true;
3491
3492	auto *BoundInterface = TypeBound->getInterface();
3493	assert(BoundInterface && "unexpected object type!");
3494
3495	// Check if the Method belongs to a protocol. We should allow any method
3496	// defined in any protocol, because any subclass could adopt the protocol.
3497	auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
3498	if (MethodProtocol) {
3499	return true;
3500	}
3501
3502	// If the Method belongs to a class, check if it belongs to the class
3503	// hierarchy of the class bound.
3504	if (ObjCInterfaceDecl *MethodInterface = Method->getClassInterface()) {
3505	// We allow methods declared within classes that are part of the hierarchy
3506	// of the class bound (superclass of, subclass of, or the same as the class
3507	// bound).
3508	return MethodInterface == BoundInterface ||
3509	MethodInterface->isSuperClassOf(I: BoundInterface) ||
3510	BoundInterface->isSuperClassOf(I: MethodInterface);
3511	}
3512	llvm_unreachable("unknown method context");
3513	}
3514
3515	/// We first select the type of the method: Instance or Factory, then collect
3516	/// all methods with that type.
3517	bool SemaObjC::CollectMultipleMethodsInGlobalPool(
3518	Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods,
3519	bool InstanceFirst, bool CheckTheOther, const ObjCObjectType *TypeBound) {
3520	if (SemaRef.ExternalSource)
3521	ReadMethodPool(Sel);
3522
3523	GlobalMethodPool::iterator Pos = MethodPool.find(Val: Sel);
3524	if (Pos == MethodPool.end())
3525	return false;
3526
3527	// Gather the non-hidden methods.
3528	ObjCMethodList &MethList = InstanceFirst ? Pos->second.first :
3529	Pos->second.second;
3530	for (ObjCMethodList *M = &MethList; M; M = M->getNext())
3531	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3532	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3533	Methods.push_back(Elt: M->getMethod());
3534	}
3535
3536	// Return if we find any method with the desired kind.
3537	if (!Methods.empty())
3538	return Methods.size() > 1;
3539
3540	if (!CheckTheOther)
3541	return false;
3542
3543	// Gather the other kind.
3544	ObjCMethodList &MethList2 = InstanceFirst ? Pos->second.second :
3545	Pos->second.first;
3546	for (ObjCMethodList *M = &MethList2; M; M = M->getNext())
3547	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible()) {
3548	if (FilterMethodsByTypeBound(Method: M->getMethod(), TypeBound))
3549	Methods.push_back(Elt: M->getMethod());
3550	}
3551
3552	return Methods.size() > 1;
3553	}
3554
3555	bool SemaObjC::AreMultipleMethodsInGlobalPool(
3556	Selector Sel, ObjCMethodDecl *BestMethod, SourceRange R,
3557	bool receiverIdOrClass, SmallVectorImpl<ObjCMethodDecl *> &Methods) {
3558	// Diagnose finding more than one method in global pool.
3559	SmallVector<ObjCMethodDecl *, 4> FilteredMethods;
3560	FilteredMethods.push_back(Elt: BestMethod);
3561
3562	for (auto *M : Methods)
3563	if (M != BestMethod && !M->hasAttr<UnavailableAttr>())
3564	FilteredMethods.push_back(Elt: M);
3565
3566	if (FilteredMethods.size() > 1)
3567	DiagnoseMultipleMethodInGlobalPool(Methods&: FilteredMethods, Sel, R,
3568	receiverIdOrClass);
3569
3570	GlobalMethodPool::iterator Pos = MethodPool.find(Val: Sel);
3571	// Test for no method in the pool which should not trigger any warning by
3572	// caller.
3573	if (Pos == MethodPool.end())
3574	return true;
3575	ObjCMethodList &MethList =
3576	BestMethod->isInstanceMethod() ? Pos->second.first : Pos->second.second;
3577	return MethList.hasMoreThanOneDecl();
3578	}
3579
3580	ObjCMethodDecl *SemaObjC::LookupMethodInGlobalPool(Selector Sel, SourceRange R,
3581	bool receiverIdOrClass,
3582	bool instance) {
3583	if (SemaRef.ExternalSource)
3584	ReadMethodPool(Sel);
3585
3586	GlobalMethodPool::iterator Pos = MethodPool.find(Val: Sel);
3587	if (Pos == MethodPool.end())
3588	return nullptr;
3589
3590	// Gather the non-hidden methods.
3591	ObjCMethodList &MethList = instance ? Pos->second.first : Pos->second.second;
3592	for (ObjCMethodList *M = &MethList; M; M = M->getNext()) {
3593	if (M->getMethod() && M->getMethod()->isUnconditionallyVisible())
3594	return M->getMethod();
3595	}
3596	return nullptr;
3597	}
3598
3599	void SemaObjC::DiagnoseMultipleMethodInGlobalPool(
3600	SmallVectorImpl<ObjCMethodDecl *> &Methods, Selector Sel, SourceRange R,
3601	bool receiverIdOrClass) {
3602	// We found multiple methods, so we may have to complain.
3603	bool issueDiagnostic = false, issueError = false;
3604
3605	// We support a warning which complains about *any* difference in
3606	// method signature.
3607	bool strictSelectorMatch =
3608	receiverIdOrClass &&
3609	!getDiagnostics().isIgnored(diag::warn_strict_multiple_method_decl,
3610	R.getBegin());
3611	if (strictSelectorMatch) {
3612	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3613	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_strict)) {
3614	issueDiagnostic = true;
3615	break;
3616	}
3617	}
3618	}
3619
3620	// If we didn't see any strict differences, we won't see any loose
3621	// differences. In ARC, however, we also need to check for loose
3622	// mismatches, because most of them are errors.
3623	if (!strictSelectorMatch ||
3624	(issueDiagnostic && getLangOpts().ObjCAutoRefCount))
3625	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3626	// This checks if the methods differ in type mismatch.
3627	if (!MatchTwoMethodDeclarations(left: Methods[0], right: Methods[I], strategy: MMS_loose) &&
3628	!isAcceptableMethodMismatch(chosen: Methods[0], other: Methods[I])) {
3629	issueDiagnostic = true;
3630	if (getLangOpts().ObjCAutoRefCount)
3631	issueError = true;
3632	break;
3633	}
3634	}
3635
3636	if (issueDiagnostic) {
3637	if (issueError)
3638	Diag(R.getBegin(), diag::err_arc_multiple_method_decl) << Sel << R;
3639	else if (strictSelectorMatch)
3640	Diag(R.getBegin(), diag::warn_strict_multiple_method_decl) << Sel << R;
3641	else
3642	Diag(R.getBegin(), diag::warn_multiple_method_decl) << Sel << R;
3643
3644	Diag(Methods[0]->getBeginLoc(),
3645	issueError ? diag::note_possibility : diag::note_using)
3646	<< Methods[0]->getSourceRange();
3647	for (unsigned I = 1, N = Methods.size(); I != N; ++I) {
3648	Diag(Methods[I]->getBeginLoc(), diag::note_also_found)
3649	<< Methods[I]->getSourceRange();
3650	}
3651	}
3652	}
3653
3654	ObjCMethodDecl *SemaObjC::LookupImplementedMethodInGlobalPool(Selector Sel) {
3655	GlobalMethodPool::iterator Pos = MethodPool.find(Val: Sel);
3656	if (Pos == MethodPool.end())
3657	return nullptr;
3658
3659	auto &Methods = Pos->second;
3660	for (const ObjCMethodList *Method = &Methods.first; Method;
3661	Method = Method->getNext())
3662	if (Method->getMethod() &&
3663	(Method->getMethod()->isDefined() ||
3664	Method->getMethod()->isPropertyAccessor()))
3665	return Method->getMethod();
3666
3667	for (const ObjCMethodList *Method = &Methods.second; Method;
3668	Method = Method->getNext())
3669	if (Method->getMethod() &&
3670	(Method->getMethod()->isDefined() ||
3671	Method->getMethod()->isPropertyAccessor()))
3672	return Method->getMethod();
3673	return nullptr;
3674	}
3675
3676	static void
3677	HelperSelectorsForTypoCorrection(
3678	SmallVectorImpl<const ObjCMethodDecl *> &BestMethod,
3679	StringRef Typo, const ObjCMethodDecl * Method) {
3680	const unsigned MaxEditDistance = 1;
3681	unsigned BestEditDistance = MaxEditDistance + 1;
3682	std::string MethodName = Method->getSelector().getAsString();
3683
3684	unsigned MinPossibleEditDistance = abs(x: (int)MethodName.size() - (int)Typo.size());
3685	if (MinPossibleEditDistance > 0 &&
3686	Typo.size() / MinPossibleEditDistance < 1)
3687	return;
3688	unsigned EditDistance = Typo.edit_distance(Other: MethodName, AllowReplacements: true, MaxEditDistance);
3689	if (EditDistance > MaxEditDistance)
3690	return;
3691	if (EditDistance == BestEditDistance)
3692	BestMethod.push_back(Elt: Method);
3693	else if (EditDistance < BestEditDistance) {
3694	BestMethod.clear();
3695	BestMethod.push_back(Elt: Method);
3696	}
3697	}
3698
3699	static bool HelperIsMethodInObjCType(Sema &S, Selector Sel,
3700	QualType ObjectType) {
3701	if (ObjectType.isNull())
3702	return true;
3703	if (S.ObjC().LookupMethodInObjectType(Sel, Ty: ObjectType,
3704	IsInstance: true /*Instance method*/))
3705	return true;
3706	return S.ObjC().LookupMethodInObjectType(Sel, Ty: ObjectType,
3707	IsInstance: false /*Class method*/) != nullptr;
3708	}
3709
3710	const ObjCMethodDecl *
3711	SemaObjC::SelectorsForTypoCorrection(Selector Sel, QualType ObjectType) {
3712	unsigned NumArgs = Sel.getNumArgs();
3713	SmallVector<const ObjCMethodDecl *, 8> Methods;
3714	bool ObjectIsId = true, ObjectIsClass = true;
3715	if (ObjectType.isNull())
3716	ObjectIsId = ObjectIsClass = false;
3717	else if (!ObjectType->isObjCObjectPointerType())
3718	return nullptr;
3719	else if (const ObjCObjectPointerType *ObjCPtr =
3720	ObjectType->getAsObjCInterfacePointerType()) {
3721	ObjectType = QualType(ObjCPtr->getInterfaceType(), 0);
3722	ObjectIsId = ObjectIsClass = false;
3723	}
3724	else if (ObjectType->isObjCIdType() || ObjectType->isObjCQualifiedIdType())
3725	ObjectIsClass = false;
3726	else if (ObjectType->isObjCClassType() || ObjectType->isObjCQualifiedClassType())
3727	ObjectIsId = false;
3728	else
3729	return nullptr;
3730
3731	for (GlobalMethodPool::iterator b = MethodPool.begin(),
3732	e = MethodPool.end(); b != e; b++) {
3733	// instance methods
3734	for (ObjCMethodList *M = &b->second.first; M; M=M->getNext())
3735	if (M->getMethod() &&
3736	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3737	(M->getMethod()->getSelector() != Sel)) {
3738	if (ObjectIsId)
3739	Methods.push_back(Elt: M->getMethod());
3740	else if (!ObjectIsClass &&
3741	HelperIsMethodInObjCType(
3742	S&: SemaRef, Sel: M->getMethod()->getSelector(), ObjectType))
3743	Methods.push_back(Elt: M->getMethod());
3744	}
3745	// class methods
3746	for (ObjCMethodList *M = &b->second.second; M; M=M->getNext())
3747	if (M->getMethod() &&
3748	(M->getMethod()->getSelector().getNumArgs() == NumArgs) &&
3749	(M->getMethod()->getSelector() != Sel)) {
3750	if (ObjectIsClass)
3751	Methods.push_back(Elt: M->getMethod());
3752	else if (!ObjectIsId &&
3753	HelperIsMethodInObjCType(
3754	S&: SemaRef, Sel: M->getMethod()->getSelector(), ObjectType))
3755	Methods.push_back(Elt: M->getMethod());
3756	}
3757	}
3758
3759	SmallVector<const ObjCMethodDecl *, 8> SelectedMethods;
3760	for (unsigned i = 0, e = Methods.size(); i < e; i++) {
3761	HelperSelectorsForTypoCorrection(BestMethod&: SelectedMethods,
3762	Typo: Sel.getAsString(), Method: Methods[i]);
3763	}
3764	return (SelectedMethods.size() == 1) ? SelectedMethods[0] : nullptr;
3765	}
3766
3767	/// DiagnoseDuplicateIvars -
3768	/// Check for duplicate ivars in the entire class at the start of
3769	/// \@implementation. This becomes necessary because class extension can
3770	/// add ivars to a class in random order which will not be known until
3771	/// class's \@implementation is seen.
3772	void SemaObjC::DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID,
3773	ObjCInterfaceDecl *SID) {
3774	for (auto *Ivar : ID->ivars()) {
3775	if (Ivar->isInvalidDecl())
3776	continue;
3777	if (IdentifierInfo *II = Ivar->getIdentifier()) {
3778	ObjCIvarDecl* prevIvar = SID->lookupInstanceVariable(IVarName: II);
3779	if (prevIvar) {
3780	Diag(Ivar->getLocation(), diag::err_duplicate_member) << II;
3781	Diag(prevIvar->getLocation(), diag::note_previous_declaration);
3782	Ivar->setInvalidDecl();
3783	}
3784	}
3785	}
3786	}
3787
3788	/// Diagnose attempts to define ARC-__weak ivars when __weak is disabled.
3789	static void DiagnoseWeakIvars(Sema &S, ObjCImplementationDecl *ID) {
3790	if (S.getLangOpts().ObjCWeak) return;
3791
3792	for (auto ivar = ID->getClassInterface()->all_declared_ivar_begin();
3793	ivar; ivar = ivar->getNextIvar()) {
3794	if (ivar->isInvalidDecl()) continue;
3795	if (ivar->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
3796	if (S.getLangOpts().ObjCWeakRuntime) {
3797	S.Diag(ivar->getLocation(), diag::err_arc_weak_disabled);
3798	} else {
3799	S.Diag(ivar->getLocation(), diag::err_arc_weak_no_runtime);
3800	}
3801	}
3802	}
3803	}
3804
3805	/// Diagnose attempts to use flexible array member with retainable object type.
3806	static void DiagnoseRetainableFlexibleArrayMember(Sema &S,
3807	ObjCInterfaceDecl *ID) {
3808	if (!S.getLangOpts().ObjCAutoRefCount)
3809	return;
3810
3811	for (auto ivar = ID->all_declared_ivar_begin(); ivar;
3812	ivar = ivar->getNextIvar()) {
3813	if (ivar->isInvalidDecl())
3814	continue;
3815	QualType IvarTy = ivar->getType();
3816	if (IvarTy->isIncompleteArrayType() &&
3817	(IvarTy.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) &&
3818	IvarTy->isObjCLifetimeType()) {
3819	S.Diag(ivar->getLocation(), diag::err_flexible_array_arc_retainable);
3820	ivar->setInvalidDecl();
3821	}
3822	}
3823	}
3824
3825	SemaObjC::ObjCContainerKind SemaObjC::getObjCContainerKind() const {
3826	switch (SemaRef.CurContext->getDeclKind()) {
3827	case Decl::ObjCInterface:
3828	return SemaObjC::OCK_Interface;
3829	case Decl::ObjCProtocol:
3830	return SemaObjC::OCK_Protocol;
3831	case Decl::ObjCCategory:
3832	if (cast<ObjCCategoryDecl>(Val: SemaRef.CurContext)->IsClassExtension())
3833	return SemaObjC::OCK_ClassExtension;
3834	return SemaObjC::OCK_Category;
3835	case Decl::ObjCImplementation:
3836	return SemaObjC::OCK_Implementation;
3837	case Decl::ObjCCategoryImpl:
3838	return SemaObjC::OCK_CategoryImplementation;
3839
3840	default:
3841	return SemaObjC::OCK_None;
3842	}
3843	}
3844
3845	static bool IsVariableSizedType(QualType T) {
3846	if (T->isIncompleteArrayType())
3847	return true;
3848	const auto *RecordTy = T->getAs<RecordType>();
3849	return (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember());
3850	}
3851
3852	static void DiagnoseVariableSizedIvars(Sema &S, ObjCContainerDecl *OCD) {
3853	ObjCInterfaceDecl *IntfDecl = nullptr;
3854	ObjCInterfaceDecl::ivar_range Ivars = llvm::make_range(
3855	x: ObjCInterfaceDecl::ivar_iterator(), y: ObjCInterfaceDecl::ivar_iterator());
3856	if ((IntfDecl = dyn_cast<ObjCInterfaceDecl>(Val: OCD))) {
3857	Ivars = IntfDecl->ivars();
3858	} else if (auto *ImplDecl = dyn_cast<ObjCImplementationDecl>(Val: OCD)) {
3859	IntfDecl = ImplDecl->getClassInterface();
3860	Ivars = ImplDecl->ivars();
3861	} else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Val: OCD)) {
3862	if (CategoryDecl->IsClassExtension()) {
3863	IntfDecl = CategoryDecl->getClassInterface();
3864	Ivars = CategoryDecl->ivars();
3865	}
3866	}
3867
3868	// Check if variable sized ivar is in interface and visible to subclasses.
3869	if (!isa<ObjCInterfaceDecl>(Val: OCD)) {
3870	for (auto *ivar : Ivars) {
3871	if (!ivar->isInvalidDecl() && IsVariableSizedType(ivar->getType())) {
3872	S.Diag(ivar->getLocation(), diag::warn_variable_sized_ivar_visibility)
3873	<< ivar->getDeclName() << ivar->getType();
3874	}
3875	}
3876	}
3877
3878	// Subsequent checks require interface decl.
3879	if (!IntfDecl)
3880	return;
3881
3882	// Check if variable sized ivar is followed by another ivar.
3883	for (ObjCIvarDecl *ivar = IntfDecl->all_declared_ivar_begin(); ivar;
3884	ivar = ivar->getNextIvar()) {
3885	if (ivar->isInvalidDecl() || !ivar->getNextIvar())
3886	continue;
3887	QualType IvarTy = ivar->getType();
3888	bool IsInvalidIvar = false;
3889	if (IvarTy->isIncompleteArrayType()) {
3890	S.Diag(ivar->getLocation(), diag::err_flexible_array_not_at_end)
3891	<< ivar->getDeclName() << IvarTy
3892	<< TagTypeKind::Class; // Use "class" for Obj-C.
3893	IsInvalidIvar = true;
3894	} else if (const RecordType *RecordTy = IvarTy->getAs<RecordType>()) {
3895	if (RecordTy->getDecl()->hasFlexibleArrayMember()) {
3896	S.Diag(ivar->getLocation(),
3897	diag::err_objc_variable_sized_type_not_at_end)
3898	<< ivar->getDeclName() << IvarTy;
3899	IsInvalidIvar = true;
3900	}
3901	}
3902	if (IsInvalidIvar) {
3903	S.Diag(ivar->getNextIvar()->getLocation(),
3904	diag::note_next_ivar_declaration)
3905	<< ivar->getNextIvar()->getSynthesize();
3906	ivar->setInvalidDecl();
3907	}
3908	}
3909
3910	// Check if ObjC container adds ivars after variable sized ivar in superclass.
3911	// Perform the check only if OCD is the first container to declare ivars to
3912	// avoid multiple warnings for the same ivar.
3913	ObjCIvarDecl *FirstIvar =
3914	(Ivars.begin() == Ivars.end()) ? nullptr : *Ivars.begin();
3915	if (FirstIvar && (FirstIvar == IntfDecl->all_declared_ivar_begin())) {
3916	const ObjCInterfaceDecl *SuperClass = IntfDecl->getSuperClass();
3917	while (SuperClass && SuperClass->ivar_empty())
3918	SuperClass = SuperClass->getSuperClass();
3919	if (SuperClass) {
3920	auto IvarIter = SuperClass->ivar_begin();
3921	std::advance(i&: IvarIter, n: SuperClass->ivar_size() - 1);
3922	const ObjCIvarDecl *LastIvar = *IvarIter;
3923	if (IsVariableSizedType(LastIvar->getType())) {
3924	S.Diag(FirstIvar->getLocation(),
3925	diag::warn_superclass_variable_sized_type_not_at_end)
3926	<< FirstIvar->getDeclName() << LastIvar->getDeclName()
3927	<< LastIvar->getType() << SuperClass->getDeclName();
3928	S.Diag(LastIvar->getLocation(), diag::note_entity_declared_at)
3929	<< LastIvar->getDeclName();
3930	}
3931	}
3932	}
3933	}
3934
3935	static void DiagnoseCategoryDirectMembersProtocolConformance(
3936	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl);
3937
3938	static void DiagnoseCategoryDirectMembersProtocolConformance(
3939	Sema &S, ObjCCategoryDecl *CDecl,
3940	const llvm::iterator_range<ObjCProtocolList::iterator> &Protocols) {
3941	for (auto *PI : Protocols)
3942	DiagnoseCategoryDirectMembersProtocolConformance(S, PDecl: PI, CDecl);
3943	}
3944
3945	static void DiagnoseCategoryDirectMembersProtocolConformance(
3946	Sema &S, ObjCProtocolDecl *PDecl, ObjCCategoryDecl *CDecl) {
3947	if (!PDecl->isThisDeclarationADefinition() && PDecl->getDefinition())
3948	PDecl = PDecl->getDefinition();
3949
3950	llvm::SmallVector<const Decl *, 4> DirectMembers;
3951	const auto *IDecl = CDecl->getClassInterface();
3952	for (auto *MD : PDecl->methods()) {
3953	if (!MD->isPropertyAccessor()) {
3954	if (const auto *CMD =
3955	IDecl->getMethod(MD->getSelector(), MD->isInstanceMethod())) {
3956	if (CMD->isDirectMethod())
3957	DirectMembers.push_back(CMD);
3958	}
3959	}
3960	}
3961	for (auto *PD : PDecl->properties()) {
3962	if (const auto *CPD = IDecl->FindPropertyVisibleInPrimaryClass(
3963	PD->getIdentifier(),
3964	PD->isClassProperty()
3965	? ObjCPropertyQueryKind::OBJC_PR_query_class
3966	: ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
3967	if (CPD->isDirectProperty())
3968	DirectMembers.push_back(CPD);
3969	}
3970	}
3971	if (!DirectMembers.empty()) {
3972	S.Diag(CDecl->getLocation(), diag::err_objc_direct_protocol_conformance)
3973	<< CDecl->IsClassExtension() << CDecl << PDecl << IDecl;
3974	for (const auto *MD : DirectMembers)
3975	S.Diag(MD->getLocation(), diag::note_direct_member_here);
3976	return;
3977	}
3978
3979	// Check on this protocols's referenced protocols, recursively.
3980	DiagnoseCategoryDirectMembersProtocolConformance(S, CDecl,
3981	Protocols: PDecl->protocols());
3982	}
3983
3984	// Note: For class/category implementations, allMethods is always null.
3985	Decl *SemaObjC::ActOnAtEnd(Scope *S, SourceRange AtEnd,
3986	ArrayRef<Decl *> allMethods,
3987	ArrayRef<DeclGroupPtrTy> allTUVars) {
3988	ASTContext &Context = getASTContext();
3989	if (getObjCContainerKind() == SemaObjC::OCK_None)
3990	return nullptr;
3991
3992	assert(AtEnd.isValid() && "Invalid location for '@end'");
3993
3994	auto *OCD = cast<ObjCContainerDecl>(Val: SemaRef.CurContext);
3995	Decl *ClassDecl = OCD;
3996
3997	bool isInterfaceDeclKind =
3998	isa<ObjCInterfaceDecl>(Val: ClassDecl) || isa<ObjCCategoryDecl>(Val: ClassDecl)
3999	|| isa<ObjCProtocolDecl>(Val: ClassDecl);
4000	bool checkIdenticalMethods = isa<ObjCImplementationDecl>(Val: ClassDecl);
4001
4002	// Make synthesized accessor stub functions visible.
4003	// ActOnPropertyImplDecl() creates them as not visible in case
4004	// they are overridden by an explicit method that is encountered
4005	// later.
4006	if (auto *OID = dyn_cast<ObjCImplementationDecl>(Val: SemaRef.CurContext)) {
4007	for (auto *PropImpl : OID->property_impls()) {
4008	if (auto *Getter = PropImpl->getGetterMethodDecl())
4009	if (Getter->isSynthesizedAccessorStub())
4010	OID->addDecl(Getter);
4011	if (auto *Setter = PropImpl->getSetterMethodDecl())
4012	if (Setter->isSynthesizedAccessorStub())
4013	OID->addDecl(Setter);
4014	}
4015	}
4016
4017	// FIXME: Remove these and use the ObjCContainerDecl/DeclContext.
4018	llvm::DenseMap<Selector, const ObjCMethodDecl*> InsMap;
4019	llvm::DenseMap<Selector, const ObjCMethodDecl*> ClsMap;
4020
4021	for (unsigned i = 0, e = allMethods.size(); i != e; i++ ) {
4022	ObjCMethodDecl *Method =
4023	cast_or_null<ObjCMethodDecl>(Val: allMethods[i]);
4024
4025	if (!Method) continue; // Already issued a diagnostic.
4026	if (Method->isInstanceMethod()) {
4027	/// Check for instance method of the same name with incompatible types
4028	const ObjCMethodDecl *&PrevMethod = InsMap[Method->getSelector()];
4029	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4030	: false;
4031	if ((isInterfaceDeclKind && PrevMethod && !match)
4032	|| (checkIdenticalMethods && match)) {
4033	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4034	<< Method->getDeclName();
4035	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4036	Method->setInvalidDecl();
4037	} else {
4038	if (PrevMethod) {
4039	Method->setAsRedeclaration(PrevMethod);
4040	if (!Context.getSourceManager().isInSystemHeader(
4041	Method->getLocation()))
4042	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4043	<< Method->getDeclName();
4044	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4045	}
4046	InsMap[Method->getSelector()] = Method;
4047	/// The following allows us to typecheck messages to "id".
4048	AddInstanceMethodToGlobalPool(Method);
4049	}
4050	} else {
4051	/// Check for class method of the same name with incompatible types
4052	const ObjCMethodDecl *&PrevMethod = ClsMap[Method->getSelector()];
4053	bool match = PrevMethod ? MatchTwoMethodDeclarations(left: Method, right: PrevMethod)
4054	: false;
4055	if ((isInterfaceDeclKind && PrevMethod && !match)
4056	|| (checkIdenticalMethods && match)) {
4057	Diag(Method->getLocation(), diag::err_duplicate_method_decl)
4058	<< Method->getDeclName();
4059	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4060	Method->setInvalidDecl();
4061	} else {
4062	if (PrevMethod) {
4063	Method->setAsRedeclaration(PrevMethod);
4064	if (!Context.getSourceManager().isInSystemHeader(
4065	Method->getLocation()))
4066	Diag(Method->getLocation(), diag::warn_duplicate_method_decl)
4067	<< Method->getDeclName();
4068	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
4069	}
4070	ClsMap[Method->getSelector()] = Method;
4071	AddFactoryMethodToGlobalPool(Method);
4072	}
4073	}
4074	}
4075	if (isa<ObjCInterfaceDecl>(Val: ClassDecl)) {
4076	// Nothing to do here.
4077	} else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl)) {
4078	// Categories are used to extend the class by declaring new methods.
4079	// By the same token, they are also used to add new properties. No
4080	// need to compare the added property to those in the class.
4081
4082	if (C->IsClassExtension()) {
4083	ObjCInterfaceDecl *CCPrimary = C->getClassInterface();
4084	DiagnoseClassExtensionDupMethods(CAT: C, ID: CCPrimary);
4085	}
4086
4087	DiagnoseCategoryDirectMembersProtocolConformance(S&: SemaRef, CDecl: C,
4088	Protocols: C->protocols());
4089	}
4090	if (ObjCContainerDecl *CDecl = dyn_cast<ObjCContainerDecl>(Val: ClassDecl)) {
4091	if (CDecl->getIdentifier())
4092	// ProcessPropertyDecl is responsible for diagnosing conflicts with any
4093	// user-defined setter/getter. It also synthesizes setter/getter methods
4094	// and adds them to the DeclContext and global method pools.
4095	for (auto *I : CDecl->properties())
4096	ProcessPropertyDecl(I);
4097	CDecl->setAtEndRange(AtEnd);
4098	}
4099	if (ObjCImplementationDecl *IC=dyn_cast<ObjCImplementationDecl>(Val: ClassDecl)) {
4100	IC->setAtEndRange(AtEnd);
4101	if (ObjCInterfaceDecl* IDecl = IC->getClassInterface()) {
4102	// Any property declared in a class extension might have user
4103	// declared setter or getter in current class extension or one
4104	// of the other class extensions. Mark them as synthesized as
4105	// property will be synthesized when property with same name is
4106	// seen in the @implementation.
4107	for (const auto *Ext : IDecl->visible_extensions()) {
4108	for (const auto *Property : Ext->instance_properties()) {
4109	// Skip over properties declared @dynamic
4110	if (const ObjCPropertyImplDecl *PIDecl
4111	= IC->FindPropertyImplDecl(Property->getIdentifier(),
4112	Property->getQueryKind()))
4113	if (PIDecl->getPropertyImplementation()
4114	== ObjCPropertyImplDecl::Dynamic)
4115	continue;
4116
4117	for (const auto *Ext : IDecl->visible_extensions()) {
4118	if (ObjCMethodDecl *GetterMethod =
4119	Ext->getInstanceMethod(Property->getGetterName()))
4120	GetterMethod->setPropertyAccessor(true);
4121	if (!Property->isReadOnly())
4122	if (ObjCMethodDecl *SetterMethod
4123	= Ext->getInstanceMethod(Property->getSetterName()))
4124	SetterMethod->setPropertyAccessor(true);
4125	}
4126	}
4127	}
4128	ImplMethodsVsClassMethods(S, IC, IDecl);
4129	AtomicPropertySetterGetterRules(IC, IDecl);
4130	DiagnoseOwningPropertyGetterSynthesis(D: IC);
4131	DiagnoseUnusedBackingIvarInAccessor(S, ImplD: IC);
4132	if (IDecl->hasDesignatedInitializers())
4133	DiagnoseMissingDesignatedInitOverrides(ImplD: IC, IFD: IDecl);
4134	DiagnoseWeakIvars(S&: SemaRef, ID: IC);
4135	DiagnoseRetainableFlexibleArrayMember(S&: SemaRef, ID: IDecl);
4136
4137	bool HasRootClassAttr = IDecl->hasAttr<ObjCRootClassAttr>();
4138	if (IDecl->getSuperClass() == nullptr) {
4139	// This class has no superclass, so check that it has been marked with
4140	// __attribute((objc_root_class)).
4141	if (!HasRootClassAttr) {
4142	SourceLocation DeclLoc(IDecl->getLocation());
4143	SourceLocation SuperClassLoc(SemaRef.getLocForEndOfToken(Loc: DeclLoc));
4144	Diag(DeclLoc, diag::warn_objc_root_class_missing)
4145	<< IDecl->getIdentifier();
4146	// See if NSObject is in the current scope, and if it is, suggest
4147	// adding " : NSObject " to the class declaration.
4148	NamedDecl *IF = SemaRef.LookupSingleName(
4149	S: SemaRef.TUScope, Name: NSAPIObj->getNSClassId(K: NSAPI::ClassId_NSObject),
4150	Loc: DeclLoc, NameKind: Sema::LookupOrdinaryName);
4151	ObjCInterfaceDecl *NSObjectDecl = dyn_cast_or_null<ObjCInterfaceDecl>(Val: IF);
4152	if (NSObjectDecl && NSObjectDecl->getDefinition()) {
4153	Diag(SuperClassLoc, diag::note_objc_needs_superclass)
4154	<< FixItHint::CreateInsertion(SuperClassLoc, " : NSObject ");
4155	} else {
4156	Diag(SuperClassLoc, diag::note_objc_needs_superclass);
4157	}
4158	}
4159	} else if (HasRootClassAttr) {
4160	// Complain that only root classes may have this attribute.
4161	Diag(IDecl->getLocation(), diag::err_objc_root_class_subclass);
4162	}
4163
4164	if (const ObjCInterfaceDecl *Super = IDecl->getSuperClass()) {
4165	// An interface can subclass another interface with a
4166	// objc_subclassing_restricted attribute when it has that attribute as
4167	// well (because of interfaces imported from Swift). Therefore we have
4168	// to check if we can subclass in the implementation as well.
4169	if (IDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4170	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4171	Diag(IC->getLocation(), diag::err_restricted_superclass_mismatch);
4172	Diag(Super->getLocation(), diag::note_class_declared);
4173	}
4174	}
4175
4176	if (IDecl->hasAttr<ObjCClassStubAttr>())
4177	Diag(IC->getLocation(), diag::err_implementation_of_class_stub);
4178
4179	if (getLangOpts().ObjCRuntime.isNonFragile()) {
4180	while (IDecl->getSuperClass()) {
4181	DiagnoseDuplicateIvars(ID: IDecl, SID: IDecl->getSuperClass());
4182	IDecl = IDecl->getSuperClass();
4183	}
4184	}
4185	}
4186	SetIvarInitializers(IC);
4187	} else if (ObjCCategoryImplDecl* CatImplClass =
4188	dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl)) {
4189	CatImplClass->setAtEndRange(AtEnd);
4190
4191	// Find category interface decl and then check that all methods declared
4192	// in this interface are implemented in the category @implementation.
4193	if (ObjCInterfaceDecl* IDecl = CatImplClass->getClassInterface()) {
4194	if (ObjCCategoryDecl *Cat
4195	= IDecl->FindCategoryDeclaration(CategoryId: CatImplClass->getIdentifier())) {
4196	ImplMethodsVsClassMethods(S, CatImplClass, Cat);
4197	}
4198	}
4199	} else if (const auto *IntfDecl = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
4200	if (const ObjCInterfaceDecl *Super = IntfDecl->getSuperClass()) {
4201	if (!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
4202	Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
4203	Diag(IntfDecl->getLocation(), diag::err_restricted_superclass_mismatch);
4204	Diag(Super->getLocation(), diag::note_class_declared);
4205	}
4206	}
4207
4208	if (IntfDecl->hasAttr<ObjCClassStubAttr>() &&
4209	!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>())
4210	Diag(IntfDecl->getLocation(), diag::err_class_stub_subclassing_mismatch);
4211	}
4212	DiagnoseVariableSizedIvars(S&: SemaRef, OCD);
4213	if (isInterfaceDeclKind) {
4214	// Reject invalid vardecls.
4215	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4216	DeclGroupRef DG = allTUVars[i].get();
4217	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4218	if (VarDecl *VDecl = dyn_cast<VarDecl>(Val: *I)) {
4219	if (!VDecl->hasExternalStorage())
4220	Diag(VDecl->getLocation(), diag::err_objc_var_decl_inclass);
4221	}
4222	}
4223	}
4224	ActOnObjCContainerFinishDefinition();
4225
4226	for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
4227	DeclGroupRef DG = allTUVars[i].get();
4228	for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
4229	(*I)->setTopLevelDeclInObjCContainer();
4230	SemaRef.Consumer.HandleTopLevelDeclInObjCContainer(D: DG);
4231	}
4232
4233	SemaRef.ActOnDocumentableDecl(D: ClassDecl);
4234	return ClassDecl;
4235	}
4236
4237	/// CvtQTToAstBitMask - utility routine to produce an AST bitmask for
4238	/// objective-c's type qualifier from the parser version of the same info.
4239	static Decl::ObjCDeclQualifier
4240	CvtQTToAstBitMask(ObjCDeclSpec::ObjCDeclQualifier PQTVal) {
4241	return (Decl::ObjCDeclQualifier) (unsigned) PQTVal;
4242	}
4243
4244	/// Check whether the declared result type of the given Objective-C
4245	/// method declaration is compatible with the method's class.
4246	///
4247	static SemaObjC::ResultTypeCompatibilityKind
4248	CheckRelatedResultTypeCompatibility(Sema &S, ObjCMethodDecl *Method,
4249	ObjCInterfaceDecl *CurrentClass) {
4250	QualType ResultType = Method->getReturnType();
4251
4252	// If an Objective-C method inherits its related result type, then its
4253	// declared result type must be compatible with its own class type. The
4254	// declared result type is compatible if:
4255	if (const ObjCObjectPointerType *ResultObjectType
4256	= ResultType->getAs<ObjCObjectPointerType>()) {
4257	// - it is id or qualified id, or
4258	if (ResultObjectType->isObjCIdType() ||
4259	ResultObjectType->isObjCQualifiedIdType())
4260	return SemaObjC::RTC_Compatible;
4261
4262	if (CurrentClass) {
4263	if (ObjCInterfaceDecl *ResultClass
4264	= ResultObjectType->getInterfaceDecl()) {
4265	// - it is the same as the method's class type, or
4266	if (declaresSameEntity(CurrentClass, ResultClass))
4267	return SemaObjC::RTC_Compatible;
4268
4269	// - it is a superclass of the method's class type
4270	if (ResultClass->isSuperClassOf(I: CurrentClass))
4271	return SemaObjC::RTC_Compatible;
4272	}
4273	} else {
4274	// Any Objective-C pointer type might be acceptable for a protocol
4275	// method; we just don't know.
4276	return SemaObjC::RTC_Unknown;
4277	}
4278	}
4279
4280	return SemaObjC::RTC_Incompatible;
4281	}
4282
4283	namespace {
4284	/// A helper class for searching for methods which a particular method
4285	/// overrides.
4286	class OverrideSearch {
4287	public:
4288	const ObjCMethodDecl *Method;
4289	llvm::SmallSetVector<ObjCMethodDecl*, 4> Overridden;
4290	bool Recursive;
4291
4292	public:
4293	OverrideSearch(Sema &S, const ObjCMethodDecl *method) : Method(method) {
4294	Selector selector = method->getSelector();
4295
4296	// Bypass this search if we've never seen an instance/class method
4297	// with this selector before.
4298	SemaObjC::GlobalMethodPool::iterator it =
4299	S.ObjC().MethodPool.find(Val: selector);
4300	if (it == S.ObjC().MethodPool.end()) {
4301	if (!S.getExternalSource()) return;
4302	S.ObjC().ReadMethodPool(Sel: selector);
4303
4304	it = S.ObjC().MethodPool.find(Val: selector);
4305	if (it == S.ObjC().MethodPool.end())
4306	return;
4307	}
4308	const ObjCMethodList &list =
4309	method->isInstanceMethod() ? it->second.first : it->second.second;
4310	if (!list.getMethod()) return;
4311
4312	const ObjCContainerDecl *container
4313	= cast<ObjCContainerDecl>(method->getDeclContext());
4314
4315	// Prevent the search from reaching this container again. This is
4316	// important with categories, which override methods from the
4317	// interface and each other.
4318	if (const ObjCCategoryDecl *Category =
4319	dyn_cast<ObjCCategoryDecl>(container)) {
4320	searchFromContainer(container);
4321	if (const ObjCInterfaceDecl *Interface = Category->getClassInterface())
4322	searchFromContainer(Interface);
4323	} else {
4324	searchFromContainer(container);
4325	}
4326	}
4327
4328	typedef decltype(Overridden)::iterator iterator;
4329	iterator begin() const { return Overridden.begin(); }
4330	iterator end() const { return Overridden.end(); }
4331
4332	private:
4333	void searchFromContainer(const ObjCContainerDecl *container) {
4334	if (container->isInvalidDecl()) return;
4335
4336	switch (container->getDeclKind()) {
4337	#define OBJCCONTAINER(type, base) \
4338	case Decl::type: \
4339	searchFrom(cast<type##Decl>(container)); \
4340	break;
4341	#define ABSTRACT_DECL(expansion)
4342	#define DECL(type, base) \
4343	case Decl::type:
4344	#include "clang/AST/DeclNodes.inc"
4345	llvm_unreachable("not an ObjC container!");
4346	}
4347	}
4348
4349	void searchFrom(const ObjCProtocolDecl *protocol) {
4350	if (!protocol->hasDefinition())
4351	return;
4352
4353	// A method in a protocol declaration overrides declarations from
4354	// referenced ("parent") protocols.
4355	search(protocols: protocol->getReferencedProtocols());
4356	}
4357
4358	void searchFrom(const ObjCCategoryDecl *category) {
4359	// A method in a category declaration overrides declarations from
4360	// the main class and from protocols the category references.
4361	// The main class is handled in the constructor.
4362	search(protocols: category->getReferencedProtocols());
4363	}
4364
4365	void searchFrom(const ObjCCategoryImplDecl *impl) {
4366	// A method in a category definition that has a category
4367	// declaration overrides declarations from the category
4368	// declaration.
4369	if (ObjCCategoryDecl *category = impl->getCategoryDecl()) {
4370	search(category);
4371	if (ObjCInterfaceDecl *Interface = category->getClassInterface())
4372	search(Interface);
4373
4374	// Otherwise it overrides declarations from the class.
4375	} else if (const auto *Interface = impl->getClassInterface()) {
4376	search(Interface);
4377	}
4378	}
4379
4380	void searchFrom(const ObjCInterfaceDecl *iface) {
4381	// A method in a class declaration overrides declarations from
4382	if (!iface->hasDefinition())
4383	return;
4384
4385	// - categories,
4386	for (auto *Cat : iface->known_categories())
4387	search(Cat);
4388
4389	// - the super class, and
4390	if (ObjCInterfaceDecl *super = iface->getSuperClass())
4391	search(super);
4392
4393	// - any referenced protocols.
4394	search(protocols: iface->getReferencedProtocols());
4395	}
4396
4397	void searchFrom(const ObjCImplementationDecl *impl) {
4398	// A method in a class implementation overrides declarations from
4399	// the class interface.
4400	if (const auto *Interface = impl->getClassInterface())
4401	search(Interface);
4402	}
4403
4404	void search(const ObjCProtocolList &protocols) {
4405	for (const auto *Proto : protocols)
4406	search(Proto);
4407	}
4408
4409	void search(const ObjCContainerDecl *container) {
4410	// Check for a method in this container which matches this selector.
4411	ObjCMethodDecl *meth = container->getMethod(Sel: Method->getSelector(),
4412	isInstance: Method->isInstanceMethod(),
4413	/*AllowHidden=*/true);
4414
4415	// If we find one, record it and bail out.
4416	if (meth) {
4417	Overridden.insert(X: meth);
4418	return;
4419	}
4420
4421	// Otherwise, search for methods that a hypothetical method here
4422	// would have overridden.
4423
4424	// Note that we're now in a recursive case.
4425	Recursive = true;
4426
4427	searchFromContainer(container);
4428	}
4429	};
4430	} // end anonymous namespace
4431
4432	void SemaObjC::CheckObjCMethodDirectOverrides(ObjCMethodDecl *method,
4433	ObjCMethodDecl *overridden) {
4434	if (overridden->isDirectMethod()) {
4435	const auto *attr = overridden->getAttr<ObjCDirectAttr>();
4436	Diag(method->getLocation(), diag::err_objc_override_direct_method);
4437	Diag(attr->getLocation(), diag::note_previous_declaration);
4438	} else if (method->isDirectMethod()) {
4439	const auto *attr = method->getAttr<ObjCDirectAttr>();
4440	Diag(attr->getLocation(), diag::err_objc_direct_on_override)
4441	<< isa<ObjCProtocolDecl>(overridden->getDeclContext());
4442	Diag(overridden->getLocation(), diag::note_previous_declaration);
4443	}
4444	}
4445
4446	void SemaObjC::CheckObjCMethodOverrides(ObjCMethodDecl *ObjCMethod,
4447	ObjCInterfaceDecl *CurrentClass,
4448	ResultTypeCompatibilityKind RTC) {
4449	ASTContext &Context = getASTContext();
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(SemaRef, 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(Val: 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(SemaRef, 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 != SemaObjC::RTC_Incompatible && overridden->hasRelatedResultType())
4508	ObjCMethod->setRelatedResultType();
4509
4510	// Then merge the declarations.
4511	SemaRef.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(nullability: *prevNullability, modifiedType: type, equivalentType: type);
4583	}
4584
4585	/// Merge information from the declaration of a method in the \@interface
4586	/// (or a category/extension) into the corresponding method in the
4587	/// @implementation (for a class or category).
4588	static void mergeInterfaceMethodToImpl(Sema &S,
4589	ObjCMethodDecl *method,
4590	ObjCMethodDecl *prevMethod) {
4591	// Merge the objc_requires_super attribute.
4592	if (prevMethod->hasAttr<ObjCRequiresSuperAttr>() &&
4593	!method->hasAttr<ObjCRequiresSuperAttr>()) {
4594	// merge the attribute into implementation.
4595	method->addAttr(
4596	ObjCRequiresSuperAttr::CreateImplicit(S.Context,
4597	method->getLocation()));
4598	}
4599
4600	// Merge nullability of the result type.
4601	QualType newReturnType
4602	= mergeTypeNullabilityForRedecl(
4603	S, loc: method->getReturnTypeSourceRange().getBegin(),
4604	type: method->getReturnType(),
4605	usesCSKeyword: method->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4606	prevLoc: prevMethod->getReturnTypeSourceRange().getBegin(),
4607	prevType: prevMethod->getReturnType(),
4608	prevUsesCSKeyword: prevMethod->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4609	method->setReturnType(newReturnType);
4610
4611	// Handle each of the parameters.
4612	unsigned numParams = method->param_size();
4613	unsigned numPrevParams = prevMethod->param_size();
4614	for (unsigned i = 0, n = std::min(a: numParams, b: numPrevParams); i != n; ++i) {
4615	ParmVarDecl *param = method->param_begin()[i];
4616	ParmVarDecl *prevParam = prevMethod->param_begin()[i];
4617
4618	// Merge nullability.
4619	QualType newParamType
4620	= mergeTypeNullabilityForRedecl(
4621	S, param->getLocation(), param->getType(),
4622	param->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability,
4623	prevParam->getLocation(), prevParam->getType(),
4624	prevParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability);
4625	param->setType(newParamType);
4626	}
4627	}
4628
4629	/// Verify that the method parameters/return value have types that are supported
4630	/// by the x86 target.
4631	static void checkObjCMethodX86VectorTypes(Sema &SemaRef,
4632	const ObjCMethodDecl *Method) {
4633	assert(SemaRef.getASTContext().getTargetInfo().getTriple().getArch() ==
4634	llvm::Triple::x86 &&
4635	"x86-specific check invoked for a different target");
4636	SourceLocation Loc;
4637	QualType T;
4638	for (const ParmVarDecl *P : Method->parameters()) {
4639	if (P->getType()->isVectorType()) {
4640	Loc = P->getBeginLoc();
4641	T = P->getType();
4642	break;
4643	}
4644	}
4645	if (Loc.isInvalid()) {
4646	if (Method->getReturnType()->isVectorType()) {
4647	Loc = Method->getReturnTypeSourceRange().getBegin();
4648	T = Method->getReturnType();
4649	} else
4650	return;
4651	}
4652
4653	// Vector parameters/return values are not supported by objc_msgSend on x86 in
4654	// iOS < 9 and macOS < 10.11.
4655	const auto &Triple = SemaRef.getASTContext().getTargetInfo().getTriple();
4656	VersionTuple AcceptedInVersion;
4657	if (Triple.getOS() == llvm::Triple::IOS)
4658	AcceptedInVersion = VersionTuple(/*Major=*/9);
4659	else if (Triple.isMacOSX())
4660	AcceptedInVersion = VersionTuple(/*Major=*/10, /*Minor=*/11);
4661	else
4662	return;
4663	if (SemaRef.getASTContext().getTargetInfo().getPlatformMinVersion() >=
4664	AcceptedInVersion)
4665	return;
4666	SemaRef.Diag(Loc, diag::err_objc_method_unsupported_param_ret_type)
4667	<< T << (Method->getReturnType()->isVectorType() ? /*return value*/ 1
4668	: /*parameter*/ 0)
4669	<< (Triple.isMacOSX() ? "macOS 10.11" : "iOS 9");
4670	}
4671
4672	static void mergeObjCDirectMembers(Sema &S, Decl *CD, ObjCMethodDecl *Method) {
4673	if (!Method->isDirectMethod() && !Method->hasAttr<UnavailableAttr>() &&
4674	CD->hasAttr<ObjCDirectMembersAttr>()) {
4675	Method->addAttr(
4676	ObjCDirectAttr::CreateImplicit(S.Context, Method->getLocation()));
4677	}
4678	}
4679
4680	static void checkObjCDirectMethodClashes(Sema &S, ObjCInterfaceDecl *IDecl,
4681	ObjCMethodDecl *Method,
4682	ObjCImplDecl *ImpDecl = nullptr) {
4683	auto Sel = Method->getSelector();
4684	bool isInstance = Method->isInstanceMethod();
4685	bool diagnosed = false;
4686
4687	auto diagClash = [&](const ObjCMethodDecl *IMD) {
4688	if (diagnosed || IMD->isImplicit())
4689	return;
4690	if (Method->isDirectMethod() || IMD->isDirectMethod()) {
4691	S.Diag(Method->getLocation(), diag::err_objc_direct_duplicate_decl)
4692	<< Method->isDirectMethod() << /* method */ 0 << IMD->isDirectMethod()
4693	<< Method->getDeclName();
4694	S.Diag(IMD->getLocation(), diag::note_previous_declaration);
4695	diagnosed = true;
4696	}
4697	};
4698
4699	// Look for any other declaration of this method anywhere we can see in this
4700	// compilation unit.
4701	//
4702	// We do not use IDecl->lookupMethod() because we have specific needs:
4703	//
4704	// - we absolutely do not need to walk protocols, because
4705	// diag::err_objc_direct_on_protocol has already been emitted
4706	// during parsing if there's a conflict,
4707	//
4708	// - when we do not find a match in a given @interface container,
4709	// we need to attempt looking it up in the @implementation block if the
4710	// translation unit sees it to find more clashes.
4711
4712	if (auto *IMD = IDecl->getMethod(Sel, isInstance))
4713	diagClash(IMD);
4714	else if (auto *Impl = IDecl->getImplementation())
4715	if (Impl != ImpDecl)
4716	if (auto *IMD = IDecl->getImplementation()->getMethod(Sel, isInstance))
4717	diagClash(IMD);
4718
4719	for (const auto *Cat : IDecl->visible_categories())
4720	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4721	diagClash(IMD);
4722	else if (auto CatImpl = Cat->getImplementation())
4723	if (CatImpl != ImpDecl)
4724	if (auto *IMD = Cat->getMethod(Sel, isInstance))
4725	diagClash(IMD);
4726	}
4727
4728	ParmVarDecl *SemaObjC::ActOnMethodParmDeclaration(Scope *S,
4729	ObjCArgInfo &ArgInfo,
4730	int ParamIndex,
4731	bool MethodDefinition) {
4732	ASTContext &Context = getASTContext();
4733	QualType ArgType;
4734	TypeSourceInfo *DI;
4735
4736	if (!ArgInfo.Type) {
4737	ArgType = Context.getObjCIdType();
4738	DI = nullptr;
4739	} else {
4740	ArgType = SemaRef.GetTypeFromParser(Ty: ArgInfo.Type, TInfo: &DI);
4741	}
4742	LookupResult R(SemaRef, ArgInfo.Name, ArgInfo.NameLoc,
4743	Sema::LookupOrdinaryName,
4744	SemaRef.forRedeclarationInCurContext());
4745	SemaRef.LookupName(R, S);
4746	if (R.isSingleResult()) {
4747	NamedDecl *PrevDecl = R.getFoundDecl();
4748	if (S->isDeclScope(PrevDecl)) {
4749	Diag(ArgInfo.NameLoc,
4750	(MethodDefinition ? diag::warn_method_param_redefinition
4751	: diag::warn_method_param_declaration))
4752	<< ArgInfo.Name;
4753	Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
4754	}
4755	}
4756	SourceLocation StartLoc =
4757	DI ? DI->getTypeLoc().getBeginLoc() : ArgInfo.NameLoc;
4758
4759	// Temporarily put parameter variables in the translation unit. This is what
4760	// ActOnParamDeclarator does in the case of C arguments to the Objective-C
4761	// method too.
4762	ParmVarDecl *Param = SemaRef.CheckParameter(
4763	Context.getTranslationUnitDecl(), StartLoc, ArgInfo.NameLoc, ArgInfo.Name,
4764	ArgType, DI, SC_None);
4765	Param->setObjCMethodScopeInfo(ParamIndex);
4766	Param->setObjCDeclQualifier(
4767	CvtQTToAstBitMask(PQTVal: ArgInfo.DeclSpec.getObjCDeclQualifier()));
4768
4769	// Apply the attributes to the parameter.
4770	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, Param, ArgInfo.ArgAttrs);
4771	SemaRef.AddPragmaAttributes(SemaRef.TUScope, Param);
4772	if (Param->hasAttr<BlocksAttr>()) {
4773	Diag(Param->getLocation(), diag::err_block_on_nonlocal);
4774	Param->setInvalidDecl();
4775	}
4776
4777	S->AddDecl(Param);
4778	SemaRef.IdResolver.AddDecl(Param);
4779	return Param;
4780	}
4781
4782	Decl *SemaObjC::ActOnMethodDeclaration(
4783	Scope *S, SourceLocation MethodLoc, SourceLocation EndLoc,
4784	tok::TokenKind MethodType, ObjCDeclSpec &ReturnQT, ParsedType ReturnType,
4785	ArrayRef<SourceLocation> SelectorLocs, Selector Sel,
4786	// optional arguments. The number of types/arguments is obtained
4787	// from the Sel.getNumArgs().
4788	ParmVarDecl **ArgInfo, DeclaratorChunk::ParamInfo *CParamInfo,
4789	unsigned CNumArgs, // c-style args
4790	const ParsedAttributesView &AttrList, tok::ObjCKeywordKind MethodDeclKind,
4791	bool isVariadic, bool MethodDefinition) {
4792	ASTContext &Context = getASTContext();
4793	// Make sure we can establish a context for the method.
4794	if (!SemaRef.CurContext->isObjCContainer()) {
4795	Diag(MethodLoc, diag::err_missing_method_context);
4796	return nullptr;
4797	}
4798
4799	Decl *ClassDecl = cast<ObjCContainerDecl>(Val: SemaRef.CurContext);
4800	QualType resultDeclType;
4801
4802	bool HasRelatedResultType = false;
4803	TypeSourceInfo *ReturnTInfo = nullptr;
4804	if (ReturnType) {
4805	resultDeclType = SemaRef.GetTypeFromParser(Ty: ReturnType, TInfo: &ReturnTInfo);
4806
4807	if (SemaRef.CheckFunctionReturnType(T: resultDeclType, Loc: MethodLoc))
4808	return nullptr;
4809
4810	QualType bareResultType = resultDeclType;
4811	(void)AttributedType::stripOuterNullability(T&: bareResultType);
4812	HasRelatedResultType = (bareResultType == Context.getObjCInstanceType());
4813	} else { // get the type for "id".
4814	resultDeclType = Context.getObjCIdType();
4815	Diag(MethodLoc, diag::warn_missing_method_return_type)
4816	<< FixItHint::CreateInsertion(SelectorLocs.front(), "(id)");
4817	}
4818
4819	ObjCMethodDecl *ObjCMethod = ObjCMethodDecl::Create(
4820	C&: Context, beginLoc: MethodLoc, endLoc: EndLoc, SelInfo: Sel, T: resultDeclType, ReturnTInfo,
4821	contextDecl: SemaRef.CurContext, isInstance: MethodType == tok::minus, isVariadic,
4822	/*isPropertyAccessor=*/false, /*isSynthesizedAccessorStub=*/false,
4823	/*isImplicitlyDeclared=*/false, /*isDefined=*/false,
4824	impControl: MethodDeclKind == tok::objc_optional
4825	? ObjCImplementationControl::Optional
4826	: ObjCImplementationControl::Required,
4827	HasRelatedResultType);
4828
4829	SmallVector<ParmVarDecl*, 16> Params;
4830	for (unsigned I = 0; I < Sel.getNumArgs(); ++I) {
4831	ParmVarDecl *Param = ArgInfo[I];
4832	Param->setDeclContext(ObjCMethod);
4833	SemaRef.ProcessAPINotes(Param);
4834	Params.push_back(Elt: Param);
4835	}
4836
4837	for (unsigned i = 0, e = CNumArgs; i != e; ++i) {
4838	ParmVarDecl *Param = cast<ParmVarDecl>(Val: CParamInfo[i].Param);
4839	QualType ArgType = Param->getType();
4840	if (ArgType.isNull())
4841	ArgType = Context.getObjCIdType();
4842	else
4843	// Perform the default array/function conversions (C99 6.7.5.3p[7,8]).
4844	ArgType = Context.getAdjustedParameterType(T: ArgType);
4845
4846	Param->setDeclContext(ObjCMethod);
4847	Params.push_back(Elt: Param);
4848	}
4849
4850	ObjCMethod->setMethodParams(C&: Context, Params, SelLocs: SelectorLocs);
4851	ObjCMethod->setObjCDeclQualifier(
4852	CvtQTToAstBitMask(PQTVal: ReturnQT.getObjCDeclQualifier()));
4853
4854	SemaRef.ProcessDeclAttributeList(SemaRef.TUScope, ObjCMethod, AttrList);
4855	SemaRef.AddPragmaAttributes(SemaRef.TUScope, ObjCMethod);
4856	SemaRef.ProcessAPINotes(ObjCMethod);
4857
4858	// Add the method now.
4859	const ObjCMethodDecl *PrevMethod = nullptr;
4860	if (ObjCImplDecl *ImpDecl = dyn_cast<ObjCImplDecl>(Val: ClassDecl)) {
4861	if (MethodType == tok::minus) {
4862	PrevMethod = ImpDecl->getInstanceMethod(Sel);
4863	ImpDecl->addInstanceMethod(method: ObjCMethod);
4864	} else {
4865	PrevMethod = ImpDecl->getClassMethod(Sel);
4866	ImpDecl->addClassMethod(method: ObjCMethod);
4867	}
4868
4869	// If this method overrides a previous @synthesize declaration,
4870	// register it with the property. Linear search through all
4871	// properties here, because the autosynthesized stub hasn't been
4872	// made visible yet, so it can be overridden by a later
4873	// user-specified implementation.
4874	for (ObjCPropertyImplDecl *PropertyImpl : ImpDecl->property_impls()) {
4875	if (auto *Setter = PropertyImpl->getSetterMethodDecl())
4876	if (Setter->getSelector() == Sel &&
4877	Setter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4878	assert(Setter->isSynthesizedAccessorStub() && "autosynth stub expected");
4879	PropertyImpl->setSetterMethodDecl(ObjCMethod);
4880	}
4881	if (auto *Getter = PropertyImpl->getGetterMethodDecl())
4882	if (Getter->getSelector() == Sel &&
4883	Getter->isInstanceMethod() == ObjCMethod->isInstanceMethod()) {
4884	assert(Getter->isSynthesizedAccessorStub() && "autosynth stub expected");
4885	PropertyImpl->setGetterMethodDecl(ObjCMethod);
4886	break;
4887	}
4888	}
4889
4890	// A method is either tagged direct explicitly, or inherits it from its
4891	// canonical declaration.
4892	//
4893	// We have to do the merge upfront and not in mergeInterfaceMethodToImpl()
4894	// because IDecl->lookupMethod() returns more possible matches than just
4895	// the canonical declaration.
4896	if (!ObjCMethod->isDirectMethod()) {
4897	const ObjCMethodDecl *CanonicalMD = ObjCMethod->getCanonicalDecl();
4898	if (CanonicalMD->isDirectMethod()) {
4899	const auto *attr = CanonicalMD->getAttr<ObjCDirectAttr>();
4900	ObjCMethod->addAttr(
4901	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4902	}
4903	}
4904
4905	// Merge information from the @interface declaration into the
4906	// @implementation.
4907	if (ObjCInterfaceDecl *IDecl = ImpDecl->getClassInterface()) {
4908	if (auto *IMD = IDecl->lookupMethod(ObjCMethod->getSelector(),
4909	ObjCMethod->isInstanceMethod())) {
4910	mergeInterfaceMethodToImpl(SemaRef, ObjCMethod, IMD);
4911
4912	// The Idecl->lookupMethod() above will find declarations for ObjCMethod
4913	// in one of these places:
4914	//
4915	// (1) the canonical declaration in an @interface container paired
4916	// with the ImplDecl,
4917	// (2) non canonical declarations in @interface not paired with the
4918	// ImplDecl for the same Class,
4919	// (3) any superclass container.
4920	//
4921	// Direct methods only allow for canonical declarations in the matching
4922	// container (case 1).
4923	//
4924	// Direct methods overriding a superclass declaration (case 3) is
4925	// handled during overrides checks in CheckObjCMethodOverrides().
4926	//
4927	// We deal with same-class container mismatches (Case 2) here.
4928	if (IDecl == IMD->getClassInterface()) {
4929	auto diagContainerMismatch = [&] {
4930	int decl = 0, impl = 0;
4931
4932	if (auto *Cat = dyn_cast<ObjCCategoryDecl>(IMD->getDeclContext()))
4933	decl = Cat->IsClassExtension() ? 1 : 2;
4934
4935	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl))
4936	impl = 1 + (decl != 0);
4937
4938	Diag(ObjCMethod->getLocation(),
4939	diag::err_objc_direct_impl_decl_mismatch)
4940	<< decl << impl;
4941	Diag(IMD->getLocation(), diag::note_previous_declaration);
4942	};
4943
4944	if (ObjCMethod->isDirectMethod()) {
4945	const auto *attr = ObjCMethod->getAttr<ObjCDirectAttr>();
4946	if (ObjCMethod->getCanonicalDecl() != IMD) {
4947	diagContainerMismatch();
4948	} else if (!IMD->isDirectMethod()) {
4949	Diag(attr->getLocation(), diag::err_objc_direct_missing_on_decl);
4950	Diag(IMD->getLocation(), diag::note_previous_declaration);
4951	}
4952	} else if (IMD->isDirectMethod()) {
4953	const auto *attr = IMD->getAttr<ObjCDirectAttr>();
4954	if (ObjCMethod->getCanonicalDecl() != IMD) {
4955	diagContainerMismatch();
4956	} else {
4957	ObjCMethod->addAttr(
4958	ObjCDirectAttr::CreateImplicit(Context, attr->getLocation()));
4959	}
4960	}
4961	}
4962
4963	// Warn about defining -dealloc in a category.
4964	if (isa<ObjCCategoryImplDecl>(Val: ImpDecl) && IMD->isOverriding() &&
4965	ObjCMethod->getSelector().getMethodFamily() == OMF_dealloc) {
4966	Diag(ObjCMethod->getLocation(), diag::warn_dealloc_in_category)
4967	<< ObjCMethod->getDeclName();
4968	}
4969	} else {
4970	mergeObjCDirectMembers(S&: SemaRef, CD: ClassDecl, Method: ObjCMethod);
4971	checkObjCDirectMethodClashes(S&: SemaRef, IDecl, Method: ObjCMethod, ImpDecl);
4972	}
4973
4974	// Warn if a method declared in a protocol to which a category or
4975	// extension conforms is non-escaping and the implementation's method is
4976	// escaping.
4977	for (auto *C : IDecl->visible_categories())
4978	for (auto &P : C->protocols())
4979	if (auto *IMD = P->lookupMethod(ObjCMethod->getSelector(),
4980	ObjCMethod->isInstanceMethod())) {
4981	assert(ObjCMethod->parameters().size() ==
4982	IMD->parameters().size() &&
4983	"Methods have different number of parameters");
4984	auto OI = IMD->param_begin(), OE = IMD->param_end();
4985	auto NI = ObjCMethod->param_begin();
4986	for (; OI != OE; ++OI, ++NI)
4987	diagnoseNoescape(*NI, *OI, C, P, SemaRef);
4988	}
4989	}
4990	} else {
4991	if (!isa<ObjCProtocolDecl>(Val: ClassDecl)) {
4992	mergeObjCDirectMembers(S&: SemaRef, CD: ClassDecl, Method: ObjCMethod);
4993
4994	ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
4995	if (!IDecl)
4996	IDecl = cast<ObjCCategoryDecl>(Val: ClassDecl)->getClassInterface();
4997	// For valid code, we should always know the primary interface
4998	// declaration by now, however for invalid code we'll keep parsing
4999	// but we won't find the primary interface and IDecl will be nil.
5000	if (IDecl)
5001	checkObjCDirectMethodClashes(S&: SemaRef, IDecl, Method: ObjCMethod);
5002	}
5003
5004	cast<DeclContext>(Val: ClassDecl)->addDecl(ObjCMethod);
5005	}
5006
5007	if (PrevMethod) {
5008	// You can never have two method definitions with the same name.
5009	Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
5010	<< ObjCMethod->getDeclName();
5011	Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
5012	ObjCMethod->setInvalidDecl();
5013	return ObjCMethod;
5014	}
5015
5016	// If this Objective-C method does not have a related result type, but we
5017	// are allowed to infer related result types, try to do so based on the
5018	// method family.
5019	ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(Val: ClassDecl);
5020	if (!CurrentClass) {
5021	if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(Val: ClassDecl))
5022	CurrentClass = Cat->getClassInterface();
5023	else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(Val: ClassDecl))
5024	CurrentClass = Impl->getClassInterface();
5025	else if (ObjCCategoryImplDecl *CatImpl
5026	= dyn_cast<ObjCCategoryImplDecl>(Val: ClassDecl))
5027	CurrentClass = CatImpl->getClassInterface();
5028	}
5029
5030	ResultTypeCompatibilityKind RTC =
5031	CheckRelatedResultTypeCompatibility(S&: SemaRef, Method: ObjCMethod, CurrentClass);
5032
5033	CheckObjCMethodOverrides(ObjCMethod, CurrentClass, RTC);
5034
5035	bool ARCError = false;
5036	if (getLangOpts().ObjCAutoRefCount)
5037	ARCError = CheckARCMethodDecl(method: ObjCMethod);
5038
5039	// Infer the related result type when possible.
5040	if (!ARCError && RTC == SemaObjC::RTC_Compatible &&
5041	!ObjCMethod->hasRelatedResultType() &&
5042	getLangOpts().ObjCInferRelatedResultType) {
5043	bool InferRelatedResultType = false;
5044	switch (ObjCMethod->getMethodFamily()) {
5045	case OMF_None:
5046	case OMF_copy:
5047	case OMF_dealloc:
5048	case OMF_finalize:
5049	case OMF_mutableCopy:
5050	case OMF_release:
5051	case OMF_retainCount:
5052	case OMF_initialize:
5053	case OMF_performSelector:
5054	break;
5055
5056	case OMF_alloc:
5057	case OMF_new:
5058	InferRelatedResultType = ObjCMethod->isClassMethod();
5059	break;
5060
5061	case OMF_init:
5062	case OMF_autorelease:
5063	case OMF_retain:
5064	case OMF_self:
5065	InferRelatedResultType = ObjCMethod->isInstanceMethod();
5066	break;
5067	}
5068
5069	if (InferRelatedResultType &&
5070	!ObjCMethod->getReturnType()->isObjCIndependentClassType())
5071	ObjCMethod->setRelatedResultType();
5072	}
5073
5074	if (MethodDefinition &&
5075	Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
5076	checkObjCMethodX86VectorTypes(SemaRef, Method: ObjCMethod);
5077
5078	// + load method cannot have availability attributes. It get called on
5079	// startup, so it has to have the availability of the deployment target.
5080	if (const auto *attr = ObjCMethod->getAttr<AvailabilityAttr>()) {
5081	if (ObjCMethod->isClassMethod() &&
5082	ObjCMethod->getSelector().getAsString() == "load") {
5083	Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
5084	<< 0;
5085	ObjCMethod->dropAttr<AvailabilityAttr>();
5086	}
5087	}
5088
5089	// Insert the invisible arguments, self and _cmd!
5090	ObjCMethod->createImplicitParams(Context, ID: ObjCMethod->getClassInterface());
5091
5092	SemaRef.ActOnDocumentableDecl(ObjCMethod);
5093
5094	return ObjCMethod;
5095	}
5096
5097	bool SemaObjC::CheckObjCDeclScope(Decl *D) {
5098	// Following is also an error. But it is caused by a missing @end
5099	// and diagnostic is issued elsewhere.
5100	if (isa<ObjCContainerDecl>(Val: SemaRef.CurContext->getRedeclContext()))
5101	return false;
5102
5103	// If we switched context to translation unit while we are still lexically in
5104	// an objc container, it means the parser missed emitting an error.
5105	if (isa<TranslationUnitDecl>(
5106	Val: SemaRef.getCurLexicalContext()->getRedeclContext()))
5107	return false;
5108
5109	Diag(D->getLocation(), diag::err_objc_decls_may_only_appear_in_global_scope);
5110	D->setInvalidDecl();
5111
5112	return true;
5113	}
5114
5115	/// Called whenever \@defs(ClassName) is encountered in the source. Inserts the
5116	/// instance variables of ClassName into Decls.
5117	void SemaObjC::ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
5118	const IdentifierInfo *ClassName,
5119	SmallVectorImpl<Decl *> &Decls) {
5120	ASTContext &Context = getASTContext();
5121	// Check that ClassName is a valid class
5122	ObjCInterfaceDecl *Class = getObjCInterfaceDecl(Id&: ClassName, IdLoc: DeclStart);
5123	if (!Class) {
5124	Diag(DeclStart, diag::err_undef_interface) << ClassName;
5125	return;
5126	}
5127	if (getLangOpts().ObjCRuntime.isNonFragile()) {
5128	Diag(DeclStart, diag::err_atdef_nonfragile_interface);
5129	return;
5130	}
5131
5132	// Collect the instance variables
5133	SmallVector<const ObjCIvarDecl*, 32> Ivars;
5134	Context.DeepCollectObjCIvars(OI: Class, leafClass: true, Ivars);
5135	// For each ivar, create a fresh ObjCAtDefsFieldDecl.
5136	for (unsigned i = 0; i < Ivars.size(); i++) {
5137	const FieldDecl* ID = Ivars[i];
5138	RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD);
5139	Decl *FD = ObjCAtDefsFieldDecl::Create(C&: Context, DC: Record,
5140	/*FIXME: StartL=*/StartLoc: ID->getLocation(),
5141	IdLoc: ID->getLocation(),
5142	Id: ID->getIdentifier(), T: ID->getType(),
5143	BW: ID->getBitWidth());
5144	Decls.push_back(Elt: FD);
5145	}
5146
5147	// Introduce all of these fields into the appropriate scope.
5148	for (SmallVectorImpl<Decl*>::iterator D = Decls.begin();
5149	D != Decls.end(); ++D) {
5150	FieldDecl *FD = cast<FieldDecl>(Val: *D);
5151	if (getLangOpts().CPlusPlus)
5152	SemaRef.PushOnScopeChains(FD, S);
5153	else if (RecordDecl *Record = dyn_cast<RecordDecl>(Val: TagD))
5154	Record->addDecl(FD);
5155	}
5156	}
5157
5158	/// Build a type-check a new Objective-C exception variable declaration.
5159	VarDecl *SemaObjC::BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType T,
5160	SourceLocation StartLoc,
5161	SourceLocation IdLoc,
5162	const IdentifierInfo *Id,
5163	bool Invalid) {
5164	ASTContext &Context = getASTContext();
5165	// ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
5166	// duration shall not be qualified by an address-space qualifier."
5167	// Since all parameters have automatic store duration, they can not have
5168	// an address space.
5169	if (T.getAddressSpace() != LangAS::Default) {
5170	Diag(IdLoc, diag::err_arg_with_address_space);
5171	Invalid = true;
5172	}
5173
5174	// An @catch parameter must be an unqualified object pointer type;
5175	// FIXME: Recover from "NSObject foo" by inserting the * in "NSObject *foo"?
5176	if (Invalid) {
5177	// Don't do any further checking.
5178	} else if (T->isDependentType()) {
5179	// Okay: we don't know what this type will instantiate to.
5180	} else if (T->isObjCQualifiedIdType()) {
5181	Invalid = true;
5182	Diag(IdLoc, diag::err_illegal_qualifiers_on_catch_parm);
5183	} else if (T->isObjCIdType()) {
5184	// Okay: we don't know what this type will instantiate to.
5185	} else if (!T->isObjCObjectPointerType()) {
5186	Invalid = true;
5187	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5188	} else if (!T->castAs<ObjCObjectPointerType>()->getInterfaceType()) {
5189	Invalid = true;
5190	Diag(IdLoc, diag::err_catch_param_not_objc_type);
5191	}
5192
5193	VarDecl *New = VarDecl::Create(C&: Context, DC: SemaRef.CurContext, StartLoc, IdLoc,
5194	Id, T, TInfo, S: SC_None);
5195	New->setExceptionVariable(true);
5196
5197	// In ARC, infer 'retaining' for variables of retainable type.
5198	if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(New))
5199	Invalid = true;
5200
5201	if (Invalid)
5202	New->setInvalidDecl();
5203	return New;
5204	}
5205
5206	Decl *SemaObjC::ActOnObjCExceptionDecl(Scope *S, Declarator &D) {
5207	const DeclSpec &DS = D.getDeclSpec();
5208
5209	// We allow the "register" storage class on exception variables because
5210	// GCC did, but we drop it completely. Any other storage class is an error.
5211	if (DS.getStorageClassSpec() == DeclSpec::SCS_register) {
5212	Diag(DS.getStorageClassSpecLoc(), diag::warn_register_objc_catch_parm)
5213	<< FixItHint::CreateRemoval(SourceRange(DS.getStorageClassSpecLoc()));
5214	} else if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
5215	Diag(DS.getStorageClassSpecLoc(), diag::err_storage_spec_on_catch_parm)
5216	<< DeclSpec::getSpecifierName(SCS);
5217	}
5218	if (DS.isInlineSpecified())
5219	Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
5220	<< getLangOpts().CPlusPlus17;
5221	if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
5222	Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
5223	diag::err_invalid_thread)
5224	<< DeclSpec::getSpecifierName(TSCS);
5225	D.getMutableDeclSpec().ClearStorageClassSpecs();
5226
5227	SemaRef.DiagnoseFunctionSpecifiers(DS: D.getDeclSpec());
5228
5229	// Check that there are no default arguments inside the type of this
5230	// exception object (C++ only).
5231	if (getLangOpts().CPlusPlus)
5232	SemaRef.CheckExtraCXXDefaultArguments(D);
5233
5234	TypeSourceInfo *TInfo = SemaRef.GetTypeForDeclarator(D);
5235	QualType ExceptionType = TInfo->getType();
5236
5237	VarDecl *New = BuildObjCExceptionDecl(TInfo, T: ExceptionType,
5238	StartLoc: D.getSourceRange().getBegin(),
5239	IdLoc: D.getIdentifierLoc(),
5240	Id: D.getIdentifier(),
5241	Invalid: D.isInvalidType());
5242
5243	// Parameter declarators cannot be qualified (C++ [dcl.meaning]p1).
5244	if (D.getCXXScopeSpec().isSet()) {
5245	Diag(D.getIdentifierLoc(), diag::err_qualified_objc_catch_parm)
5246	<< D.getCXXScopeSpec().getRange();
5247	New->setInvalidDecl();
5248	}
5249
5250	// Add the parameter declaration into this scope.
5251	S->AddDecl(New);
5252	if (D.getIdentifier())
5253	SemaRef.IdResolver.AddDecl(New);
5254
5255	SemaRef.ProcessDeclAttributes(S, New, D);
5256
5257	if (New->hasAttr<BlocksAttr>())
5258	Diag(New->getLocation(), diag::err_block_on_nonlocal);
5259	return New;
5260	}
5261
5262	/// CollectIvarsToConstructOrDestruct - Collect those ivars which require
5263	/// initialization.
5264	void SemaObjC::CollectIvarsToConstructOrDestruct(
5265	ObjCInterfaceDecl *OI, SmallVectorImpl<ObjCIvarDecl *> &Ivars) {
5266	ASTContext &Context = getASTContext();
5267	for (ObjCIvarDecl *Iv = OI->all_declared_ivar_begin(); Iv;
5268	Iv= Iv->getNextIvar()) {
5269	QualType QT = Context.getBaseElementType(Iv->getType());
5270	if (QT->isRecordType())
5271	Ivars.push_back(Elt: Iv);
5272	}
5273	}
5274
5275	void SemaObjC::DiagnoseUseOfUnimplementedSelectors() {
5276	ASTContext &Context = getASTContext();
5277	// Load referenced selectors from the external source.
5278	if (SemaRef.ExternalSource) {
5279	SmallVector<std::pair<Selector, SourceLocation>, 4> Sels;
5280	SemaRef.ExternalSource->ReadReferencedSelectors(Sels);
5281	for (unsigned I = 0, N = Sels.size(); I != N; ++I)
5282	ReferencedSelectors[Sels[I].first] = Sels[I].second;
5283	}
5284
5285	// Warning will be issued only when selector table is
5286	// generated (which means there is at lease one implementation
5287	// in the TU). This is to match gcc's behavior.
5288	if (ReferencedSelectors.empty() ||
5289	!Context.AnyObjCImplementation())
5290	return;
5291	for (auto &SelectorAndLocation : ReferencedSelectors) {
5292	Selector Sel = SelectorAndLocation.first;
5293	SourceLocation Loc = SelectorAndLocation.second;
5294	if (!LookupImplementedMethodInGlobalPool(Sel))
5295	Diag(Loc, diag::warn_unimplemented_selector) << Sel;
5296	}
5297	}
5298
5299	ObjCIvarDecl *
5300	SemaObjC::GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
5301	const ObjCPropertyDecl *&PDecl) const {
5302	if (Method->isClassMethod())
5303	return nullptr;
5304	const ObjCInterfaceDecl *IDecl = Method->getClassInterface();
5305	if (!IDecl)
5306	return nullptr;
5307	Method = IDecl->lookupMethod(Sel: Method->getSelector(), /*isInstance=*/true,
5308	/*shallowCategoryLookup=*/false,
5309	/*followSuper=*/false);
5310	if (!Method || !Method->isPropertyAccessor())
5311	return nullptr;
5312	if ((PDecl = Method->findPropertyDecl()))
5313	if (ObjCIvarDecl *IV = PDecl->getPropertyIvarDecl()) {
5314	// property backing ivar must belong to property's class
5315	// or be a private ivar in class's implementation.
5316	// FIXME. fix the const-ness issue.
5317	IV = const_cast<ObjCInterfaceDecl *>(IDecl)->lookupInstanceVariable(
5318	IV->getIdentifier());
5319	return IV;
5320	}
5321	return nullptr;
5322	}
5323
5324	namespace {
5325	/// Used by SemaObjC::DiagnoseUnusedBackingIvarInAccessor to check if a property
5326	/// accessor references the backing ivar.
5327	class UnusedBackingIvarChecker : public DynamicRecursiveASTVisitor {
5328	public:
5329	Sema &S;
5330	const ObjCMethodDecl *Method;
5331	const ObjCIvarDecl *IvarD;
5332	bool AccessedIvar;
5333	bool InvokedSelfMethod;
5334
5335	UnusedBackingIvarChecker(Sema &S, const ObjCMethodDecl *Method,
5336	const ObjCIvarDecl *IvarD)
5337	: S(S), Method(Method), IvarD(IvarD), AccessedIvar(false),
5338	InvokedSelfMethod(false) {
5339	assert(IvarD);
5340	}
5341
5342	bool VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) override {
5343	if (E->getDecl() == IvarD) {
5344	AccessedIvar = true;
5345	return false;
5346	}
5347	return true;
5348	}
5349
5350	bool VisitObjCMessageExpr(ObjCMessageExpr *E) override {
5351	if (E->getReceiverKind() == ObjCMessageExpr::Instance &&
5352	S.ObjC().isSelfExpr(RExpr: E->getInstanceReceiver(), Method)) {
5353	InvokedSelfMethod = true;
5354	}
5355	return true;
5356	}
5357	};
5358	} // end anonymous namespace
5359
5360	void SemaObjC::DiagnoseUnusedBackingIvarInAccessor(
5361	Scope *S, const ObjCImplementationDecl *ImplD) {
5362	if (S->hasUnrecoverableErrorOccurred())
5363	return;
5364
5365	for (const auto *CurMethod : ImplD->instance_methods()) {
5366	unsigned DIAG = diag::warn_unused_property_backing_ivar;
5367	SourceLocation Loc = CurMethod->getLocation();
5368	if (getDiagnostics().isIgnored(DIAG, Loc))
5369	continue;
5370
5371	const ObjCPropertyDecl *PDecl;
5372	const ObjCIvarDecl *IV = GetIvarBackingPropertyAccessor(CurMethod, PDecl);
5373	if (!IV)
5374	continue;
5375
5376	if (CurMethod->isSynthesizedAccessorStub())
5377	continue;
5378
5379	UnusedBackingIvarChecker Checker(SemaRef, CurMethod, IV);
5380	Checker.TraverseStmt(CurMethod->getBody());
5381	if (Checker.AccessedIvar)
5382	continue;
5383
5384	// Do not issue this warning if backing ivar is used somewhere and accessor
5385	// implementation makes a self call. This is to prevent false positive in
5386	// cases where the ivar is accessed by another method that the accessor
5387	// delegates to.
5388	if (!IV->isReferenced() || !Checker.InvokedSelfMethod) {
5389	Diag(Loc, DIAG) << IV;
5390	Diag(PDecl->getLocation(), diag::note_property_declare);
5391	}
5392	}
5393	}
5394
5395	QualType SemaObjC::AdjustParameterTypeForObjCAutoRefCount(
5396	QualType T, SourceLocation NameLoc, TypeSourceInfo *TSInfo) {
5397	ASTContext &Context = getASTContext();
5398	// In ARC, infer a lifetime qualifier for appropriate parameter types.
5399	if (!getLangOpts().ObjCAutoRefCount ||
5400	T.getObjCLifetime() != Qualifiers::OCL_None || !T->isObjCLifetimeType())
5401	return T;
5402
5403	Qualifiers::ObjCLifetime Lifetime;
5404
5405	// Special cases for arrays:
5406	// - if it's const, use __unsafe_unretained
5407	// - otherwise, it's an error
5408	if (T->isArrayType()) {
5409	if (!T.isConstQualified()) {
5410	if (SemaRef.DelayedDiagnostics.shouldDelayDiagnostics())
5411	SemaRef.DelayedDiagnostics.add(
5412	sema::DelayedDiagnostic::makeForbiddenType(
5413	NameLoc, diag::err_arc_array_param_no_ownership, T, false));
5414	else
5415	Diag(NameLoc, diag::err_arc_array_param_no_ownership)
5416	<< TSInfo->getTypeLoc().getSourceRange();
5417	}
5418	Lifetime = Qualifiers::OCL_ExplicitNone;
5419	} else {
5420	Lifetime = T->getObjCARCImplicitLifetime();
5421	}
5422	T = Context.getLifetimeQualifiedType(type: T, lifetime: Lifetime);
5423
5424	return T;
5425	}
5426
5427	ObjCInterfaceDecl *SemaObjC::getObjCInterfaceDecl(const IdentifierInfo *&Id,
5428	SourceLocation IdLoc,
5429	bool DoTypoCorrection) {
5430	// The third "scope" argument is 0 since we aren't enabling lazy built-in
5431	// creation from this context.
5432	NamedDecl *IDecl = SemaRef.LookupSingleName(S: SemaRef.TUScope, Name: Id, Loc: IdLoc,
5433	NameKind: Sema::LookupOrdinaryName);
5434
5435	if (!IDecl && DoTypoCorrection) {
5436	// Perform typo correction at the given location, but only if we
5437	// find an Objective-C class name.
5438	DeclFilterCCC<ObjCInterfaceDecl> CCC{};
5439	if (TypoCorrection C = SemaRef.CorrectTypo(
5440	Typo: DeclarationNameInfo(Id, IdLoc), LookupKind: Sema::LookupOrdinaryName,
5441	S: SemaRef.TUScope, SS: nullptr, CCC, Mode: CorrectTypoKind::ErrorRecovery)) {
5442	SemaRef.diagnoseTypo(C, PDiag(diag::err_undef_interface_suggest) << Id);
5443	IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
5444	Id = IDecl->getIdentifier();
5445	}
5446	}
5447	ObjCInterfaceDecl *Def = dyn_cast_or_null<ObjCInterfaceDecl>(Val: IDecl);
5448	// This routine must always return a class definition, if any.
5449	if (Def && Def->getDefinition())
5450	Def = Def->getDefinition();
5451	return Def;
5452	}
5453
5454	bool SemaObjC::inferObjCARCLifetime(ValueDecl *decl) {
5455	ASTContext &Context = getASTContext();
5456	QualType type = decl->getType();
5457	Qualifiers::ObjCLifetime lifetime = type.getObjCLifetime();
5458	if (lifetime == Qualifiers::OCL_Autoreleasing) {
5459	// Various kinds of declaration aren't allowed to be __autoreleasing.
5460	unsigned kind = -1U;
5461	if (VarDecl *var = dyn_cast<VarDecl>(Val: decl)) {
5462	if (var->hasAttr<BlocksAttr>())
5463	kind = 0; // __block
5464	else if (!var->hasLocalStorage())
5465	kind = 1; // global
5466	} else if (isa<ObjCIvarDecl>(Val: decl)) {
5467	kind = 3; // ivar
5468	} else if (isa<FieldDecl>(Val: decl)) {
5469	kind = 2; // field
5470	}
5471
5472	if (kind != -1U) {
5473	Diag(decl->getLocation(), diag::err_arc_autoreleasing_var) << kind;
5474	}
5475	} else if (lifetime == Qualifiers::OCL_None) {
5476	// Try to infer lifetime.
5477	if (!type->isObjCLifetimeType())
5478	return false;
5479
5480	lifetime = type->getObjCARCImplicitLifetime();
5481	type = Context.getLifetimeQualifiedType(type, lifetime);
5482	decl->setType(type);
5483	}
5484
5485	if (VarDecl *var = dyn_cast<VarDecl>(Val: decl)) {
5486	// Thread-local variables cannot have lifetime.
5487	if (lifetime && lifetime != Qualifiers::OCL_ExplicitNone &&
5488	var->getTLSKind()) {
5489	Diag(var->getLocation(), diag::err_arc_thread_ownership)
5490	<< var->getType();
5491	return true;
5492	}
5493	}
5494
5495	return false;
5496	}
5497
5498	ObjCContainerDecl *SemaObjC::getObjCDeclContext() const {
5499	return (dyn_cast_or_null<ObjCContainerDecl>(Val: SemaRef.CurContext));
5500	}
5501
5502	void SemaObjC::SetIvarInitializers(ObjCImplementationDecl *ObjCImplementation) {
5503	if (!getLangOpts().CPlusPlus)
5504	return;
5505	if (ObjCInterfaceDecl *OID = ObjCImplementation->getClassInterface()) {
5506	ASTContext &Context = getASTContext();
5507	SmallVector<ObjCIvarDecl *, 8> ivars;
5508	CollectIvarsToConstructOrDestruct(OI: OID, Ivars&: ivars);
5509	if (ivars.empty())
5510	return;
5511	SmallVector<CXXCtorInitializer *, 32> AllToInit;
5512	for (unsigned i = 0; i < ivars.size(); i++) {
5513	FieldDecl *Field = ivars[i];
5514	if (Field->isInvalidDecl())
5515	continue;
5516
5517	CXXCtorInitializer *Member;
5518	InitializedEntity InitEntity = InitializedEntity::InitializeMember(Member: Field);
5519	InitializationKind InitKind =
5520	InitializationKind::CreateDefault(InitLoc: ObjCImplementation->getLocation());
5521
5522	InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, {});
5523	ExprResult MemberInit =
5524	InitSeq.Perform(S&: SemaRef, Entity: InitEntity, Kind: InitKind, Args: {});
5525	MemberInit = SemaRef.MaybeCreateExprWithCleanups(SubExpr: MemberInit);
5526	// Note, MemberInit could actually come back empty if no initialization
5527	// is required (e.g., because it would call a trivial default constructor)
5528	if (!MemberInit.get() || MemberInit.isInvalid())
5529	continue;
5530
5531	Member = new (Context)
5532	CXXCtorInitializer(Context, Field, SourceLocation(), SourceLocation(),
5533	MemberInit.getAs<Expr>(), SourceLocation());
5534	AllToInit.push_back(Elt: Member);
5535
5536	// Be sure that the destructor is accessible and is marked as referenced.
5537	if (const RecordType *RecordTy =
5538	Context.getBaseElementType(Field->getType())
5539	->getAs<RecordType>()) {
5540	CXXRecordDecl *RD = cast<CXXRecordDecl>(Val: RecordTy->getDecl());
5541	if (CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(Class: RD)) {
5542	SemaRef.MarkFunctionReferenced(Loc: Field->getLocation(), Func: Destructor);
5543	SemaRef.CheckDestructorAccess(
5544	Field->getLocation(), Destructor,
5545	PDiag(diag::err_access_dtor_ivar)
5546	<< Context.getBaseElementType(Field->getType()));
5547	}
5548	}
5549	}
5550	ObjCImplementation->setIvarInitializers(C&: Context, initializers: AllToInit.data(),
5551	numInitializers: AllToInit.size());
5552	}
5553	}
5554
5555	/// TranslateIvarVisibility - Translate visibility from a token ID to an
5556	/// AST enum value.
5557	static ObjCIvarDecl::AccessControl
5558	TranslateIvarVisibility(tok::ObjCKeywordKind ivarVisibility) {
5559	switch (ivarVisibility) {
5560	default:
5561	llvm_unreachable("Unknown visitibility kind");
5562	case tok::objc_private:
5563	return ObjCIvarDecl::Private;
5564	case tok::objc_public:
5565	return ObjCIvarDecl::Public;
5566	case tok::objc_protected:
5567	return ObjCIvarDecl::Protected;
5568	case tok::objc_package:
5569	return ObjCIvarDecl::Package;
5570	}
5571	}
5572
5573	/// ActOnIvar - Each ivar field of an objective-c class is passed into this
5574	/// in order to create an IvarDecl object for it.
5575	Decl *SemaObjC::ActOnIvar(Scope *S, SourceLocation DeclStart, Declarator &D,
5576	Expr *BitWidth, tok::ObjCKeywordKind Visibility) {
5577
5578	const IdentifierInfo *II = D.getIdentifier();
5579	SourceLocation Loc = DeclStart;
5580	if (II)
5581	Loc = D.getIdentifierLoc();
5582
5583	// FIXME: Unnamed fields can be handled in various different ways, for
5584	// example, unnamed unions inject all members into the struct namespace!
5585
5586	TypeSourceInfo *TInfo = SemaRef.GetTypeForDeclarator(D);
5587	QualType T = TInfo->getType();
5588
5589	if (BitWidth) {
5590	// 6.7.2.1p3, 6.7.2.1p4
5591	BitWidth =
5592	SemaRef.VerifyBitField(FieldLoc: Loc, FieldName: II, FieldTy: T, /*IsMsStruct*/ false, BitWidth)
5593	.get();
5594	if (!BitWidth)
5595	D.setInvalidType();
5596	} else {
5597	// Not a bitfield.
5598
5599	// validate II.
5600	}
5601	if (T->isReferenceType()) {
5602	Diag(Loc, diag::err_ivar_reference_type);
5603	D.setInvalidType();
5604	}
5605	// C99 6.7.2.1p8: A member of a structure or union may have any type other
5606	// than a variably modified type.
5607	else if (T->isVariablyModifiedType()) {
5608	if (!SemaRef.tryToFixVariablyModifiedVarType(
5609	TInfo, T, Loc, diag::err_typecheck_ivar_variable_size))
5610	D.setInvalidType();
5611	}
5612
5613	// Get the visibility (access control) for this ivar.
5614	ObjCIvarDecl::AccessControl ac = Visibility != tok::objc_not_keyword
5615	? TranslateIvarVisibility(ivarVisibility: Visibility)
5616	: ObjCIvarDecl::None;
5617	// Must set ivar's DeclContext to its enclosing interface.
5618	ObjCContainerDecl *EnclosingDecl =
5619	cast<ObjCContainerDecl>(Val: SemaRef.CurContext);
5620	if (!EnclosingDecl || EnclosingDecl->isInvalidDecl())
5621	return nullptr;
5622	ObjCContainerDecl *EnclosingContext;
5623	if (ObjCImplementationDecl *IMPDecl =
5624	dyn_cast<ObjCImplementationDecl>(Val: EnclosingDecl)) {
5625	if (getLangOpts().ObjCRuntime.isFragile()) {
5626	// Case of ivar declared in an implementation. Context is that of its
5627	// class.
5628	EnclosingContext = IMPDecl->getClassInterface();
5629	assert(EnclosingContext && "Implementation has no class interface!");
5630	} else
5631	EnclosingContext = EnclosingDecl;
5632	} else {
5633	if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(Val: EnclosingDecl)) {
5634	if (getLangOpts().ObjCRuntime.isFragile() || !CDecl->IsClassExtension()) {
5635	Diag(Loc, diag::err_misplaced_ivar) << CDecl->IsClassExtension();
5636	return nullptr;
5637	}
5638	}
5639	EnclosingContext = EnclosingDecl;
5640	}
5641
5642	// Construct the decl.
5643	ObjCIvarDecl *NewID =
5644	ObjCIvarDecl::Create(C&: getASTContext(), DC: EnclosingContext, StartLoc: DeclStart, IdLoc: Loc,
5645	Id: II, T, TInfo, ac, BW: BitWidth);
5646
5647	if (T->containsErrors())
5648	NewID->setInvalidDecl();
5649
5650	if (II) {
5651	NamedDecl *PrevDecl =
5652	SemaRef.LookupSingleName(S, Name: II, Loc, NameKind: Sema::LookupMemberName,
5653	Redecl: RedeclarationKind::ForVisibleRedeclaration);
5654	if (PrevDecl && SemaRef.isDeclInScope(PrevDecl, EnclosingContext, S) &&
5655	!isa<TagDecl>(Val: PrevDecl)) {
5656	Diag(Loc, diag::err_duplicate_member) << II;
5657	Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
5658	NewID->setInvalidDecl();
5659	}
5660	}
5661
5662	// Process attributes attached to the ivar.
5663	SemaRef.ProcessDeclAttributes(S, NewID, D);
5664
5665	if (D.isInvalidType())
5666	NewID->setInvalidDecl();
5667
5668	// In ARC, infer 'retaining' for ivars of retainable type.
5669	if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewID))
5670	NewID->setInvalidDecl();
5671
5672	if (D.getDeclSpec().isModulePrivateSpecified())
5673	NewID->setModulePrivate();
5674
5675	if (II) {
5676	// FIXME: When interfaces are DeclContexts, we'll need to add
5677	// these to the interface.
5678	S->AddDecl(NewID);
5679	SemaRef.IdResolver.AddDecl(NewID);
5680	}
5681
5682	if (getLangOpts().ObjCRuntime.isNonFragile() && !NewID->isInvalidDecl() &&
5683	isa<ObjCInterfaceDecl>(EnclosingDecl))
5684	Diag(Loc, diag::warn_ivars_in_interface);
5685
5686	return NewID;
5687	}
5688