1 //===--- SemaObjCProperty.cpp - Semantic Analysis for ObjC @property ------===//
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 @property and
10 //  @synthesize declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Sema/SemaInternal.h"
15 #include "clang/AST/ASTMutationListener.h"
16 #include "clang/AST/DeclObjC.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/ExprObjC.h"
19 #include "clang/Basic/SourceManager.h"
20 #include "clang/Lex/Lexer.h"
21 #include "clang/Lex/Preprocessor.h"
22 #include "clang/Sema/Initialization.h"
23 #include "llvm/ADT/DenseSet.h"
24 #include "llvm/ADT/SmallString.h"
25 
26 using namespace clang;
27 
28 //===----------------------------------------------------------------------===//
29 // Grammar actions.
30 //===----------------------------------------------------------------------===//
31 
32 /// getImpliedARCOwnership - Given a set of property attributes and a
33 /// type, infer an expected lifetime.  The type's ownership qualification
34 /// is not considered.
35 ///
36 /// Returns OCL_None if the attributes as stated do not imply an ownership.
37 /// Never returns OCL_Autoreleasing.
38 static Qualifiers::ObjCLifetime getImpliedARCOwnership(
39                                ObjCPropertyDecl::PropertyAttributeKind attrs,
40                                                 QualType type) {
41   // retain, strong, copy, weak, and unsafe_unretained are only legal
42   // on properties of retainable pointer type.
43   if (attrs & (ObjCPropertyDecl::OBJC_PR_retain |
44                ObjCPropertyDecl::OBJC_PR_strong |
45                ObjCPropertyDecl::OBJC_PR_copy)) {
46     return Qualifiers::OCL_Strong;
47   } else if (attrs & ObjCPropertyDecl::OBJC_PR_weak) {
48     return Qualifiers::OCL_Weak;
49   } else if (attrs & ObjCPropertyDecl::OBJC_PR_unsafe_unretained) {
50     return Qualifiers::OCL_ExplicitNone;
51   }
52 
53   // assign can appear on other types, so we have to check the
54   // property type.
55   if (attrs & ObjCPropertyDecl::OBJC_PR_assign &&
56       type->isObjCRetainableType()) {
57     return Qualifiers::OCL_ExplicitNone;
58   }
59 
60   return Qualifiers::OCL_None;
61 }
62 
63 /// Check the internal consistency of a property declaration with
64 /// an explicit ownership qualifier.
65 static void checkPropertyDeclWithOwnership(Sema &S,
66                                            ObjCPropertyDecl *property) {
67   if (property->isInvalidDecl()) return;
68 
69   ObjCPropertyDecl::PropertyAttributeKind propertyKind
70     = property->getPropertyAttributes();
71   Qualifiers::ObjCLifetime propertyLifetime
72     = property->getType().getObjCLifetime();
73 
74   assert(propertyLifetime != Qualifiers::OCL_None);
75 
76   Qualifiers::ObjCLifetime expectedLifetime
77     = getImpliedARCOwnership(propertyKind, property->getType());
78   if (!expectedLifetime) {
79     // We have a lifetime qualifier but no dominating property
80     // attribute.  That's okay, but restore reasonable invariants by
81     // setting the property attribute according to the lifetime
82     // qualifier.
83     ObjCPropertyDecl::PropertyAttributeKind attr;
84     if (propertyLifetime == Qualifiers::OCL_Strong) {
85       attr = ObjCPropertyDecl::OBJC_PR_strong;
86     } else if (propertyLifetime == Qualifiers::OCL_Weak) {
87       attr = ObjCPropertyDecl::OBJC_PR_weak;
88     } else {
89       assert(propertyLifetime == Qualifiers::OCL_ExplicitNone);
90       attr = ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
91     }
92     property->setPropertyAttributes(attr);
93     return;
94   }
95 
96   if (propertyLifetime == expectedLifetime) return;
97 
98   property->setInvalidDecl();
99   S.Diag(property->getLocation(),
100          diag::err_arc_inconsistent_property_ownership)
101     << property->getDeclName()
102     << expectedLifetime
103     << propertyLifetime;
104 }
105 
106 /// Check this Objective-C property against a property declared in the
107 /// given protocol.
108 static void
109 CheckPropertyAgainstProtocol(Sema &S, ObjCPropertyDecl *Prop,
110                              ObjCProtocolDecl *Proto,
111                              llvm::SmallPtrSetImpl<ObjCProtocolDecl *> &Known) {
112   // Have we seen this protocol before?
113   if (!Known.insert(Proto).second)
114     return;
115 
116   // Look for a property with the same name.
117   DeclContext::lookup_result R = Proto->lookup(Prop->getDeclName());
118   for (unsigned I = 0, N = R.size(); I != N; ++I) {
119     if (ObjCPropertyDecl *ProtoProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
120       S.DiagnosePropertyMismatch(Prop, ProtoProp, Proto->getIdentifier(), true);
121       return;
122     }
123   }
124 
125   // Check this property against any protocols we inherit.
126   for (auto *P : Proto->protocols())
127     CheckPropertyAgainstProtocol(S, Prop, P, Known);
128 }
129 
130 static unsigned deducePropertyOwnershipFromType(Sema &S, QualType T) {
131   // In GC mode, just look for the __weak qualifier.
132   if (S.getLangOpts().getGC() != LangOptions::NonGC) {
133     if (T.isObjCGCWeak()) return ObjCDeclSpec::DQ_PR_weak;
134 
135   // In ARC/MRC, look for an explicit ownership qualifier.
136   // For some reason, this only applies to __weak.
137   } else if (auto ownership = T.getObjCLifetime()) {
138     switch (ownership) {
139     case Qualifiers::OCL_Weak:
140       return ObjCDeclSpec::DQ_PR_weak;
141     case Qualifiers::OCL_Strong:
142       return ObjCDeclSpec::DQ_PR_strong;
143     case Qualifiers::OCL_ExplicitNone:
144       return ObjCDeclSpec::DQ_PR_unsafe_unretained;
145     case Qualifiers::OCL_Autoreleasing:
146     case Qualifiers::OCL_None:
147       return 0;
148     }
149     llvm_unreachable("bad qualifier");
150   }
151 
152   return 0;
153 }
154 
155 static const unsigned OwnershipMask =
156   (ObjCPropertyDecl::OBJC_PR_assign |
157    ObjCPropertyDecl::OBJC_PR_retain |
158    ObjCPropertyDecl::OBJC_PR_copy   |
159    ObjCPropertyDecl::OBJC_PR_weak   |
160    ObjCPropertyDecl::OBJC_PR_strong |
161    ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
162 
163 static unsigned getOwnershipRule(unsigned attr) {
164   unsigned result = attr & OwnershipMask;
165 
166   // From an ownership perspective, assign and unsafe_unretained are
167   // identical; make sure one also implies the other.
168   if (result & (ObjCPropertyDecl::OBJC_PR_assign |
169                 ObjCPropertyDecl::OBJC_PR_unsafe_unretained)) {
170     result |= ObjCPropertyDecl::OBJC_PR_assign |
171               ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
172   }
173 
174   return result;
175 }
176 
177 Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
178                           SourceLocation LParenLoc,
179                           FieldDeclarator &FD,
180                           ObjCDeclSpec &ODS,
181                           Selector GetterSel,
182                           Selector SetterSel,
183                           tok::ObjCKeywordKind MethodImplKind,
184                           DeclContext *lexicalDC) {
185   unsigned Attributes = ODS.getPropertyAttributes();
186   FD.D.setObjCWeakProperty((Attributes & ObjCDeclSpec::DQ_PR_weak) != 0);
187   TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
188   QualType T = TSI->getType();
189   if (!getOwnershipRule(Attributes)) {
190     Attributes |= deducePropertyOwnershipFromType(*this, T);
191   }
192   bool isReadWrite = ((Attributes & ObjCDeclSpec::DQ_PR_readwrite) ||
193                       // default is readwrite!
194                       !(Attributes & ObjCDeclSpec::DQ_PR_readonly));
195 
196   // Proceed with constructing the ObjCPropertyDecls.
197   ObjCContainerDecl *ClassDecl = cast<ObjCContainerDecl>(CurContext);
198   ObjCPropertyDecl *Res = nullptr;
199   if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
200     if (CDecl->IsClassExtension()) {
201       Res = HandlePropertyInClassExtension(S, AtLoc, LParenLoc,
202                                            FD,
203                                            GetterSel, ODS.getGetterNameLoc(),
204                                            SetterSel, ODS.getSetterNameLoc(),
205                                            isReadWrite, Attributes,
206                                            ODS.getPropertyAttributes(),
207                                            T, TSI, MethodImplKind);
208       if (!Res)
209         return nullptr;
210     }
211   }
212 
213   if (!Res) {
214     Res = CreatePropertyDecl(S, ClassDecl, AtLoc, LParenLoc, FD,
215                              GetterSel, ODS.getGetterNameLoc(), SetterSel,
216                              ODS.getSetterNameLoc(), isReadWrite, Attributes,
217                              ODS.getPropertyAttributes(), T, TSI,
218                              MethodImplKind);
219     if (lexicalDC)
220       Res->setLexicalDeclContext(lexicalDC);
221   }
222 
223   // Validate the attributes on the @property.
224   CheckObjCPropertyAttributes(Res, AtLoc, Attributes,
225                               (isa<ObjCInterfaceDecl>(ClassDecl) ||
226                                isa<ObjCProtocolDecl>(ClassDecl)));
227 
228   // Check consistency if the type has explicit ownership qualification.
229   if (Res->getType().getObjCLifetime())
230     checkPropertyDeclWithOwnership(*this, Res);
231 
232   llvm::SmallPtrSet<ObjCProtocolDecl *, 16> KnownProtos;
233   if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
234     // For a class, compare the property against a property in our superclass.
235     bool FoundInSuper = false;
236     ObjCInterfaceDecl *CurrentInterfaceDecl = IFace;
237     while (ObjCInterfaceDecl *Super = CurrentInterfaceDecl->getSuperClass()) {
238       DeclContext::lookup_result R = Super->lookup(Res->getDeclName());
239       for (unsigned I = 0, N = R.size(); I != N; ++I) {
240         if (ObjCPropertyDecl *SuperProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
241           DiagnosePropertyMismatch(Res, SuperProp, Super->getIdentifier(), false);
242           FoundInSuper = true;
243           break;
244         }
245       }
246       if (FoundInSuper)
247         break;
248       else
249         CurrentInterfaceDecl = Super;
250     }
251 
252     if (FoundInSuper) {
253       // Also compare the property against a property in our protocols.
254       for (auto *P : CurrentInterfaceDecl->protocols()) {
255         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
256       }
257     } else {
258       // Slower path: look in all protocols we referenced.
259       for (auto *P : IFace->all_referenced_protocols()) {
260         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
261       }
262     }
263   } else if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
264     // We don't check if class extension. Because properties in class extension
265     // are meant to override some of the attributes and checking has already done
266     // when property in class extension is constructed.
267     if (!Cat->IsClassExtension())
268       for (auto *P : Cat->protocols())
269         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
270   } else {
271     ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(ClassDecl);
272     for (auto *P : Proto->protocols())
273       CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
274   }
275 
276   ActOnDocumentableDecl(Res);
277   return Res;
278 }
279 
280 static ObjCPropertyDecl::PropertyAttributeKind
281 makePropertyAttributesAsWritten(unsigned Attributes) {
282   unsigned attributesAsWritten = 0;
283   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
284     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readonly;
285   if (Attributes & ObjCDeclSpec::DQ_PR_readwrite)
286     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readwrite;
287   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
288     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_getter;
289   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
290     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_setter;
291   if (Attributes & ObjCDeclSpec::DQ_PR_assign)
292     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_assign;
293   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
294     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_retain;
295   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
296     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_strong;
297   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
298     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_weak;
299   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
300     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_copy;
301   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
302     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
303   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
304     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_nonatomic;
305   if (Attributes & ObjCDeclSpec::DQ_PR_atomic)
306     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_atomic;
307   if (Attributes & ObjCDeclSpec::DQ_PR_class)
308     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_class;
309 
310   return (ObjCPropertyDecl::PropertyAttributeKind)attributesAsWritten;
311 }
312 
313 static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
314                                  SourceLocation LParenLoc, SourceLocation &Loc) {
315   if (LParenLoc.isMacroID())
316     return false;
317 
318   SourceManager &SM = Context.getSourceManager();
319   std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
320   // Try to load the file buffer.
321   bool invalidTemp = false;
322   StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
323   if (invalidTemp)
324     return false;
325   const char *tokenBegin = file.data() + locInfo.second;
326 
327   // Lex from the start of the given location.
328   Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
329               Context.getLangOpts(),
330               file.begin(), tokenBegin, file.end());
331   Token Tok;
332   do {
333     lexer.LexFromRawLexer(Tok);
334     if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
335       Loc = Tok.getLocation();
336       return true;
337     }
338   } while (Tok.isNot(tok::r_paren));
339   return false;
340 }
341 
342 /// Check for a mismatch in the atomicity of the given properties.
343 static void checkAtomicPropertyMismatch(Sema &S,
344                                         ObjCPropertyDecl *OldProperty,
345                                         ObjCPropertyDecl *NewProperty,
346                                         bool PropagateAtomicity) {
347   // If the atomicity of both matches, we're done.
348   bool OldIsAtomic =
349     (OldProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
350       == 0;
351   bool NewIsAtomic =
352     (NewProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
353       == 0;
354   if (OldIsAtomic == NewIsAtomic) return;
355 
356   // Determine whether the given property is readonly and implicitly
357   // atomic.
358   auto isImplicitlyReadonlyAtomic = [](ObjCPropertyDecl *Property) -> bool {
359     // Is it readonly?
360     auto Attrs = Property->getPropertyAttributes();
361     if ((Attrs & ObjCPropertyDecl::OBJC_PR_readonly) == 0) return false;
362 
363     // Is it nonatomic?
364     if (Attrs & ObjCPropertyDecl::OBJC_PR_nonatomic) return false;
365 
366     // Was 'atomic' specified directly?
367     if (Property->getPropertyAttributesAsWritten() &
368           ObjCPropertyDecl::OBJC_PR_atomic)
369       return false;
370 
371     return true;
372   };
373 
374   // If we're allowed to propagate atomicity, and the new property did
375   // not specify atomicity at all, propagate.
376   const unsigned AtomicityMask =
377     (ObjCPropertyDecl::OBJC_PR_atomic | ObjCPropertyDecl::OBJC_PR_nonatomic);
378   if (PropagateAtomicity &&
379       ((NewProperty->getPropertyAttributesAsWritten() & AtomicityMask) == 0)) {
380     unsigned Attrs = NewProperty->getPropertyAttributes();
381     Attrs = Attrs & ~AtomicityMask;
382     if (OldIsAtomic)
383       Attrs |= ObjCPropertyDecl::OBJC_PR_atomic;
384     else
385       Attrs |= ObjCPropertyDecl::OBJC_PR_nonatomic;
386 
387     NewProperty->overwritePropertyAttributes(Attrs);
388     return;
389   }
390 
391   // One of the properties is atomic; if it's a readonly property, and
392   // 'atomic' wasn't explicitly specified, we're okay.
393   if ((OldIsAtomic && isImplicitlyReadonlyAtomic(OldProperty)) ||
394       (NewIsAtomic && isImplicitlyReadonlyAtomic(NewProperty)))
395     return;
396 
397   // Diagnose the conflict.
398   const IdentifierInfo *OldContextName;
399   auto *OldDC = OldProperty->getDeclContext();
400   if (auto Category = dyn_cast<ObjCCategoryDecl>(OldDC))
401     OldContextName = Category->getClassInterface()->getIdentifier();
402   else
403     OldContextName = cast<ObjCContainerDecl>(OldDC)->getIdentifier();
404 
405   S.Diag(NewProperty->getLocation(), diag::warn_property_attribute)
406     << NewProperty->getDeclName() << "atomic"
407     << OldContextName;
408   S.Diag(OldProperty->getLocation(), diag::note_property_declare);
409 }
410 
411 ObjCPropertyDecl *
412 Sema::HandlePropertyInClassExtension(Scope *S,
413                                      SourceLocation AtLoc,
414                                      SourceLocation LParenLoc,
415                                      FieldDeclarator &FD,
416                                      Selector GetterSel,
417                                      SourceLocation GetterNameLoc,
418                                      Selector SetterSel,
419                                      SourceLocation SetterNameLoc,
420                                      const bool isReadWrite,
421                                      unsigned &Attributes,
422                                      const unsigned AttributesAsWritten,
423                                      QualType T,
424                                      TypeSourceInfo *TSI,
425                                      tok::ObjCKeywordKind MethodImplKind) {
426   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
427   // Diagnose if this property is already in continuation class.
428   DeclContext *DC = CurContext;
429   IdentifierInfo *PropertyId = FD.D.getIdentifier();
430   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
431 
432   // We need to look in the @interface to see if the @property was
433   // already declared.
434   if (!CCPrimary) {
435     Diag(CDecl->getLocation(), diag::err_continuation_class);
436     return nullptr;
437   }
438 
439   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
440                          (Attributes & ObjCDeclSpec::DQ_PR_class);
441 
442   // Find the property in the extended class's primary class or
443   // extensions.
444   ObjCPropertyDecl *PIDecl = CCPrimary->FindPropertyVisibleInPrimaryClass(
445       PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty));
446 
447   // If we found a property in an extension, complain.
448   if (PIDecl && isa<ObjCCategoryDecl>(PIDecl->getDeclContext())) {
449     Diag(AtLoc, diag::err_duplicate_property);
450     Diag(PIDecl->getLocation(), diag::note_property_declare);
451     return nullptr;
452   }
453 
454   // Check for consistency with the previous declaration, if there is one.
455   if (PIDecl) {
456     // A readonly property declared in the primary class can be refined
457     // by adding a readwrite property within an extension.
458     // Anything else is an error.
459     if (!(PIDecl->isReadOnly() && isReadWrite)) {
460       // Tailor the diagnostics for the common case where a readwrite
461       // property is declared both in the @interface and the continuation.
462       // This is a common error where the user often intended the original
463       // declaration to be readonly.
464       unsigned diag =
465         (Attributes & ObjCDeclSpec::DQ_PR_readwrite) &&
466         (PIDecl->getPropertyAttributesAsWritten() &
467            ObjCPropertyDecl::OBJC_PR_readwrite)
468         ? diag::err_use_continuation_class_redeclaration_readwrite
469         : diag::err_use_continuation_class;
470       Diag(AtLoc, diag)
471         << CCPrimary->getDeclName();
472       Diag(PIDecl->getLocation(), diag::note_property_declare);
473       return nullptr;
474     }
475 
476     // Check for consistency of getters.
477     if (PIDecl->getGetterName() != GetterSel) {
478      // If the getter was written explicitly, complain.
479       if (AttributesAsWritten & ObjCDeclSpec::DQ_PR_getter) {
480         Diag(AtLoc, diag::warn_property_redecl_getter_mismatch)
481           << PIDecl->getGetterName() << GetterSel;
482         Diag(PIDecl->getLocation(), diag::note_property_declare);
483       }
484 
485       // Always adopt the getter from the original declaration.
486       GetterSel = PIDecl->getGetterName();
487       Attributes |= ObjCDeclSpec::DQ_PR_getter;
488     }
489 
490     // Check consistency of ownership.
491     unsigned ExistingOwnership
492       = getOwnershipRule(PIDecl->getPropertyAttributes());
493     unsigned NewOwnership = getOwnershipRule(Attributes);
494     if (ExistingOwnership && NewOwnership != ExistingOwnership) {
495       // If the ownership was written explicitly, complain.
496       if (getOwnershipRule(AttributesAsWritten)) {
497         Diag(AtLoc, diag::warn_property_attr_mismatch);
498         Diag(PIDecl->getLocation(), diag::note_property_declare);
499       }
500 
501       // Take the ownership from the original property.
502       Attributes = (Attributes & ~OwnershipMask) | ExistingOwnership;
503     }
504 
505     // If the redeclaration is 'weak' but the original property is not,
506     if ((Attributes & ObjCPropertyDecl::OBJC_PR_weak) &&
507         !(PIDecl->getPropertyAttributesAsWritten()
508             & ObjCPropertyDecl::OBJC_PR_weak) &&
509         PIDecl->getType()->getAs<ObjCObjectPointerType>() &&
510         PIDecl->getType().getObjCLifetime() == Qualifiers::OCL_None) {
511       Diag(AtLoc, diag::warn_property_implicitly_mismatched);
512       Diag(PIDecl->getLocation(), diag::note_property_declare);
513     }
514   }
515 
516   // Create a new ObjCPropertyDecl with the DeclContext being
517   // the class extension.
518   ObjCPropertyDecl *PDecl = CreatePropertyDecl(S, CDecl, AtLoc, LParenLoc,
519                                                FD, GetterSel, GetterNameLoc,
520                                                SetterSel, SetterNameLoc,
521                                                isReadWrite,
522                                                Attributes, AttributesAsWritten,
523                                                T, TSI, MethodImplKind, DC);
524 
525   // If there was no declaration of a property with the same name in
526   // the primary class, we're done.
527   if (!PIDecl) {
528     ProcessPropertyDecl(PDecl);
529     return PDecl;
530   }
531 
532   if (!Context.hasSameType(PIDecl->getType(), PDecl->getType())) {
533     bool IncompatibleObjC = false;
534     QualType ConvertedType;
535     // Relax the strict type matching for property type in continuation class.
536     // Allow property object type of continuation class to be different as long
537     // as it narrows the object type in its primary class property. Note that
538     // this conversion is safe only because the wider type is for a 'readonly'
539     // property in primary class and 'narrowed' type for a 'readwrite' property
540     // in continuation class.
541     QualType PrimaryClassPropertyT = Context.getCanonicalType(PIDecl->getType());
542     QualType ClassExtPropertyT = Context.getCanonicalType(PDecl->getType());
543     if (!isa<ObjCObjectPointerType>(PrimaryClassPropertyT) ||
544         !isa<ObjCObjectPointerType>(ClassExtPropertyT) ||
545         (!isObjCPointerConversion(ClassExtPropertyT, PrimaryClassPropertyT,
546                                   ConvertedType, IncompatibleObjC))
547         || IncompatibleObjC) {
548       Diag(AtLoc,
549           diag::err_type_mismatch_continuation_class) << PDecl->getType();
550       Diag(PIDecl->getLocation(), diag::note_property_declare);
551       return nullptr;
552     }
553   }
554 
555   // Check that atomicity of property in class extension matches the previous
556   // declaration.
557   checkAtomicPropertyMismatch(*this, PIDecl, PDecl, true);
558 
559   // Make sure getter/setter are appropriately synthesized.
560   ProcessPropertyDecl(PDecl);
561   return PDecl;
562 }
563 
564 ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
565                                            ObjCContainerDecl *CDecl,
566                                            SourceLocation AtLoc,
567                                            SourceLocation LParenLoc,
568                                            FieldDeclarator &FD,
569                                            Selector GetterSel,
570                                            SourceLocation GetterNameLoc,
571                                            Selector SetterSel,
572                                            SourceLocation SetterNameLoc,
573                                            const bool isReadWrite,
574                                            const unsigned Attributes,
575                                            const unsigned AttributesAsWritten,
576                                            QualType T,
577                                            TypeSourceInfo *TInfo,
578                                            tok::ObjCKeywordKind MethodImplKind,
579                                            DeclContext *lexicalDC){
580   IdentifierInfo *PropertyId = FD.D.getIdentifier();
581 
582   // Property defaults to 'assign' if it is readwrite, unless this is ARC
583   // and the type is retainable.
584   bool isAssign;
585   if (Attributes & (ObjCDeclSpec::DQ_PR_assign |
586                     ObjCDeclSpec::DQ_PR_unsafe_unretained)) {
587     isAssign = true;
588   } else if (getOwnershipRule(Attributes) || !isReadWrite) {
589     isAssign = false;
590   } else {
591     isAssign = (!getLangOpts().ObjCAutoRefCount ||
592                 !T->isObjCRetainableType());
593   }
594 
595   // Issue a warning if property is 'assign' as default and its
596   // object, which is gc'able conforms to NSCopying protocol
597   if (getLangOpts().getGC() != LangOptions::NonGC &&
598       isAssign && !(Attributes & ObjCDeclSpec::DQ_PR_assign)) {
599     if (const ObjCObjectPointerType *ObjPtrTy =
600           T->getAs<ObjCObjectPointerType>()) {
601       ObjCInterfaceDecl *IDecl = ObjPtrTy->getObjectType()->getInterface();
602       if (IDecl)
603         if (ObjCProtocolDecl* PNSCopying =
604             LookupProtocol(&Context.Idents.get("NSCopying"), AtLoc))
605           if (IDecl->ClassImplementsProtocol(PNSCopying, true))
606             Diag(AtLoc, diag::warn_implements_nscopying) << PropertyId;
607     }
608   }
609 
610   if (T->isObjCObjectType()) {
611     SourceLocation StarLoc = TInfo->getTypeLoc().getEndLoc();
612     StarLoc = getLocForEndOfToken(StarLoc);
613     Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object)
614       << FixItHint::CreateInsertion(StarLoc, "*");
615     T = Context.getObjCObjectPointerType(T);
616     SourceLocation TLoc = TInfo->getTypeLoc().getBeginLoc();
617     TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
618   }
619 
620   DeclContext *DC = CDecl;
621   ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
622                                                      FD.D.getIdentifierLoc(),
623                                                      PropertyId, AtLoc,
624                                                      LParenLoc, T, TInfo);
625 
626   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
627                          (Attributes & ObjCDeclSpec::DQ_PR_class);
628   // Class property and instance property can have the same name.
629   if (ObjCPropertyDecl *prevDecl = ObjCPropertyDecl::findPropertyDecl(
630           DC, PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty))) {
631     Diag(PDecl->getLocation(), diag::err_duplicate_property);
632     Diag(prevDecl->getLocation(), diag::note_property_declare);
633     PDecl->setInvalidDecl();
634   }
635   else {
636     DC->addDecl(PDecl);
637     if (lexicalDC)
638       PDecl->setLexicalDeclContext(lexicalDC);
639   }
640 
641   if (T->isArrayType() || T->isFunctionType()) {
642     Diag(AtLoc, diag::err_property_type) << T;
643     PDecl->setInvalidDecl();
644   }
645 
646   ProcessDeclAttributes(S, PDecl, FD.D);
647 
648   // Regardless of setter/getter attribute, we save the default getter/setter
649   // selector names in anticipation of declaration of setter/getter methods.
650   PDecl->setGetterName(GetterSel, GetterNameLoc);
651   PDecl->setSetterName(SetterSel, SetterNameLoc);
652   PDecl->setPropertyAttributesAsWritten(
653                           makePropertyAttributesAsWritten(AttributesAsWritten));
654 
655   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
656     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
657 
658   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
659     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_getter);
660 
661   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
662     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_setter);
663 
664   if (isReadWrite)
665     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
666 
667   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
668     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
669 
670   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
671     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
672 
673   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
674     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
675 
676   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
677     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
678 
679   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
680     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
681 
682   if (isAssign)
683     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
684 
685   // In the semantic attributes, one of nonatomic or atomic is always set.
686   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
687     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
688   else
689     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_atomic);
690 
691   // 'unsafe_unretained' is alias for 'assign'.
692   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
693     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
694   if (isAssign)
695     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
696 
697   if (MethodImplKind == tok::objc_required)
698     PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
699   else if (MethodImplKind == tok::objc_optional)
700     PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
701 
702   if (Attributes & ObjCDeclSpec::DQ_PR_nullability)
703     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nullability);
704 
705   if (Attributes & ObjCDeclSpec::DQ_PR_null_resettable)
706     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_null_resettable);
707 
708  if (Attributes & ObjCDeclSpec::DQ_PR_class)
709     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_class);
710 
711   return PDecl;
712 }
713 
714 static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
715                                  ObjCPropertyDecl *property,
716                                  ObjCIvarDecl *ivar) {
717   if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;
718 
719   QualType ivarType = ivar->getType();
720   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
721 
722   // The lifetime implied by the property's attributes.
723   Qualifiers::ObjCLifetime propertyLifetime =
724     getImpliedARCOwnership(property->getPropertyAttributes(),
725                            property->getType());
726 
727   // We're fine if they match.
728   if (propertyLifetime == ivarLifetime) return;
729 
730   // None isn't a valid lifetime for an object ivar in ARC, and
731   // __autoreleasing is never valid; don't diagnose twice.
732   if ((ivarLifetime == Qualifiers::OCL_None &&
733        S.getLangOpts().ObjCAutoRefCount) ||
734       ivarLifetime == Qualifiers::OCL_Autoreleasing)
735     return;
736 
737   // If the ivar is private, and it's implicitly __unsafe_unretained
738   // because of its type, then pretend it was actually implicitly
739   // __strong.  This is only sound because we're processing the
740   // property implementation before parsing any method bodies.
741   if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
742       propertyLifetime == Qualifiers::OCL_Strong &&
743       ivar->getAccessControl() == ObjCIvarDecl::Private) {
744     SplitQualType split = ivarType.split();
745     if (split.Quals.hasObjCLifetime()) {
746       assert(ivarType->isObjCARCImplicitlyUnretainedType());
747       split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
748       ivarType = S.Context.getQualifiedType(split);
749       ivar->setType(ivarType);
750       return;
751     }
752   }
753 
754   switch (propertyLifetime) {
755   case Qualifiers::OCL_Strong:
756     S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
757       << property->getDeclName()
758       << ivar->getDeclName()
759       << ivarLifetime;
760     break;
761 
762   case Qualifiers::OCL_Weak:
763     S.Diag(ivar->getLocation(), diag::err_weak_property)
764       << property->getDeclName()
765       << ivar->getDeclName();
766     break;
767 
768   case Qualifiers::OCL_ExplicitNone:
769     S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
770       << property->getDeclName()
771       << ivar->getDeclName()
772       << ((property->getPropertyAttributesAsWritten()
773            & ObjCPropertyDecl::OBJC_PR_assign) != 0);
774     break;
775 
776   case Qualifiers::OCL_Autoreleasing:
777     llvm_unreachable("properties cannot be autoreleasing");
778 
779   case Qualifiers::OCL_None:
780     // Any other property should be ignored.
781     return;
782   }
783 
784   S.Diag(property->getLocation(), diag::note_property_declare);
785   if (propertyImplLoc.isValid())
786     S.Diag(propertyImplLoc, diag::note_property_synthesize);
787 }
788 
789 /// setImpliedPropertyAttributeForReadOnlyProperty -
790 /// This routine evaludates life-time attributes for a 'readonly'
791 /// property with no known lifetime of its own, using backing
792 /// 'ivar's attribute, if any. If no backing 'ivar', property's
793 /// life-time is assumed 'strong'.
794 static void setImpliedPropertyAttributeForReadOnlyProperty(
795               ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
796   Qualifiers::ObjCLifetime propertyLifetime =
797     getImpliedARCOwnership(property->getPropertyAttributes(),
798                            property->getType());
799   if (propertyLifetime != Qualifiers::OCL_None)
800     return;
801 
802   if (!ivar) {
803     // if no backing ivar, make property 'strong'.
804     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
805     return;
806   }
807   // property assumes owenership of backing ivar.
808   QualType ivarType = ivar->getType();
809   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
810   if (ivarLifetime == Qualifiers::OCL_Strong)
811     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
812   else if (ivarLifetime == Qualifiers::OCL_Weak)
813     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
814 }
815 
816 static bool
817 isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
818                                 ObjCPropertyDecl::PropertyAttributeKind Kind) {
819   return (Attr1 & Kind) != (Attr2 & Kind);
820 }
821 
822 static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
823                                               unsigned Kinds) {
824   return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
825 }
826 
827 /// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
828 /// property declaration that should be synthesised in all of the inherited
829 /// protocols. It also diagnoses properties declared in inherited protocols with
830 /// mismatched types or attributes, since any of them can be candidate for
831 /// synthesis.
832 static ObjCPropertyDecl *
833 SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
834                                         ObjCInterfaceDecl *ClassDecl,
835                                         ObjCPropertyDecl *Property) {
836   assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&
837          "Expected a property from a protocol");
838   ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
839   ObjCInterfaceDecl::PropertyDeclOrder Properties;
840   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
841     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
842       PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
843                                                 Properties);
844   }
845   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
846     while (SDecl) {
847       for (const auto *PI : SDecl->all_referenced_protocols()) {
848         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
849           PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
850                                                     Properties);
851       }
852       SDecl = SDecl->getSuperClass();
853     }
854   }
855 
856   if (Properties.empty())
857     return Property;
858 
859   ObjCPropertyDecl *OriginalProperty = Property;
860   size_t SelectedIndex = 0;
861   for (const auto &Prop : llvm::enumerate(Properties)) {
862     // Select the 'readwrite' property if such property exists.
863     if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
864       Property = Prop.value();
865       SelectedIndex = Prop.index();
866     }
867   }
868   if (Property != OriginalProperty) {
869     // Check that the old property is compatible with the new one.
870     Properties[SelectedIndex] = OriginalProperty;
871   }
872 
873   QualType RHSType = S.Context.getCanonicalType(Property->getType());
874   unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
875   enum MismatchKind {
876     IncompatibleType = 0,
877     HasNoExpectedAttribute,
878     HasUnexpectedAttribute,
879     DifferentGetter,
880     DifferentSetter
881   };
882   // Represents a property from another protocol that conflicts with the
883   // selected declaration.
884   struct MismatchingProperty {
885     const ObjCPropertyDecl *Prop;
886     MismatchKind Kind;
887     StringRef AttributeName;
888   };
889   SmallVector<MismatchingProperty, 4> Mismatches;
890   for (ObjCPropertyDecl *Prop : Properties) {
891     // Verify the property attributes.
892     unsigned Attr = Prop->getPropertyAttributesAsWritten();
893     if (Attr != OriginalAttributes) {
894       auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
895         MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
896                                                  : HasUnexpectedAttribute;
897         Mismatches.push_back({Prop, Kind, AttributeName});
898       };
899       // The ownership might be incompatible unless the property has no explicit
900       // ownership.
901       bool HasOwnership = (Attr & (ObjCPropertyDecl::OBJC_PR_retain |
902                                    ObjCPropertyDecl::OBJC_PR_strong |
903                                    ObjCPropertyDecl::OBJC_PR_copy |
904                                    ObjCPropertyDecl::OBJC_PR_assign |
905                                    ObjCPropertyDecl::OBJC_PR_unsafe_unretained |
906                                    ObjCPropertyDecl::OBJC_PR_weak)) != 0;
907       if (HasOwnership &&
908           isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
909                                           ObjCPropertyDecl::OBJC_PR_copy)) {
910         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_copy, "copy");
911         continue;
912       }
913       if (HasOwnership && areIncompatiblePropertyAttributes(
914                               OriginalAttributes, Attr,
915                               ObjCPropertyDecl::OBJC_PR_retain |
916                                   ObjCPropertyDecl::OBJC_PR_strong)) {
917         Diag(OriginalAttributes & (ObjCPropertyDecl::OBJC_PR_retain |
918                                    ObjCPropertyDecl::OBJC_PR_strong),
919              "retain (or strong)");
920         continue;
921       }
922       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
923                                           ObjCPropertyDecl::OBJC_PR_atomic)) {
924         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_atomic, "atomic");
925         continue;
926       }
927     }
928     if (Property->getGetterName() != Prop->getGetterName()) {
929       Mismatches.push_back({Prop, DifferentGetter, ""});
930       continue;
931     }
932     if (!Property->isReadOnly() && !Prop->isReadOnly() &&
933         Property->getSetterName() != Prop->getSetterName()) {
934       Mismatches.push_back({Prop, DifferentSetter, ""});
935       continue;
936     }
937     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
938     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
939       bool IncompatibleObjC = false;
940       QualType ConvertedType;
941       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
942           || IncompatibleObjC) {
943         Mismatches.push_back({Prop, IncompatibleType, ""});
944         continue;
945       }
946     }
947   }
948 
949   if (Mismatches.empty())
950     return Property;
951 
952   // Diagnose incompability.
953   {
954     bool HasIncompatibleAttributes = false;
955     for (const auto &Note : Mismatches)
956       HasIncompatibleAttributes =
957           Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
958     // Promote the warning to an error if there are incompatible attributes or
959     // incompatible types together with readwrite/readonly incompatibility.
960     auto Diag = S.Diag(Property->getLocation(),
961                        Property != OriginalProperty || HasIncompatibleAttributes
962                            ? diag::err_protocol_property_mismatch
963                            : diag::warn_protocol_property_mismatch);
964     Diag << Mismatches[0].Kind;
965     switch (Mismatches[0].Kind) {
966     case IncompatibleType:
967       Diag << Property->getType();
968       break;
969     case HasNoExpectedAttribute:
970     case HasUnexpectedAttribute:
971       Diag << Mismatches[0].AttributeName;
972       break;
973     case DifferentGetter:
974       Diag << Property->getGetterName();
975       break;
976     case DifferentSetter:
977       Diag << Property->getSetterName();
978       break;
979     }
980   }
981   for (const auto &Note : Mismatches) {
982     auto Diag =
983         S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
984         << Note.Kind;
985     switch (Note.Kind) {
986     case IncompatibleType:
987       Diag << Note.Prop->getType();
988       break;
989     case HasNoExpectedAttribute:
990     case HasUnexpectedAttribute:
991       Diag << Note.AttributeName;
992       break;
993     case DifferentGetter:
994       Diag << Note.Prop->getGetterName();
995       break;
996     case DifferentSetter:
997       Diag << Note.Prop->getSetterName();
998       break;
999     }
1000   }
1001   if (AtLoc.isValid())
1002     S.Diag(AtLoc, diag::note_property_synthesize);
1003 
1004   return Property;
1005 }
1006 
1007 /// Determine whether any storage attributes were written on the property.
1008 static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
1009                                        ObjCPropertyQueryKind QueryKind) {
1010   if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;
1011 
1012   // If this is a readwrite property in a class extension that refines
1013   // a readonly property in the original class definition, check it as
1014   // well.
1015 
1016   // If it's a readonly property, we're not interested.
1017   if (Prop->isReadOnly()) return false;
1018 
1019   // Is it declared in an extension?
1020   auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
1021   if (!Category || !Category->IsClassExtension()) return false;
1022 
1023   // Find the corresponding property in the primary class definition.
1024   auto OrigClass = Category->getClassInterface();
1025   for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
1026     if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
1027       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1028   }
1029 
1030   // Look through all of the protocols.
1031   for (const auto *Proto : OrigClass->all_referenced_protocols()) {
1032     if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
1033             Prop->getIdentifier(), QueryKind))
1034       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1035   }
1036 
1037   return false;
1038 }
1039 
1040 /// Create a synthesized property accessor stub inside the \@implementation.
1041 static ObjCMethodDecl *
1042 RedeclarePropertyAccessor(ASTContext &Context, ObjCImplementationDecl *Impl,
1043                           ObjCMethodDecl *AccessorDecl, SourceLocation AtLoc,
1044                           SourceLocation PropertyLoc) {
1045   ObjCMethodDecl *Decl = AccessorDecl;
1046   ObjCMethodDecl *ImplDecl = ObjCMethodDecl::Create(
1047       Context, AtLoc, PropertyLoc, Decl->getSelector(), Decl->getReturnType(),
1048       Decl->getReturnTypeSourceInfo(), Impl, Decl->isInstanceMethod(),
1049       Decl->isVariadic(), Decl->isPropertyAccessor(), /* isSynthesized*/ true,
1050       Decl->isImplicit(), Decl->isDefined(), Decl->getImplementationControl(),
1051       Decl->hasRelatedResultType());
1052   ImplDecl->getMethodFamily();
1053   if (Decl->hasAttrs())
1054     ImplDecl->setAttrs(Decl->getAttrs());
1055   ImplDecl->setSelfDecl(Decl->getSelfDecl());
1056   ImplDecl->setCmdDecl(Decl->getCmdDecl());
1057   SmallVector<SourceLocation, 1> SelLocs;
1058   Decl->getSelectorLocs(SelLocs);
1059   ImplDecl->setMethodParams(Context, Decl->parameters(), SelLocs);
1060   ImplDecl->setLexicalDeclContext(Impl);
1061   ImplDecl->setDefined(false);
1062   return ImplDecl;
1063 }
1064 
1065 /// ActOnPropertyImplDecl - This routine performs semantic checks and
1066 /// builds the AST node for a property implementation declaration; declared
1067 /// as \@synthesize or \@dynamic.
1068 ///
1069 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
1070                                   SourceLocation AtLoc,
1071                                   SourceLocation PropertyLoc,
1072                                   bool Synthesize,
1073                                   IdentifierInfo *PropertyId,
1074                                   IdentifierInfo *PropertyIvar,
1075                                   SourceLocation PropertyIvarLoc,
1076                                   ObjCPropertyQueryKind QueryKind) {
1077   ObjCContainerDecl *ClassImpDecl =
1078     dyn_cast<ObjCContainerDecl>(CurContext);
1079   // Make sure we have a context for the property implementation declaration.
1080   if (!ClassImpDecl) {
1081     Diag(AtLoc, diag::err_missing_property_context);
1082     return nullptr;
1083   }
1084   if (PropertyIvarLoc.isInvalid())
1085     PropertyIvarLoc = PropertyLoc;
1086   SourceLocation PropertyDiagLoc = PropertyLoc;
1087   if (PropertyDiagLoc.isInvalid())
1088     PropertyDiagLoc = ClassImpDecl->getBeginLoc();
1089   ObjCPropertyDecl *property = nullptr;
1090   ObjCInterfaceDecl *IDecl = nullptr;
1091   // Find the class or category class where this property must have
1092   // a declaration.
1093   ObjCImplementationDecl *IC = nullptr;
1094   ObjCCategoryImplDecl *CatImplClass = nullptr;
1095   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
1096     IDecl = IC->getClassInterface();
1097     // We always synthesize an interface for an implementation
1098     // without an interface decl. So, IDecl is always non-zero.
1099     assert(IDecl &&
1100            "ActOnPropertyImplDecl - @implementation without @interface");
1101 
1102     // Look for this property declaration in the @implementation's @interface
1103     property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
1104     if (!property) {
1105       Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
1106       return nullptr;
1107     }
1108     if (property->isClassProperty() && Synthesize) {
1109       Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
1110       return nullptr;
1111     }
1112     unsigned PIkind = property->getPropertyAttributesAsWritten();
1113     if ((PIkind & (ObjCPropertyDecl::OBJC_PR_atomic |
1114                    ObjCPropertyDecl::OBJC_PR_nonatomic) ) == 0) {
1115       if (AtLoc.isValid())
1116         Diag(AtLoc, diag::warn_implicit_atomic_property);
1117       else
1118         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
1119       Diag(property->getLocation(), diag::note_property_declare);
1120     }
1121 
1122     if (const ObjCCategoryDecl *CD =
1123         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
1124       if (!CD->IsClassExtension()) {
1125         Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
1126         Diag(property->getLocation(), diag::note_property_declare);
1127         return nullptr;
1128       }
1129     }
1130     if (Synthesize&&
1131         (PIkind & ObjCPropertyDecl::OBJC_PR_readonly) &&
1132         property->hasAttr<IBOutletAttr>() &&
1133         !AtLoc.isValid()) {
1134       bool ReadWriteProperty = false;
1135       // Search into the class extensions and see if 'readonly property is
1136       // redeclared 'readwrite', then no warning is to be issued.
1137       for (auto *Ext : IDecl->known_extensions()) {
1138         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
1139         if (!R.empty())
1140           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
1141             PIkind = ExtProp->getPropertyAttributesAsWritten();
1142             if (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite) {
1143               ReadWriteProperty = true;
1144               break;
1145             }
1146           }
1147       }
1148 
1149       if (!ReadWriteProperty) {
1150         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
1151             << property;
1152         SourceLocation readonlyLoc;
1153         if (LocPropertyAttribute(Context, "readonly",
1154                                  property->getLParenLoc(), readonlyLoc)) {
1155           SourceLocation endLoc =
1156             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
1157           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
1158           Diag(property->getLocation(),
1159                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
1160           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
1161         }
1162       }
1163     }
1164     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
1165       property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
1166                                                          property);
1167 
1168   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
1169     if (Synthesize) {
1170       Diag(AtLoc, diag::err_synthesize_category_decl);
1171       return nullptr;
1172     }
1173     IDecl = CatImplClass->getClassInterface();
1174     if (!IDecl) {
1175       Diag(AtLoc, diag::err_missing_property_interface);
1176       return nullptr;
1177     }
1178     ObjCCategoryDecl *Category =
1179     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
1180 
1181     // If category for this implementation not found, it is an error which
1182     // has already been reported eralier.
1183     if (!Category)
1184       return nullptr;
1185     // Look for this property declaration in @implementation's category
1186     property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
1187     if (!property) {
1188       Diag(PropertyLoc, diag::err_bad_category_property_decl)
1189       << Category->getDeclName();
1190       return nullptr;
1191     }
1192   } else {
1193     Diag(AtLoc, diag::err_bad_property_context);
1194     return nullptr;
1195   }
1196   ObjCIvarDecl *Ivar = nullptr;
1197   bool CompleteTypeErr = false;
1198   bool compat = true;
1199   // Check that we have a valid, previously declared ivar for @synthesize
1200   if (Synthesize) {
1201     // @synthesize
1202     if (!PropertyIvar)
1203       PropertyIvar = PropertyId;
1204     // Check that this is a previously declared 'ivar' in 'IDecl' interface
1205     ObjCInterfaceDecl *ClassDeclared;
1206     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
1207     QualType PropType = property->getType();
1208     QualType PropertyIvarType = PropType.getNonReferenceType();
1209 
1210     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
1211                             diag::err_incomplete_synthesized_property,
1212                             property->getDeclName())) {
1213       Diag(property->getLocation(), diag::note_property_declare);
1214       CompleteTypeErr = true;
1215     }
1216 
1217     if (getLangOpts().ObjCAutoRefCount &&
1218         (property->getPropertyAttributesAsWritten() &
1219          ObjCPropertyDecl::OBJC_PR_readonly) &&
1220         PropertyIvarType->isObjCRetainableType()) {
1221       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
1222     }
1223 
1224     ObjCPropertyDecl::PropertyAttributeKind kind
1225       = property->getPropertyAttributes();
1226 
1227     bool isARCWeak = false;
1228     if (kind & ObjCPropertyDecl::OBJC_PR_weak) {
1229       // Add GC __weak to the ivar type if the property is weak.
1230       if (getLangOpts().getGC() != LangOptions::NonGC) {
1231         assert(!getLangOpts().ObjCAutoRefCount);
1232         if (PropertyIvarType.isObjCGCStrong()) {
1233           Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
1234           Diag(property->getLocation(), diag::note_property_declare);
1235         } else {
1236           PropertyIvarType =
1237             Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
1238         }
1239 
1240       // Otherwise, check whether ARC __weak is enabled and works with
1241       // the property type.
1242       } else {
1243         if (!getLangOpts().ObjCWeak) {
1244           // Only complain here when synthesizing an ivar.
1245           if (!Ivar) {
1246             Diag(PropertyDiagLoc,
1247                  getLangOpts().ObjCWeakRuntime
1248                    ? diag::err_synthesizing_arc_weak_property_disabled
1249                    : diag::err_synthesizing_arc_weak_property_no_runtime);
1250             Diag(property->getLocation(), diag::note_property_declare);
1251           }
1252           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1253         } else {
1254           isARCWeak = true;
1255           if (const ObjCObjectPointerType *ObjT =
1256                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1257             const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1258             if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1259               Diag(property->getLocation(),
1260                    diag::err_arc_weak_unavailable_property)
1261                 << PropertyIvarType;
1262               Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1263                 << ClassImpDecl->getName();
1264             }
1265           }
1266         }
1267       }
1268     }
1269 
1270     if (AtLoc.isInvalid()) {
1271       // Check when default synthesizing a property that there is
1272       // an ivar matching property name and issue warning; since this
1273       // is the most common case of not using an ivar used for backing
1274       // property in non-default synthesis case.
1275       ObjCInterfaceDecl *ClassDeclared=nullptr;
1276       ObjCIvarDecl *originalIvar =
1277       IDecl->lookupInstanceVariable(property->getIdentifier(),
1278                                     ClassDeclared);
1279       if (originalIvar) {
1280         Diag(PropertyDiagLoc,
1281              diag::warn_autosynthesis_property_ivar_match)
1282         << PropertyId << (Ivar == nullptr) << PropertyIvar
1283         << originalIvar->getIdentifier();
1284         Diag(property->getLocation(), diag::note_property_declare);
1285         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
1286       }
1287     }
1288 
1289     if (!Ivar) {
1290       // In ARC, give the ivar a lifetime qualifier based on the
1291       // property attributes.
1292       if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
1293           !PropertyIvarType.getObjCLifetime() &&
1294           PropertyIvarType->isObjCRetainableType()) {
1295 
1296         // It's an error if we have to do this and the user didn't
1297         // explicitly write an ownership attribute on the property.
1298         if (!hasWrittenStorageAttribute(property, QueryKind) &&
1299             !(kind & ObjCPropertyDecl::OBJC_PR_strong)) {
1300           Diag(PropertyDiagLoc,
1301                diag::err_arc_objc_property_default_assign_on_object);
1302           Diag(property->getLocation(), diag::note_property_declare);
1303         } else {
1304           Qualifiers::ObjCLifetime lifetime =
1305             getImpliedARCOwnership(kind, PropertyIvarType);
1306           assert(lifetime && "no lifetime for property?");
1307 
1308           Qualifiers qs;
1309           qs.addObjCLifetime(lifetime);
1310           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1311         }
1312       }
1313 
1314       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1315                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1316                                   PropertyIvarType, /*TInfo=*/nullptr,
1317                                   ObjCIvarDecl::Private,
1318                                   (Expr *)nullptr, true);
1319       if (RequireNonAbstractType(PropertyIvarLoc,
1320                                  PropertyIvarType,
1321                                  diag::err_abstract_type_in_decl,
1322                                  AbstractSynthesizedIvarType)) {
1323         Diag(property->getLocation(), diag::note_property_declare);
1324         // An abstract type is as bad as an incomplete type.
1325         CompleteTypeErr = true;
1326       }
1327       if (!CompleteTypeErr) {
1328         const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
1329         if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
1330           Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
1331             << PropertyIvarType;
1332           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1333         }
1334       }
1335       if (CompleteTypeErr)
1336         Ivar->setInvalidDecl();
1337       ClassImpDecl->addDecl(Ivar);
1338       IDecl->makeDeclVisibleInContext(Ivar);
1339 
1340       if (getLangOpts().ObjCRuntime.isFragile())
1341         Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
1342             << PropertyId;
1343       // Note! I deliberately want it to fall thru so, we have a
1344       // a property implementation and to avoid future warnings.
1345     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1346                !declaresSameEntity(ClassDeclared, IDecl)) {
1347       Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
1348       << property->getDeclName() << Ivar->getDeclName()
1349       << ClassDeclared->getDeclName();
1350       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1351       << Ivar << Ivar->getName();
1352       // Note! I deliberately want it to fall thru so more errors are caught.
1353     }
1354     property->setPropertyIvarDecl(Ivar);
1355 
1356     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1357 
1358     // Check that type of property and its ivar are type compatible.
1359     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1360       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1361           && isa<ObjCObjectPointerType>(IvarType))
1362         compat =
1363           Context.canAssignObjCInterfaces(
1364                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1365                                   IvarType->getAs<ObjCObjectPointerType>());
1366       else {
1367         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1368                                              IvarType)
1369                     == Compatible);
1370       }
1371       if (!compat) {
1372         Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1373           << property->getDeclName() << PropType
1374           << Ivar->getDeclName() << IvarType;
1375         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1376         // Note! I deliberately want it to fall thru so, we have a
1377         // a property implementation and to avoid future warnings.
1378       }
1379       else {
1380         // FIXME! Rules for properties are somewhat different that those
1381         // for assignments. Use a new routine to consolidate all cases;
1382         // specifically for property redeclarations as well as for ivars.
1383         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1384         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1385         if (lhsType != rhsType &&
1386             lhsType->isArithmeticType()) {
1387           Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1388             << property->getDeclName() << PropType
1389             << Ivar->getDeclName() << IvarType;
1390           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1391           // Fall thru - see previous comment
1392         }
1393       }
1394       // __weak is explicit. So it works on Canonical type.
1395       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1396            getLangOpts().getGC() != LangOptions::NonGC)) {
1397         Diag(PropertyDiagLoc, diag::err_weak_property)
1398         << property->getDeclName() << Ivar->getDeclName();
1399         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1400         // Fall thru - see previous comment
1401       }
1402       // Fall thru - see previous comment
1403       if ((property->getType()->isObjCObjectPointerType() ||
1404            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1405           getLangOpts().getGC() != LangOptions::NonGC) {
1406         Diag(PropertyDiagLoc, diag::err_strong_property)
1407         << property->getDeclName() << Ivar->getDeclName();
1408         // Fall thru - see previous comment
1409       }
1410     }
1411     if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
1412         Ivar->getType().getObjCLifetime())
1413       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1414   } else if (PropertyIvar)
1415     // @dynamic
1416     Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);
1417 
1418   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1419   ObjCPropertyImplDecl *PIDecl =
1420   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1421                                property,
1422                                (Synthesize ?
1423                                 ObjCPropertyImplDecl::Synthesize
1424                                 : ObjCPropertyImplDecl::Dynamic),
1425                                Ivar, PropertyIvarLoc);
1426 
1427   if (CompleteTypeErr || !compat)
1428     PIDecl->setInvalidDecl();
1429 
1430   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1431     getterMethod->createImplicitParams(Context, IDecl);
1432 
1433     // Redeclare the getter within the implementation as DeclContext.
1434     if (Synthesize) {
1435       // If the method hasn't been overridden, create a synthesized implementation.
1436       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1437           getterMethod->getSelector(), getterMethod->isInstanceMethod());
1438       if (!OMD)
1439         OMD = RedeclarePropertyAccessor(Context, IC, getterMethod, AtLoc,
1440                                         PropertyLoc);
1441       PIDecl->setGetterMethodDecl(OMD);
1442     }
1443 
1444     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1445         Ivar->getType()->isRecordType()) {
1446       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1447       // returned by the getter as it must conform to C++'s copy-return rules.
1448       // FIXME. Eventually we want to do this for Objective-C as well.
1449       SynthesizedFunctionScope Scope(*this, getterMethod);
1450       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1451       DeclRefExpr *SelfExpr = new (Context)
1452           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1453                       PropertyDiagLoc);
1454       MarkDeclRefReferenced(SelfExpr);
1455       Expr *LoadSelfExpr =
1456         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1457                                  CK_LValueToRValue, SelfExpr, nullptr,
1458                                  VK_RValue);
1459       Expr *IvarRefExpr =
1460         new (Context) ObjCIvarRefExpr(Ivar,
1461                                       Ivar->getUsageType(SelfDecl->getType()),
1462                                       PropertyDiagLoc,
1463                                       Ivar->getLocation(),
1464                                       LoadSelfExpr, true, true);
1465       ExprResult Res = PerformCopyInitialization(
1466           InitializedEntity::InitializeResult(PropertyDiagLoc,
1467                                               getterMethod->getReturnType(),
1468                                               /*NRVO=*/false),
1469           PropertyDiagLoc, IvarRefExpr);
1470       if (!Res.isInvalid()) {
1471         Expr *ResExpr = Res.getAs<Expr>();
1472         if (ResExpr)
1473           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1474         PIDecl->setGetterCXXConstructor(ResExpr);
1475       }
1476     }
1477     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1478         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1479       Diag(getterMethod->getLocation(),
1480            diag::warn_property_getter_owning_mismatch);
1481       Diag(property->getLocation(), diag::note_property_declare);
1482     }
1483     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1484       switch (getterMethod->getMethodFamily()) {
1485         case OMF_retain:
1486         case OMF_retainCount:
1487         case OMF_release:
1488         case OMF_autorelease:
1489           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1490             << 1 << getterMethod->getSelector();
1491           break;
1492         default:
1493           break;
1494       }
1495   }
1496 
1497   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1498     setterMethod->createImplicitParams(Context, IDecl);
1499 
1500     // Redeclare the setter within the implementation as DeclContext.
1501     if (Synthesize) {
1502       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1503           setterMethod->getSelector(), setterMethod->isInstanceMethod());
1504       if (!OMD)
1505         OMD = RedeclarePropertyAccessor(Context, IC, setterMethod,
1506                                         AtLoc, PropertyLoc);
1507       PIDecl->setSetterMethodDecl(OMD);
1508     }
1509 
1510     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1511         Ivar->getType()->isRecordType()) {
1512       // FIXME. Eventually we want to do this for Objective-C as well.
1513       SynthesizedFunctionScope Scope(*this, setterMethod);
1514       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1515       DeclRefExpr *SelfExpr = new (Context)
1516           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1517                       PropertyDiagLoc);
1518       MarkDeclRefReferenced(SelfExpr);
1519       Expr *LoadSelfExpr =
1520         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1521                                  CK_LValueToRValue, SelfExpr, nullptr,
1522                                  VK_RValue);
1523       Expr *lhs =
1524         new (Context) ObjCIvarRefExpr(Ivar,
1525                                       Ivar->getUsageType(SelfDecl->getType()),
1526                                       PropertyDiagLoc,
1527                                       Ivar->getLocation(),
1528                                       LoadSelfExpr, true, true);
1529       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1530       ParmVarDecl *Param = (*P);
1531       QualType T = Param->getType().getNonReferenceType();
1532       DeclRefExpr *rhs = new (Context)
1533           DeclRefExpr(Context, Param, false, T, VK_LValue, PropertyDiagLoc);
1534       MarkDeclRefReferenced(rhs);
1535       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1536                                   BO_Assign, lhs, rhs);
1537       if (property->getPropertyAttributes() &
1538           ObjCPropertyDecl::OBJC_PR_atomic) {
1539         Expr *callExpr = Res.getAs<Expr>();
1540         if (const CXXOperatorCallExpr *CXXCE =
1541               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1542           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1543             if (!FuncDecl->isTrivial())
1544               if (property->getType()->isReferenceType()) {
1545                 Diag(PropertyDiagLoc,
1546                      diag::err_atomic_property_nontrivial_assign_op)
1547                     << property->getType();
1548                 Diag(FuncDecl->getBeginLoc(), diag::note_callee_decl)
1549                     << FuncDecl;
1550               }
1551       }
1552       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1553     }
1554   }
1555 
1556   if (IC) {
1557     if (Synthesize)
1558       if (ObjCPropertyImplDecl *PPIDecl =
1559           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1560         Diag(PropertyLoc, diag::err_duplicate_ivar_use)
1561         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1562         << PropertyIvar;
1563         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1564       }
1565 
1566     if (ObjCPropertyImplDecl *PPIDecl
1567         = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
1568       Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
1569       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1570       return nullptr;
1571     }
1572     IC->addPropertyImplementation(PIDecl);
1573     if (getLangOpts().ObjCDefaultSynthProperties &&
1574         getLangOpts().ObjCRuntime.isNonFragile() &&
1575         !IDecl->isObjCRequiresPropertyDefs()) {
1576       // Diagnose if an ivar was lazily synthesdized due to a previous
1577       // use and if 1) property is @dynamic or 2) property is synthesized
1578       // but it requires an ivar of different name.
1579       ObjCInterfaceDecl *ClassDeclared=nullptr;
1580       ObjCIvarDecl *Ivar = nullptr;
1581       if (!Synthesize)
1582         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1583       else {
1584         if (PropertyIvar && PropertyIvar != PropertyId)
1585           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1586       }
1587       // Issue diagnostics only if Ivar belongs to current class.
1588       if (Ivar && Ivar->getSynthesize() &&
1589           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1590         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1591         << PropertyId;
1592         Ivar->setInvalidDecl();
1593       }
1594     }
1595   } else {
1596     if (Synthesize)
1597       if (ObjCPropertyImplDecl *PPIDecl =
1598           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1599         Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
1600         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1601         << PropertyIvar;
1602         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1603       }
1604 
1605     if (ObjCPropertyImplDecl *PPIDecl =
1606         CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
1607       Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
1608       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1609       return nullptr;
1610     }
1611     CatImplClass->addPropertyImplementation(PIDecl);
1612   }
1613 
1614   return PIDecl;
1615 }
1616 
1617 //===----------------------------------------------------------------------===//
1618 // Helper methods.
1619 //===----------------------------------------------------------------------===//
1620 
1621 /// DiagnosePropertyMismatch - Compares two properties for their
1622 /// attributes and types and warns on a variety of inconsistencies.
1623 ///
1624 void
1625 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1626                                ObjCPropertyDecl *SuperProperty,
1627                                const IdentifierInfo *inheritedName,
1628                                bool OverridingProtocolProperty) {
1629   ObjCPropertyDecl::PropertyAttributeKind CAttr =
1630     Property->getPropertyAttributes();
1631   ObjCPropertyDecl::PropertyAttributeKind SAttr =
1632     SuperProperty->getPropertyAttributes();
1633 
1634   // We allow readonly properties without an explicit ownership
1635   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1636   // to be overridden by a property with any explicit ownership in the subclass.
1637   if (!OverridingProtocolProperty &&
1638       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1639     ;
1640   else {
1641     if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
1642         && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
1643       Diag(Property->getLocation(), diag::warn_readonly_property)
1644         << Property->getDeclName() << inheritedName;
1645     if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
1646         != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
1647       Diag(Property->getLocation(), diag::warn_property_attribute)
1648         << Property->getDeclName() << "copy" << inheritedName;
1649     else if (!(SAttr & ObjCPropertyDecl::OBJC_PR_readonly)){
1650       unsigned CAttrRetain =
1651         (CAttr &
1652          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1653       unsigned SAttrRetain =
1654         (SAttr &
1655          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1656       bool CStrong = (CAttrRetain != 0);
1657       bool SStrong = (SAttrRetain != 0);
1658       if (CStrong != SStrong)
1659         Diag(Property->getLocation(), diag::warn_property_attribute)
1660           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1661     }
1662   }
1663 
1664   // Check for nonatomic; note that nonatomic is effectively
1665   // meaningless for readonly properties, so don't diagnose if the
1666   // atomic property is 'readonly'.
1667   checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
1668   // Readonly properties from protocols can be implemented as "readwrite"
1669   // with a custom setter name.
1670   if (Property->getSetterName() != SuperProperty->getSetterName() &&
1671       !(SuperProperty->isReadOnly() &&
1672         isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
1673     Diag(Property->getLocation(), diag::warn_property_attribute)
1674       << Property->getDeclName() << "setter" << inheritedName;
1675     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1676   }
1677   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1678     Diag(Property->getLocation(), diag::warn_property_attribute)
1679       << Property->getDeclName() << "getter" << inheritedName;
1680     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1681   }
1682 
1683   QualType LHSType =
1684     Context.getCanonicalType(SuperProperty->getType());
1685   QualType RHSType =
1686     Context.getCanonicalType(Property->getType());
1687 
1688   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1689     // Do cases not handled in above.
1690     // FIXME. For future support of covariant property types, revisit this.
1691     bool IncompatibleObjC = false;
1692     QualType ConvertedType;
1693     if (!isObjCPointerConversion(RHSType, LHSType,
1694                                  ConvertedType, IncompatibleObjC) ||
1695         IncompatibleObjC) {
1696         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1697         << Property->getType() << SuperProperty->getType() << inheritedName;
1698       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1699     }
1700   }
1701 }
1702 
1703 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1704                                             ObjCMethodDecl *GetterMethod,
1705                                             SourceLocation Loc) {
1706   if (!GetterMethod)
1707     return false;
1708   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1709   QualType PropertyRValueType =
1710       property->getType().getNonReferenceType().getAtomicUnqualifiedType();
1711   bool compat = Context.hasSameType(PropertyRValueType, GetterType);
1712   if (!compat) {
1713     const ObjCObjectPointerType *propertyObjCPtr = nullptr;
1714     const ObjCObjectPointerType *getterObjCPtr = nullptr;
1715     if ((propertyObjCPtr =
1716              PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
1717         (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
1718       compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
1719     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
1720               != Compatible) {
1721           Diag(Loc, diag::err_property_accessor_type)
1722             << property->getDeclName() << PropertyRValueType
1723             << GetterMethod->getSelector() << GetterType;
1724           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1725           return true;
1726     } else {
1727       compat = true;
1728       QualType lhsType = Context.getCanonicalType(PropertyRValueType);
1729       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1730       if (lhsType != rhsType && lhsType->isArithmeticType())
1731         compat = false;
1732     }
1733   }
1734 
1735   if (!compat) {
1736     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1737     << property->getDeclName()
1738     << GetterMethod->getSelector();
1739     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1740     return true;
1741   }
1742 
1743   return false;
1744 }
1745 
1746 /// CollectImmediateProperties - This routine collects all properties in
1747 /// the class and its conforming protocols; but not those in its super class.
1748 static void
1749 CollectImmediateProperties(ObjCContainerDecl *CDecl,
1750                            ObjCContainerDecl::PropertyMap &PropMap,
1751                            ObjCContainerDecl::PropertyMap &SuperPropMap,
1752                            bool CollectClassPropsOnly = false,
1753                            bool IncludeProtocols = true) {
1754   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1755     for (auto *Prop : IDecl->properties()) {
1756       if (CollectClassPropsOnly && !Prop->isClassProperty())
1757         continue;
1758       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1759           Prop;
1760     }
1761 
1762     // Collect the properties from visible extensions.
1763     for (auto *Ext : IDecl->visible_extensions())
1764       CollectImmediateProperties(Ext, PropMap, SuperPropMap,
1765                                  CollectClassPropsOnly, IncludeProtocols);
1766 
1767     if (IncludeProtocols) {
1768       // Scan through class's protocols.
1769       for (auto *PI : IDecl->all_referenced_protocols())
1770         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1771                                    CollectClassPropsOnly);
1772     }
1773   }
1774   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1775     for (auto *Prop : CATDecl->properties()) {
1776       if (CollectClassPropsOnly && !Prop->isClassProperty())
1777         continue;
1778       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1779           Prop;
1780     }
1781     if (IncludeProtocols) {
1782       // Scan through class's protocols.
1783       for (auto *PI : CATDecl->protocols())
1784         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1785                                    CollectClassPropsOnly);
1786     }
1787   }
1788   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1789     for (auto *Prop : PDecl->properties()) {
1790       if (CollectClassPropsOnly && !Prop->isClassProperty())
1791         continue;
1792       ObjCPropertyDecl *PropertyFromSuper =
1793           SuperPropMap[std::make_pair(Prop->getIdentifier(),
1794                                       Prop->isClassProperty())];
1795       // Exclude property for protocols which conform to class's super-class,
1796       // as super-class has to implement the property.
1797       if (!PropertyFromSuper ||
1798           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1799         ObjCPropertyDecl *&PropEntry =
1800             PropMap[std::make_pair(Prop->getIdentifier(),
1801                                    Prop->isClassProperty())];
1802         if (!PropEntry)
1803           PropEntry = Prop;
1804       }
1805     }
1806     // Scan through protocol's protocols.
1807     for (auto *PI : PDecl->protocols())
1808       CollectImmediateProperties(PI, PropMap, SuperPropMap,
1809                                  CollectClassPropsOnly);
1810   }
1811 }
1812 
1813 /// CollectSuperClassPropertyImplementations - This routine collects list of
1814 /// properties to be implemented in super class(s) and also coming from their
1815 /// conforming protocols.
1816 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1817                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1818   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1819     ObjCInterfaceDecl::PropertyDeclOrder PO;
1820     while (SDecl) {
1821       SDecl->collectPropertiesToImplement(PropMap, PO);
1822       SDecl = SDecl->getSuperClass();
1823     }
1824   }
1825 }
1826 
1827 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1828 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1829 /// declared in class 'IFace'.
1830 bool
1831 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1832                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1833   if (!IV->getSynthesize())
1834     return false;
1835   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1836                                             Method->isInstanceMethod());
1837   if (!IMD || !IMD->isPropertyAccessor())
1838     return false;
1839 
1840   // look up a property declaration whose one of its accessors is implemented
1841   // by this method.
1842   for (const auto *Property : IFace->instance_properties()) {
1843     if ((Property->getGetterName() == IMD->getSelector() ||
1844          Property->getSetterName() == IMD->getSelector()) &&
1845         (Property->getPropertyIvarDecl() == IV))
1846       return true;
1847   }
1848   // Also look up property declaration in class extension whose one of its
1849   // accessors is implemented by this method.
1850   for (const auto *Ext : IFace->known_extensions())
1851     for (const auto *Property : Ext->instance_properties())
1852       if ((Property->getGetterName() == IMD->getSelector() ||
1853            Property->getSetterName() == IMD->getSelector()) &&
1854           (Property->getPropertyIvarDecl() == IV))
1855         return true;
1856   return false;
1857 }
1858 
1859 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1860                                          ObjCPropertyDecl *Prop) {
1861   bool SuperClassImplementsGetter = false;
1862   bool SuperClassImplementsSetter = false;
1863   if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1864     SuperClassImplementsSetter = true;
1865 
1866   while (IDecl->getSuperClass()) {
1867     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1868     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1869       SuperClassImplementsGetter = true;
1870 
1871     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1872       SuperClassImplementsSetter = true;
1873     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1874       return true;
1875     IDecl = IDecl->getSuperClass();
1876   }
1877   return false;
1878 }
1879 
1880 /// Default synthesizes all properties which must be synthesized
1881 /// in class's \@implementation.
1882 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
1883                                        ObjCInterfaceDecl *IDecl,
1884                                        SourceLocation AtEnd) {
1885   ObjCInterfaceDecl::PropertyMap PropMap;
1886   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1887   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1888   if (PropMap.empty())
1889     return;
1890   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1891   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1892 
1893   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1894     ObjCPropertyDecl *Prop = PropertyOrder[i];
1895     // Is there a matching property synthesize/dynamic?
1896     if (Prop->isInvalidDecl() ||
1897         Prop->isClassProperty() ||
1898         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1899       continue;
1900     // Property may have been synthesized by user.
1901     if (IMPDecl->FindPropertyImplDecl(
1902             Prop->getIdentifier(), Prop->getQueryKind()))
1903       continue;
1904     ObjCMethodDecl *ImpMethod = IMPDecl->getInstanceMethod(Prop->getGetterName());
1905     if (ImpMethod && !ImpMethod->getBody()) {
1906       if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1907         continue;
1908       ImpMethod = IMPDecl->getInstanceMethod(Prop->getSetterName());
1909       if (ImpMethod && !ImpMethod->getBody())
1910         continue;
1911     }
1912     if (ObjCPropertyImplDecl *PID =
1913         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1914       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1915         << Prop->getIdentifier();
1916       if (PID->getLocation().isValid())
1917         Diag(PID->getLocation(), diag::note_property_synthesize);
1918       continue;
1919     }
1920     ObjCPropertyDecl *PropInSuperClass =
1921         SuperPropMap[std::make_pair(Prop->getIdentifier(),
1922                                     Prop->isClassProperty())];
1923     if (ObjCProtocolDecl *Proto =
1924           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1925       // We won't auto-synthesize properties declared in protocols.
1926       // Suppress the warning if class's superclass implements property's
1927       // getter and implements property's setter (if readwrite property).
1928       // Or, if property is going to be implemented in its super class.
1929       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1930         Diag(IMPDecl->getLocation(),
1931              diag::warn_auto_synthesizing_protocol_property)
1932           << Prop << Proto;
1933         Diag(Prop->getLocation(), diag::note_property_declare);
1934         std::string FixIt =
1935             (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
1936         Diag(AtEnd, diag::note_add_synthesize_directive)
1937             << FixItHint::CreateInsertion(AtEnd, FixIt);
1938       }
1939       continue;
1940     }
1941     // If property to be implemented in the super class, ignore.
1942     if (PropInSuperClass) {
1943       if ((Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readwrite) &&
1944           (PropInSuperClass->getPropertyAttributes() &
1945            ObjCPropertyDecl::OBJC_PR_readonly) &&
1946           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1947           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1948         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1949         << Prop->getIdentifier();
1950         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1951       }
1952       else {
1953         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1954         << Prop->getIdentifier();
1955         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1956         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1957       }
1958       continue;
1959     }
1960     // We use invalid SourceLocations for the synthesized ivars since they
1961     // aren't really synthesized at a particular location; they just exist.
1962     // Saying that they are located at the @implementation isn't really going
1963     // to help users.
1964     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1965       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1966                             true,
1967                             /* property = */ Prop->getIdentifier(),
1968                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1969                             Prop->getLocation(), Prop->getQueryKind()));
1970     if (PIDecl && !Prop->isUnavailable()) {
1971       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1972       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1973     }
1974   }
1975 }
1976 
1977 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
1978                                        SourceLocation AtEnd) {
1979   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
1980     return;
1981   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
1982   if (!IC)
1983     return;
1984   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
1985     if (!IDecl->isObjCRequiresPropertyDefs())
1986       DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
1987 }
1988 
1989 static void DiagnoseUnimplementedAccessor(
1990     Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
1991     ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
1992     ObjCPropertyDecl *Prop,
1993     llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
1994   // Check to see if we have a corresponding selector in SMap and with the
1995   // right method type.
1996   auto I = llvm::find_if(SMap, [&](const ObjCMethodDecl *x) {
1997     return x->getSelector() == Method &&
1998            x->isClassMethod() == Prop->isClassProperty();
1999   });
2000   // When reporting on missing property setter/getter implementation in
2001   // categories, do not report when they are declared in primary class,
2002   // class's protocol, or one of it super classes. This is because,
2003   // the class is going to implement them.
2004   if (I == SMap.end() &&
2005       (PrimaryClass == nullptr ||
2006        !PrimaryClass->lookupPropertyAccessor(Method, C,
2007                                              Prop->isClassProperty()))) {
2008     unsigned diag =
2009         isa<ObjCCategoryDecl>(CDecl)
2010             ? (Prop->isClassProperty()
2011                    ? diag::warn_impl_required_in_category_for_class_property
2012                    : diag::warn_setter_getter_impl_required_in_category)
2013             : (Prop->isClassProperty()
2014                    ? diag::warn_impl_required_for_class_property
2015                    : diag::warn_setter_getter_impl_required);
2016     S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
2017     S.Diag(Prop->getLocation(), diag::note_property_declare);
2018     if (S.LangOpts.ObjCDefaultSynthProperties &&
2019         S.LangOpts.ObjCRuntime.isNonFragile())
2020       if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
2021         if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
2022           S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
2023   }
2024 }
2025 
2026 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
2027                                            ObjCContainerDecl *CDecl,
2028                                            bool SynthesizeProperties) {
2029   ObjCContainerDecl::PropertyMap PropMap;
2030   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
2031 
2032   // Since we don't synthesize class properties, we should emit diagnose even
2033   // if SynthesizeProperties is true.
2034   ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2035   // Gather properties which need not be implemented in this class
2036   // or category.
2037   if (!IDecl)
2038     if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
2039       // For categories, no need to implement properties declared in
2040       // its primary class (and its super classes) if property is
2041       // declared in one of those containers.
2042       if ((IDecl = C->getClassInterface())) {
2043         ObjCInterfaceDecl::PropertyDeclOrder PO;
2044         IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
2045       }
2046     }
2047   if (IDecl)
2048     CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
2049 
2050   // When SynthesizeProperties is true, we only check class properties.
2051   CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
2052                              SynthesizeProperties/*CollectClassPropsOnly*/);
2053 
2054   // Scan the @interface to see if any of the protocols it adopts
2055   // require an explicit implementation, via attribute
2056   // 'objc_protocol_requires_explicit_implementation'.
2057   if (IDecl) {
2058     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
2059 
2060     for (auto *PDecl : IDecl->all_referenced_protocols()) {
2061       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2062         continue;
2063       // Lazily construct a set of all the properties in the @interface
2064       // of the class, without looking at the superclass.  We cannot
2065       // use the call to CollectImmediateProperties() above as that
2066       // utilizes information from the super class's properties as well
2067       // as scans the adopted protocols.  This work only triggers for protocols
2068       // with the attribute, which is very rare, and only occurs when
2069       // analyzing the @implementation.
2070       if (!LazyMap) {
2071         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2072         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
2073         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
2074                                    /* CollectClassPropsOnly */ false,
2075                                    /* IncludeProtocols */ false);
2076       }
2077       // Add the properties of 'PDecl' to the list of properties that
2078       // need to be implemented.
2079       for (auto *PropDecl : PDecl->properties()) {
2080         if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
2081                                       PropDecl->isClassProperty())])
2082           continue;
2083         PropMap[std::make_pair(PropDecl->getIdentifier(),
2084                                PropDecl->isClassProperty())] = PropDecl;
2085       }
2086     }
2087   }
2088 
2089   if (PropMap.empty())
2090     return;
2091 
2092   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
2093   for (const auto *I : IMPDecl->property_impls())
2094     PropImplMap.insert(I->getPropertyDecl());
2095 
2096   llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
2097   // Collect property accessors implemented in current implementation.
2098   for (const auto *I : IMPDecl->methods())
2099     InsMap.insert(I);
2100 
2101   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
2102   ObjCInterfaceDecl *PrimaryClass = nullptr;
2103   if (C && !C->IsClassExtension())
2104     if ((PrimaryClass = C->getClassInterface()))
2105       // Report unimplemented properties in the category as well.
2106       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
2107         // When reporting on missing setter/getters, do not report when
2108         // setter/getter is implemented in category's primary class
2109         // implementation.
2110         for (const auto *I : IMP->methods())
2111           InsMap.insert(I);
2112       }
2113 
2114   for (ObjCContainerDecl::PropertyMap::iterator
2115        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
2116     ObjCPropertyDecl *Prop = P->second;
2117     // Is there a matching property synthesize/dynamic?
2118     if (Prop->isInvalidDecl() ||
2119         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
2120         PropImplMap.count(Prop) ||
2121         Prop->getAvailability() == AR_Unavailable)
2122       continue;
2123 
2124     // Diagnose unimplemented getters and setters.
2125     DiagnoseUnimplementedAccessor(*this,
2126           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
2127     if (!Prop->isReadOnly())
2128       DiagnoseUnimplementedAccessor(*this,
2129                                     PrimaryClass, Prop->getSetterName(),
2130                                     IMPDecl, CDecl, C, Prop, InsMap);
2131   }
2132 }
2133 
2134 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
2135   for (const auto *propertyImpl : impDecl->property_impls()) {
2136     const auto *property = propertyImpl->getPropertyDecl();
2137     // Warn about null_resettable properties with synthesized setters,
2138     // because the setter won't properly handle nil.
2139     if (propertyImpl->getPropertyImplementation()
2140           == ObjCPropertyImplDecl::Synthesize &&
2141         (property->getPropertyAttributes() &
2142          ObjCPropertyDecl::OBJC_PR_null_resettable) &&
2143         property->getGetterMethodDecl() &&
2144         property->getSetterMethodDecl()) {
2145       auto *getterImpl = propertyImpl->getGetterMethodDecl();
2146       auto *setterImpl = propertyImpl->getSetterMethodDecl();
2147       if ((!getterImpl || getterImpl->isSynthesizedAccessorStub()) &&
2148           (!setterImpl || setterImpl->isSynthesizedAccessorStub())) {
2149         SourceLocation loc = propertyImpl->getLocation();
2150         if (loc.isInvalid())
2151           loc = impDecl->getBeginLoc();
2152 
2153         Diag(loc, diag::warn_null_resettable_setter)
2154           << setterImpl->getSelector() << property->getDeclName();
2155       }
2156     }
2157   }
2158 }
2159 
2160 void
2161 Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
2162                                        ObjCInterfaceDecl* IDecl) {
2163   // Rules apply in non-GC mode only
2164   if (getLangOpts().getGC() != LangOptions::NonGC)
2165     return;
2166   ObjCContainerDecl::PropertyMap PM;
2167   for (auto *Prop : IDecl->properties())
2168     PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2169   for (const auto *Ext : IDecl->known_extensions())
2170     for (auto *Prop : Ext->properties())
2171       PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2172 
2173   for (ObjCContainerDecl::PropertyMap::iterator I = PM.begin(), E = PM.end();
2174        I != E; ++I) {
2175     const ObjCPropertyDecl *Property = I->second;
2176     ObjCMethodDecl *GetterMethod = nullptr;
2177     ObjCMethodDecl *SetterMethod = nullptr;
2178     bool LookedUpGetterSetter = false;
2179 
2180     unsigned Attributes = Property->getPropertyAttributes();
2181     unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();
2182 
2183     if (!(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic) &&
2184         !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_nonatomic)) {
2185       GetterMethod = Property->isClassProperty() ?
2186                      IMPDecl->getClassMethod(Property->getGetterName()) :
2187                      IMPDecl->getInstanceMethod(Property->getGetterName());
2188       SetterMethod = Property->isClassProperty() ?
2189                      IMPDecl->getClassMethod(Property->getSetterName()) :
2190                      IMPDecl->getInstanceMethod(Property->getSetterName());
2191       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2192         GetterMethod = nullptr;
2193       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2194         SetterMethod = nullptr;
2195       LookedUpGetterSetter = true;
2196       if (GetterMethod) {
2197         Diag(GetterMethod->getLocation(),
2198              diag::warn_default_atomic_custom_getter_setter)
2199           << Property->getIdentifier() << 0;
2200         Diag(Property->getLocation(), diag::note_property_declare);
2201       }
2202       if (SetterMethod) {
2203         Diag(SetterMethod->getLocation(),
2204              diag::warn_default_atomic_custom_getter_setter)
2205           << Property->getIdentifier() << 1;
2206         Diag(Property->getLocation(), diag::note_property_declare);
2207       }
2208     }
2209 
2210     // We only care about readwrite atomic property.
2211     if ((Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
2212         !(Attributes & ObjCPropertyDecl::OBJC_PR_readwrite))
2213       continue;
2214     if (const ObjCPropertyImplDecl *PIDecl = IMPDecl->FindPropertyImplDecl(
2215             Property->getIdentifier(), Property->getQueryKind())) {
2216       if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
2217         continue;
2218       GetterMethod = PIDecl->getGetterMethodDecl();
2219       SetterMethod = PIDecl->getSetterMethodDecl();
2220       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2221         GetterMethod = nullptr;
2222       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2223         SetterMethod = nullptr;
2224       if ((bool)GetterMethod ^ (bool)SetterMethod) {
2225         SourceLocation MethodLoc =
2226           (GetterMethod ? GetterMethod->getLocation()
2227                         : SetterMethod->getLocation());
2228         Diag(MethodLoc, diag::warn_atomic_property_rule)
2229           << Property->getIdentifier() << (GetterMethod != nullptr)
2230           << (SetterMethod != nullptr);
2231         // fixit stuff.
2232         if (Property->getLParenLoc().isValid() &&
2233             !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic)) {
2234           // @property () ... case.
2235           SourceLocation AfterLParen =
2236             getLocForEndOfToken(Property->getLParenLoc());
2237           StringRef NonatomicStr = AttributesAsWritten? "nonatomic, "
2238                                                       : "nonatomic";
2239           Diag(Property->getLocation(),
2240                diag::note_atomic_property_fixup_suggest)
2241             << FixItHint::CreateInsertion(AfterLParen, NonatomicStr);
2242         } else if (Property->getLParenLoc().isInvalid()) {
2243           //@property id etc.
2244           SourceLocation startLoc =
2245             Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2246           Diag(Property->getLocation(),
2247                diag::note_atomic_property_fixup_suggest)
2248             << FixItHint::CreateInsertion(startLoc, "(nonatomic) ");
2249         }
2250         else
2251           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
2252         Diag(Property->getLocation(), diag::note_property_declare);
2253       }
2254     }
2255   }
2256 }
2257 
2258 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
2259   if (getLangOpts().getGC() == LangOptions::GCOnly)
2260     return;
2261 
2262   for (const auto *PID : D->property_impls()) {
2263     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2264     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
2265         !PD->isClassProperty()) {
2266       ObjCMethodDecl *IM = PID->getGetterMethodDecl();
2267       if (IM && !IM->isSynthesizedAccessorStub())
2268         continue;
2269       ObjCMethodDecl *method = PD->getGetterMethodDecl();
2270       if (!method)
2271         continue;
2272       ObjCMethodFamily family = method->getMethodFamily();
2273       if (family == OMF_alloc || family == OMF_copy ||
2274           family == OMF_mutableCopy || family == OMF_new) {
2275         if (getLangOpts().ObjCAutoRefCount)
2276           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
2277         else
2278           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
2279 
2280         // Look for a getter explicitly declared alongside the property.
2281         // If we find one, use its location for the note.
2282         SourceLocation noteLoc = PD->getLocation();
2283         SourceLocation fixItLoc;
2284         for (auto *getterRedecl : method->redecls()) {
2285           if (getterRedecl->isImplicit())
2286             continue;
2287           if (getterRedecl->getDeclContext() != PD->getDeclContext())
2288             continue;
2289           noteLoc = getterRedecl->getLocation();
2290           fixItLoc = getterRedecl->getEndLoc();
2291         }
2292 
2293         Preprocessor &PP = getPreprocessor();
2294         TokenValue tokens[] = {
2295           tok::kw___attribute, tok::l_paren, tok::l_paren,
2296           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
2297           PP.getIdentifierInfo("none"), tok::r_paren,
2298           tok::r_paren, tok::r_paren
2299         };
2300         StringRef spelling = "__attribute__((objc_method_family(none)))";
2301         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
2302         if (!macroName.empty())
2303           spelling = macroName;
2304 
2305         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
2306             << method->getDeclName() << spelling;
2307         if (fixItLoc.isValid()) {
2308           SmallString<64> fixItText(" ");
2309           fixItText += spelling;
2310           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
2311         }
2312       }
2313     }
2314   }
2315 }
2316 
2317 void Sema::DiagnoseMissingDesignatedInitOverrides(
2318                                             const ObjCImplementationDecl *ImplD,
2319                                             const ObjCInterfaceDecl *IFD) {
2320   assert(IFD->hasDesignatedInitializers());
2321   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
2322   if (!SuperD)
2323     return;
2324 
2325   SelectorSet InitSelSet;
2326   for (const auto *I : ImplD->instance_methods())
2327     if (I->getMethodFamily() == OMF_init)
2328       InitSelSet.insert(I->getSelector());
2329 
2330   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
2331   SuperD->getDesignatedInitializers(DesignatedInits);
2332   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
2333          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
2334     const ObjCMethodDecl *MD = *I;
2335     if (!InitSelSet.count(MD->getSelector())) {
2336       // Don't emit a diagnostic if the overriding method in the subclass is
2337       // marked as unavailable.
2338       bool Ignore = false;
2339       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
2340         Ignore = IMD->isUnavailable();
2341       } else {
2342         // Check the methods declared in the class extensions too.
2343         for (auto *Ext : IFD->visible_extensions())
2344           if (auto *IMD = Ext->getInstanceMethod(MD->getSelector())) {
2345             Ignore = IMD->isUnavailable();
2346             break;
2347           }
2348       }
2349       if (!Ignore) {
2350         Diag(ImplD->getLocation(),
2351              diag::warn_objc_implementation_missing_designated_init_override)
2352           << MD->getSelector();
2353         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
2354       }
2355     }
2356   }
2357 }
2358 
2359 /// AddPropertyAttrs - Propagates attributes from a property to the
2360 /// implicitly-declared getter or setter for that property.
2361 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
2362                              ObjCPropertyDecl *Property) {
2363   // Should we just clone all attributes over?
2364   for (const auto *A : Property->attrs()) {
2365     if (isa<DeprecatedAttr>(A) ||
2366         isa<UnavailableAttr>(A) ||
2367         isa<AvailabilityAttr>(A))
2368       PropertyMethod->addAttr(A->clone(S.Context));
2369   }
2370 }
2371 
2372 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2373 /// have the property type and issue diagnostics if they don't.
2374 /// Also synthesize a getter/setter method if none exist (and update the
2375 /// appropriate lookup tables.
2376 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
2377   ObjCMethodDecl *GetterMethod, *SetterMethod;
2378   ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
2379   if (CD->isInvalidDecl())
2380     return;
2381 
2382   bool IsClassProperty = property->isClassProperty();
2383   GetterMethod = IsClassProperty ?
2384     CD->getClassMethod(property->getGetterName()) :
2385     CD->getInstanceMethod(property->getGetterName());
2386 
2387   // if setter or getter is not found in class extension, it might be
2388   // in the primary class.
2389   if (!GetterMethod)
2390     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2391       if (CatDecl->IsClassExtension())
2392         GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2393                          getClassMethod(property->getGetterName()) :
2394                        CatDecl->getClassInterface()->
2395                          getInstanceMethod(property->getGetterName());
2396 
2397   SetterMethod = IsClassProperty ?
2398                  CD->getClassMethod(property->getSetterName()) :
2399                  CD->getInstanceMethod(property->getSetterName());
2400   if (!SetterMethod)
2401     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2402       if (CatDecl->IsClassExtension())
2403         SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2404                           getClassMethod(property->getSetterName()) :
2405                        CatDecl->getClassInterface()->
2406                           getInstanceMethod(property->getSetterName());
2407   DiagnosePropertyAccessorMismatch(property, GetterMethod,
2408                                    property->getLocation());
2409 
2410   if (!property->isReadOnly() && SetterMethod) {
2411     if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
2412         Context.VoidTy)
2413       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2414     if (SetterMethod->param_size() != 1 ||
2415         !Context.hasSameUnqualifiedType(
2416           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2417           property->getType().getNonReferenceType())) {
2418       Diag(property->getLocation(),
2419            diag::warn_accessor_property_type_mismatch)
2420         << property->getDeclName()
2421         << SetterMethod->getSelector();
2422       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2423     }
2424   }
2425 
2426   // Synthesize getter/setter methods if none exist.
2427   // Find the default getter and if one not found, add one.
2428   // FIXME: The synthesized property we set here is misleading. We almost always
2429   // synthesize these methods unless the user explicitly provided prototypes
2430   // (which is odd, but allowed). Sema should be typechecking that the
2431   // declarations jive in that situation (which it is not currently).
2432   if (!GetterMethod) {
2433     // No instance/class method of same name as property getter name was found.
2434     // Declare a getter method and add it to the list of methods
2435     // for this class.
2436     SourceLocation Loc = property->getLocation();
2437 
2438     // The getter returns the declared property type with all qualifiers
2439     // removed.
2440     QualType resultTy = property->getType().getAtomicUnqualifiedType();
2441 
2442     // If the property is null_resettable, the getter returns nonnull.
2443     if (property->getPropertyAttributes() &
2444         ObjCPropertyDecl::OBJC_PR_null_resettable) {
2445       QualType modifiedTy = resultTy;
2446       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2447         if (*nullability == NullabilityKind::Unspecified)
2448           resultTy = Context.getAttributedType(attr::TypeNonNull,
2449                                                modifiedTy, modifiedTy);
2450       }
2451     }
2452 
2453     GetterMethod = ObjCMethodDecl::Create(
2454         Context, Loc, Loc, property->getGetterName(), resultTy, nullptr, CD,
2455         !IsClassProperty, /*isVariadic=*/false,
2456         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
2457         /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2458         (property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
2459             ? ObjCMethodDecl::Optional
2460             : ObjCMethodDecl::Required);
2461     CD->addDecl(GetterMethod);
2462 
2463     AddPropertyAttrs(*this, GetterMethod, property);
2464 
2465     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2466       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2467                                                                      Loc));
2468 
2469     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2470       GetterMethod->addAttr(
2471         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2472 
2473     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2474       GetterMethod->addAttr(SectionAttr::CreateImplicit(
2475           Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2476           SectionAttr::GNU_section));
2477 
2478     if (getLangOpts().ObjCAutoRefCount)
2479       CheckARCMethodDecl(GetterMethod);
2480   } else
2481     // A user declared getter will be synthesize when @synthesize of
2482     // the property with the same name is seen in the @implementation
2483     GetterMethod->setPropertyAccessor(true);
2484   property->setGetterMethodDecl(GetterMethod);
2485 
2486   // Skip setter if property is read-only.
2487   if (!property->isReadOnly()) {
2488     // Find the default setter and if one not found, add one.
2489     if (!SetterMethod) {
2490       // No instance/class method of same name as property setter name was
2491       // found.
2492       // Declare a setter method and add it to the list of methods
2493       // for this class.
2494       SourceLocation Loc = property->getLocation();
2495 
2496       SetterMethod =
2497         ObjCMethodDecl::Create(Context, Loc, Loc,
2498                                property->getSetterName(), Context.VoidTy,
2499                                nullptr, CD, !IsClassProperty,
2500                                /*isVariadic=*/false,
2501                                /*isPropertyAccessor=*/true,
2502                                /*isSynthesizedAccessorStub=*/false,
2503                                /*isImplicitlyDeclared=*/true,
2504                                /*isDefined=*/false,
2505                                (property->getPropertyImplementation() ==
2506                                 ObjCPropertyDecl::Optional) ?
2507                                 ObjCMethodDecl::Optional :
2508                                 ObjCMethodDecl::Required);
2509 
2510       // Remove all qualifiers from the setter's parameter type.
2511       QualType paramTy =
2512           property->getType().getUnqualifiedType().getAtomicUnqualifiedType();
2513 
2514       // If the property is null_resettable, the setter accepts a
2515       // nullable value.
2516       if (property->getPropertyAttributes() &
2517           ObjCPropertyDecl::OBJC_PR_null_resettable) {
2518         QualType modifiedTy = paramTy;
2519         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2520           if (*nullability == NullabilityKind::Unspecified)
2521             paramTy = Context.getAttributedType(attr::TypeNullable,
2522                                                 modifiedTy, modifiedTy);
2523         }
2524       }
2525 
2526       // Invent the arguments for the setter. We don't bother making a
2527       // nice name for the argument.
2528       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2529                                                   Loc, Loc,
2530                                                   property->getIdentifier(),
2531                                                   paramTy,
2532                                                   /*TInfo=*/nullptr,
2533                                                   SC_None,
2534                                                   nullptr);
2535       SetterMethod->setMethodParams(Context, Argument, None);
2536 
2537       AddPropertyAttrs(*this, SetterMethod, property);
2538 
2539       CD->addDecl(SetterMethod);
2540       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2541         SetterMethod->addAttr(SectionAttr::CreateImplicit(
2542             Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2543             SectionAttr::GNU_section));
2544       // It's possible for the user to have set a very odd custom
2545       // setter selector that causes it to have a method family.
2546       if (getLangOpts().ObjCAutoRefCount)
2547         CheckARCMethodDecl(SetterMethod);
2548     } else
2549       // A user declared setter will be synthesize when @synthesize of
2550       // the property with the same name is seen in the @implementation
2551       SetterMethod->setPropertyAccessor(true);
2552     property->setSetterMethodDecl(SetterMethod);
2553   }
2554   // Add any synthesized methods to the global pool. This allows us to
2555   // handle the following, which is supported by GCC (and part of the design).
2556   //
2557   // @interface Foo
2558   // @property double bar;
2559   // @end
2560   //
2561   // void thisIsUnfortunate() {
2562   //   id foo;
2563   //   double bar = [foo bar];
2564   // }
2565   //
2566   if (!IsClassProperty) {
2567     if (GetterMethod)
2568       AddInstanceMethodToGlobalPool(GetterMethod);
2569     if (SetterMethod)
2570       AddInstanceMethodToGlobalPool(SetterMethod);
2571   } else {
2572     if (GetterMethod)
2573       AddFactoryMethodToGlobalPool(GetterMethod);
2574     if (SetterMethod)
2575       AddFactoryMethodToGlobalPool(SetterMethod);
2576   }
2577 
2578   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2579   if (!CurrentClass) {
2580     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2581       CurrentClass = Cat->getClassInterface();
2582     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2583       CurrentClass = Impl->getClassInterface();
2584   }
2585   if (GetterMethod)
2586     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2587   if (SetterMethod)
2588     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2589 }
2590 
2591 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2592                                        SourceLocation Loc,
2593                                        unsigned &Attributes,
2594                                        bool propertyInPrimaryClass) {
2595   // FIXME: Improve the reported location.
2596   if (!PDecl || PDecl->isInvalidDecl())
2597     return;
2598 
2599   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2600       (Attributes & ObjCDeclSpec::DQ_PR_readwrite))
2601     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2602     << "readonly" << "readwrite";
2603 
2604   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2605   QualType PropertyTy = PropertyDecl->getType();
2606 
2607   // Check for copy or retain on non-object types.
2608   if ((Attributes & (ObjCDeclSpec::DQ_PR_weak | ObjCDeclSpec::DQ_PR_copy |
2609                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong)) &&
2610       !PropertyTy->isObjCRetainableType() &&
2611       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2612     Diag(Loc, diag::err_objc_property_requires_object)
2613       << (Attributes & ObjCDeclSpec::DQ_PR_weak ? "weak" :
2614           Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain (or strong)");
2615     Attributes &= ~(ObjCDeclSpec::DQ_PR_weak   | ObjCDeclSpec::DQ_PR_copy |
2616                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong);
2617     PropertyDecl->setInvalidDecl();
2618   }
2619 
2620   // Check for assign on object types.
2621   if ((Attributes & ObjCDeclSpec::DQ_PR_assign) &&
2622       !(Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) &&
2623       PropertyTy->isObjCRetainableType() &&
2624       !PropertyTy->isObjCARCImplicitlyUnretainedType()) {
2625     Diag(Loc, diag::warn_objc_property_assign_on_object);
2626   }
2627 
2628   // Check for more than one of { assign, copy, retain }.
2629   if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
2630     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2631       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2632         << "assign" << "copy";
2633       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2634     }
2635     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2636       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2637         << "assign" << "retain";
2638       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2639     }
2640     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2641       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2642         << "assign" << "strong";
2643       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2644     }
2645     if (getLangOpts().ObjCAutoRefCount  &&
2646         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2647       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2648         << "assign" << "weak";
2649       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2650     }
2651     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2652       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2653   } else if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) {
2654     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2655       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2656         << "unsafe_unretained" << "copy";
2657       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2658     }
2659     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2660       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2661         << "unsafe_unretained" << "retain";
2662       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2663     }
2664     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2665       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2666         << "unsafe_unretained" << "strong";
2667       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2668     }
2669     if (getLangOpts().ObjCAutoRefCount  &&
2670         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2671       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2672         << "unsafe_unretained" << "weak";
2673       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2674     }
2675   } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2676     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2677       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2678         << "copy" << "retain";
2679       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2680     }
2681     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2682       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2683         << "copy" << "strong";
2684       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2685     }
2686     if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2687       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2688         << "copy" << "weak";
2689       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2690     }
2691   }
2692   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2693            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2694       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2695         << "retain" << "weak";
2696       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2697   }
2698   else if ((Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2699            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2700       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2701         << "strong" << "weak";
2702       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2703   }
2704 
2705   if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2706     // 'weak' and 'nonnull' are mutually exclusive.
2707     if (auto nullability = PropertyTy->getNullability(Context)) {
2708       if (*nullability == NullabilityKind::NonNull)
2709         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2710           << "nonnull" << "weak";
2711     }
2712   }
2713 
2714   if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
2715       (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
2716       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2717         << "atomic" << "nonatomic";
2718       Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
2719   }
2720 
2721   // Warn if user supplied no assignment attribute, property is
2722   // readwrite, and this is an object type.
2723   if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
2724     if (Attributes & ObjCDeclSpec::DQ_PR_readonly) {
2725       // do nothing
2726     } else if (getLangOpts().ObjCAutoRefCount) {
2727       // With arc, @property definitions should default to strong when
2728       // not specified.
2729       PropertyDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
2730     } else if (PropertyTy->isObjCObjectPointerType()) {
2731         bool isAnyClassTy =
2732           (PropertyTy->isObjCClassType() ||
2733            PropertyTy->isObjCQualifiedClassType());
2734         // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2735         // issue any warning.
2736         if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2737           ;
2738         else if (propertyInPrimaryClass) {
2739           // Don't issue warning on property with no life time in class
2740           // extension as it is inherited from property in primary class.
2741           // Skip this warning in gc-only mode.
2742           if (getLangOpts().getGC() != LangOptions::GCOnly)
2743             Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2744 
2745           // If non-gc code warn that this is likely inappropriate.
2746           if (getLangOpts().getGC() == LangOptions::NonGC)
2747             Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2748         }
2749     }
2750 
2751     // FIXME: Implement warning dependent on NSCopying being
2752     // implemented. See also:
2753     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2754     // (please trim this list while you are at it).
2755   }
2756 
2757   if (!(Attributes & ObjCDeclSpec::DQ_PR_copy)
2758       &&!(Attributes & ObjCDeclSpec::DQ_PR_readonly)
2759       && getLangOpts().getGC() == LangOptions::GCOnly
2760       && PropertyTy->isBlockPointerType())
2761     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2762   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2763            !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2764            !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2765            PropertyTy->isBlockPointerType())
2766       Diag(Loc, diag::warn_objc_property_retain_of_block);
2767 
2768   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2769       (Attributes & ObjCDeclSpec::DQ_PR_setter))
2770     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2771 }
2772