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   if (Attributes & ObjCDeclSpec::DQ_PR_direct)
310     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_direct;
311 
312   return (ObjCPropertyDecl::PropertyAttributeKind)attributesAsWritten;
313 }
314 
315 static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
316                                  SourceLocation LParenLoc, SourceLocation &Loc) {
317   if (LParenLoc.isMacroID())
318     return false;
319 
320   SourceManager &SM = Context.getSourceManager();
321   std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
322   // Try to load the file buffer.
323   bool invalidTemp = false;
324   StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
325   if (invalidTemp)
326     return false;
327   const char *tokenBegin = file.data() + locInfo.second;
328 
329   // Lex from the start of the given location.
330   Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
331               Context.getLangOpts(),
332               file.begin(), tokenBegin, file.end());
333   Token Tok;
334   do {
335     lexer.LexFromRawLexer(Tok);
336     if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
337       Loc = Tok.getLocation();
338       return true;
339     }
340   } while (Tok.isNot(tok::r_paren));
341   return false;
342 }
343 
344 /// Check for a mismatch in the atomicity of the given properties.
345 static void checkAtomicPropertyMismatch(Sema &S,
346                                         ObjCPropertyDecl *OldProperty,
347                                         ObjCPropertyDecl *NewProperty,
348                                         bool PropagateAtomicity) {
349   // If the atomicity of both matches, we're done.
350   bool OldIsAtomic =
351     (OldProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
352       == 0;
353   bool NewIsAtomic =
354     (NewProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
355       == 0;
356   if (OldIsAtomic == NewIsAtomic) return;
357 
358   // Determine whether the given property is readonly and implicitly
359   // atomic.
360   auto isImplicitlyReadonlyAtomic = [](ObjCPropertyDecl *Property) -> bool {
361     // Is it readonly?
362     auto Attrs = Property->getPropertyAttributes();
363     if ((Attrs & ObjCPropertyDecl::OBJC_PR_readonly) == 0) return false;
364 
365     // Is it nonatomic?
366     if (Attrs & ObjCPropertyDecl::OBJC_PR_nonatomic) return false;
367 
368     // Was 'atomic' specified directly?
369     if (Property->getPropertyAttributesAsWritten() &
370           ObjCPropertyDecl::OBJC_PR_atomic)
371       return false;
372 
373     return true;
374   };
375 
376   // If we're allowed to propagate atomicity, and the new property did
377   // not specify atomicity at all, propagate.
378   const unsigned AtomicityMask =
379     (ObjCPropertyDecl::OBJC_PR_atomic | ObjCPropertyDecl::OBJC_PR_nonatomic);
380   if (PropagateAtomicity &&
381       ((NewProperty->getPropertyAttributesAsWritten() & AtomicityMask) == 0)) {
382     unsigned Attrs = NewProperty->getPropertyAttributes();
383     Attrs = Attrs & ~AtomicityMask;
384     if (OldIsAtomic)
385       Attrs |= ObjCPropertyDecl::OBJC_PR_atomic;
386     else
387       Attrs |= ObjCPropertyDecl::OBJC_PR_nonatomic;
388 
389     NewProperty->overwritePropertyAttributes(Attrs);
390     return;
391   }
392 
393   // One of the properties is atomic; if it's a readonly property, and
394   // 'atomic' wasn't explicitly specified, we're okay.
395   if ((OldIsAtomic && isImplicitlyReadonlyAtomic(OldProperty)) ||
396       (NewIsAtomic && isImplicitlyReadonlyAtomic(NewProperty)))
397     return;
398 
399   // Diagnose the conflict.
400   const IdentifierInfo *OldContextName;
401   auto *OldDC = OldProperty->getDeclContext();
402   if (auto Category = dyn_cast<ObjCCategoryDecl>(OldDC))
403     OldContextName = Category->getClassInterface()->getIdentifier();
404   else
405     OldContextName = cast<ObjCContainerDecl>(OldDC)->getIdentifier();
406 
407   S.Diag(NewProperty->getLocation(), diag::warn_property_attribute)
408     << NewProperty->getDeclName() << "atomic"
409     << OldContextName;
410   S.Diag(OldProperty->getLocation(), diag::note_property_declare);
411 }
412 
413 ObjCPropertyDecl *
414 Sema::HandlePropertyInClassExtension(Scope *S,
415                                      SourceLocation AtLoc,
416                                      SourceLocation LParenLoc,
417                                      FieldDeclarator &FD,
418                                      Selector GetterSel,
419                                      SourceLocation GetterNameLoc,
420                                      Selector SetterSel,
421                                      SourceLocation SetterNameLoc,
422                                      const bool isReadWrite,
423                                      unsigned &Attributes,
424                                      const unsigned AttributesAsWritten,
425                                      QualType T,
426                                      TypeSourceInfo *TSI,
427                                      tok::ObjCKeywordKind MethodImplKind) {
428   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
429   // Diagnose if this property is already in continuation class.
430   DeclContext *DC = CurContext;
431   IdentifierInfo *PropertyId = FD.D.getIdentifier();
432   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
433 
434   // We need to look in the @interface to see if the @property was
435   // already declared.
436   if (!CCPrimary) {
437     Diag(CDecl->getLocation(), diag::err_continuation_class);
438     return nullptr;
439   }
440 
441   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
442                          (Attributes & ObjCDeclSpec::DQ_PR_class);
443 
444   // Find the property in the extended class's primary class or
445   // extensions.
446   ObjCPropertyDecl *PIDecl = CCPrimary->FindPropertyVisibleInPrimaryClass(
447       PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty));
448 
449   // If we found a property in an extension, complain.
450   if (PIDecl && isa<ObjCCategoryDecl>(PIDecl->getDeclContext())) {
451     Diag(AtLoc, diag::err_duplicate_property);
452     Diag(PIDecl->getLocation(), diag::note_property_declare);
453     return nullptr;
454   }
455 
456   // Check for consistency with the previous declaration, if there is one.
457   if (PIDecl) {
458     // A readonly property declared in the primary class can be refined
459     // by adding a readwrite property within an extension.
460     // Anything else is an error.
461     if (!(PIDecl->isReadOnly() && isReadWrite)) {
462       // Tailor the diagnostics for the common case where a readwrite
463       // property is declared both in the @interface and the continuation.
464       // This is a common error where the user often intended the original
465       // declaration to be readonly.
466       unsigned diag =
467         (Attributes & ObjCDeclSpec::DQ_PR_readwrite) &&
468         (PIDecl->getPropertyAttributesAsWritten() &
469            ObjCPropertyDecl::OBJC_PR_readwrite)
470         ? diag::err_use_continuation_class_redeclaration_readwrite
471         : diag::err_use_continuation_class;
472       Diag(AtLoc, diag)
473         << CCPrimary->getDeclName();
474       Diag(PIDecl->getLocation(), diag::note_property_declare);
475       return nullptr;
476     }
477 
478     // Check for consistency of getters.
479     if (PIDecl->getGetterName() != GetterSel) {
480      // If the getter was written explicitly, complain.
481       if (AttributesAsWritten & ObjCDeclSpec::DQ_PR_getter) {
482         Diag(AtLoc, diag::warn_property_redecl_getter_mismatch)
483           << PIDecl->getGetterName() << GetterSel;
484         Diag(PIDecl->getLocation(), diag::note_property_declare);
485       }
486 
487       // Always adopt the getter from the original declaration.
488       GetterSel = PIDecl->getGetterName();
489       Attributes |= ObjCDeclSpec::DQ_PR_getter;
490     }
491 
492     // Check consistency of ownership.
493     unsigned ExistingOwnership
494       = getOwnershipRule(PIDecl->getPropertyAttributes());
495     unsigned NewOwnership = getOwnershipRule(Attributes);
496     if (ExistingOwnership && NewOwnership != ExistingOwnership) {
497       // If the ownership was written explicitly, complain.
498       if (getOwnershipRule(AttributesAsWritten)) {
499         Diag(AtLoc, diag::warn_property_attr_mismatch);
500         Diag(PIDecl->getLocation(), diag::note_property_declare);
501       }
502 
503       // Take the ownership from the original property.
504       Attributes = (Attributes & ~OwnershipMask) | ExistingOwnership;
505     }
506 
507     // If the redeclaration is 'weak' but the original property is not,
508     if ((Attributes & ObjCPropertyDecl::OBJC_PR_weak) &&
509         !(PIDecl->getPropertyAttributesAsWritten()
510             & ObjCPropertyDecl::OBJC_PR_weak) &&
511         PIDecl->getType()->getAs<ObjCObjectPointerType>() &&
512         PIDecl->getType().getObjCLifetime() == Qualifiers::OCL_None) {
513       Diag(AtLoc, diag::warn_property_implicitly_mismatched);
514       Diag(PIDecl->getLocation(), diag::note_property_declare);
515     }
516   }
517 
518   // Create a new ObjCPropertyDecl with the DeclContext being
519   // the class extension.
520   ObjCPropertyDecl *PDecl = CreatePropertyDecl(S, CDecl, AtLoc, LParenLoc,
521                                                FD, GetterSel, GetterNameLoc,
522                                                SetterSel, SetterNameLoc,
523                                                isReadWrite,
524                                                Attributes, AttributesAsWritten,
525                                                T, TSI, MethodImplKind, DC);
526 
527   // If there was no declaration of a property with the same name in
528   // the primary class, we're done.
529   if (!PIDecl) {
530     ProcessPropertyDecl(PDecl);
531     return PDecl;
532   }
533 
534   if (!Context.hasSameType(PIDecl->getType(), PDecl->getType())) {
535     bool IncompatibleObjC = false;
536     QualType ConvertedType;
537     // Relax the strict type matching for property type in continuation class.
538     // Allow property object type of continuation class to be different as long
539     // as it narrows the object type in its primary class property. Note that
540     // this conversion is safe only because the wider type is for a 'readonly'
541     // property in primary class and 'narrowed' type for a 'readwrite' property
542     // in continuation class.
543     QualType PrimaryClassPropertyT = Context.getCanonicalType(PIDecl->getType());
544     QualType ClassExtPropertyT = Context.getCanonicalType(PDecl->getType());
545     if (!isa<ObjCObjectPointerType>(PrimaryClassPropertyT) ||
546         !isa<ObjCObjectPointerType>(ClassExtPropertyT) ||
547         (!isObjCPointerConversion(ClassExtPropertyT, PrimaryClassPropertyT,
548                                   ConvertedType, IncompatibleObjC))
549         || IncompatibleObjC) {
550       Diag(AtLoc,
551           diag::err_type_mismatch_continuation_class) << PDecl->getType();
552       Diag(PIDecl->getLocation(), diag::note_property_declare);
553       return nullptr;
554     }
555   }
556 
557   // Check that atomicity of property in class extension matches the previous
558   // declaration.
559   checkAtomicPropertyMismatch(*this, PIDecl, PDecl, true);
560 
561   // Make sure getter/setter are appropriately synthesized.
562   ProcessPropertyDecl(PDecl);
563   return PDecl;
564 }
565 
566 ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
567                                            ObjCContainerDecl *CDecl,
568                                            SourceLocation AtLoc,
569                                            SourceLocation LParenLoc,
570                                            FieldDeclarator &FD,
571                                            Selector GetterSel,
572                                            SourceLocation GetterNameLoc,
573                                            Selector SetterSel,
574                                            SourceLocation SetterNameLoc,
575                                            const bool isReadWrite,
576                                            const unsigned Attributes,
577                                            const unsigned AttributesAsWritten,
578                                            QualType T,
579                                            TypeSourceInfo *TInfo,
580                                            tok::ObjCKeywordKind MethodImplKind,
581                                            DeclContext *lexicalDC){
582   IdentifierInfo *PropertyId = FD.D.getIdentifier();
583 
584   // Property defaults to 'assign' if it is readwrite, unless this is ARC
585   // and the type is retainable.
586   bool isAssign;
587   if (Attributes & (ObjCDeclSpec::DQ_PR_assign |
588                     ObjCDeclSpec::DQ_PR_unsafe_unretained)) {
589     isAssign = true;
590   } else if (getOwnershipRule(Attributes) || !isReadWrite) {
591     isAssign = false;
592   } else {
593     isAssign = (!getLangOpts().ObjCAutoRefCount ||
594                 !T->isObjCRetainableType());
595   }
596 
597   // Issue a warning if property is 'assign' as default and its
598   // object, which is gc'able conforms to NSCopying protocol
599   if (getLangOpts().getGC() != LangOptions::NonGC &&
600       isAssign && !(Attributes & ObjCDeclSpec::DQ_PR_assign)) {
601     if (const ObjCObjectPointerType *ObjPtrTy =
602           T->getAs<ObjCObjectPointerType>()) {
603       ObjCInterfaceDecl *IDecl = ObjPtrTy->getObjectType()->getInterface();
604       if (IDecl)
605         if (ObjCProtocolDecl* PNSCopying =
606             LookupProtocol(&Context.Idents.get("NSCopying"), AtLoc))
607           if (IDecl->ClassImplementsProtocol(PNSCopying, true))
608             Diag(AtLoc, diag::warn_implements_nscopying) << PropertyId;
609     }
610   }
611 
612   if (T->isObjCObjectType()) {
613     SourceLocation StarLoc = TInfo->getTypeLoc().getEndLoc();
614     StarLoc = getLocForEndOfToken(StarLoc);
615     Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object)
616       << FixItHint::CreateInsertion(StarLoc, "*");
617     T = Context.getObjCObjectPointerType(T);
618     SourceLocation TLoc = TInfo->getTypeLoc().getBeginLoc();
619     TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
620   }
621 
622   DeclContext *DC = CDecl;
623   ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
624                                                      FD.D.getIdentifierLoc(),
625                                                      PropertyId, AtLoc,
626                                                      LParenLoc, T, TInfo);
627 
628   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
629                          (Attributes & ObjCDeclSpec::DQ_PR_class);
630   // Class property and instance property can have the same name.
631   if (ObjCPropertyDecl *prevDecl = ObjCPropertyDecl::findPropertyDecl(
632           DC, PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty))) {
633     Diag(PDecl->getLocation(), diag::err_duplicate_property);
634     Diag(prevDecl->getLocation(), diag::note_property_declare);
635     PDecl->setInvalidDecl();
636   }
637   else {
638     DC->addDecl(PDecl);
639     if (lexicalDC)
640       PDecl->setLexicalDeclContext(lexicalDC);
641   }
642 
643   if (T->isArrayType() || T->isFunctionType()) {
644     Diag(AtLoc, diag::err_property_type) << T;
645     PDecl->setInvalidDecl();
646   }
647 
648   ProcessDeclAttributes(S, PDecl, FD.D);
649 
650   // Regardless of setter/getter attribute, we save the default getter/setter
651   // selector names in anticipation of declaration of setter/getter methods.
652   PDecl->setGetterName(GetterSel, GetterNameLoc);
653   PDecl->setSetterName(SetterSel, SetterNameLoc);
654   PDecl->setPropertyAttributesAsWritten(
655                           makePropertyAttributesAsWritten(AttributesAsWritten));
656 
657   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
658     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
659 
660   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
661     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_getter);
662 
663   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
664     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_setter);
665 
666   if (isReadWrite)
667     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
668 
669   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
670     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
671 
672   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
673     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
674 
675   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
676     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
677 
678   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
679     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
680 
681   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
682     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
683 
684   if (isAssign)
685     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
686 
687   // In the semantic attributes, one of nonatomic or atomic is always set.
688   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
689     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
690   else
691     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_atomic);
692 
693   // 'unsafe_unretained' is alias for 'assign'.
694   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
695     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
696   if (isAssign)
697     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
698 
699   if (MethodImplKind == tok::objc_required)
700     PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
701   else if (MethodImplKind == tok::objc_optional)
702     PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
703 
704   if (Attributes & ObjCDeclSpec::DQ_PR_nullability)
705     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nullability);
706 
707   if (Attributes & ObjCDeclSpec::DQ_PR_null_resettable)
708     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_null_resettable);
709 
710   if (Attributes & ObjCDeclSpec::DQ_PR_class)
711     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_class);
712 
713   if ((Attributes & ObjCDeclSpec::DQ_PR_direct) ||
714       CDecl->hasAttr<ObjCDirectMembersAttr>()) {
715     if (isa<ObjCProtocolDecl>(CDecl)) {
716       Diag(PDecl->getLocation(), diag::err_objc_direct_on_protocol) << true;
717     } else if (getLangOpts().ObjCRuntime.allowsDirectDispatch()) {
718       PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_direct);
719     } else {
720       Diag(PDecl->getLocation(), diag::warn_objc_direct_property_ignored)
721           << PDecl->getDeclName();
722     }
723   }
724 
725   return PDecl;
726 }
727 
728 static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
729                                  ObjCPropertyDecl *property,
730                                  ObjCIvarDecl *ivar) {
731   if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;
732 
733   QualType ivarType = ivar->getType();
734   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
735 
736   // The lifetime implied by the property's attributes.
737   Qualifiers::ObjCLifetime propertyLifetime =
738     getImpliedARCOwnership(property->getPropertyAttributes(),
739                            property->getType());
740 
741   // We're fine if they match.
742   if (propertyLifetime == ivarLifetime) return;
743 
744   // None isn't a valid lifetime for an object ivar in ARC, and
745   // __autoreleasing is never valid; don't diagnose twice.
746   if ((ivarLifetime == Qualifiers::OCL_None &&
747        S.getLangOpts().ObjCAutoRefCount) ||
748       ivarLifetime == Qualifiers::OCL_Autoreleasing)
749     return;
750 
751   // If the ivar is private, and it's implicitly __unsafe_unretained
752   // because of its type, then pretend it was actually implicitly
753   // __strong.  This is only sound because we're processing the
754   // property implementation before parsing any method bodies.
755   if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
756       propertyLifetime == Qualifiers::OCL_Strong &&
757       ivar->getAccessControl() == ObjCIvarDecl::Private) {
758     SplitQualType split = ivarType.split();
759     if (split.Quals.hasObjCLifetime()) {
760       assert(ivarType->isObjCARCImplicitlyUnretainedType());
761       split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
762       ivarType = S.Context.getQualifiedType(split);
763       ivar->setType(ivarType);
764       return;
765     }
766   }
767 
768   switch (propertyLifetime) {
769   case Qualifiers::OCL_Strong:
770     S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
771       << property->getDeclName()
772       << ivar->getDeclName()
773       << ivarLifetime;
774     break;
775 
776   case Qualifiers::OCL_Weak:
777     S.Diag(ivar->getLocation(), diag::err_weak_property)
778       << property->getDeclName()
779       << ivar->getDeclName();
780     break;
781 
782   case Qualifiers::OCL_ExplicitNone:
783     S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
784       << property->getDeclName()
785       << ivar->getDeclName()
786       << ((property->getPropertyAttributesAsWritten()
787            & ObjCPropertyDecl::OBJC_PR_assign) != 0);
788     break;
789 
790   case Qualifiers::OCL_Autoreleasing:
791     llvm_unreachable("properties cannot be autoreleasing");
792 
793   case Qualifiers::OCL_None:
794     // Any other property should be ignored.
795     return;
796   }
797 
798   S.Diag(property->getLocation(), diag::note_property_declare);
799   if (propertyImplLoc.isValid())
800     S.Diag(propertyImplLoc, diag::note_property_synthesize);
801 }
802 
803 /// setImpliedPropertyAttributeForReadOnlyProperty -
804 /// This routine evaludates life-time attributes for a 'readonly'
805 /// property with no known lifetime of its own, using backing
806 /// 'ivar's attribute, if any. If no backing 'ivar', property's
807 /// life-time is assumed 'strong'.
808 static void setImpliedPropertyAttributeForReadOnlyProperty(
809               ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
810   Qualifiers::ObjCLifetime propertyLifetime =
811     getImpliedARCOwnership(property->getPropertyAttributes(),
812                            property->getType());
813   if (propertyLifetime != Qualifiers::OCL_None)
814     return;
815 
816   if (!ivar) {
817     // if no backing ivar, make property 'strong'.
818     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
819     return;
820   }
821   // property assumes owenership of backing ivar.
822   QualType ivarType = ivar->getType();
823   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
824   if (ivarLifetime == Qualifiers::OCL_Strong)
825     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
826   else if (ivarLifetime == Qualifiers::OCL_Weak)
827     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
828 }
829 
830 static bool
831 isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
832                                 ObjCPropertyDecl::PropertyAttributeKind Kind) {
833   return (Attr1 & Kind) != (Attr2 & Kind);
834 }
835 
836 static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
837                                               unsigned Kinds) {
838   return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
839 }
840 
841 /// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
842 /// property declaration that should be synthesised in all of the inherited
843 /// protocols. It also diagnoses properties declared in inherited protocols with
844 /// mismatched types or attributes, since any of them can be candidate for
845 /// synthesis.
846 static ObjCPropertyDecl *
847 SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
848                                         ObjCInterfaceDecl *ClassDecl,
849                                         ObjCPropertyDecl *Property) {
850   assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&
851          "Expected a property from a protocol");
852   ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
853   ObjCInterfaceDecl::PropertyDeclOrder Properties;
854   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
855     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
856       PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
857                                                 Properties);
858   }
859   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
860     while (SDecl) {
861       for (const auto *PI : SDecl->all_referenced_protocols()) {
862         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
863           PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
864                                                     Properties);
865       }
866       SDecl = SDecl->getSuperClass();
867     }
868   }
869 
870   if (Properties.empty())
871     return Property;
872 
873   ObjCPropertyDecl *OriginalProperty = Property;
874   size_t SelectedIndex = 0;
875   for (const auto &Prop : llvm::enumerate(Properties)) {
876     // Select the 'readwrite' property if such property exists.
877     if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
878       Property = Prop.value();
879       SelectedIndex = Prop.index();
880     }
881   }
882   if (Property != OriginalProperty) {
883     // Check that the old property is compatible with the new one.
884     Properties[SelectedIndex] = OriginalProperty;
885   }
886 
887   QualType RHSType = S.Context.getCanonicalType(Property->getType());
888   unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
889   enum MismatchKind {
890     IncompatibleType = 0,
891     HasNoExpectedAttribute,
892     HasUnexpectedAttribute,
893     DifferentGetter,
894     DifferentSetter
895   };
896   // Represents a property from another protocol that conflicts with the
897   // selected declaration.
898   struct MismatchingProperty {
899     const ObjCPropertyDecl *Prop;
900     MismatchKind Kind;
901     StringRef AttributeName;
902   };
903   SmallVector<MismatchingProperty, 4> Mismatches;
904   for (ObjCPropertyDecl *Prop : Properties) {
905     // Verify the property attributes.
906     unsigned Attr = Prop->getPropertyAttributesAsWritten();
907     if (Attr != OriginalAttributes) {
908       auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
909         MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
910                                                  : HasUnexpectedAttribute;
911         Mismatches.push_back({Prop, Kind, AttributeName});
912       };
913       // The ownership might be incompatible unless the property has no explicit
914       // ownership.
915       bool HasOwnership = (Attr & (ObjCPropertyDecl::OBJC_PR_retain |
916                                    ObjCPropertyDecl::OBJC_PR_strong |
917                                    ObjCPropertyDecl::OBJC_PR_copy |
918                                    ObjCPropertyDecl::OBJC_PR_assign |
919                                    ObjCPropertyDecl::OBJC_PR_unsafe_unretained |
920                                    ObjCPropertyDecl::OBJC_PR_weak)) != 0;
921       if (HasOwnership &&
922           isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
923                                           ObjCPropertyDecl::OBJC_PR_copy)) {
924         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_copy, "copy");
925         continue;
926       }
927       if (HasOwnership && areIncompatiblePropertyAttributes(
928                               OriginalAttributes, Attr,
929                               ObjCPropertyDecl::OBJC_PR_retain |
930                                   ObjCPropertyDecl::OBJC_PR_strong)) {
931         Diag(OriginalAttributes & (ObjCPropertyDecl::OBJC_PR_retain |
932                                    ObjCPropertyDecl::OBJC_PR_strong),
933              "retain (or strong)");
934         continue;
935       }
936       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
937                                           ObjCPropertyDecl::OBJC_PR_atomic)) {
938         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_atomic, "atomic");
939         continue;
940       }
941     }
942     if (Property->getGetterName() != Prop->getGetterName()) {
943       Mismatches.push_back({Prop, DifferentGetter, ""});
944       continue;
945     }
946     if (!Property->isReadOnly() && !Prop->isReadOnly() &&
947         Property->getSetterName() != Prop->getSetterName()) {
948       Mismatches.push_back({Prop, DifferentSetter, ""});
949       continue;
950     }
951     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
952     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
953       bool IncompatibleObjC = false;
954       QualType ConvertedType;
955       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
956           || IncompatibleObjC) {
957         Mismatches.push_back({Prop, IncompatibleType, ""});
958         continue;
959       }
960     }
961   }
962 
963   if (Mismatches.empty())
964     return Property;
965 
966   // Diagnose incompability.
967   {
968     bool HasIncompatibleAttributes = false;
969     for (const auto &Note : Mismatches)
970       HasIncompatibleAttributes =
971           Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
972     // Promote the warning to an error if there are incompatible attributes or
973     // incompatible types together with readwrite/readonly incompatibility.
974     auto Diag = S.Diag(Property->getLocation(),
975                        Property != OriginalProperty || HasIncompatibleAttributes
976                            ? diag::err_protocol_property_mismatch
977                            : diag::warn_protocol_property_mismatch);
978     Diag << Mismatches[0].Kind;
979     switch (Mismatches[0].Kind) {
980     case IncompatibleType:
981       Diag << Property->getType();
982       break;
983     case HasNoExpectedAttribute:
984     case HasUnexpectedAttribute:
985       Diag << Mismatches[0].AttributeName;
986       break;
987     case DifferentGetter:
988       Diag << Property->getGetterName();
989       break;
990     case DifferentSetter:
991       Diag << Property->getSetterName();
992       break;
993     }
994   }
995   for (const auto &Note : Mismatches) {
996     auto Diag =
997         S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
998         << Note.Kind;
999     switch (Note.Kind) {
1000     case IncompatibleType:
1001       Diag << Note.Prop->getType();
1002       break;
1003     case HasNoExpectedAttribute:
1004     case HasUnexpectedAttribute:
1005       Diag << Note.AttributeName;
1006       break;
1007     case DifferentGetter:
1008       Diag << Note.Prop->getGetterName();
1009       break;
1010     case DifferentSetter:
1011       Diag << Note.Prop->getSetterName();
1012       break;
1013     }
1014   }
1015   if (AtLoc.isValid())
1016     S.Diag(AtLoc, diag::note_property_synthesize);
1017 
1018   return Property;
1019 }
1020 
1021 /// Determine whether any storage attributes were written on the property.
1022 static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
1023                                        ObjCPropertyQueryKind QueryKind) {
1024   if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;
1025 
1026   // If this is a readwrite property in a class extension that refines
1027   // a readonly property in the original class definition, check it as
1028   // well.
1029 
1030   // If it's a readonly property, we're not interested.
1031   if (Prop->isReadOnly()) return false;
1032 
1033   // Is it declared in an extension?
1034   auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
1035   if (!Category || !Category->IsClassExtension()) return false;
1036 
1037   // Find the corresponding property in the primary class definition.
1038   auto OrigClass = Category->getClassInterface();
1039   for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
1040     if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
1041       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1042   }
1043 
1044   // Look through all of the protocols.
1045   for (const auto *Proto : OrigClass->all_referenced_protocols()) {
1046     if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
1047             Prop->getIdentifier(), QueryKind))
1048       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1049   }
1050 
1051   return false;
1052 }
1053 
1054 /// Create a synthesized property accessor stub inside the \@implementation.
1055 static ObjCMethodDecl *
1056 RedeclarePropertyAccessor(ASTContext &Context, ObjCImplementationDecl *Impl,
1057                           ObjCMethodDecl *AccessorDecl, SourceLocation AtLoc,
1058                           SourceLocation PropertyLoc) {
1059   ObjCMethodDecl *Decl = AccessorDecl;
1060   ObjCMethodDecl *ImplDecl = ObjCMethodDecl::Create(
1061       Context, AtLoc.isValid() ? AtLoc : Decl->getBeginLoc(),
1062       PropertyLoc.isValid() ? PropertyLoc : Decl->getEndLoc(),
1063       Decl->getSelector(), Decl->getReturnType(),
1064       Decl->getReturnTypeSourceInfo(), Impl, Decl->isInstanceMethod(),
1065       Decl->isVariadic(), Decl->isPropertyAccessor(),
1066       /* isSynthesized*/ true, Decl->isImplicit(), Decl->isDefined(),
1067       Decl->getImplementationControl(), Decl->hasRelatedResultType());
1068   ImplDecl->getMethodFamily();
1069   if (Decl->hasAttrs())
1070     ImplDecl->setAttrs(Decl->getAttrs());
1071   ImplDecl->setSelfDecl(Decl->getSelfDecl());
1072   ImplDecl->setCmdDecl(Decl->getCmdDecl());
1073   SmallVector<SourceLocation, 1> SelLocs;
1074   Decl->getSelectorLocs(SelLocs);
1075   ImplDecl->setMethodParams(Context, Decl->parameters(), SelLocs);
1076   ImplDecl->setLexicalDeclContext(Impl);
1077   ImplDecl->setDefined(false);
1078   return ImplDecl;
1079 }
1080 
1081 /// ActOnPropertyImplDecl - This routine performs semantic checks and
1082 /// builds the AST node for a property implementation declaration; declared
1083 /// as \@synthesize or \@dynamic.
1084 ///
1085 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
1086                                   SourceLocation AtLoc,
1087                                   SourceLocation PropertyLoc,
1088                                   bool Synthesize,
1089                                   IdentifierInfo *PropertyId,
1090                                   IdentifierInfo *PropertyIvar,
1091                                   SourceLocation PropertyIvarLoc,
1092                                   ObjCPropertyQueryKind QueryKind) {
1093   ObjCContainerDecl *ClassImpDecl =
1094     dyn_cast<ObjCContainerDecl>(CurContext);
1095   // Make sure we have a context for the property implementation declaration.
1096   if (!ClassImpDecl) {
1097     Diag(AtLoc, diag::err_missing_property_context);
1098     return nullptr;
1099   }
1100   if (PropertyIvarLoc.isInvalid())
1101     PropertyIvarLoc = PropertyLoc;
1102   SourceLocation PropertyDiagLoc = PropertyLoc;
1103   if (PropertyDiagLoc.isInvalid())
1104     PropertyDiagLoc = ClassImpDecl->getBeginLoc();
1105   ObjCPropertyDecl *property = nullptr;
1106   ObjCInterfaceDecl *IDecl = nullptr;
1107   // Find the class or category class where this property must have
1108   // a declaration.
1109   ObjCImplementationDecl *IC = nullptr;
1110   ObjCCategoryImplDecl *CatImplClass = nullptr;
1111   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
1112     IDecl = IC->getClassInterface();
1113     // We always synthesize an interface for an implementation
1114     // without an interface decl. So, IDecl is always non-zero.
1115     assert(IDecl &&
1116            "ActOnPropertyImplDecl - @implementation without @interface");
1117 
1118     // Look for this property declaration in the @implementation's @interface
1119     property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
1120     if (!property) {
1121       Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
1122       return nullptr;
1123     }
1124     if (property->isClassProperty() && Synthesize) {
1125       Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
1126       return nullptr;
1127     }
1128     unsigned PIkind = property->getPropertyAttributesAsWritten();
1129     if ((PIkind & (ObjCPropertyDecl::OBJC_PR_atomic |
1130                    ObjCPropertyDecl::OBJC_PR_nonatomic) ) == 0) {
1131       if (AtLoc.isValid())
1132         Diag(AtLoc, diag::warn_implicit_atomic_property);
1133       else
1134         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
1135       Diag(property->getLocation(), diag::note_property_declare);
1136     }
1137 
1138     if (const ObjCCategoryDecl *CD =
1139         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
1140       if (!CD->IsClassExtension()) {
1141         Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
1142         Diag(property->getLocation(), diag::note_property_declare);
1143         return nullptr;
1144       }
1145     }
1146     if (Synthesize&&
1147         (PIkind & ObjCPropertyDecl::OBJC_PR_readonly) &&
1148         property->hasAttr<IBOutletAttr>() &&
1149         !AtLoc.isValid()) {
1150       bool ReadWriteProperty = false;
1151       // Search into the class extensions and see if 'readonly property is
1152       // redeclared 'readwrite', then no warning is to be issued.
1153       for (auto *Ext : IDecl->known_extensions()) {
1154         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
1155         if (!R.empty())
1156           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
1157             PIkind = ExtProp->getPropertyAttributesAsWritten();
1158             if (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite) {
1159               ReadWriteProperty = true;
1160               break;
1161             }
1162           }
1163       }
1164 
1165       if (!ReadWriteProperty) {
1166         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
1167             << property;
1168         SourceLocation readonlyLoc;
1169         if (LocPropertyAttribute(Context, "readonly",
1170                                  property->getLParenLoc(), readonlyLoc)) {
1171           SourceLocation endLoc =
1172             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
1173           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
1174           Diag(property->getLocation(),
1175                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
1176           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
1177         }
1178       }
1179     }
1180     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
1181       property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
1182                                                          property);
1183 
1184   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
1185     if (Synthesize) {
1186       Diag(AtLoc, diag::err_synthesize_category_decl);
1187       return nullptr;
1188     }
1189     IDecl = CatImplClass->getClassInterface();
1190     if (!IDecl) {
1191       Diag(AtLoc, diag::err_missing_property_interface);
1192       return nullptr;
1193     }
1194     ObjCCategoryDecl *Category =
1195     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
1196 
1197     // If category for this implementation not found, it is an error which
1198     // has already been reported eralier.
1199     if (!Category)
1200       return nullptr;
1201     // Look for this property declaration in @implementation's category
1202     property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
1203     if (!property) {
1204       Diag(PropertyLoc, diag::err_bad_category_property_decl)
1205       << Category->getDeclName();
1206       return nullptr;
1207     }
1208   } else {
1209     Diag(AtLoc, diag::err_bad_property_context);
1210     return nullptr;
1211   }
1212   ObjCIvarDecl *Ivar = nullptr;
1213   bool CompleteTypeErr = false;
1214   bool compat = true;
1215   // Check that we have a valid, previously declared ivar for @synthesize
1216   if (Synthesize) {
1217     // @synthesize
1218     if (!PropertyIvar)
1219       PropertyIvar = PropertyId;
1220     // Check that this is a previously declared 'ivar' in 'IDecl' interface
1221     ObjCInterfaceDecl *ClassDeclared;
1222     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
1223     QualType PropType = property->getType();
1224     QualType PropertyIvarType = PropType.getNonReferenceType();
1225 
1226     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
1227                             diag::err_incomplete_synthesized_property,
1228                             property->getDeclName())) {
1229       Diag(property->getLocation(), diag::note_property_declare);
1230       CompleteTypeErr = true;
1231     }
1232 
1233     if (getLangOpts().ObjCAutoRefCount &&
1234         (property->getPropertyAttributesAsWritten() &
1235          ObjCPropertyDecl::OBJC_PR_readonly) &&
1236         PropertyIvarType->isObjCRetainableType()) {
1237       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
1238     }
1239 
1240     ObjCPropertyDecl::PropertyAttributeKind kind
1241       = property->getPropertyAttributes();
1242 
1243     bool isARCWeak = false;
1244     if (kind & ObjCPropertyDecl::OBJC_PR_weak) {
1245       // Add GC __weak to the ivar type if the property is weak.
1246       if (getLangOpts().getGC() != LangOptions::NonGC) {
1247         assert(!getLangOpts().ObjCAutoRefCount);
1248         if (PropertyIvarType.isObjCGCStrong()) {
1249           Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
1250           Diag(property->getLocation(), diag::note_property_declare);
1251         } else {
1252           PropertyIvarType =
1253             Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
1254         }
1255 
1256       // Otherwise, check whether ARC __weak is enabled and works with
1257       // the property type.
1258       } else {
1259         if (!getLangOpts().ObjCWeak) {
1260           // Only complain here when synthesizing an ivar.
1261           if (!Ivar) {
1262             Diag(PropertyDiagLoc,
1263                  getLangOpts().ObjCWeakRuntime
1264                    ? diag::err_synthesizing_arc_weak_property_disabled
1265                    : diag::err_synthesizing_arc_weak_property_no_runtime);
1266             Diag(property->getLocation(), diag::note_property_declare);
1267           }
1268           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1269         } else {
1270           isARCWeak = true;
1271           if (const ObjCObjectPointerType *ObjT =
1272                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1273             const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1274             if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1275               Diag(property->getLocation(),
1276                    diag::err_arc_weak_unavailable_property)
1277                 << PropertyIvarType;
1278               Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1279                 << ClassImpDecl->getName();
1280             }
1281           }
1282         }
1283       }
1284     }
1285 
1286     if (AtLoc.isInvalid()) {
1287       // Check when default synthesizing a property that there is
1288       // an ivar matching property name and issue warning; since this
1289       // is the most common case of not using an ivar used for backing
1290       // property in non-default synthesis case.
1291       ObjCInterfaceDecl *ClassDeclared=nullptr;
1292       ObjCIvarDecl *originalIvar =
1293       IDecl->lookupInstanceVariable(property->getIdentifier(),
1294                                     ClassDeclared);
1295       if (originalIvar) {
1296         Diag(PropertyDiagLoc,
1297              diag::warn_autosynthesis_property_ivar_match)
1298         << PropertyId << (Ivar == nullptr) << PropertyIvar
1299         << originalIvar->getIdentifier();
1300         Diag(property->getLocation(), diag::note_property_declare);
1301         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
1302       }
1303     }
1304 
1305     if (!Ivar) {
1306       // In ARC, give the ivar a lifetime qualifier based on the
1307       // property attributes.
1308       if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
1309           !PropertyIvarType.getObjCLifetime() &&
1310           PropertyIvarType->isObjCRetainableType()) {
1311 
1312         // It's an error if we have to do this and the user didn't
1313         // explicitly write an ownership attribute on the property.
1314         if (!hasWrittenStorageAttribute(property, QueryKind) &&
1315             !(kind & ObjCPropertyDecl::OBJC_PR_strong)) {
1316           Diag(PropertyDiagLoc,
1317                diag::err_arc_objc_property_default_assign_on_object);
1318           Diag(property->getLocation(), diag::note_property_declare);
1319         } else {
1320           Qualifiers::ObjCLifetime lifetime =
1321             getImpliedARCOwnership(kind, PropertyIvarType);
1322           assert(lifetime && "no lifetime for property?");
1323 
1324           Qualifiers qs;
1325           qs.addObjCLifetime(lifetime);
1326           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1327         }
1328       }
1329 
1330       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1331                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1332                                   PropertyIvarType, /*TInfo=*/nullptr,
1333                                   ObjCIvarDecl::Private,
1334                                   (Expr *)nullptr, true);
1335       if (RequireNonAbstractType(PropertyIvarLoc,
1336                                  PropertyIvarType,
1337                                  diag::err_abstract_type_in_decl,
1338                                  AbstractSynthesizedIvarType)) {
1339         Diag(property->getLocation(), diag::note_property_declare);
1340         // An abstract type is as bad as an incomplete type.
1341         CompleteTypeErr = true;
1342       }
1343       if (!CompleteTypeErr) {
1344         const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
1345         if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
1346           Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
1347             << PropertyIvarType;
1348           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1349         }
1350       }
1351       if (CompleteTypeErr)
1352         Ivar->setInvalidDecl();
1353       ClassImpDecl->addDecl(Ivar);
1354       IDecl->makeDeclVisibleInContext(Ivar);
1355 
1356       if (getLangOpts().ObjCRuntime.isFragile())
1357         Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
1358             << PropertyId;
1359       // Note! I deliberately want it to fall thru so, we have a
1360       // a property implementation and to avoid future warnings.
1361     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1362                !declaresSameEntity(ClassDeclared, IDecl)) {
1363       Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
1364       << property->getDeclName() << Ivar->getDeclName()
1365       << ClassDeclared->getDeclName();
1366       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1367       << Ivar << Ivar->getName();
1368       // Note! I deliberately want it to fall thru so more errors are caught.
1369     }
1370     property->setPropertyIvarDecl(Ivar);
1371 
1372     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1373 
1374     // Check that type of property and its ivar are type compatible.
1375     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1376       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1377           && isa<ObjCObjectPointerType>(IvarType))
1378         compat =
1379           Context.canAssignObjCInterfaces(
1380                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1381                                   IvarType->getAs<ObjCObjectPointerType>());
1382       else {
1383         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1384                                              IvarType)
1385                     == Compatible);
1386       }
1387       if (!compat) {
1388         Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1389           << property->getDeclName() << PropType
1390           << Ivar->getDeclName() << IvarType;
1391         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1392         // Note! I deliberately want it to fall thru so, we have a
1393         // a property implementation and to avoid future warnings.
1394       }
1395       else {
1396         // FIXME! Rules for properties are somewhat different that those
1397         // for assignments. Use a new routine to consolidate all cases;
1398         // specifically for property redeclarations as well as for ivars.
1399         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1400         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1401         if (lhsType != rhsType &&
1402             lhsType->isArithmeticType()) {
1403           Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1404             << property->getDeclName() << PropType
1405             << Ivar->getDeclName() << IvarType;
1406           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1407           // Fall thru - see previous comment
1408         }
1409       }
1410       // __weak is explicit. So it works on Canonical type.
1411       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1412            getLangOpts().getGC() != LangOptions::NonGC)) {
1413         Diag(PropertyDiagLoc, diag::err_weak_property)
1414         << property->getDeclName() << Ivar->getDeclName();
1415         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1416         // Fall thru - see previous comment
1417       }
1418       // Fall thru - see previous comment
1419       if ((property->getType()->isObjCObjectPointerType() ||
1420            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1421           getLangOpts().getGC() != LangOptions::NonGC) {
1422         Diag(PropertyDiagLoc, diag::err_strong_property)
1423         << property->getDeclName() << Ivar->getDeclName();
1424         // Fall thru - see previous comment
1425       }
1426     }
1427     if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
1428         Ivar->getType().getObjCLifetime())
1429       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1430   } else if (PropertyIvar)
1431     // @dynamic
1432     Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);
1433 
1434   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1435   ObjCPropertyImplDecl *PIDecl =
1436   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1437                                property,
1438                                (Synthesize ?
1439                                 ObjCPropertyImplDecl::Synthesize
1440                                 : ObjCPropertyImplDecl::Dynamic),
1441                                Ivar, PropertyIvarLoc);
1442 
1443   if (CompleteTypeErr || !compat)
1444     PIDecl->setInvalidDecl();
1445 
1446   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1447     getterMethod->createImplicitParams(Context, IDecl);
1448 
1449     // Redeclare the getter within the implementation as DeclContext.
1450     if (Synthesize) {
1451       // If the method hasn't been overridden, create a synthesized implementation.
1452       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1453           getterMethod->getSelector(), getterMethod->isInstanceMethod());
1454       if (!OMD)
1455         OMD = RedeclarePropertyAccessor(Context, IC, getterMethod, AtLoc,
1456                                         PropertyLoc);
1457       PIDecl->setGetterMethodDecl(OMD);
1458     }
1459 
1460     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1461         Ivar->getType()->isRecordType()) {
1462       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1463       // returned by the getter as it must conform to C++'s copy-return rules.
1464       // FIXME. Eventually we want to do this for Objective-C as well.
1465       SynthesizedFunctionScope Scope(*this, getterMethod);
1466       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1467       DeclRefExpr *SelfExpr = new (Context)
1468           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1469                       PropertyDiagLoc);
1470       MarkDeclRefReferenced(SelfExpr);
1471       Expr *LoadSelfExpr =
1472         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1473                                  CK_LValueToRValue, SelfExpr, nullptr,
1474                                  VK_RValue);
1475       Expr *IvarRefExpr =
1476         new (Context) ObjCIvarRefExpr(Ivar,
1477                                       Ivar->getUsageType(SelfDecl->getType()),
1478                                       PropertyDiagLoc,
1479                                       Ivar->getLocation(),
1480                                       LoadSelfExpr, true, true);
1481       ExprResult Res = PerformCopyInitialization(
1482           InitializedEntity::InitializeResult(PropertyDiagLoc,
1483                                               getterMethod->getReturnType(),
1484                                               /*NRVO=*/false),
1485           PropertyDiagLoc, IvarRefExpr);
1486       if (!Res.isInvalid()) {
1487         Expr *ResExpr = Res.getAs<Expr>();
1488         if (ResExpr)
1489           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1490         PIDecl->setGetterCXXConstructor(ResExpr);
1491       }
1492     }
1493     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1494         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1495       Diag(getterMethod->getLocation(),
1496            diag::warn_property_getter_owning_mismatch);
1497       Diag(property->getLocation(), diag::note_property_declare);
1498     }
1499     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1500       switch (getterMethod->getMethodFamily()) {
1501         case OMF_retain:
1502         case OMF_retainCount:
1503         case OMF_release:
1504         case OMF_autorelease:
1505           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1506             << 1 << getterMethod->getSelector();
1507           break;
1508         default:
1509           break;
1510       }
1511   }
1512 
1513   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1514     setterMethod->createImplicitParams(Context, IDecl);
1515 
1516     // Redeclare the setter within the implementation as DeclContext.
1517     if (Synthesize) {
1518       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1519           setterMethod->getSelector(), setterMethod->isInstanceMethod());
1520       if (!OMD)
1521         OMD = RedeclarePropertyAccessor(Context, IC, setterMethod,
1522                                         AtLoc, PropertyLoc);
1523       PIDecl->setSetterMethodDecl(OMD);
1524     }
1525 
1526     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1527         Ivar->getType()->isRecordType()) {
1528       // FIXME. Eventually we want to do this for Objective-C as well.
1529       SynthesizedFunctionScope Scope(*this, setterMethod);
1530       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1531       DeclRefExpr *SelfExpr = new (Context)
1532           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1533                       PropertyDiagLoc);
1534       MarkDeclRefReferenced(SelfExpr);
1535       Expr *LoadSelfExpr =
1536         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1537                                  CK_LValueToRValue, SelfExpr, nullptr,
1538                                  VK_RValue);
1539       Expr *lhs =
1540         new (Context) ObjCIvarRefExpr(Ivar,
1541                                       Ivar->getUsageType(SelfDecl->getType()),
1542                                       PropertyDiagLoc,
1543                                       Ivar->getLocation(),
1544                                       LoadSelfExpr, true, true);
1545       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1546       ParmVarDecl *Param = (*P);
1547       QualType T = Param->getType().getNonReferenceType();
1548       DeclRefExpr *rhs = new (Context)
1549           DeclRefExpr(Context, Param, false, T, VK_LValue, PropertyDiagLoc);
1550       MarkDeclRefReferenced(rhs);
1551       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1552                                   BO_Assign, lhs, rhs);
1553       if (property->getPropertyAttributes() &
1554           ObjCPropertyDecl::OBJC_PR_atomic) {
1555         Expr *callExpr = Res.getAs<Expr>();
1556         if (const CXXOperatorCallExpr *CXXCE =
1557               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1558           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1559             if (!FuncDecl->isTrivial())
1560               if (property->getType()->isReferenceType()) {
1561                 Diag(PropertyDiagLoc,
1562                      diag::err_atomic_property_nontrivial_assign_op)
1563                     << property->getType();
1564                 Diag(FuncDecl->getBeginLoc(), diag::note_callee_decl)
1565                     << FuncDecl;
1566               }
1567       }
1568       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1569     }
1570   }
1571 
1572   if (IC) {
1573     if (Synthesize)
1574       if (ObjCPropertyImplDecl *PPIDecl =
1575           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1576         Diag(PropertyLoc, diag::err_duplicate_ivar_use)
1577         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1578         << PropertyIvar;
1579         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1580       }
1581 
1582     if (ObjCPropertyImplDecl *PPIDecl
1583         = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
1584       Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
1585       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1586       return nullptr;
1587     }
1588     IC->addPropertyImplementation(PIDecl);
1589     if (getLangOpts().ObjCDefaultSynthProperties &&
1590         getLangOpts().ObjCRuntime.isNonFragile() &&
1591         !IDecl->isObjCRequiresPropertyDefs()) {
1592       // Diagnose if an ivar was lazily synthesdized due to a previous
1593       // use and if 1) property is @dynamic or 2) property is synthesized
1594       // but it requires an ivar of different name.
1595       ObjCInterfaceDecl *ClassDeclared=nullptr;
1596       ObjCIvarDecl *Ivar = nullptr;
1597       if (!Synthesize)
1598         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1599       else {
1600         if (PropertyIvar && PropertyIvar != PropertyId)
1601           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1602       }
1603       // Issue diagnostics only if Ivar belongs to current class.
1604       if (Ivar && Ivar->getSynthesize() &&
1605           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1606         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1607         << PropertyId;
1608         Ivar->setInvalidDecl();
1609       }
1610     }
1611   } else {
1612     if (Synthesize)
1613       if (ObjCPropertyImplDecl *PPIDecl =
1614           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1615         Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
1616         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1617         << PropertyIvar;
1618         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1619       }
1620 
1621     if (ObjCPropertyImplDecl *PPIDecl =
1622         CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
1623       Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
1624       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1625       return nullptr;
1626     }
1627     CatImplClass->addPropertyImplementation(PIDecl);
1628   }
1629 
1630   if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic &&
1631       PIDecl->getPropertyDecl() &&
1632       PIDecl->getPropertyDecl()->isDirectProperty()) {
1633     Diag(PropertyLoc, diag::err_objc_direct_dynamic_property);
1634     Diag(PIDecl->getPropertyDecl()->getLocation(),
1635          diag::note_previous_declaration);
1636     return nullptr;
1637   }
1638 
1639   return PIDecl;
1640 }
1641 
1642 //===----------------------------------------------------------------------===//
1643 // Helper methods.
1644 //===----------------------------------------------------------------------===//
1645 
1646 /// DiagnosePropertyMismatch - Compares two properties for their
1647 /// attributes and types and warns on a variety of inconsistencies.
1648 ///
1649 void
1650 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1651                                ObjCPropertyDecl *SuperProperty,
1652                                const IdentifierInfo *inheritedName,
1653                                bool OverridingProtocolProperty) {
1654   ObjCPropertyDecl::PropertyAttributeKind CAttr =
1655     Property->getPropertyAttributes();
1656   ObjCPropertyDecl::PropertyAttributeKind SAttr =
1657     SuperProperty->getPropertyAttributes();
1658 
1659   // We allow readonly properties without an explicit ownership
1660   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1661   // to be overridden by a property with any explicit ownership in the subclass.
1662   if (!OverridingProtocolProperty &&
1663       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1664     ;
1665   else {
1666     if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
1667         && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
1668       Diag(Property->getLocation(), diag::warn_readonly_property)
1669         << Property->getDeclName() << inheritedName;
1670     if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
1671         != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
1672       Diag(Property->getLocation(), diag::warn_property_attribute)
1673         << Property->getDeclName() << "copy" << inheritedName;
1674     else if (!(SAttr & ObjCPropertyDecl::OBJC_PR_readonly)){
1675       unsigned CAttrRetain =
1676         (CAttr &
1677          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1678       unsigned SAttrRetain =
1679         (SAttr &
1680          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1681       bool CStrong = (CAttrRetain != 0);
1682       bool SStrong = (SAttrRetain != 0);
1683       if (CStrong != SStrong)
1684         Diag(Property->getLocation(), diag::warn_property_attribute)
1685           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1686     }
1687   }
1688 
1689   // Check for nonatomic; note that nonatomic is effectively
1690   // meaningless for readonly properties, so don't diagnose if the
1691   // atomic property is 'readonly'.
1692   checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
1693   // Readonly properties from protocols can be implemented as "readwrite"
1694   // with a custom setter name.
1695   if (Property->getSetterName() != SuperProperty->getSetterName() &&
1696       !(SuperProperty->isReadOnly() &&
1697         isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
1698     Diag(Property->getLocation(), diag::warn_property_attribute)
1699       << Property->getDeclName() << "setter" << inheritedName;
1700     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1701   }
1702   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1703     Diag(Property->getLocation(), diag::warn_property_attribute)
1704       << Property->getDeclName() << "getter" << inheritedName;
1705     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1706   }
1707 
1708   QualType LHSType =
1709     Context.getCanonicalType(SuperProperty->getType());
1710   QualType RHSType =
1711     Context.getCanonicalType(Property->getType());
1712 
1713   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1714     // Do cases not handled in above.
1715     // FIXME. For future support of covariant property types, revisit this.
1716     bool IncompatibleObjC = false;
1717     QualType ConvertedType;
1718     if (!isObjCPointerConversion(RHSType, LHSType,
1719                                  ConvertedType, IncompatibleObjC) ||
1720         IncompatibleObjC) {
1721         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1722         << Property->getType() << SuperProperty->getType() << inheritedName;
1723       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1724     }
1725   }
1726 }
1727 
1728 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1729                                             ObjCMethodDecl *GetterMethod,
1730                                             SourceLocation Loc) {
1731   if (!GetterMethod)
1732     return false;
1733   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1734   QualType PropertyRValueType =
1735       property->getType().getNonReferenceType().getAtomicUnqualifiedType();
1736   bool compat = Context.hasSameType(PropertyRValueType, GetterType);
1737   if (!compat) {
1738     const ObjCObjectPointerType *propertyObjCPtr = nullptr;
1739     const ObjCObjectPointerType *getterObjCPtr = nullptr;
1740     if ((propertyObjCPtr =
1741              PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
1742         (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
1743       compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
1744     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
1745               != Compatible) {
1746           Diag(Loc, diag::err_property_accessor_type)
1747             << property->getDeclName() << PropertyRValueType
1748             << GetterMethod->getSelector() << GetterType;
1749           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1750           return true;
1751     } else {
1752       compat = true;
1753       QualType lhsType = Context.getCanonicalType(PropertyRValueType);
1754       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1755       if (lhsType != rhsType && lhsType->isArithmeticType())
1756         compat = false;
1757     }
1758   }
1759 
1760   if (!compat) {
1761     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1762     << property->getDeclName()
1763     << GetterMethod->getSelector();
1764     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1765     return true;
1766   }
1767 
1768   return false;
1769 }
1770 
1771 /// CollectImmediateProperties - This routine collects all properties in
1772 /// the class and its conforming protocols; but not those in its super class.
1773 static void
1774 CollectImmediateProperties(ObjCContainerDecl *CDecl,
1775                            ObjCContainerDecl::PropertyMap &PropMap,
1776                            ObjCContainerDecl::PropertyMap &SuperPropMap,
1777                            bool CollectClassPropsOnly = false,
1778                            bool IncludeProtocols = true) {
1779   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1780     for (auto *Prop : IDecl->properties()) {
1781       if (CollectClassPropsOnly && !Prop->isClassProperty())
1782         continue;
1783       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1784           Prop;
1785     }
1786 
1787     // Collect the properties from visible extensions.
1788     for (auto *Ext : IDecl->visible_extensions())
1789       CollectImmediateProperties(Ext, PropMap, SuperPropMap,
1790                                  CollectClassPropsOnly, IncludeProtocols);
1791 
1792     if (IncludeProtocols) {
1793       // Scan through class's protocols.
1794       for (auto *PI : IDecl->all_referenced_protocols())
1795         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1796                                    CollectClassPropsOnly);
1797     }
1798   }
1799   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1800     for (auto *Prop : CATDecl->properties()) {
1801       if (CollectClassPropsOnly && !Prop->isClassProperty())
1802         continue;
1803       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1804           Prop;
1805     }
1806     if (IncludeProtocols) {
1807       // Scan through class's protocols.
1808       for (auto *PI : CATDecl->protocols())
1809         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1810                                    CollectClassPropsOnly);
1811     }
1812   }
1813   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1814     for (auto *Prop : PDecl->properties()) {
1815       if (CollectClassPropsOnly && !Prop->isClassProperty())
1816         continue;
1817       ObjCPropertyDecl *PropertyFromSuper =
1818           SuperPropMap[std::make_pair(Prop->getIdentifier(),
1819                                       Prop->isClassProperty())];
1820       // Exclude property for protocols which conform to class's super-class,
1821       // as super-class has to implement the property.
1822       if (!PropertyFromSuper ||
1823           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1824         ObjCPropertyDecl *&PropEntry =
1825             PropMap[std::make_pair(Prop->getIdentifier(),
1826                                    Prop->isClassProperty())];
1827         if (!PropEntry)
1828           PropEntry = Prop;
1829       }
1830     }
1831     // Scan through protocol's protocols.
1832     for (auto *PI : PDecl->protocols())
1833       CollectImmediateProperties(PI, PropMap, SuperPropMap,
1834                                  CollectClassPropsOnly);
1835   }
1836 }
1837 
1838 /// CollectSuperClassPropertyImplementations - This routine collects list of
1839 /// properties to be implemented in super class(s) and also coming from their
1840 /// conforming protocols.
1841 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1842                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1843   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1844     ObjCInterfaceDecl::PropertyDeclOrder PO;
1845     while (SDecl) {
1846       SDecl->collectPropertiesToImplement(PropMap, PO);
1847       SDecl = SDecl->getSuperClass();
1848     }
1849   }
1850 }
1851 
1852 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1853 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1854 /// declared in class 'IFace'.
1855 bool
1856 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1857                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1858   if (!IV->getSynthesize())
1859     return false;
1860   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1861                                             Method->isInstanceMethod());
1862   if (!IMD || !IMD->isPropertyAccessor())
1863     return false;
1864 
1865   // look up a property declaration whose one of its accessors is implemented
1866   // by this method.
1867   for (const auto *Property : IFace->instance_properties()) {
1868     if ((Property->getGetterName() == IMD->getSelector() ||
1869          Property->getSetterName() == IMD->getSelector()) &&
1870         (Property->getPropertyIvarDecl() == IV))
1871       return true;
1872   }
1873   // Also look up property declaration in class extension whose one of its
1874   // accessors is implemented by this method.
1875   for (const auto *Ext : IFace->known_extensions())
1876     for (const auto *Property : Ext->instance_properties())
1877       if ((Property->getGetterName() == IMD->getSelector() ||
1878            Property->getSetterName() == IMD->getSelector()) &&
1879           (Property->getPropertyIvarDecl() == IV))
1880         return true;
1881   return false;
1882 }
1883 
1884 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1885                                          ObjCPropertyDecl *Prop) {
1886   bool SuperClassImplementsGetter = false;
1887   bool SuperClassImplementsSetter = false;
1888   if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1889     SuperClassImplementsSetter = true;
1890 
1891   while (IDecl->getSuperClass()) {
1892     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1893     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1894       SuperClassImplementsGetter = true;
1895 
1896     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1897       SuperClassImplementsSetter = true;
1898     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1899       return true;
1900     IDecl = IDecl->getSuperClass();
1901   }
1902   return false;
1903 }
1904 
1905 /// Default synthesizes all properties which must be synthesized
1906 /// in class's \@implementation.
1907 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
1908                                        ObjCInterfaceDecl *IDecl,
1909                                        SourceLocation AtEnd) {
1910   ObjCInterfaceDecl::PropertyMap PropMap;
1911   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1912   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1913   if (PropMap.empty())
1914     return;
1915   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1916   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1917 
1918   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1919     ObjCPropertyDecl *Prop = PropertyOrder[i];
1920     // Is there a matching property synthesize/dynamic?
1921     if (Prop->isInvalidDecl() ||
1922         Prop->isClassProperty() ||
1923         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1924       continue;
1925     // Property may have been synthesized by user.
1926     if (IMPDecl->FindPropertyImplDecl(
1927             Prop->getIdentifier(), Prop->getQueryKind()))
1928       continue;
1929     ObjCMethodDecl *ImpMethod = IMPDecl->getInstanceMethod(Prop->getGetterName());
1930     if (ImpMethod && !ImpMethod->getBody()) {
1931       if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1932         continue;
1933       ImpMethod = IMPDecl->getInstanceMethod(Prop->getSetterName());
1934       if (ImpMethod && !ImpMethod->getBody())
1935         continue;
1936     }
1937     if (ObjCPropertyImplDecl *PID =
1938         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1939       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1940         << Prop->getIdentifier();
1941       if (PID->getLocation().isValid())
1942         Diag(PID->getLocation(), diag::note_property_synthesize);
1943       continue;
1944     }
1945     ObjCPropertyDecl *PropInSuperClass =
1946         SuperPropMap[std::make_pair(Prop->getIdentifier(),
1947                                     Prop->isClassProperty())];
1948     if (ObjCProtocolDecl *Proto =
1949           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1950       // We won't auto-synthesize properties declared in protocols.
1951       // Suppress the warning if class's superclass implements property's
1952       // getter and implements property's setter (if readwrite property).
1953       // Or, if property is going to be implemented in its super class.
1954       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1955         Diag(IMPDecl->getLocation(),
1956              diag::warn_auto_synthesizing_protocol_property)
1957           << Prop << Proto;
1958         Diag(Prop->getLocation(), diag::note_property_declare);
1959         std::string FixIt =
1960             (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
1961         Diag(AtEnd, diag::note_add_synthesize_directive)
1962             << FixItHint::CreateInsertion(AtEnd, FixIt);
1963       }
1964       continue;
1965     }
1966     // If property to be implemented in the super class, ignore.
1967     if (PropInSuperClass) {
1968       if ((Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readwrite) &&
1969           (PropInSuperClass->getPropertyAttributes() &
1970            ObjCPropertyDecl::OBJC_PR_readonly) &&
1971           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1972           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1973         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1974         << Prop->getIdentifier();
1975         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1976       }
1977       else {
1978         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1979         << Prop->getIdentifier();
1980         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1981         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1982       }
1983       continue;
1984     }
1985     // We use invalid SourceLocations for the synthesized ivars since they
1986     // aren't really synthesized at a particular location; they just exist.
1987     // Saying that they are located at the @implementation isn't really going
1988     // to help users.
1989     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1990       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1991                             true,
1992                             /* property = */ Prop->getIdentifier(),
1993                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1994                             Prop->getLocation(), Prop->getQueryKind()));
1995     if (PIDecl && !Prop->isUnavailable()) {
1996       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1997       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1998     }
1999   }
2000 }
2001 
2002 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
2003                                        SourceLocation AtEnd) {
2004   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
2005     return;
2006   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
2007   if (!IC)
2008     return;
2009   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
2010     if (!IDecl->isObjCRequiresPropertyDefs())
2011       DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
2012 }
2013 
2014 static void DiagnoseUnimplementedAccessor(
2015     Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
2016     ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
2017     ObjCPropertyDecl *Prop,
2018     llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
2019   // Check to see if we have a corresponding selector in SMap and with the
2020   // right method type.
2021   auto I = llvm::find_if(SMap, [&](const ObjCMethodDecl *x) {
2022     return x->getSelector() == Method &&
2023            x->isClassMethod() == Prop->isClassProperty();
2024   });
2025   // When reporting on missing property setter/getter implementation in
2026   // categories, do not report when they are declared in primary class,
2027   // class's protocol, or one of it super classes. This is because,
2028   // the class is going to implement them.
2029   if (I == SMap.end() &&
2030       (PrimaryClass == nullptr ||
2031        !PrimaryClass->lookupPropertyAccessor(Method, C,
2032                                              Prop->isClassProperty()))) {
2033     unsigned diag =
2034         isa<ObjCCategoryDecl>(CDecl)
2035             ? (Prop->isClassProperty()
2036                    ? diag::warn_impl_required_in_category_for_class_property
2037                    : diag::warn_setter_getter_impl_required_in_category)
2038             : (Prop->isClassProperty()
2039                    ? diag::warn_impl_required_for_class_property
2040                    : diag::warn_setter_getter_impl_required);
2041     S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
2042     S.Diag(Prop->getLocation(), diag::note_property_declare);
2043     if (S.LangOpts.ObjCDefaultSynthProperties &&
2044         S.LangOpts.ObjCRuntime.isNonFragile())
2045       if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
2046         if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
2047           S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
2048   }
2049 }
2050 
2051 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
2052                                            ObjCContainerDecl *CDecl,
2053                                            bool SynthesizeProperties) {
2054   ObjCContainerDecl::PropertyMap PropMap;
2055   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
2056 
2057   // Since we don't synthesize class properties, we should emit diagnose even
2058   // if SynthesizeProperties is true.
2059   ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2060   // Gather properties which need not be implemented in this class
2061   // or category.
2062   if (!IDecl)
2063     if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
2064       // For categories, no need to implement properties declared in
2065       // its primary class (and its super classes) if property is
2066       // declared in one of those containers.
2067       if ((IDecl = C->getClassInterface())) {
2068         ObjCInterfaceDecl::PropertyDeclOrder PO;
2069         IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
2070       }
2071     }
2072   if (IDecl)
2073     CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
2074 
2075   // When SynthesizeProperties is true, we only check class properties.
2076   CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
2077                              SynthesizeProperties/*CollectClassPropsOnly*/);
2078 
2079   // Scan the @interface to see if any of the protocols it adopts
2080   // require an explicit implementation, via attribute
2081   // 'objc_protocol_requires_explicit_implementation'.
2082   if (IDecl) {
2083     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
2084 
2085     for (auto *PDecl : IDecl->all_referenced_protocols()) {
2086       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2087         continue;
2088       // Lazily construct a set of all the properties in the @interface
2089       // of the class, without looking at the superclass.  We cannot
2090       // use the call to CollectImmediateProperties() above as that
2091       // utilizes information from the super class's properties as well
2092       // as scans the adopted protocols.  This work only triggers for protocols
2093       // with the attribute, which is very rare, and only occurs when
2094       // analyzing the @implementation.
2095       if (!LazyMap) {
2096         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2097         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
2098         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
2099                                    /* CollectClassPropsOnly */ false,
2100                                    /* IncludeProtocols */ false);
2101       }
2102       // Add the properties of 'PDecl' to the list of properties that
2103       // need to be implemented.
2104       for (auto *PropDecl : PDecl->properties()) {
2105         if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
2106                                       PropDecl->isClassProperty())])
2107           continue;
2108         PropMap[std::make_pair(PropDecl->getIdentifier(),
2109                                PropDecl->isClassProperty())] = PropDecl;
2110       }
2111     }
2112   }
2113 
2114   if (PropMap.empty())
2115     return;
2116 
2117   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
2118   for (const auto *I : IMPDecl->property_impls())
2119     PropImplMap.insert(I->getPropertyDecl());
2120 
2121   llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
2122   // Collect property accessors implemented in current implementation.
2123   for (const auto *I : IMPDecl->methods())
2124     InsMap.insert(I);
2125 
2126   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
2127   ObjCInterfaceDecl *PrimaryClass = nullptr;
2128   if (C && !C->IsClassExtension())
2129     if ((PrimaryClass = C->getClassInterface()))
2130       // Report unimplemented properties in the category as well.
2131       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
2132         // When reporting on missing setter/getters, do not report when
2133         // setter/getter is implemented in category's primary class
2134         // implementation.
2135         for (const auto *I : IMP->methods())
2136           InsMap.insert(I);
2137       }
2138 
2139   for (ObjCContainerDecl::PropertyMap::iterator
2140        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
2141     ObjCPropertyDecl *Prop = P->second;
2142     // Is there a matching property synthesize/dynamic?
2143     if (Prop->isInvalidDecl() ||
2144         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
2145         PropImplMap.count(Prop) ||
2146         Prop->getAvailability() == AR_Unavailable)
2147       continue;
2148 
2149     // Diagnose unimplemented getters and setters.
2150     DiagnoseUnimplementedAccessor(*this,
2151           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
2152     if (!Prop->isReadOnly())
2153       DiagnoseUnimplementedAccessor(*this,
2154                                     PrimaryClass, Prop->getSetterName(),
2155                                     IMPDecl, CDecl, C, Prop, InsMap);
2156   }
2157 }
2158 
2159 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
2160   for (const auto *propertyImpl : impDecl->property_impls()) {
2161     const auto *property = propertyImpl->getPropertyDecl();
2162     // Warn about null_resettable properties with synthesized setters,
2163     // because the setter won't properly handle nil.
2164     if (propertyImpl->getPropertyImplementation()
2165           == ObjCPropertyImplDecl::Synthesize &&
2166         (property->getPropertyAttributes() &
2167          ObjCPropertyDecl::OBJC_PR_null_resettable) &&
2168         property->getGetterMethodDecl() &&
2169         property->getSetterMethodDecl()) {
2170       auto *getterImpl = propertyImpl->getGetterMethodDecl();
2171       auto *setterImpl = propertyImpl->getSetterMethodDecl();
2172       if ((!getterImpl || getterImpl->isSynthesizedAccessorStub()) &&
2173           (!setterImpl || setterImpl->isSynthesizedAccessorStub())) {
2174         SourceLocation loc = propertyImpl->getLocation();
2175         if (loc.isInvalid())
2176           loc = impDecl->getBeginLoc();
2177 
2178         Diag(loc, diag::warn_null_resettable_setter)
2179           << setterImpl->getSelector() << property->getDeclName();
2180       }
2181     }
2182   }
2183 }
2184 
2185 void
2186 Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
2187                                        ObjCInterfaceDecl* IDecl) {
2188   // Rules apply in non-GC mode only
2189   if (getLangOpts().getGC() != LangOptions::NonGC)
2190     return;
2191   ObjCContainerDecl::PropertyMap PM;
2192   for (auto *Prop : IDecl->properties())
2193     PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2194   for (const auto *Ext : IDecl->known_extensions())
2195     for (auto *Prop : Ext->properties())
2196       PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2197 
2198   for (ObjCContainerDecl::PropertyMap::iterator I = PM.begin(), E = PM.end();
2199        I != E; ++I) {
2200     const ObjCPropertyDecl *Property = I->second;
2201     ObjCMethodDecl *GetterMethod = nullptr;
2202     ObjCMethodDecl *SetterMethod = nullptr;
2203 
2204     unsigned Attributes = Property->getPropertyAttributes();
2205     unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();
2206 
2207     if (!(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic) &&
2208         !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_nonatomic)) {
2209       GetterMethod = Property->isClassProperty() ?
2210                      IMPDecl->getClassMethod(Property->getGetterName()) :
2211                      IMPDecl->getInstanceMethod(Property->getGetterName());
2212       SetterMethod = Property->isClassProperty() ?
2213                      IMPDecl->getClassMethod(Property->getSetterName()) :
2214                      IMPDecl->getInstanceMethod(Property->getSetterName());
2215       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2216         GetterMethod = nullptr;
2217       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2218         SetterMethod = nullptr;
2219       if (GetterMethod) {
2220         Diag(GetterMethod->getLocation(),
2221              diag::warn_default_atomic_custom_getter_setter)
2222           << Property->getIdentifier() << 0;
2223         Diag(Property->getLocation(), diag::note_property_declare);
2224       }
2225       if (SetterMethod) {
2226         Diag(SetterMethod->getLocation(),
2227              diag::warn_default_atomic_custom_getter_setter)
2228           << Property->getIdentifier() << 1;
2229         Diag(Property->getLocation(), diag::note_property_declare);
2230       }
2231     }
2232 
2233     // We only care about readwrite atomic property.
2234     if ((Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
2235         !(Attributes & ObjCPropertyDecl::OBJC_PR_readwrite))
2236       continue;
2237     if (const ObjCPropertyImplDecl *PIDecl = IMPDecl->FindPropertyImplDecl(
2238             Property->getIdentifier(), Property->getQueryKind())) {
2239       if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
2240         continue;
2241       GetterMethod = PIDecl->getGetterMethodDecl();
2242       SetterMethod = PIDecl->getSetterMethodDecl();
2243       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2244         GetterMethod = nullptr;
2245       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2246         SetterMethod = nullptr;
2247       if ((bool)GetterMethod ^ (bool)SetterMethod) {
2248         SourceLocation MethodLoc =
2249           (GetterMethod ? GetterMethod->getLocation()
2250                         : SetterMethod->getLocation());
2251         Diag(MethodLoc, diag::warn_atomic_property_rule)
2252           << Property->getIdentifier() << (GetterMethod != nullptr)
2253           << (SetterMethod != nullptr);
2254         // fixit stuff.
2255         if (Property->getLParenLoc().isValid() &&
2256             !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic)) {
2257           // @property () ... case.
2258           SourceLocation AfterLParen =
2259             getLocForEndOfToken(Property->getLParenLoc());
2260           StringRef NonatomicStr = AttributesAsWritten? "nonatomic, "
2261                                                       : "nonatomic";
2262           Diag(Property->getLocation(),
2263                diag::note_atomic_property_fixup_suggest)
2264             << FixItHint::CreateInsertion(AfterLParen, NonatomicStr);
2265         } else if (Property->getLParenLoc().isInvalid()) {
2266           //@property id etc.
2267           SourceLocation startLoc =
2268             Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2269           Diag(Property->getLocation(),
2270                diag::note_atomic_property_fixup_suggest)
2271             << FixItHint::CreateInsertion(startLoc, "(nonatomic) ");
2272         }
2273         else
2274           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
2275         Diag(Property->getLocation(), diag::note_property_declare);
2276       }
2277     }
2278   }
2279 }
2280 
2281 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
2282   if (getLangOpts().getGC() == LangOptions::GCOnly)
2283     return;
2284 
2285   for (const auto *PID : D->property_impls()) {
2286     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2287     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
2288         !PD->isClassProperty()) {
2289       ObjCMethodDecl *IM = PID->getGetterMethodDecl();
2290       if (IM && !IM->isSynthesizedAccessorStub())
2291         continue;
2292       ObjCMethodDecl *method = PD->getGetterMethodDecl();
2293       if (!method)
2294         continue;
2295       ObjCMethodFamily family = method->getMethodFamily();
2296       if (family == OMF_alloc || family == OMF_copy ||
2297           family == OMF_mutableCopy || family == OMF_new) {
2298         if (getLangOpts().ObjCAutoRefCount)
2299           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
2300         else
2301           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
2302 
2303         // Look for a getter explicitly declared alongside the property.
2304         // If we find one, use its location for the note.
2305         SourceLocation noteLoc = PD->getLocation();
2306         SourceLocation fixItLoc;
2307         for (auto *getterRedecl : method->redecls()) {
2308           if (getterRedecl->isImplicit())
2309             continue;
2310           if (getterRedecl->getDeclContext() != PD->getDeclContext())
2311             continue;
2312           noteLoc = getterRedecl->getLocation();
2313           fixItLoc = getterRedecl->getEndLoc();
2314         }
2315 
2316         Preprocessor &PP = getPreprocessor();
2317         TokenValue tokens[] = {
2318           tok::kw___attribute, tok::l_paren, tok::l_paren,
2319           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
2320           PP.getIdentifierInfo("none"), tok::r_paren,
2321           tok::r_paren, tok::r_paren
2322         };
2323         StringRef spelling = "__attribute__((objc_method_family(none)))";
2324         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
2325         if (!macroName.empty())
2326           spelling = macroName;
2327 
2328         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
2329             << method->getDeclName() << spelling;
2330         if (fixItLoc.isValid()) {
2331           SmallString<64> fixItText(" ");
2332           fixItText += spelling;
2333           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
2334         }
2335       }
2336     }
2337   }
2338 }
2339 
2340 void Sema::DiagnoseMissingDesignatedInitOverrides(
2341                                             const ObjCImplementationDecl *ImplD,
2342                                             const ObjCInterfaceDecl *IFD) {
2343   assert(IFD->hasDesignatedInitializers());
2344   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
2345   if (!SuperD)
2346     return;
2347 
2348   SelectorSet InitSelSet;
2349   for (const auto *I : ImplD->instance_methods())
2350     if (I->getMethodFamily() == OMF_init)
2351       InitSelSet.insert(I->getSelector());
2352 
2353   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
2354   SuperD->getDesignatedInitializers(DesignatedInits);
2355   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
2356          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
2357     const ObjCMethodDecl *MD = *I;
2358     if (!InitSelSet.count(MD->getSelector())) {
2359       // Don't emit a diagnostic if the overriding method in the subclass is
2360       // marked as unavailable.
2361       bool Ignore = false;
2362       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
2363         Ignore = IMD->isUnavailable();
2364       } else {
2365         // Check the methods declared in the class extensions too.
2366         for (auto *Ext : IFD->visible_extensions())
2367           if (auto *IMD = Ext->getInstanceMethod(MD->getSelector())) {
2368             Ignore = IMD->isUnavailable();
2369             break;
2370           }
2371       }
2372       if (!Ignore) {
2373         Diag(ImplD->getLocation(),
2374              diag::warn_objc_implementation_missing_designated_init_override)
2375           << MD->getSelector();
2376         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
2377       }
2378     }
2379   }
2380 }
2381 
2382 /// AddPropertyAttrs - Propagates attributes from a property to the
2383 /// implicitly-declared getter or setter for that property.
2384 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
2385                              ObjCPropertyDecl *Property) {
2386   // Should we just clone all attributes over?
2387   for (const auto *A : Property->attrs()) {
2388     if (isa<DeprecatedAttr>(A) ||
2389         isa<UnavailableAttr>(A) ||
2390         isa<AvailabilityAttr>(A))
2391       PropertyMethod->addAttr(A->clone(S.Context));
2392   }
2393 }
2394 
2395 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2396 /// have the property type and issue diagnostics if they don't.
2397 /// Also synthesize a getter/setter method if none exist (and update the
2398 /// appropriate lookup tables.
2399 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
2400   ObjCMethodDecl *GetterMethod, *SetterMethod;
2401   ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
2402   if (CD->isInvalidDecl())
2403     return;
2404 
2405   bool IsClassProperty = property->isClassProperty();
2406   GetterMethod = IsClassProperty ?
2407     CD->getClassMethod(property->getGetterName()) :
2408     CD->getInstanceMethod(property->getGetterName());
2409 
2410   // if setter or getter is not found in class extension, it might be
2411   // in the primary class.
2412   if (!GetterMethod)
2413     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2414       if (CatDecl->IsClassExtension())
2415         GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2416                          getClassMethod(property->getGetterName()) :
2417                        CatDecl->getClassInterface()->
2418                          getInstanceMethod(property->getGetterName());
2419 
2420   SetterMethod = IsClassProperty ?
2421                  CD->getClassMethod(property->getSetterName()) :
2422                  CD->getInstanceMethod(property->getSetterName());
2423   if (!SetterMethod)
2424     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2425       if (CatDecl->IsClassExtension())
2426         SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2427                           getClassMethod(property->getSetterName()) :
2428                        CatDecl->getClassInterface()->
2429                           getInstanceMethod(property->getSetterName());
2430   DiagnosePropertyAccessorMismatch(property, GetterMethod,
2431                                    property->getLocation());
2432 
2433   // synthesizing accessors must not result in a direct method that is not
2434   // monomorphic
2435   if (!GetterMethod) {
2436     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
2437       auto *ExistingGetter = CatDecl->getClassInterface()->lookupMethod(
2438           property->getGetterName(), !IsClassProperty, true, false, CatDecl);
2439       if (ExistingGetter) {
2440         if (ExistingGetter->isDirectMethod() || property->isDirectProperty()) {
2441           Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
2442               << property->isDirectProperty() << 1 /* property */
2443               << ExistingGetter->isDirectMethod()
2444               << ExistingGetter->getDeclName();
2445           Diag(ExistingGetter->getLocation(), diag::note_previous_declaration);
2446         }
2447       }
2448     }
2449   }
2450 
2451   if (!property->isReadOnly() && !SetterMethod) {
2452     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
2453       auto *ExistingSetter = CatDecl->getClassInterface()->lookupMethod(
2454           property->getSetterName(), !IsClassProperty, true, false, CatDecl);
2455       if (ExistingSetter) {
2456         if (ExistingSetter->isDirectMethod() || property->isDirectProperty()) {
2457           Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
2458               << property->isDirectProperty() << 1 /* property */
2459               << ExistingSetter->isDirectMethod()
2460               << ExistingSetter->getDeclName();
2461           Diag(ExistingSetter->getLocation(), diag::note_previous_declaration);
2462         }
2463       }
2464     }
2465   }
2466 
2467   if (!property->isReadOnly() && SetterMethod) {
2468     if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
2469         Context.VoidTy)
2470       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2471     if (SetterMethod->param_size() != 1 ||
2472         !Context.hasSameUnqualifiedType(
2473           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2474           property->getType().getNonReferenceType())) {
2475       Diag(property->getLocation(),
2476            diag::warn_accessor_property_type_mismatch)
2477         << property->getDeclName()
2478         << SetterMethod->getSelector();
2479       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2480     }
2481   }
2482 
2483   // Synthesize getter/setter methods if none exist.
2484   // Find the default getter and if one not found, add one.
2485   // FIXME: The synthesized property we set here is misleading. We almost always
2486   // synthesize these methods unless the user explicitly provided prototypes
2487   // (which is odd, but allowed). Sema should be typechecking that the
2488   // declarations jive in that situation (which it is not currently).
2489   if (!GetterMethod) {
2490     // No instance/class method of same name as property getter name was found.
2491     // Declare a getter method and add it to the list of methods
2492     // for this class.
2493     SourceLocation Loc = property->getLocation();
2494 
2495     // The getter returns the declared property type with all qualifiers
2496     // removed.
2497     QualType resultTy = property->getType().getAtomicUnqualifiedType();
2498 
2499     // If the property is null_resettable, the getter returns nonnull.
2500     if (property->getPropertyAttributes() &
2501         ObjCPropertyDecl::OBJC_PR_null_resettable) {
2502       QualType modifiedTy = resultTy;
2503       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2504         if (*nullability == NullabilityKind::Unspecified)
2505           resultTy = Context.getAttributedType(attr::TypeNonNull,
2506                                                modifiedTy, modifiedTy);
2507       }
2508     }
2509 
2510     GetterMethod = ObjCMethodDecl::Create(
2511         Context, Loc, Loc, property->getGetterName(), resultTy, nullptr, CD,
2512         !IsClassProperty, /*isVariadic=*/false,
2513         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
2514         /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2515         (property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
2516             ? ObjCMethodDecl::Optional
2517             : ObjCMethodDecl::Required);
2518     CD->addDecl(GetterMethod);
2519 
2520     AddPropertyAttrs(*this, GetterMethod, property);
2521 
2522     if (property->isDirectProperty())
2523       GetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2524 
2525     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2526       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2527                                                                      Loc));
2528 
2529     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2530       GetterMethod->addAttr(
2531         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2532 
2533     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2534       GetterMethod->addAttr(SectionAttr::CreateImplicit(
2535           Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2536           SectionAttr::GNU_section));
2537 
2538     if (getLangOpts().ObjCAutoRefCount)
2539       CheckARCMethodDecl(GetterMethod);
2540   } else
2541     // A user declared getter will be synthesize when @synthesize of
2542     // the property with the same name is seen in the @implementation
2543     GetterMethod->setPropertyAccessor(true);
2544 
2545   GetterMethod->createImplicitParams(Context,
2546                                      GetterMethod->getClassInterface());
2547   property->setGetterMethodDecl(GetterMethod);
2548 
2549   // Skip setter if property is read-only.
2550   if (!property->isReadOnly()) {
2551     // Find the default setter and if one not found, add one.
2552     if (!SetterMethod) {
2553       // No instance/class method of same name as property setter name was
2554       // found.
2555       // Declare a setter method and add it to the list of methods
2556       // for this class.
2557       SourceLocation Loc = property->getLocation();
2558 
2559       SetterMethod =
2560         ObjCMethodDecl::Create(Context, Loc, Loc,
2561                                property->getSetterName(), Context.VoidTy,
2562                                nullptr, CD, !IsClassProperty,
2563                                /*isVariadic=*/false,
2564                                /*isPropertyAccessor=*/true,
2565                                /*isSynthesizedAccessorStub=*/false,
2566                                /*isImplicitlyDeclared=*/true,
2567                                /*isDefined=*/false,
2568                                (property->getPropertyImplementation() ==
2569                                 ObjCPropertyDecl::Optional) ?
2570                                 ObjCMethodDecl::Optional :
2571                                 ObjCMethodDecl::Required);
2572 
2573       // Remove all qualifiers from the setter's parameter type.
2574       QualType paramTy =
2575           property->getType().getUnqualifiedType().getAtomicUnqualifiedType();
2576 
2577       // If the property is null_resettable, the setter accepts a
2578       // nullable value.
2579       if (property->getPropertyAttributes() &
2580           ObjCPropertyDecl::OBJC_PR_null_resettable) {
2581         QualType modifiedTy = paramTy;
2582         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2583           if (*nullability == NullabilityKind::Unspecified)
2584             paramTy = Context.getAttributedType(attr::TypeNullable,
2585                                                 modifiedTy, modifiedTy);
2586         }
2587       }
2588 
2589       // Invent the arguments for the setter. We don't bother making a
2590       // nice name for the argument.
2591       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2592                                                   Loc, Loc,
2593                                                   property->getIdentifier(),
2594                                                   paramTy,
2595                                                   /*TInfo=*/nullptr,
2596                                                   SC_None,
2597                                                   nullptr);
2598       SetterMethod->setMethodParams(Context, Argument, None);
2599 
2600       AddPropertyAttrs(*this, SetterMethod, property);
2601 
2602       if (property->isDirectProperty())
2603         SetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2604 
2605       CD->addDecl(SetterMethod);
2606       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2607         SetterMethod->addAttr(SectionAttr::CreateImplicit(
2608             Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2609             SectionAttr::GNU_section));
2610       // It's possible for the user to have set a very odd custom
2611       // setter selector that causes it to have a method family.
2612       if (getLangOpts().ObjCAutoRefCount)
2613         CheckARCMethodDecl(SetterMethod);
2614     } else
2615       // A user declared setter will be synthesize when @synthesize of
2616       // the property with the same name is seen in the @implementation
2617       SetterMethod->setPropertyAccessor(true);
2618 
2619     SetterMethod->createImplicitParams(Context,
2620                                        SetterMethod->getClassInterface());
2621     property->setSetterMethodDecl(SetterMethod);
2622   }
2623   // Add any synthesized methods to the global pool. This allows us to
2624   // handle the following, which is supported by GCC (and part of the design).
2625   //
2626   // @interface Foo
2627   // @property double bar;
2628   // @end
2629   //
2630   // void thisIsUnfortunate() {
2631   //   id foo;
2632   //   double bar = [foo bar];
2633   // }
2634   //
2635   if (!IsClassProperty) {
2636     if (GetterMethod)
2637       AddInstanceMethodToGlobalPool(GetterMethod);
2638     if (SetterMethod)
2639       AddInstanceMethodToGlobalPool(SetterMethod);
2640   } else {
2641     if (GetterMethod)
2642       AddFactoryMethodToGlobalPool(GetterMethod);
2643     if (SetterMethod)
2644       AddFactoryMethodToGlobalPool(SetterMethod);
2645   }
2646 
2647   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2648   if (!CurrentClass) {
2649     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2650       CurrentClass = Cat->getClassInterface();
2651     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2652       CurrentClass = Impl->getClassInterface();
2653   }
2654   if (GetterMethod)
2655     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2656   if (SetterMethod)
2657     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2658 }
2659 
2660 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2661                                        SourceLocation Loc,
2662                                        unsigned &Attributes,
2663                                        bool propertyInPrimaryClass) {
2664   // FIXME: Improve the reported location.
2665   if (!PDecl || PDecl->isInvalidDecl())
2666     return;
2667 
2668   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2669       (Attributes & ObjCDeclSpec::DQ_PR_readwrite))
2670     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2671     << "readonly" << "readwrite";
2672 
2673   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2674   QualType PropertyTy = PropertyDecl->getType();
2675 
2676   // Check for copy or retain on non-object types.
2677   if ((Attributes & (ObjCDeclSpec::DQ_PR_weak | ObjCDeclSpec::DQ_PR_copy |
2678                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong)) &&
2679       !PropertyTy->isObjCRetainableType() &&
2680       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2681     Diag(Loc, diag::err_objc_property_requires_object)
2682       << (Attributes & ObjCDeclSpec::DQ_PR_weak ? "weak" :
2683           Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain (or strong)");
2684     Attributes &= ~(ObjCDeclSpec::DQ_PR_weak   | ObjCDeclSpec::DQ_PR_copy |
2685                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong);
2686     PropertyDecl->setInvalidDecl();
2687   }
2688 
2689   // Check for assign on object types.
2690   if ((Attributes & ObjCDeclSpec::DQ_PR_assign) &&
2691       !(Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) &&
2692       PropertyTy->isObjCRetainableType() &&
2693       !PropertyTy->isObjCARCImplicitlyUnretainedType()) {
2694     Diag(Loc, diag::warn_objc_property_assign_on_object);
2695   }
2696 
2697   // Check for more than one of { assign, copy, retain }.
2698   if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
2699     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2700       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2701         << "assign" << "copy";
2702       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2703     }
2704     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2705       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2706         << "assign" << "retain";
2707       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2708     }
2709     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2710       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2711         << "assign" << "strong";
2712       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2713     }
2714     if (getLangOpts().ObjCAutoRefCount  &&
2715         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2716       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2717         << "assign" << "weak";
2718       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2719     }
2720     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2721       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2722   } else if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) {
2723     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2724       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2725         << "unsafe_unretained" << "copy";
2726       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2727     }
2728     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2729       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2730         << "unsafe_unretained" << "retain";
2731       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2732     }
2733     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2734       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2735         << "unsafe_unretained" << "strong";
2736       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2737     }
2738     if (getLangOpts().ObjCAutoRefCount  &&
2739         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2740       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2741         << "unsafe_unretained" << "weak";
2742       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2743     }
2744   } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2745     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2746       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2747         << "copy" << "retain";
2748       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2749     }
2750     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2751       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2752         << "copy" << "strong";
2753       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2754     }
2755     if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2756       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2757         << "copy" << "weak";
2758       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2759     }
2760   }
2761   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2762            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2763       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2764         << "retain" << "weak";
2765       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2766   }
2767   else if ((Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2768            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2769       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2770         << "strong" << "weak";
2771       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2772   }
2773 
2774   if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2775     // 'weak' and 'nonnull' are mutually exclusive.
2776     if (auto nullability = PropertyTy->getNullability(Context)) {
2777       if (*nullability == NullabilityKind::NonNull)
2778         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2779           << "nonnull" << "weak";
2780     }
2781   }
2782 
2783   if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
2784       (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
2785       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2786         << "atomic" << "nonatomic";
2787       Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
2788   }
2789 
2790   // Warn if user supplied no assignment attribute, property is
2791   // readwrite, and this is an object type.
2792   if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
2793     if (Attributes & ObjCDeclSpec::DQ_PR_readonly) {
2794       // do nothing
2795     } else if (getLangOpts().ObjCAutoRefCount) {
2796       // With arc, @property definitions should default to strong when
2797       // not specified.
2798       PropertyDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
2799     } else if (PropertyTy->isObjCObjectPointerType()) {
2800         bool isAnyClassTy =
2801           (PropertyTy->isObjCClassType() ||
2802            PropertyTy->isObjCQualifiedClassType());
2803         // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2804         // issue any warning.
2805         if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2806           ;
2807         else if (propertyInPrimaryClass) {
2808           // Don't issue warning on property with no life time in class
2809           // extension as it is inherited from property in primary class.
2810           // Skip this warning in gc-only mode.
2811           if (getLangOpts().getGC() != LangOptions::GCOnly)
2812             Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2813 
2814           // If non-gc code warn that this is likely inappropriate.
2815           if (getLangOpts().getGC() == LangOptions::NonGC)
2816             Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2817         }
2818     }
2819 
2820     // FIXME: Implement warning dependent on NSCopying being
2821     // implemented. See also:
2822     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2823     // (please trim this list while you are at it).
2824   }
2825 
2826   if (!(Attributes & ObjCDeclSpec::DQ_PR_copy)
2827       &&!(Attributes & ObjCDeclSpec::DQ_PR_readonly)
2828       && getLangOpts().getGC() == LangOptions::GCOnly
2829       && PropertyTy->isBlockPointerType())
2830     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2831   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2832            !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2833            !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2834            PropertyTy->isBlockPointerType())
2835       Diag(Loc, diag::warn_objc_property_retain_of_block);
2836 
2837   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2838       (Attributes & ObjCDeclSpec::DQ_PR_setter))
2839     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2840 }
2841