1 //===--- SemaObjCProperty.cpp - Semantic Analysis for ObjC @property ------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements semantic analysis for Objective C @property and
11 //  @synthesize declarations.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Sema/SemaInternal.h"
16 #include "clang/AST/ASTMutationListener.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/ExprObjC.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Lex/Lexer.h"
22 #include "clang/Lex/Preprocessor.h"
23 #include "clang/Sema/Initialization.h"
24 #include "llvm/ADT/DenseSet.h"
25 #include "llvm/ADT/SmallString.h"
26 
27 using namespace clang;
28 
29 //===----------------------------------------------------------------------===//
30 // Grammar actions.
31 //===----------------------------------------------------------------------===//
32 
33 /// getImpliedARCOwnership - Given a set of property attributes and a
34 /// type, infer an expected lifetime.  The type's ownership qualification
35 /// is not considered.
36 ///
37 /// Returns OCL_None if the attributes as stated do not imply an ownership.
38 /// Never returns OCL_Autoreleasing.
39 static Qualifiers::ObjCLifetime getImpliedARCOwnership(
40                                ObjCPropertyDecl::PropertyAttributeKind attrs,
41                                                 QualType type) {
42   // retain, strong, copy, weak, and unsafe_unretained are only legal
43   // on properties of retainable pointer type.
44   if (attrs & (ObjCPropertyDecl::OBJC_PR_retain |
45                ObjCPropertyDecl::OBJC_PR_strong |
46                ObjCPropertyDecl::OBJC_PR_copy)) {
47     return Qualifiers::OCL_Strong;
48   } else if (attrs & ObjCPropertyDecl::OBJC_PR_weak) {
49     return Qualifiers::OCL_Weak;
50   } else if (attrs & ObjCPropertyDecl::OBJC_PR_unsafe_unretained) {
51     return Qualifiers::OCL_ExplicitNone;
52   }
53 
54   // assign can appear on other types, so we have to check the
55   // property type.
56   if (attrs & ObjCPropertyDecl::OBJC_PR_assign &&
57       type->isObjCRetainableType()) {
58     return Qualifiers::OCL_ExplicitNone;
59   }
60 
61   return Qualifiers::OCL_None;
62 }
63 
64 /// Check the internal consistency of a property declaration.
65 static void checkARCPropertyDecl(Sema &S, ObjCPropertyDecl *property) {
66   if (property->isInvalidDecl()) return;
67 
68   ObjCPropertyDecl::PropertyAttributeKind propertyKind
69     = property->getPropertyAttributes();
70   Qualifiers::ObjCLifetime propertyLifetime
71     = property->getType().getObjCLifetime();
72 
73   // Nothing to do if we don't have a lifetime.
74   if (propertyLifetime == Qualifiers::OCL_None) return;
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 /// \brief 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 Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
131                           SourceLocation LParenLoc,
132                           FieldDeclarator &FD,
133                           ObjCDeclSpec &ODS,
134                           Selector GetterSel,
135                           Selector SetterSel,
136                           bool *isOverridingProperty,
137                           tok::ObjCKeywordKind MethodImplKind,
138                           DeclContext *lexicalDC) {
139   unsigned Attributes = ODS.getPropertyAttributes();
140   FD.D.setObjCWeakProperty((Attributes & ObjCDeclSpec::DQ_PR_weak) != 0);
141   TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
142   QualType T = TSI->getType();
143   Attributes |= deduceWeakPropertyFromType(T);
144   bool isReadWrite = ((Attributes & ObjCDeclSpec::DQ_PR_readwrite) ||
145                       // default is readwrite!
146                       !(Attributes & ObjCDeclSpec::DQ_PR_readonly));
147   // property is defaulted to 'assign' if it is readwrite and is
148   // not retain or copy
149   bool isAssign = ((Attributes & ObjCDeclSpec::DQ_PR_assign) ||
150                    (isReadWrite &&
151                     !(Attributes & ObjCDeclSpec::DQ_PR_retain) &&
152                     !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
153                     !(Attributes & ObjCDeclSpec::DQ_PR_copy) &&
154                     !(Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) &&
155                     !(Attributes & ObjCDeclSpec::DQ_PR_weak)));
156 
157   // Proceed with constructing the ObjCPropertyDecls.
158   ObjCContainerDecl *ClassDecl = cast<ObjCContainerDecl>(CurContext);
159   ObjCPropertyDecl *Res = nullptr;
160   if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
161     if (CDecl->IsClassExtension()) {
162       Res = HandlePropertyInClassExtension(S, AtLoc, LParenLoc,
163                                            FD, GetterSel, SetterSel,
164                                            isAssign, isReadWrite,
165                                            Attributes,
166                                            ODS.getPropertyAttributes(),
167                                            isOverridingProperty, T, TSI,
168                                            MethodImplKind);
169       if (!Res)
170         return nullptr;
171     }
172   }
173 
174   if (!Res) {
175     Res = CreatePropertyDecl(S, ClassDecl, AtLoc, LParenLoc, FD,
176                              GetterSel, SetterSel, isAssign, isReadWrite,
177                              Attributes, ODS.getPropertyAttributes(),
178                              T, TSI, MethodImplKind);
179     if (lexicalDC)
180       Res->setLexicalDeclContext(lexicalDC);
181   }
182 
183   // Validate the attributes on the @property.
184   CheckObjCPropertyAttributes(Res, AtLoc, Attributes,
185                               (isa<ObjCInterfaceDecl>(ClassDecl) ||
186                                isa<ObjCProtocolDecl>(ClassDecl)));
187 
188   if (getLangOpts().ObjCAutoRefCount)
189     checkARCPropertyDecl(*this, Res);
190 
191   llvm::SmallPtrSet<ObjCProtocolDecl *, 16> KnownProtos;
192   if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
193     // For a class, compare the property against a property in our superclass.
194     bool FoundInSuper = false;
195     ObjCInterfaceDecl *CurrentInterfaceDecl = IFace;
196     while (ObjCInterfaceDecl *Super = CurrentInterfaceDecl->getSuperClass()) {
197       DeclContext::lookup_result R = Super->lookup(Res->getDeclName());
198       for (unsigned I = 0, N = R.size(); I != N; ++I) {
199         if (ObjCPropertyDecl *SuperProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
200           DiagnosePropertyMismatch(Res, SuperProp, Super->getIdentifier(), false);
201           FoundInSuper = true;
202           break;
203         }
204       }
205       if (FoundInSuper)
206         break;
207       else
208         CurrentInterfaceDecl = Super;
209     }
210 
211     if (FoundInSuper) {
212       // Also compare the property against a property in our protocols.
213       for (auto *P : CurrentInterfaceDecl->protocols()) {
214         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
215       }
216     } else {
217       // Slower path: look in all protocols we referenced.
218       for (auto *P : IFace->all_referenced_protocols()) {
219         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
220       }
221     }
222   } else if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
223     for (auto *P : Cat->protocols())
224       CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
225   } else {
226     ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(ClassDecl);
227     for (auto *P : Proto->protocols())
228       CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
229   }
230 
231   ActOnDocumentableDecl(Res);
232   return Res;
233 }
234 
235 static ObjCPropertyDecl::PropertyAttributeKind
236 makePropertyAttributesAsWritten(unsigned Attributes) {
237   unsigned attributesAsWritten = 0;
238   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
239     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readonly;
240   if (Attributes & ObjCDeclSpec::DQ_PR_readwrite)
241     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readwrite;
242   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
243     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_getter;
244   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
245     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_setter;
246   if (Attributes & ObjCDeclSpec::DQ_PR_assign)
247     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_assign;
248   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
249     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_retain;
250   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
251     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_strong;
252   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
253     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_weak;
254   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
255     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_copy;
256   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
257     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
258   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
259     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_nonatomic;
260   if (Attributes & ObjCDeclSpec::DQ_PR_atomic)
261     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_atomic;
262 
263   return (ObjCPropertyDecl::PropertyAttributeKind)attributesAsWritten;
264 }
265 
266 static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
267                                  SourceLocation LParenLoc, SourceLocation &Loc) {
268   if (LParenLoc.isMacroID())
269     return false;
270 
271   SourceManager &SM = Context.getSourceManager();
272   std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
273   // Try to load the file buffer.
274   bool invalidTemp = false;
275   StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
276   if (invalidTemp)
277     return false;
278   const char *tokenBegin = file.data() + locInfo.second;
279 
280   // Lex from the start of the given location.
281   Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
282               Context.getLangOpts(),
283               file.begin(), tokenBegin, file.end());
284   Token Tok;
285   do {
286     lexer.LexFromRawLexer(Tok);
287     if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
288       Loc = Tok.getLocation();
289       return true;
290     }
291   } while (Tok.isNot(tok::r_paren));
292   return false;
293 
294 }
295 
296 static unsigned getOwnershipRule(unsigned attr) {
297   return attr & (ObjCPropertyDecl::OBJC_PR_assign |
298                  ObjCPropertyDecl::OBJC_PR_retain |
299                  ObjCPropertyDecl::OBJC_PR_copy   |
300                  ObjCPropertyDecl::OBJC_PR_weak   |
301                  ObjCPropertyDecl::OBJC_PR_strong |
302                  ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
303 }
304 
305 ObjCPropertyDecl *
306 Sema::HandlePropertyInClassExtension(Scope *S,
307                                      SourceLocation AtLoc,
308                                      SourceLocation LParenLoc,
309                                      FieldDeclarator &FD,
310                                      Selector GetterSel, Selector SetterSel,
311                                      const bool isAssign,
312                                      const bool isReadWrite,
313                                      const unsigned Attributes,
314                                      const unsigned AttributesAsWritten,
315                                      bool *isOverridingProperty,
316                                      QualType T,
317                                      TypeSourceInfo *TSI,
318                                      tok::ObjCKeywordKind MethodImplKind) {
319   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
320   // Diagnose if this property is already in continuation class.
321   DeclContext *DC = CurContext;
322   IdentifierInfo *PropertyId = FD.D.getIdentifier();
323   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
324 
325   if (CCPrimary) {
326     // Check for duplicate declaration of this property in current and
327     // other class extensions.
328     for (const auto *Ext : CCPrimary->known_extensions()) {
329       if (ObjCPropertyDecl *prevDecl
330             = ObjCPropertyDecl::findPropertyDecl(Ext, PropertyId)) {
331         Diag(AtLoc, diag::err_duplicate_property);
332         Diag(prevDecl->getLocation(), diag::note_property_declare);
333         return nullptr;
334       }
335     }
336   }
337 
338   // Create a new ObjCPropertyDecl with the DeclContext being
339   // the class extension.
340   // FIXME. We should really be using CreatePropertyDecl for this.
341   ObjCPropertyDecl *PDecl =
342     ObjCPropertyDecl::Create(Context, DC, FD.D.getIdentifierLoc(),
343                              PropertyId, AtLoc, LParenLoc, T, TSI);
344   PDecl->setPropertyAttributesAsWritten(
345                           makePropertyAttributesAsWritten(AttributesAsWritten));
346   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
347     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
348   if (Attributes & ObjCDeclSpec::DQ_PR_readwrite)
349     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
350   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
351     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
352   if (Attributes & ObjCDeclSpec::DQ_PR_atomic)
353     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_atomic);
354   if (Attributes & ObjCDeclSpec::DQ_PR_nullability)
355     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nullability);
356   if (Attributes & ObjCDeclSpec::DQ_PR_null_resettable)
357     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_null_resettable);
358 
359   // Set setter/getter selector name. Needed later.
360   PDecl->setGetterName(GetterSel);
361   PDecl->setSetterName(SetterSel);
362   ProcessDeclAttributes(S, PDecl, FD.D);
363   DC->addDecl(PDecl);
364 
365   // We need to look in the @interface to see if the @property was
366   // already declared.
367   if (!CCPrimary) {
368     Diag(CDecl->getLocation(), diag::err_continuation_class);
369     *isOverridingProperty = true;
370     return nullptr;
371   }
372 
373   // Find the property in continuation class's primary class only.
374   ObjCPropertyDecl *PIDecl =
375     CCPrimary->FindPropertyVisibleInPrimaryClass(PropertyId);
376 
377   if (!PIDecl) {
378     // No matching property found in the primary class. Just fall thru
379     // and add property to continuation class's primary class.
380     ObjCPropertyDecl *PrimaryPDecl =
381       CreatePropertyDecl(S, CCPrimary, AtLoc, LParenLoc,
382                          FD, GetterSel, SetterSel, isAssign, isReadWrite,
383                          Attributes,AttributesAsWritten, T, TSI, MethodImplKind,
384                          DC);
385 
386     // A case of continuation class adding a new property in the class. This
387     // is not what it was meant for. However, gcc supports it and so should we.
388     // Make sure setter/getters are declared here.
389     ProcessPropertyDecl(PrimaryPDecl, CCPrimary,
390                         /* redeclaredProperty = */ nullptr,
391                         /* lexicalDC = */ CDecl);
392     PDecl->setGetterMethodDecl(PrimaryPDecl->getGetterMethodDecl());
393     PDecl->setSetterMethodDecl(PrimaryPDecl->getSetterMethodDecl());
394     if (ASTMutationListener *L = Context.getASTMutationListener())
395       L->AddedObjCPropertyInClassExtension(PrimaryPDecl, /*OrigProp=*/nullptr,
396                                            CDecl);
397     return PrimaryPDecl;
398   }
399   if (!Context.hasSameType(PIDecl->getType(), PDecl->getType())) {
400     bool IncompatibleObjC = false;
401     QualType ConvertedType;
402     // Relax the strict type matching for property type in continuation class.
403     // Allow property object type of continuation class to be different as long
404     // as it narrows the object type in its primary class property. Note that
405     // this conversion is safe only because the wider type is for a 'readonly'
406     // property in primary class and 'narrowed' type for a 'readwrite' property
407     // in continuation class.
408     QualType PrimaryClassPropertyT = Context.getCanonicalType(PIDecl->getType());
409     QualType ClassExtPropertyT = Context.getCanonicalType(PDecl->getType());
410     if (!isa<ObjCObjectPointerType>(PrimaryClassPropertyT) ||
411         !isa<ObjCObjectPointerType>(ClassExtPropertyT) ||
412         (!isObjCPointerConversion(ClassExtPropertyT, PrimaryClassPropertyT,
413                                   ConvertedType, IncompatibleObjC))
414         || IncompatibleObjC) {
415       Diag(AtLoc,
416           diag::err_type_mismatch_continuation_class) << PDecl->getType();
417       Diag(PIDecl->getLocation(), diag::note_property_declare);
418       return nullptr;
419     }
420   }
421 
422   // The property 'PIDecl's readonly attribute will be over-ridden
423   // with continuation class's readwrite property attribute!
424   unsigned PIkind = PIDecl->getPropertyAttributesAsWritten();
425   if (isReadWrite && (PIkind & ObjCPropertyDecl::OBJC_PR_readonly)) {
426     PIkind &= ~ObjCPropertyDecl::OBJC_PR_readonly;
427     PIkind |= ObjCPropertyDecl::OBJC_PR_readwrite;
428     PIkind |= deduceWeakPropertyFromType(PIDecl->getType());
429     unsigned ClassExtensionMemoryModel = getOwnershipRule(Attributes);
430     unsigned PrimaryClassMemoryModel = getOwnershipRule(PIkind);
431     if (PrimaryClassMemoryModel && ClassExtensionMemoryModel &&
432         (PrimaryClassMemoryModel != ClassExtensionMemoryModel)) {
433       Diag(AtLoc, diag::warn_property_attr_mismatch);
434       Diag(PIDecl->getLocation(), diag::note_property_declare);
435     }
436     else if (getLangOpts().ObjCAutoRefCount) {
437       QualType PrimaryPropertyQT =
438         Context.getCanonicalType(PIDecl->getType()).getUnqualifiedType();
439       if (isa<ObjCObjectPointerType>(PrimaryPropertyQT)) {
440         bool PropertyIsWeak = ((PIkind & ObjCPropertyDecl::OBJC_PR_weak) != 0);
441         Qualifiers::ObjCLifetime PrimaryPropertyLifeTime =
442           PrimaryPropertyQT.getObjCLifetime();
443         if (PrimaryPropertyLifeTime == Qualifiers::OCL_None &&
444             (Attributes & ObjCDeclSpec::DQ_PR_weak) &&
445             !PropertyIsWeak) {
446               Diag(AtLoc, diag::warn_property_implicitly_mismatched);
447               Diag(PIDecl->getLocation(), diag::note_property_declare);
448             }
449         }
450     }
451 
452     DeclContext *DC = cast<DeclContext>(CCPrimary);
453     if (!ObjCPropertyDecl::findPropertyDecl(DC,
454                                  PIDecl->getDeclName().getAsIdentifierInfo())) {
455       // In mrr mode, 'readwrite' property must have an explicit
456       // memory attribute. If none specified, select the default (assign).
457       if (!getLangOpts().ObjCAutoRefCount) {
458         if (!(PIkind & (ObjCDeclSpec::DQ_PR_assign |
459                         ObjCDeclSpec::DQ_PR_retain |
460                         ObjCDeclSpec::DQ_PR_strong |
461                         ObjCDeclSpec::DQ_PR_copy |
462                         ObjCDeclSpec::DQ_PR_unsafe_unretained |
463                         ObjCDeclSpec::DQ_PR_weak)))
464           PIkind |= ObjCPropertyDecl::OBJC_PR_assign;
465       }
466 
467       // Protocol is not in the primary class. Must build one for it.
468       ObjCDeclSpec ProtocolPropertyODS;
469       // FIXME. Assuming that ObjCDeclSpec::ObjCPropertyAttributeKind
470       // and ObjCPropertyDecl::PropertyAttributeKind have identical
471       // values.  Should consolidate both into one enum type.
472       ProtocolPropertyODS.
473       setPropertyAttributes((ObjCDeclSpec::ObjCPropertyAttributeKind)
474                             PIkind);
475       // Must re-establish the context from class extension to primary
476       // class context.
477       ContextRAII SavedContext(*this, CCPrimary);
478 
479       Decl *ProtocolPtrTy =
480         ActOnProperty(S, AtLoc, LParenLoc, FD, ProtocolPropertyODS,
481                       PIDecl->getGetterName(),
482                       PIDecl->getSetterName(),
483                       isOverridingProperty,
484                       MethodImplKind,
485                       /* lexicalDC = */ CDecl);
486       PIDecl = cast<ObjCPropertyDecl>(ProtocolPtrTy);
487     }
488     PIDecl->makeitReadWriteAttribute();
489     if (Attributes & ObjCDeclSpec::DQ_PR_retain)
490       PIDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
491     if (Attributes & ObjCDeclSpec::DQ_PR_strong)
492       PIDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
493     if (Attributes & ObjCDeclSpec::DQ_PR_copy)
494       PIDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
495     PIDecl->setSetterName(SetterSel);
496   } else {
497     // Tailor the diagnostics for the common case where a readwrite
498     // property is declared both in the @interface and the continuation.
499     // This is a common error where the user often intended the original
500     // declaration to be readonly.
501     unsigned diag =
502       (Attributes & ObjCDeclSpec::DQ_PR_readwrite) &&
503       (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite)
504       ? diag::err_use_continuation_class_redeclaration_readwrite
505       : diag::err_use_continuation_class;
506     Diag(AtLoc, diag)
507       << CCPrimary->getDeclName();
508     Diag(PIDecl->getLocation(), diag::note_property_declare);
509     return nullptr;
510   }
511   *isOverridingProperty = true;
512   // Make sure setter decl is synthesized, and added to primary class's list.
513   ProcessPropertyDecl(PIDecl, CCPrimary, PDecl, CDecl);
514   PDecl->setGetterMethodDecl(PIDecl->getGetterMethodDecl());
515   PDecl->setSetterMethodDecl(PIDecl->getSetterMethodDecl());
516   if (ASTMutationListener *L = Context.getASTMutationListener())
517     L->AddedObjCPropertyInClassExtension(PDecl, PIDecl, CDecl);
518   return PDecl;
519 }
520 
521 ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
522                                            ObjCContainerDecl *CDecl,
523                                            SourceLocation AtLoc,
524                                            SourceLocation LParenLoc,
525                                            FieldDeclarator &FD,
526                                            Selector GetterSel,
527                                            Selector SetterSel,
528                                            const bool isAssign,
529                                            const bool isReadWrite,
530                                            const unsigned Attributes,
531                                            const unsigned AttributesAsWritten,
532                                            QualType T,
533                                            TypeSourceInfo *TInfo,
534                                            tok::ObjCKeywordKind MethodImplKind,
535                                            DeclContext *lexicalDC){
536   IdentifierInfo *PropertyId = FD.D.getIdentifier();
537 
538   // Issue a warning if property is 'assign' as default and its object, which is
539   // gc'able conforms to NSCopying protocol
540   if (getLangOpts().getGC() != LangOptions::NonGC &&
541       isAssign && !(Attributes & ObjCDeclSpec::DQ_PR_assign))
542     if (const ObjCObjectPointerType *ObjPtrTy =
543           T->getAs<ObjCObjectPointerType>()) {
544       ObjCInterfaceDecl *IDecl = ObjPtrTy->getObjectType()->getInterface();
545       if (IDecl)
546         if (ObjCProtocolDecl* PNSCopying =
547             LookupProtocol(&Context.Idents.get("NSCopying"), AtLoc))
548           if (IDecl->ClassImplementsProtocol(PNSCopying, true))
549             Diag(AtLoc, diag::warn_implements_nscopying) << PropertyId;
550     }
551 
552   if (T->isObjCObjectType()) {
553     SourceLocation StarLoc = TInfo->getTypeLoc().getLocEnd();
554     StarLoc = getLocForEndOfToken(StarLoc);
555     Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object)
556       << FixItHint::CreateInsertion(StarLoc, "*");
557     T = Context.getObjCObjectPointerType(T);
558     SourceLocation TLoc = TInfo->getTypeLoc().getLocStart();
559     TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
560   }
561 
562   DeclContext *DC = cast<DeclContext>(CDecl);
563   ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
564                                                      FD.D.getIdentifierLoc(),
565                                                      PropertyId, AtLoc,
566                                                      LParenLoc, T, TInfo);
567 
568   if (ObjCPropertyDecl *prevDecl =
569         ObjCPropertyDecl::findPropertyDecl(DC, PropertyId)) {
570     Diag(PDecl->getLocation(), diag::err_duplicate_property);
571     Diag(prevDecl->getLocation(), diag::note_property_declare);
572     PDecl->setInvalidDecl();
573   }
574   else {
575     DC->addDecl(PDecl);
576     if (lexicalDC)
577       PDecl->setLexicalDeclContext(lexicalDC);
578   }
579 
580   if (T->isArrayType() || T->isFunctionType()) {
581     Diag(AtLoc, diag::err_property_type) << T;
582     PDecl->setInvalidDecl();
583   }
584 
585   ProcessDeclAttributes(S, PDecl, FD.D);
586 
587   // Regardless of setter/getter attribute, we save the default getter/setter
588   // selector names in anticipation of declaration of setter/getter methods.
589   PDecl->setGetterName(GetterSel);
590   PDecl->setSetterName(SetterSel);
591   PDecl->setPropertyAttributesAsWritten(
592                           makePropertyAttributesAsWritten(AttributesAsWritten));
593 
594   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
595     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
596 
597   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
598     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_getter);
599 
600   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
601     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_setter);
602 
603   if (isReadWrite)
604     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
605 
606   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
607     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
608 
609   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
610     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
611 
612   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
613     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
614 
615   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
616     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
617 
618   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
619     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
620 
621   if (isAssign)
622     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
623 
624   // In the semantic attributes, one of nonatomic or atomic is always set.
625   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
626     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
627   else
628     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_atomic);
629 
630   // 'unsafe_unretained' is alias for 'assign'.
631   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
632     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
633   if (isAssign)
634     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
635 
636   if (MethodImplKind == tok::objc_required)
637     PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
638   else if (MethodImplKind == tok::objc_optional)
639     PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
640 
641   if (Attributes & ObjCDeclSpec::DQ_PR_nullability)
642     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nullability);
643 
644   if (Attributes & ObjCDeclSpec::DQ_PR_null_resettable)
645     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_null_resettable);
646 
647   return PDecl;
648 }
649 
650 static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
651                                  ObjCPropertyDecl *property,
652                                  ObjCIvarDecl *ivar) {
653   if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;
654 
655   QualType ivarType = ivar->getType();
656   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
657 
658   // The lifetime implied by the property's attributes.
659   Qualifiers::ObjCLifetime propertyLifetime =
660     getImpliedARCOwnership(property->getPropertyAttributes(),
661                            property->getType());
662 
663   // We're fine if they match.
664   if (propertyLifetime == ivarLifetime) return;
665 
666   // These aren't valid lifetimes for object ivars;  don't diagnose twice.
667   if (ivarLifetime == Qualifiers::OCL_None ||
668       ivarLifetime == Qualifiers::OCL_Autoreleasing)
669     return;
670 
671   // If the ivar is private, and it's implicitly __unsafe_unretained
672   // becaues of its type, then pretend it was actually implicitly
673   // __strong.  This is only sound because we're processing the
674   // property implementation before parsing any method bodies.
675   if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
676       propertyLifetime == Qualifiers::OCL_Strong &&
677       ivar->getAccessControl() == ObjCIvarDecl::Private) {
678     SplitQualType split = ivarType.split();
679     if (split.Quals.hasObjCLifetime()) {
680       assert(ivarType->isObjCARCImplicitlyUnretainedType());
681       split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
682       ivarType = S.Context.getQualifiedType(split);
683       ivar->setType(ivarType);
684       return;
685     }
686   }
687 
688   switch (propertyLifetime) {
689   case Qualifiers::OCL_Strong:
690     S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
691       << property->getDeclName()
692       << ivar->getDeclName()
693       << ivarLifetime;
694     break;
695 
696   case Qualifiers::OCL_Weak:
697     S.Diag(ivar->getLocation(), diag::error_weak_property)
698       << property->getDeclName()
699       << ivar->getDeclName();
700     break;
701 
702   case Qualifiers::OCL_ExplicitNone:
703     S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
704       << property->getDeclName()
705       << ivar->getDeclName()
706       << ((property->getPropertyAttributesAsWritten()
707            & ObjCPropertyDecl::OBJC_PR_assign) != 0);
708     break;
709 
710   case Qualifiers::OCL_Autoreleasing:
711     llvm_unreachable("properties cannot be autoreleasing");
712 
713   case Qualifiers::OCL_None:
714     // Any other property should be ignored.
715     return;
716   }
717 
718   S.Diag(property->getLocation(), diag::note_property_declare);
719   if (propertyImplLoc.isValid())
720     S.Diag(propertyImplLoc, diag::note_property_synthesize);
721 }
722 
723 /// setImpliedPropertyAttributeForReadOnlyProperty -
724 /// This routine evaludates life-time attributes for a 'readonly'
725 /// property with no known lifetime of its own, using backing
726 /// 'ivar's attribute, if any. If no backing 'ivar', property's
727 /// life-time is assumed 'strong'.
728 static void setImpliedPropertyAttributeForReadOnlyProperty(
729               ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
730   Qualifiers::ObjCLifetime propertyLifetime =
731     getImpliedARCOwnership(property->getPropertyAttributes(),
732                            property->getType());
733   if (propertyLifetime != Qualifiers::OCL_None)
734     return;
735 
736   if (!ivar) {
737     // if no backing ivar, make property 'strong'.
738     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
739     return;
740   }
741   // property assumes owenership of backing ivar.
742   QualType ivarType = ivar->getType();
743   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
744   if (ivarLifetime == Qualifiers::OCL_Strong)
745     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
746   else if (ivarLifetime == Qualifiers::OCL_Weak)
747     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
748   return;
749 }
750 
751 /// DiagnosePropertyMismatchDeclInProtocols - diagnose properties declared
752 /// in inherited protocols with mismatched types. Since any of them can
753 /// be candidate for synthesis.
754 static void
755 DiagnosePropertyMismatchDeclInProtocols(Sema &S, SourceLocation AtLoc,
756                                         ObjCInterfaceDecl *ClassDecl,
757                                         ObjCPropertyDecl *Property) {
758   ObjCInterfaceDecl::ProtocolPropertyMap PropMap;
759   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
760     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
761       PDecl->collectInheritedProtocolProperties(Property, PropMap);
762   }
763   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass())
764     while (SDecl) {
765       for (const auto *PI : SDecl->all_referenced_protocols()) {
766         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
767           PDecl->collectInheritedProtocolProperties(Property, PropMap);
768       }
769       SDecl = SDecl->getSuperClass();
770     }
771 
772   if (PropMap.empty())
773     return;
774 
775   QualType RHSType = S.Context.getCanonicalType(Property->getType());
776   bool FirsTime = true;
777   for (ObjCInterfaceDecl::ProtocolPropertyMap::iterator
778        I = PropMap.begin(), E = PropMap.end(); I != E; I++) {
779     ObjCPropertyDecl *Prop = I->second;
780     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
781     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
782       bool IncompatibleObjC = false;
783       QualType ConvertedType;
784       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
785           || IncompatibleObjC) {
786         if (FirsTime) {
787           S.Diag(Property->getLocation(), diag::warn_protocol_property_mismatch)
788             << Property->getType();
789           FirsTime = false;
790         }
791         S.Diag(Prop->getLocation(), diag::note_protocol_property_declare)
792           << Prop->getType();
793       }
794     }
795   }
796   if (!FirsTime && AtLoc.isValid())
797     S.Diag(AtLoc, diag::note_property_synthesize);
798 }
799 
800 /// ActOnPropertyImplDecl - This routine performs semantic checks and
801 /// builds the AST node for a property implementation declaration; declared
802 /// as \@synthesize or \@dynamic.
803 ///
804 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
805                                   SourceLocation AtLoc,
806                                   SourceLocation PropertyLoc,
807                                   bool Synthesize,
808                                   IdentifierInfo *PropertyId,
809                                   IdentifierInfo *PropertyIvar,
810                                   SourceLocation PropertyIvarLoc) {
811   ObjCContainerDecl *ClassImpDecl =
812     dyn_cast<ObjCContainerDecl>(CurContext);
813   // Make sure we have a context for the property implementation declaration.
814   if (!ClassImpDecl) {
815     Diag(AtLoc, diag::error_missing_property_context);
816     return nullptr;
817   }
818   if (PropertyIvarLoc.isInvalid())
819     PropertyIvarLoc = PropertyLoc;
820   SourceLocation PropertyDiagLoc = PropertyLoc;
821   if (PropertyDiagLoc.isInvalid())
822     PropertyDiagLoc = ClassImpDecl->getLocStart();
823   ObjCPropertyDecl *property = nullptr;
824   ObjCInterfaceDecl *IDecl = nullptr;
825   // Find the class or category class where this property must have
826   // a declaration.
827   ObjCImplementationDecl *IC = nullptr;
828   ObjCCategoryImplDecl *CatImplClass = nullptr;
829   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
830     IDecl = IC->getClassInterface();
831     // We always synthesize an interface for an implementation
832     // without an interface decl. So, IDecl is always non-zero.
833     assert(IDecl &&
834            "ActOnPropertyImplDecl - @implementation without @interface");
835 
836     // Look for this property declaration in the @implementation's @interface
837     property = IDecl->FindPropertyDeclaration(PropertyId);
838     if (!property) {
839       Diag(PropertyLoc, diag::error_bad_property_decl) << IDecl->getDeclName();
840       return nullptr;
841     }
842     unsigned PIkind = property->getPropertyAttributesAsWritten();
843     if ((PIkind & (ObjCPropertyDecl::OBJC_PR_atomic |
844                    ObjCPropertyDecl::OBJC_PR_nonatomic) ) == 0) {
845       if (AtLoc.isValid())
846         Diag(AtLoc, diag::warn_implicit_atomic_property);
847       else
848         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
849       Diag(property->getLocation(), diag::note_property_declare);
850     }
851 
852     if (const ObjCCategoryDecl *CD =
853         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
854       if (!CD->IsClassExtension()) {
855         Diag(PropertyLoc, diag::error_category_property) << CD->getDeclName();
856         Diag(property->getLocation(), diag::note_property_declare);
857         return nullptr;
858       }
859     }
860     if (Synthesize&&
861         (PIkind & ObjCPropertyDecl::OBJC_PR_readonly) &&
862         property->hasAttr<IBOutletAttr>() &&
863         !AtLoc.isValid()) {
864       bool ReadWriteProperty = false;
865       // Search into the class extensions and see if 'readonly property is
866       // redeclared 'readwrite', then no warning is to be issued.
867       for (auto *Ext : IDecl->known_extensions()) {
868         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
869         if (!R.empty())
870           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
871             PIkind = ExtProp->getPropertyAttributesAsWritten();
872             if (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite) {
873               ReadWriteProperty = true;
874               break;
875             }
876           }
877       }
878 
879       if (!ReadWriteProperty) {
880         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
881             << property;
882         SourceLocation readonlyLoc;
883         if (LocPropertyAttribute(Context, "readonly",
884                                  property->getLParenLoc(), readonlyLoc)) {
885           SourceLocation endLoc =
886             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
887           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
888           Diag(property->getLocation(),
889                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
890           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
891         }
892       }
893     }
894     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
895       DiagnosePropertyMismatchDeclInProtocols(*this, AtLoc, IDecl, property);
896 
897   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
898     if (Synthesize) {
899       Diag(AtLoc, diag::error_synthesize_category_decl);
900       return nullptr;
901     }
902     IDecl = CatImplClass->getClassInterface();
903     if (!IDecl) {
904       Diag(AtLoc, diag::error_missing_property_interface);
905       return nullptr;
906     }
907     ObjCCategoryDecl *Category =
908     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
909 
910     // If category for this implementation not found, it is an error which
911     // has already been reported eralier.
912     if (!Category)
913       return nullptr;
914     // Look for this property declaration in @implementation's category
915     property = Category->FindPropertyDeclaration(PropertyId);
916     if (!property) {
917       Diag(PropertyLoc, diag::error_bad_category_property_decl)
918       << Category->getDeclName();
919       return nullptr;
920     }
921   } else {
922     Diag(AtLoc, diag::error_bad_property_context);
923     return nullptr;
924   }
925   ObjCIvarDecl *Ivar = nullptr;
926   bool CompleteTypeErr = false;
927   bool compat = true;
928   // Check that we have a valid, previously declared ivar for @synthesize
929   if (Synthesize) {
930     // @synthesize
931     if (!PropertyIvar)
932       PropertyIvar = PropertyId;
933     // Check that this is a previously declared 'ivar' in 'IDecl' interface
934     ObjCInterfaceDecl *ClassDeclared;
935     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
936     QualType PropType = property->getType();
937     QualType PropertyIvarType = PropType.getNonReferenceType();
938 
939     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
940                             diag::err_incomplete_synthesized_property,
941                             property->getDeclName())) {
942       Diag(property->getLocation(), diag::note_property_declare);
943       CompleteTypeErr = true;
944     }
945 
946     if (getLangOpts().ObjCAutoRefCount &&
947         (property->getPropertyAttributesAsWritten() &
948          ObjCPropertyDecl::OBJC_PR_readonly) &&
949         PropertyIvarType->isObjCRetainableType()) {
950       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
951     }
952 
953     ObjCPropertyDecl::PropertyAttributeKind kind
954       = property->getPropertyAttributes();
955 
956     // Add GC __weak to the ivar type if the property is weak.
957     if ((kind & ObjCPropertyDecl::OBJC_PR_weak) &&
958         getLangOpts().getGC() != LangOptions::NonGC) {
959       assert(!getLangOpts().ObjCAutoRefCount);
960       if (PropertyIvarType.isObjCGCStrong()) {
961         Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
962         Diag(property->getLocation(), diag::note_property_declare);
963       } else {
964         PropertyIvarType =
965           Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
966       }
967     }
968     if (AtLoc.isInvalid()) {
969       // Check when default synthesizing a property that there is
970       // an ivar matching property name and issue warning; since this
971       // is the most common case of not using an ivar used for backing
972       // property in non-default synthesis case.
973       ObjCInterfaceDecl *ClassDeclared=nullptr;
974       ObjCIvarDecl *originalIvar =
975       IDecl->lookupInstanceVariable(property->getIdentifier(),
976                                     ClassDeclared);
977       if (originalIvar) {
978         Diag(PropertyDiagLoc,
979              diag::warn_autosynthesis_property_ivar_match)
980         << PropertyId << (Ivar == nullptr) << PropertyIvar
981         << originalIvar->getIdentifier();
982         Diag(property->getLocation(), diag::note_property_declare);
983         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
984       }
985     }
986 
987     if (!Ivar) {
988       // In ARC, give the ivar a lifetime qualifier based on the
989       // property attributes.
990       if (getLangOpts().ObjCAutoRefCount &&
991           !PropertyIvarType.getObjCLifetime() &&
992           PropertyIvarType->isObjCRetainableType()) {
993 
994         // It's an error if we have to do this and the user didn't
995         // explicitly write an ownership attribute on the property.
996         if (!property->hasWrittenStorageAttribute() &&
997             !(kind & ObjCPropertyDecl::OBJC_PR_strong)) {
998           Diag(PropertyDiagLoc,
999                diag::err_arc_objc_property_default_assign_on_object);
1000           Diag(property->getLocation(), diag::note_property_declare);
1001         } else {
1002           Qualifiers::ObjCLifetime lifetime =
1003             getImpliedARCOwnership(kind, PropertyIvarType);
1004           assert(lifetime && "no lifetime for property?");
1005           if (lifetime == Qualifiers::OCL_Weak) {
1006             bool err = false;
1007             if (const ObjCObjectPointerType *ObjT =
1008                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1009               const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1010               if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1011                 Diag(property->getLocation(),
1012                      diag::err_arc_weak_unavailable_property) << PropertyIvarType;
1013                 Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1014                   << ClassImpDecl->getName();
1015                 err = true;
1016               }
1017             }
1018             if (!err && !getLangOpts().ObjCARCWeak) {
1019               Diag(PropertyDiagLoc, diag::err_arc_weak_no_runtime);
1020               Diag(property->getLocation(), diag::note_property_declare);
1021             }
1022           }
1023 
1024           Qualifiers qs;
1025           qs.addObjCLifetime(lifetime);
1026           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1027         }
1028       }
1029 
1030       if (kind & ObjCPropertyDecl::OBJC_PR_weak &&
1031           !getLangOpts().ObjCAutoRefCount &&
1032           getLangOpts().getGC() == LangOptions::NonGC) {
1033         Diag(PropertyDiagLoc, diag::error_synthesize_weak_non_arc_or_gc);
1034         Diag(property->getLocation(), diag::note_property_declare);
1035       }
1036 
1037       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1038                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1039                                   PropertyIvarType, /*Dinfo=*/nullptr,
1040                                   ObjCIvarDecl::Private,
1041                                   (Expr *)nullptr, true);
1042       if (RequireNonAbstractType(PropertyIvarLoc,
1043                                  PropertyIvarType,
1044                                  diag::err_abstract_type_in_decl,
1045                                  AbstractSynthesizedIvarType)) {
1046         Diag(property->getLocation(), diag::note_property_declare);
1047         Ivar->setInvalidDecl();
1048       } else if (CompleteTypeErr)
1049           Ivar->setInvalidDecl();
1050       ClassImpDecl->addDecl(Ivar);
1051       IDecl->makeDeclVisibleInContext(Ivar);
1052 
1053       if (getLangOpts().ObjCRuntime.isFragile())
1054         Diag(PropertyDiagLoc, diag::error_missing_property_ivar_decl)
1055             << PropertyId;
1056       // Note! I deliberately want it to fall thru so, we have a
1057       // a property implementation and to avoid future warnings.
1058     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1059                !declaresSameEntity(ClassDeclared, IDecl)) {
1060       Diag(PropertyDiagLoc, diag::error_ivar_in_superclass_use)
1061       << property->getDeclName() << Ivar->getDeclName()
1062       << ClassDeclared->getDeclName();
1063       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1064       << Ivar << Ivar->getName();
1065       // Note! I deliberately want it to fall thru so more errors are caught.
1066     }
1067     property->setPropertyIvarDecl(Ivar);
1068 
1069     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1070 
1071     // Check that type of property and its ivar are type compatible.
1072     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1073       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1074           && isa<ObjCObjectPointerType>(IvarType))
1075         compat =
1076           Context.canAssignObjCInterfaces(
1077                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1078                                   IvarType->getAs<ObjCObjectPointerType>());
1079       else {
1080         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1081                                              IvarType)
1082                     == Compatible);
1083       }
1084       if (!compat) {
1085         Diag(PropertyDiagLoc, diag::error_property_ivar_type)
1086           << property->getDeclName() << PropType
1087           << Ivar->getDeclName() << IvarType;
1088         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1089         // Note! I deliberately want it to fall thru so, we have a
1090         // a property implementation and to avoid future warnings.
1091       }
1092       else {
1093         // FIXME! Rules for properties are somewhat different that those
1094         // for assignments. Use a new routine to consolidate all cases;
1095         // specifically for property redeclarations as well as for ivars.
1096         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1097         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1098         if (lhsType != rhsType &&
1099             lhsType->isArithmeticType()) {
1100           Diag(PropertyDiagLoc, diag::error_property_ivar_type)
1101             << property->getDeclName() << PropType
1102             << Ivar->getDeclName() << IvarType;
1103           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1104           // Fall thru - see previous comment
1105         }
1106       }
1107       // __weak is explicit. So it works on Canonical type.
1108       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1109            getLangOpts().getGC() != LangOptions::NonGC)) {
1110         Diag(PropertyDiagLoc, diag::error_weak_property)
1111         << property->getDeclName() << Ivar->getDeclName();
1112         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1113         // Fall thru - see previous comment
1114       }
1115       // Fall thru - see previous comment
1116       if ((property->getType()->isObjCObjectPointerType() ||
1117            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1118           getLangOpts().getGC() != LangOptions::NonGC) {
1119         Diag(PropertyDiagLoc, diag::error_strong_property)
1120         << property->getDeclName() << Ivar->getDeclName();
1121         // Fall thru - see previous comment
1122       }
1123     }
1124     if (getLangOpts().ObjCAutoRefCount)
1125       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1126   } else if (PropertyIvar)
1127     // @dynamic
1128     Diag(PropertyDiagLoc, diag::error_dynamic_property_ivar_decl);
1129 
1130   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1131   ObjCPropertyImplDecl *PIDecl =
1132   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1133                                property,
1134                                (Synthesize ?
1135                                 ObjCPropertyImplDecl::Synthesize
1136                                 : ObjCPropertyImplDecl::Dynamic),
1137                                Ivar, PropertyIvarLoc);
1138 
1139   if (CompleteTypeErr || !compat)
1140     PIDecl->setInvalidDecl();
1141 
1142   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1143     getterMethod->createImplicitParams(Context, IDecl);
1144     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1145         Ivar->getType()->isRecordType()) {
1146       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1147       // returned by the getter as it must conform to C++'s copy-return rules.
1148       // FIXME. Eventually we want to do this for Objective-C as well.
1149       SynthesizedFunctionScope Scope(*this, getterMethod);
1150       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1151       DeclRefExpr *SelfExpr =
1152         new (Context) DeclRefExpr(SelfDecl, false, SelfDecl->getType(),
1153                                   VK_LValue, PropertyDiagLoc);
1154       MarkDeclRefReferenced(SelfExpr);
1155       Expr *LoadSelfExpr =
1156         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1157                                  CK_LValueToRValue, SelfExpr, nullptr,
1158                                  VK_RValue);
1159       Expr *IvarRefExpr =
1160         new (Context) ObjCIvarRefExpr(Ivar,
1161                                       Ivar->getUsageType(SelfDecl->getType()),
1162                                       PropertyDiagLoc,
1163                                       Ivar->getLocation(),
1164                                       LoadSelfExpr, true, true);
1165       ExprResult Res = PerformCopyInitialization(
1166           InitializedEntity::InitializeResult(PropertyDiagLoc,
1167                                               getterMethod->getReturnType(),
1168                                               /*NRVO=*/false),
1169           PropertyDiagLoc, IvarRefExpr);
1170       if (!Res.isInvalid()) {
1171         Expr *ResExpr = Res.getAs<Expr>();
1172         if (ResExpr)
1173           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1174         PIDecl->setGetterCXXConstructor(ResExpr);
1175       }
1176     }
1177     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1178         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1179       Diag(getterMethod->getLocation(),
1180            diag::warn_property_getter_owning_mismatch);
1181       Diag(property->getLocation(), diag::note_property_declare);
1182     }
1183     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1184       switch (getterMethod->getMethodFamily()) {
1185         case OMF_retain:
1186         case OMF_retainCount:
1187         case OMF_release:
1188         case OMF_autorelease:
1189           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1190             << 1 << getterMethod->getSelector();
1191           break;
1192         default:
1193           break;
1194       }
1195   }
1196   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1197     setterMethod->createImplicitParams(Context, IDecl);
1198     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1199         Ivar->getType()->isRecordType()) {
1200       // FIXME. Eventually we want to do this for Objective-C as well.
1201       SynthesizedFunctionScope Scope(*this, setterMethod);
1202       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1203       DeclRefExpr *SelfExpr =
1204         new (Context) DeclRefExpr(SelfDecl, false, SelfDecl->getType(),
1205                                   VK_LValue, PropertyDiagLoc);
1206       MarkDeclRefReferenced(SelfExpr);
1207       Expr *LoadSelfExpr =
1208         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1209                                  CK_LValueToRValue, SelfExpr, nullptr,
1210                                  VK_RValue);
1211       Expr *lhs =
1212         new (Context) ObjCIvarRefExpr(Ivar,
1213                                       Ivar->getUsageType(SelfDecl->getType()),
1214                                       PropertyDiagLoc,
1215                                       Ivar->getLocation(),
1216                                       LoadSelfExpr, true, true);
1217       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1218       ParmVarDecl *Param = (*P);
1219       QualType T = Param->getType().getNonReferenceType();
1220       DeclRefExpr *rhs = new (Context) DeclRefExpr(Param, false, T,
1221                                                    VK_LValue, PropertyDiagLoc);
1222       MarkDeclRefReferenced(rhs);
1223       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1224                                   BO_Assign, lhs, rhs);
1225       if (property->getPropertyAttributes() &
1226           ObjCPropertyDecl::OBJC_PR_atomic) {
1227         Expr *callExpr = Res.getAs<Expr>();
1228         if (const CXXOperatorCallExpr *CXXCE =
1229               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1230           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1231             if (!FuncDecl->isTrivial())
1232               if (property->getType()->isReferenceType()) {
1233                 Diag(PropertyDiagLoc,
1234                      diag::err_atomic_property_nontrivial_assign_op)
1235                     << property->getType();
1236                 Diag(FuncDecl->getLocStart(),
1237                      diag::note_callee_decl) << FuncDecl;
1238               }
1239       }
1240       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1241     }
1242   }
1243 
1244   if (IC) {
1245     if (Synthesize)
1246       if (ObjCPropertyImplDecl *PPIDecl =
1247           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1248         Diag(PropertyLoc, diag::error_duplicate_ivar_use)
1249         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1250         << PropertyIvar;
1251         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1252       }
1253 
1254     if (ObjCPropertyImplDecl *PPIDecl
1255         = IC->FindPropertyImplDecl(PropertyId)) {
1256       Diag(PropertyLoc, diag::error_property_implemented) << PropertyId;
1257       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1258       return nullptr;
1259     }
1260     IC->addPropertyImplementation(PIDecl);
1261     if (getLangOpts().ObjCDefaultSynthProperties &&
1262         getLangOpts().ObjCRuntime.isNonFragile() &&
1263         !IDecl->isObjCRequiresPropertyDefs()) {
1264       // Diagnose if an ivar was lazily synthesdized due to a previous
1265       // use and if 1) property is @dynamic or 2) property is synthesized
1266       // but it requires an ivar of different name.
1267       ObjCInterfaceDecl *ClassDeclared=nullptr;
1268       ObjCIvarDecl *Ivar = nullptr;
1269       if (!Synthesize)
1270         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1271       else {
1272         if (PropertyIvar && PropertyIvar != PropertyId)
1273           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1274       }
1275       // Issue diagnostics only if Ivar belongs to current class.
1276       if (Ivar && Ivar->getSynthesize() &&
1277           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1278         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1279         << PropertyId;
1280         Ivar->setInvalidDecl();
1281       }
1282     }
1283   } else {
1284     if (Synthesize)
1285       if (ObjCPropertyImplDecl *PPIDecl =
1286           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1287         Diag(PropertyDiagLoc, diag::error_duplicate_ivar_use)
1288         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1289         << PropertyIvar;
1290         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1291       }
1292 
1293     if (ObjCPropertyImplDecl *PPIDecl =
1294         CatImplClass->FindPropertyImplDecl(PropertyId)) {
1295       Diag(PropertyDiagLoc, diag::error_property_implemented) << PropertyId;
1296       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1297       return nullptr;
1298     }
1299     CatImplClass->addPropertyImplementation(PIDecl);
1300   }
1301 
1302   return PIDecl;
1303 }
1304 
1305 //===----------------------------------------------------------------------===//
1306 // Helper methods.
1307 //===----------------------------------------------------------------------===//
1308 
1309 /// DiagnosePropertyMismatch - Compares two properties for their
1310 /// attributes and types and warns on a variety of inconsistencies.
1311 ///
1312 void
1313 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1314                                ObjCPropertyDecl *SuperProperty,
1315                                const IdentifierInfo *inheritedName,
1316                                bool OverridingProtocolProperty) {
1317   ObjCPropertyDecl::PropertyAttributeKind CAttr =
1318     Property->getPropertyAttributes();
1319   ObjCPropertyDecl::PropertyAttributeKind SAttr =
1320     SuperProperty->getPropertyAttributes();
1321 
1322   // We allow readonly properties without an explicit ownership
1323   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1324   // to be overridden by a property with any explicit ownership in the subclass.
1325   if (!OverridingProtocolProperty &&
1326       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1327     ;
1328   else {
1329     if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
1330         && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
1331       Diag(Property->getLocation(), diag::warn_readonly_property)
1332         << Property->getDeclName() << inheritedName;
1333     if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
1334         != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
1335       Diag(Property->getLocation(), diag::warn_property_attribute)
1336         << Property->getDeclName() << "copy" << inheritedName;
1337     else if (!(SAttr & ObjCPropertyDecl::OBJC_PR_readonly)){
1338       unsigned CAttrRetain =
1339         (CAttr &
1340          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1341       unsigned SAttrRetain =
1342         (SAttr &
1343          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1344       bool CStrong = (CAttrRetain != 0);
1345       bool SStrong = (SAttrRetain != 0);
1346       if (CStrong != SStrong)
1347         Diag(Property->getLocation(), diag::warn_property_attribute)
1348           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1349     }
1350   }
1351 
1352   if ((CAttr & ObjCPropertyDecl::OBJC_PR_nonatomic)
1353       != (SAttr & ObjCPropertyDecl::OBJC_PR_nonatomic)) {
1354     Diag(Property->getLocation(), diag::warn_property_attribute)
1355       << Property->getDeclName() << "atomic" << inheritedName;
1356     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1357   }
1358   if (Property->getSetterName() != SuperProperty->getSetterName()) {
1359     Diag(Property->getLocation(), diag::warn_property_attribute)
1360       << Property->getDeclName() << "setter" << inheritedName;
1361     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1362   }
1363   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1364     Diag(Property->getLocation(), diag::warn_property_attribute)
1365       << Property->getDeclName() << "getter" << inheritedName;
1366     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1367   }
1368 
1369   QualType LHSType =
1370     Context.getCanonicalType(SuperProperty->getType());
1371   QualType RHSType =
1372     Context.getCanonicalType(Property->getType());
1373 
1374   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1375     // Do cases not handled in above.
1376     // FIXME. For future support of covariant property types, revisit this.
1377     bool IncompatibleObjC = false;
1378     QualType ConvertedType;
1379     if (!isObjCPointerConversion(RHSType, LHSType,
1380                                  ConvertedType, IncompatibleObjC) ||
1381         IncompatibleObjC) {
1382         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1383         << Property->getType() << SuperProperty->getType() << inheritedName;
1384       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1385     }
1386   }
1387 }
1388 
1389 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1390                                             ObjCMethodDecl *GetterMethod,
1391                                             SourceLocation Loc) {
1392   if (!GetterMethod)
1393     return false;
1394   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1395   QualType PropertyIvarType = property->getType().getNonReferenceType();
1396   bool compat = Context.hasSameType(PropertyIvarType, GetterType);
1397   if (!compat) {
1398     if (isa<ObjCObjectPointerType>(PropertyIvarType) &&
1399         isa<ObjCObjectPointerType>(GetterType))
1400       compat =
1401         Context.canAssignObjCInterfaces(
1402                                       GetterType->getAs<ObjCObjectPointerType>(),
1403                                       PropertyIvarType->getAs<ObjCObjectPointerType>());
1404     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyIvarType)
1405               != Compatible) {
1406           Diag(Loc, diag::error_property_accessor_type)
1407             << property->getDeclName() << PropertyIvarType
1408             << GetterMethod->getSelector() << GetterType;
1409           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1410           return true;
1411     } else {
1412       compat = true;
1413       QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1414       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1415       if (lhsType != rhsType && lhsType->isArithmeticType())
1416         compat = false;
1417     }
1418   }
1419 
1420   if (!compat) {
1421     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1422     << property->getDeclName()
1423     << GetterMethod->getSelector();
1424     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1425     return true;
1426   }
1427 
1428   return false;
1429 }
1430 
1431 /// CollectImmediateProperties - This routine collects all properties in
1432 /// the class and its conforming protocols; but not those in its super class.
1433 static void CollectImmediateProperties(ObjCContainerDecl *CDecl,
1434                                        ObjCContainerDecl::PropertyMap &PropMap,
1435                                        ObjCContainerDecl::PropertyMap &SuperPropMap,
1436                                        bool IncludeProtocols = true) {
1437 
1438   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1439     for (auto *Prop : IDecl->properties())
1440       PropMap[Prop->getIdentifier()] = Prop;
1441     if (IncludeProtocols) {
1442       // Scan through class's protocols.
1443       for (auto *PI : IDecl->all_referenced_protocols())
1444         CollectImmediateProperties(PI, PropMap, SuperPropMap);
1445     }
1446   }
1447   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1448     if (!CATDecl->IsClassExtension())
1449       for (auto *Prop : CATDecl->properties())
1450         PropMap[Prop->getIdentifier()] = Prop;
1451     if (IncludeProtocols) {
1452       // Scan through class's protocols.
1453       for (auto *PI : CATDecl->protocols())
1454         CollectImmediateProperties(PI, PropMap, SuperPropMap);
1455     }
1456   }
1457   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1458     for (auto *Prop : PDecl->properties()) {
1459       ObjCPropertyDecl *PropertyFromSuper = SuperPropMap[Prop->getIdentifier()];
1460       // Exclude property for protocols which conform to class's super-class,
1461       // as super-class has to implement the property.
1462       if (!PropertyFromSuper ||
1463           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1464         ObjCPropertyDecl *&PropEntry = PropMap[Prop->getIdentifier()];
1465         if (!PropEntry)
1466           PropEntry = Prop;
1467       }
1468     }
1469     // scan through protocol's protocols.
1470     for (auto *PI : PDecl->protocols())
1471       CollectImmediateProperties(PI, PropMap, SuperPropMap);
1472   }
1473 }
1474 
1475 /// CollectSuperClassPropertyImplementations - This routine collects list of
1476 /// properties to be implemented in super class(s) and also coming from their
1477 /// conforming protocols.
1478 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1479                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1480   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1481     ObjCInterfaceDecl::PropertyDeclOrder PO;
1482     while (SDecl) {
1483       SDecl->collectPropertiesToImplement(PropMap, PO);
1484       SDecl = SDecl->getSuperClass();
1485     }
1486   }
1487 }
1488 
1489 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1490 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1491 /// declared in class 'IFace'.
1492 bool
1493 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1494                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1495   if (!IV->getSynthesize())
1496     return false;
1497   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1498                                             Method->isInstanceMethod());
1499   if (!IMD || !IMD->isPropertyAccessor())
1500     return false;
1501 
1502   // look up a property declaration whose one of its accessors is implemented
1503   // by this method.
1504   for (const auto *Property : IFace->properties()) {
1505     if ((Property->getGetterName() == IMD->getSelector() ||
1506          Property->getSetterName() == IMD->getSelector()) &&
1507         (Property->getPropertyIvarDecl() == IV))
1508       return true;
1509   }
1510   return false;
1511 }
1512 
1513 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1514                                          ObjCPropertyDecl *Prop) {
1515   bool SuperClassImplementsGetter = false;
1516   bool SuperClassImplementsSetter = false;
1517   if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1518     SuperClassImplementsSetter = true;
1519 
1520   while (IDecl->getSuperClass()) {
1521     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1522     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1523       SuperClassImplementsGetter = true;
1524 
1525     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1526       SuperClassImplementsSetter = true;
1527     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1528       return true;
1529     IDecl = IDecl->getSuperClass();
1530   }
1531   return false;
1532 }
1533 
1534 /// \brief Default synthesizes all properties which must be synthesized
1535 /// in class's \@implementation.
1536 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl* IMPDecl,
1537                                        ObjCInterfaceDecl *IDecl) {
1538 
1539   ObjCInterfaceDecl::PropertyMap PropMap;
1540   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1541   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1542   if (PropMap.empty())
1543     return;
1544   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1545   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1546 
1547   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1548     ObjCPropertyDecl *Prop = PropertyOrder[i];
1549     // Is there a matching property synthesize/dynamic?
1550     if (Prop->isInvalidDecl() ||
1551         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1552       continue;
1553     // Property may have been synthesized by user.
1554     if (IMPDecl->FindPropertyImplDecl(Prop->getIdentifier()))
1555       continue;
1556     if (IMPDecl->getInstanceMethod(Prop->getGetterName())) {
1557       if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1558         continue;
1559       if (IMPDecl->getInstanceMethod(Prop->getSetterName()))
1560         continue;
1561     }
1562     if (ObjCPropertyImplDecl *PID =
1563         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1564       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1565         << Prop->getIdentifier();
1566       if (!PID->getLocation().isInvalid())
1567         Diag(PID->getLocation(), diag::note_property_synthesize);
1568       continue;
1569     }
1570     ObjCPropertyDecl *PropInSuperClass = SuperPropMap[Prop->getIdentifier()];
1571     if (ObjCProtocolDecl *Proto =
1572           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1573       // We won't auto-synthesize properties declared in protocols.
1574       // Suppress the warning if class's superclass implements property's
1575       // getter and implements property's setter (if readwrite property).
1576       // Or, if property is going to be implemented in its super class.
1577       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1578         Diag(IMPDecl->getLocation(),
1579              diag::warn_auto_synthesizing_protocol_property)
1580           << Prop << Proto;
1581         Diag(Prop->getLocation(), diag::note_property_declare);
1582       }
1583       continue;
1584     }
1585     // If property to be implemented in the super class, ignore.
1586     if (PropInSuperClass) {
1587       if ((Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readwrite) &&
1588           (PropInSuperClass->getPropertyAttributes() &
1589            ObjCPropertyDecl::OBJC_PR_readonly) &&
1590           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1591           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1592         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1593         << Prop->getIdentifier();
1594         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1595       }
1596       else {
1597         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1598         << Prop->getIdentifier();
1599         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1600         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1601       }
1602       continue;
1603     }
1604     // We use invalid SourceLocations for the synthesized ivars since they
1605     // aren't really synthesized at a particular location; they just exist.
1606     // Saying that they are located at the @implementation isn't really going
1607     // to help users.
1608     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1609       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1610                             true,
1611                             /* property = */ Prop->getIdentifier(),
1612                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1613                             Prop->getLocation()));
1614     if (PIDecl) {
1615       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1616       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1617     }
1618   }
1619 }
1620 
1621 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D) {
1622   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
1623     return;
1624   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
1625   if (!IC)
1626     return;
1627   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
1628     if (!IDecl->isObjCRequiresPropertyDefs())
1629       DefaultSynthesizeProperties(S, IC, IDecl);
1630 }
1631 
1632 static void DiagnoseUnimplementedAccessor(Sema &S,
1633                                           ObjCInterfaceDecl *PrimaryClass,
1634                                           Selector Method,
1635                                           ObjCImplDecl* IMPDecl,
1636                                           ObjCContainerDecl *CDecl,
1637                                           ObjCCategoryDecl *C,
1638                                           ObjCPropertyDecl *Prop,
1639                                           Sema::SelectorSet &SMap) {
1640   // When reporting on missing property setter/getter implementation in
1641   // categories, do not report when they are declared in primary class,
1642   // class's protocol, or one of it super classes. This is because,
1643   // the class is going to implement them.
1644   if (!SMap.count(Method) &&
1645       (PrimaryClass == nullptr ||
1646        !PrimaryClass->lookupPropertyAccessor(Method, C))) {
1647         S.Diag(IMPDecl->getLocation(),
1648                isa<ObjCCategoryDecl>(CDecl) ?
1649                diag::warn_setter_getter_impl_required_in_category :
1650                diag::warn_setter_getter_impl_required)
1651             << Prop->getDeclName() << Method;
1652         S.Diag(Prop->getLocation(),
1653              diag::note_property_declare);
1654         if (S.LangOpts.ObjCDefaultSynthProperties &&
1655             S.LangOpts.ObjCRuntime.isNonFragile())
1656           if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
1657             if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
1658             S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
1659       }
1660 }
1661 
1662 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
1663                                            ObjCContainerDecl *CDecl,
1664                                            bool SynthesizeProperties) {
1665   ObjCContainerDecl::PropertyMap PropMap;
1666   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
1667 
1668   if (!SynthesizeProperties) {
1669     ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
1670     // Gather properties which need not be implemented in this class
1671     // or category.
1672     if (!IDecl)
1673       if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1674         // For categories, no need to implement properties declared in
1675         // its primary class (and its super classes) if property is
1676         // declared in one of those containers.
1677         if ((IDecl = C->getClassInterface())) {
1678           ObjCInterfaceDecl::PropertyDeclOrder PO;
1679           IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
1680         }
1681       }
1682     if (IDecl)
1683       CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
1684 
1685     CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap);
1686   }
1687 
1688   // Scan the @interface to see if any of the protocols it adopts
1689   // require an explicit implementation, via attribute
1690   // 'objc_protocol_requires_explicit_implementation'.
1691   if (IDecl) {
1692     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
1693 
1694     for (auto *PDecl : IDecl->all_referenced_protocols()) {
1695       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
1696         continue;
1697       // Lazily construct a set of all the properties in the @interface
1698       // of the class, without looking at the superclass.  We cannot
1699       // use the call to CollectImmediateProperties() above as that
1700       // utilizes information from the super class's properties as well
1701       // as scans the adopted protocols.  This work only triggers for protocols
1702       // with the attribute, which is very rare, and only occurs when
1703       // analyzing the @implementation.
1704       if (!LazyMap) {
1705         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
1706         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
1707         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
1708                                    /* IncludeProtocols */ false);
1709       }
1710       // Add the properties of 'PDecl' to the list of properties that
1711       // need to be implemented.
1712       for (auto *PropDecl : PDecl->properties()) {
1713         if ((*LazyMap)[PropDecl->getIdentifier()])
1714           continue;
1715         PropMap[PropDecl->getIdentifier()] = PropDecl;
1716       }
1717     }
1718   }
1719 
1720   if (PropMap.empty())
1721     return;
1722 
1723   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
1724   for (const auto *I : IMPDecl->property_impls())
1725     PropImplMap.insert(I->getPropertyDecl());
1726 
1727   SelectorSet InsMap;
1728   // Collect property accessors implemented in current implementation.
1729   for (const auto *I : IMPDecl->instance_methods())
1730     InsMap.insert(I->getSelector());
1731 
1732   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
1733   ObjCInterfaceDecl *PrimaryClass = nullptr;
1734   if (C && !C->IsClassExtension())
1735     if ((PrimaryClass = C->getClassInterface()))
1736       // Report unimplemented properties in the category as well.
1737       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
1738         // When reporting on missing setter/getters, do not report when
1739         // setter/getter is implemented in category's primary class
1740         // implementation.
1741         for (const auto *I : IMP->instance_methods())
1742           InsMap.insert(I->getSelector());
1743       }
1744 
1745   for (ObjCContainerDecl::PropertyMap::iterator
1746        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
1747     ObjCPropertyDecl *Prop = P->second;
1748     // Is there a matching propery synthesize/dynamic?
1749     if (Prop->isInvalidDecl() ||
1750         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
1751         PropImplMap.count(Prop) ||
1752         Prop->getAvailability() == AR_Unavailable)
1753       continue;
1754 
1755     // Diagnose unimplemented getters and setters.
1756     DiagnoseUnimplementedAccessor(*this,
1757           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
1758     if (!Prop->isReadOnly())
1759       DiagnoseUnimplementedAccessor(*this,
1760                                     PrimaryClass, Prop->getSetterName(),
1761                                     IMPDecl, CDecl, C, Prop, InsMap);
1762   }
1763 }
1764 
1765 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
1766   for (const auto *propertyImpl : impDecl->property_impls()) {
1767     const auto *property = propertyImpl->getPropertyDecl();
1768 
1769     // Warn about null_resettable properties with synthesized setters,
1770     // because the setter won't properly handle nil.
1771     if (propertyImpl->getPropertyImplementation()
1772           == ObjCPropertyImplDecl::Synthesize &&
1773         (property->getPropertyAttributes() &
1774          ObjCPropertyDecl::OBJC_PR_null_resettable) &&
1775         property->getGetterMethodDecl() &&
1776         property->getSetterMethodDecl()) {
1777       auto *getterMethod = property->getGetterMethodDecl();
1778       auto *setterMethod = property->getSetterMethodDecl();
1779       if (!impDecl->getInstanceMethod(setterMethod->getSelector()) &&
1780           !impDecl->getInstanceMethod(getterMethod->getSelector())) {
1781         SourceLocation loc = propertyImpl->getLocation();
1782         if (loc.isInvalid())
1783           loc = impDecl->getLocStart();
1784 
1785         Diag(loc, diag::warn_null_resettable_setter)
1786           << setterMethod->getSelector() << property->getDeclName();
1787       }
1788     }
1789   }
1790 }
1791 
1792 void
1793 Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
1794                                        ObjCContainerDecl* IDecl) {
1795   // Rules apply in non-GC mode only
1796   if (getLangOpts().getGC() != LangOptions::NonGC)
1797     return;
1798   for (const auto *Property : IDecl->properties()) {
1799     ObjCMethodDecl *GetterMethod = nullptr;
1800     ObjCMethodDecl *SetterMethod = nullptr;
1801     bool LookedUpGetterSetter = false;
1802 
1803     unsigned Attributes = Property->getPropertyAttributes();
1804     unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();
1805 
1806     if (!(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic) &&
1807         !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_nonatomic)) {
1808       GetterMethod = IMPDecl->getInstanceMethod(Property->getGetterName());
1809       SetterMethod = IMPDecl->getInstanceMethod(Property->getSetterName());
1810       LookedUpGetterSetter = true;
1811       if (GetterMethod) {
1812         Diag(GetterMethod->getLocation(),
1813              diag::warn_default_atomic_custom_getter_setter)
1814           << Property->getIdentifier() << 0;
1815         Diag(Property->getLocation(), diag::note_property_declare);
1816       }
1817       if (SetterMethod) {
1818         Diag(SetterMethod->getLocation(),
1819              diag::warn_default_atomic_custom_getter_setter)
1820           << Property->getIdentifier() << 1;
1821         Diag(Property->getLocation(), diag::note_property_declare);
1822       }
1823     }
1824 
1825     // We only care about readwrite atomic property.
1826     if ((Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
1827         !(Attributes & ObjCPropertyDecl::OBJC_PR_readwrite))
1828       continue;
1829     if (const ObjCPropertyImplDecl *PIDecl
1830          = IMPDecl->FindPropertyImplDecl(Property->getIdentifier())) {
1831       if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
1832         continue;
1833       if (!LookedUpGetterSetter) {
1834         GetterMethod = IMPDecl->getInstanceMethod(Property->getGetterName());
1835         SetterMethod = IMPDecl->getInstanceMethod(Property->getSetterName());
1836       }
1837       if ((GetterMethod && !SetterMethod) || (!GetterMethod && SetterMethod)) {
1838         SourceLocation MethodLoc =
1839           (GetterMethod ? GetterMethod->getLocation()
1840                         : SetterMethod->getLocation());
1841         Diag(MethodLoc, diag::warn_atomic_property_rule)
1842           << Property->getIdentifier() << (GetterMethod != nullptr)
1843           << (SetterMethod != nullptr);
1844         // fixit stuff.
1845         if (!AttributesAsWritten) {
1846           if (Property->getLParenLoc().isValid()) {
1847             // @property () ... case.
1848             SourceRange PropSourceRange(Property->getAtLoc(),
1849                                         Property->getLParenLoc());
1850             Diag(Property->getLocation(), diag::note_atomic_property_fixup_suggest) <<
1851               FixItHint::CreateReplacement(PropSourceRange, "@property (nonatomic");
1852           }
1853           else {
1854             //@property id etc.
1855             SourceLocation endLoc =
1856               Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
1857             endLoc = endLoc.getLocWithOffset(-1);
1858             SourceRange PropSourceRange(Property->getAtLoc(), endLoc);
1859             Diag(Property->getLocation(), diag::note_atomic_property_fixup_suggest) <<
1860               FixItHint::CreateReplacement(PropSourceRange, "@property (nonatomic) ");
1861           }
1862         }
1863         else if (!(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic)) {
1864           // @property () ... case.
1865           SourceLocation endLoc = Property->getLParenLoc();
1866           SourceRange PropSourceRange(Property->getAtLoc(), endLoc);
1867           Diag(Property->getLocation(), diag::note_atomic_property_fixup_suggest) <<
1868            FixItHint::CreateReplacement(PropSourceRange, "@property (nonatomic, ");
1869         }
1870         else
1871           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
1872         Diag(Property->getLocation(), diag::note_property_declare);
1873       }
1874     }
1875   }
1876 }
1877 
1878 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
1879   if (getLangOpts().getGC() == LangOptions::GCOnly)
1880     return;
1881 
1882   for (const auto *PID : D->property_impls()) {
1883     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
1884     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
1885         !D->getInstanceMethod(PD->getGetterName())) {
1886       ObjCMethodDecl *method = PD->getGetterMethodDecl();
1887       if (!method)
1888         continue;
1889       ObjCMethodFamily family = method->getMethodFamily();
1890       if (family == OMF_alloc || family == OMF_copy ||
1891           family == OMF_mutableCopy || family == OMF_new) {
1892         if (getLangOpts().ObjCAutoRefCount)
1893           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
1894         else
1895           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
1896 
1897         // Look for a getter explicitly declared alongside the property.
1898         // If we find one, use its location for the note.
1899         SourceLocation noteLoc = PD->getLocation();
1900         SourceLocation fixItLoc;
1901         for (auto *getterRedecl : method->redecls()) {
1902           if (getterRedecl->isImplicit())
1903             continue;
1904           if (getterRedecl->getDeclContext() != PD->getDeclContext())
1905             continue;
1906           noteLoc = getterRedecl->getLocation();
1907           fixItLoc = getterRedecl->getLocEnd();
1908         }
1909 
1910         Preprocessor &PP = getPreprocessor();
1911         TokenValue tokens[] = {
1912           tok::kw___attribute, tok::l_paren, tok::l_paren,
1913           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
1914           PP.getIdentifierInfo("none"), tok::r_paren,
1915           tok::r_paren, tok::r_paren
1916         };
1917         StringRef spelling = "__attribute__((objc_method_family(none)))";
1918         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
1919         if (!macroName.empty())
1920           spelling = macroName;
1921 
1922         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
1923             << method->getDeclName() << spelling;
1924         if (fixItLoc.isValid()) {
1925           SmallString<64> fixItText(" ");
1926           fixItText += spelling;
1927           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
1928         }
1929       }
1930     }
1931   }
1932 }
1933 
1934 void Sema::DiagnoseMissingDesignatedInitOverrides(
1935                                             const ObjCImplementationDecl *ImplD,
1936                                             const ObjCInterfaceDecl *IFD) {
1937   assert(IFD->hasDesignatedInitializers());
1938   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
1939   if (!SuperD)
1940     return;
1941 
1942   SelectorSet InitSelSet;
1943   for (const auto *I : ImplD->instance_methods())
1944     if (I->getMethodFamily() == OMF_init)
1945       InitSelSet.insert(I->getSelector());
1946 
1947   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
1948   SuperD->getDesignatedInitializers(DesignatedInits);
1949   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
1950          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
1951     const ObjCMethodDecl *MD = *I;
1952     if (!InitSelSet.count(MD->getSelector())) {
1953       bool Ignore = false;
1954       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
1955         Ignore = IMD->isUnavailable();
1956       }
1957       if (!Ignore) {
1958         Diag(ImplD->getLocation(),
1959              diag::warn_objc_implementation_missing_designated_init_override)
1960           << MD->getSelector();
1961         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
1962       }
1963     }
1964   }
1965 }
1966 
1967 /// AddPropertyAttrs - Propagates attributes from a property to the
1968 /// implicitly-declared getter or setter for that property.
1969 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
1970                              ObjCPropertyDecl *Property) {
1971   // Should we just clone all attributes over?
1972   for (const auto *A : Property->attrs()) {
1973     if (isa<DeprecatedAttr>(A) ||
1974         isa<UnavailableAttr>(A) ||
1975         isa<AvailabilityAttr>(A))
1976       PropertyMethod->addAttr(A->clone(S.Context));
1977   }
1978 }
1979 
1980 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
1981 /// have the property type and issue diagnostics if they don't.
1982 /// Also synthesize a getter/setter method if none exist (and update the
1983 /// appropriate lookup tables. FIXME: Should reconsider if adding synthesized
1984 /// methods is the "right" thing to do.
1985 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property,
1986                                ObjCContainerDecl *CD,
1987                                ObjCPropertyDecl *redeclaredProperty,
1988                                ObjCContainerDecl *lexicalDC) {
1989 
1990   ObjCMethodDecl *GetterMethod, *SetterMethod;
1991 
1992   if (CD->isInvalidDecl())
1993     return;
1994 
1995   GetterMethod = CD->getInstanceMethod(property->getGetterName());
1996   SetterMethod = CD->getInstanceMethod(property->getSetterName());
1997   DiagnosePropertyAccessorMismatch(property, GetterMethod,
1998                                    property->getLocation());
1999 
2000   if (SetterMethod) {
2001     ObjCPropertyDecl::PropertyAttributeKind CAttr =
2002       property->getPropertyAttributes();
2003     if ((!(CAttr & ObjCPropertyDecl::OBJC_PR_readonly)) &&
2004         Context.getCanonicalType(SetterMethod->getReturnType()) !=
2005             Context.VoidTy)
2006       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2007     if (SetterMethod->param_size() != 1 ||
2008         !Context.hasSameUnqualifiedType(
2009           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2010           property->getType().getNonReferenceType())) {
2011       Diag(property->getLocation(),
2012            diag::warn_accessor_property_type_mismatch)
2013         << property->getDeclName()
2014         << SetterMethod->getSelector();
2015       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2016     }
2017   }
2018 
2019   // Synthesize getter/setter methods if none exist.
2020   // Find the default getter and if one not found, add one.
2021   // FIXME: The synthesized property we set here is misleading. We almost always
2022   // synthesize these methods unless the user explicitly provided prototypes
2023   // (which is odd, but allowed). Sema should be typechecking that the
2024   // declarations jive in that situation (which it is not currently).
2025   if (!GetterMethod) {
2026     // No instance method of same name as property getter name was found.
2027     // Declare a getter method and add it to the list of methods
2028     // for this class.
2029     SourceLocation Loc = redeclaredProperty ?
2030       redeclaredProperty->getLocation() :
2031       property->getLocation();
2032 
2033     // If the property is null_resettable, the getter returns nonnull.
2034     QualType resultTy = property->getType();
2035     if (property->getPropertyAttributes() &
2036         ObjCPropertyDecl::OBJC_PR_null_resettable) {
2037       QualType modifiedTy = resultTy;
2038       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2039         if (*nullability == NullabilityKind::Unspecified)
2040           resultTy = Context.getAttributedType(AttributedType::attr_nonnull,
2041                                                modifiedTy, modifiedTy);
2042       }
2043     }
2044 
2045     GetterMethod = ObjCMethodDecl::Create(Context, Loc, Loc,
2046                              property->getGetterName(),
2047                              resultTy, nullptr, CD,
2048                              /*isInstance=*/true, /*isVariadic=*/false,
2049                              /*isPropertyAccessor=*/true,
2050                              /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2051                              (property->getPropertyImplementation() ==
2052                               ObjCPropertyDecl::Optional) ?
2053                              ObjCMethodDecl::Optional :
2054                              ObjCMethodDecl::Required);
2055     CD->addDecl(GetterMethod);
2056 
2057     AddPropertyAttrs(*this, GetterMethod, property);
2058 
2059     // FIXME: Eventually this shouldn't be needed, as the lexical context
2060     // and the real context should be the same.
2061     if (lexicalDC)
2062       GetterMethod->setLexicalDeclContext(lexicalDC);
2063     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2064       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2065                                                                      Loc));
2066 
2067     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2068       GetterMethod->addAttr(
2069         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2070 
2071     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2072       GetterMethod->addAttr(
2073           SectionAttr::CreateImplicit(Context, SectionAttr::GNU_section,
2074                                       SA->getName(), Loc));
2075 
2076     if (getLangOpts().ObjCAutoRefCount)
2077       CheckARCMethodDecl(GetterMethod);
2078   } else
2079     // A user declared getter will be synthesize when @synthesize of
2080     // the property with the same name is seen in the @implementation
2081     GetterMethod->setPropertyAccessor(true);
2082   property->setGetterMethodDecl(GetterMethod);
2083 
2084   // Skip setter if property is read-only.
2085   if (!property->isReadOnly()) {
2086     // Find the default setter and if one not found, add one.
2087     if (!SetterMethod) {
2088       // No instance method of same name as property setter name was found.
2089       // Declare a setter method and add it to the list of methods
2090       // for this class.
2091       SourceLocation Loc = redeclaredProperty ?
2092         redeclaredProperty->getLocation() :
2093         property->getLocation();
2094 
2095       SetterMethod =
2096         ObjCMethodDecl::Create(Context, Loc, Loc,
2097                                property->getSetterName(), Context.VoidTy,
2098                                nullptr, CD, /*isInstance=*/true,
2099                                /*isVariadic=*/false,
2100                                /*isPropertyAccessor=*/true,
2101                                /*isImplicitlyDeclared=*/true,
2102                                /*isDefined=*/false,
2103                                (property->getPropertyImplementation() ==
2104                                 ObjCPropertyDecl::Optional) ?
2105                                 ObjCMethodDecl::Optional :
2106                                 ObjCMethodDecl::Required);
2107 
2108       // If the property is null_resettable, the setter accepts a
2109       // nullable value.
2110       QualType paramTy = property->getType().getUnqualifiedType();
2111       if (property->getPropertyAttributes() &
2112           ObjCPropertyDecl::OBJC_PR_null_resettable) {
2113         QualType modifiedTy = paramTy;
2114         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2115           if (*nullability == NullabilityKind::Unspecified)
2116             paramTy = Context.getAttributedType(AttributedType::attr_nullable,
2117                                                 modifiedTy, modifiedTy);
2118         }
2119       }
2120 
2121       // Invent the arguments for the setter. We don't bother making a
2122       // nice name for the argument.
2123       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2124                                                   Loc, Loc,
2125                                                   property->getIdentifier(),
2126                                                   paramTy,
2127                                                   /*TInfo=*/nullptr,
2128                                                   SC_None,
2129                                                   nullptr);
2130       SetterMethod->setMethodParams(Context, Argument, None);
2131 
2132       AddPropertyAttrs(*this, SetterMethod, property);
2133 
2134       CD->addDecl(SetterMethod);
2135       // FIXME: Eventually this shouldn't be needed, as the lexical context
2136       // and the real context should be the same.
2137       if (lexicalDC)
2138         SetterMethod->setLexicalDeclContext(lexicalDC);
2139       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2140         SetterMethod->addAttr(
2141             SectionAttr::CreateImplicit(Context, SectionAttr::GNU_section,
2142                                         SA->getName(), Loc));
2143       // It's possible for the user to have set a very odd custom
2144       // setter selector that causes it to have a method family.
2145       if (getLangOpts().ObjCAutoRefCount)
2146         CheckARCMethodDecl(SetterMethod);
2147     } else
2148       // A user declared setter will be synthesize when @synthesize of
2149       // the property with the same name is seen in the @implementation
2150       SetterMethod->setPropertyAccessor(true);
2151     property->setSetterMethodDecl(SetterMethod);
2152   }
2153   // Add any synthesized methods to the global pool. This allows us to
2154   // handle the following, which is supported by GCC (and part of the design).
2155   //
2156   // @interface Foo
2157   // @property double bar;
2158   // @end
2159   //
2160   // void thisIsUnfortunate() {
2161   //   id foo;
2162   //   double bar = [foo bar];
2163   // }
2164   //
2165   if (GetterMethod)
2166     AddInstanceMethodToGlobalPool(GetterMethod);
2167   if (SetterMethod)
2168     AddInstanceMethodToGlobalPool(SetterMethod);
2169 
2170   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2171   if (!CurrentClass) {
2172     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2173       CurrentClass = Cat->getClassInterface();
2174     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2175       CurrentClass = Impl->getClassInterface();
2176   }
2177   if (GetterMethod)
2178     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2179   if (SetterMethod)
2180     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2181 }
2182 
2183 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2184                                        SourceLocation Loc,
2185                                        unsigned &Attributes,
2186                                        bool propertyInPrimaryClass) {
2187   // FIXME: Improve the reported location.
2188   if (!PDecl || PDecl->isInvalidDecl())
2189     return;
2190 
2191   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2192       (Attributes & ObjCDeclSpec::DQ_PR_readwrite))
2193     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2194     << "readonly" << "readwrite";
2195 
2196   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2197   QualType PropertyTy = PropertyDecl->getType();
2198   unsigned PropertyOwnership = getOwnershipRule(Attributes);
2199 
2200   // 'readonly' property with no obvious lifetime.
2201   // its life time will be determined by its backing ivar.
2202   if (getLangOpts().ObjCAutoRefCount &&
2203       Attributes & ObjCDeclSpec::DQ_PR_readonly &&
2204       PropertyTy->isObjCRetainableType() &&
2205       !PropertyOwnership)
2206     return;
2207 
2208   // Check for copy or retain on non-object types.
2209   if ((Attributes & (ObjCDeclSpec::DQ_PR_weak | ObjCDeclSpec::DQ_PR_copy |
2210                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong)) &&
2211       !PropertyTy->isObjCRetainableType() &&
2212       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2213     Diag(Loc, diag::err_objc_property_requires_object)
2214       << (Attributes & ObjCDeclSpec::DQ_PR_weak ? "weak" :
2215           Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain (or strong)");
2216     Attributes &= ~(ObjCDeclSpec::DQ_PR_weak   | ObjCDeclSpec::DQ_PR_copy |
2217                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong);
2218     PropertyDecl->setInvalidDecl();
2219   }
2220 
2221   // Check for more than one of { assign, copy, retain }.
2222   if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
2223     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2224       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2225         << "assign" << "copy";
2226       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2227     }
2228     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2229       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2230         << "assign" << "retain";
2231       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2232     }
2233     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2234       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2235         << "assign" << "strong";
2236       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2237     }
2238     if (getLangOpts().ObjCAutoRefCount  &&
2239         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2240       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2241         << "assign" << "weak";
2242       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2243     }
2244     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2245       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2246   } else if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) {
2247     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2248       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2249         << "unsafe_unretained" << "copy";
2250       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2251     }
2252     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2253       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2254         << "unsafe_unretained" << "retain";
2255       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2256     }
2257     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2258       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2259         << "unsafe_unretained" << "strong";
2260       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2261     }
2262     if (getLangOpts().ObjCAutoRefCount  &&
2263         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2264       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2265         << "unsafe_unretained" << "weak";
2266       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2267     }
2268   } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2269     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2270       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2271         << "copy" << "retain";
2272       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2273     }
2274     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2275       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2276         << "copy" << "strong";
2277       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2278     }
2279     if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2280       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2281         << "copy" << "weak";
2282       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2283     }
2284   }
2285   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2286            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2287       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2288         << "retain" << "weak";
2289       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2290   }
2291   else if ((Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2292            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2293       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2294         << "strong" << "weak";
2295       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2296   }
2297 
2298   if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2299     // 'weak' and 'nonnull' are mutually exclusive.
2300     if (auto nullability = PropertyTy->getNullability(Context)) {
2301       if (*nullability == NullabilityKind::NonNull)
2302         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2303           << "nonnull" << "weak";
2304     } else {
2305         PropertyTy =
2306           Context.getAttributedType(
2307             AttributedType::getNullabilityAttrKind(NullabilityKind::Nullable),
2308             PropertyTy, PropertyTy);
2309         TypeSourceInfo *TSInfo = PropertyDecl->getTypeSourceInfo();
2310         PropertyDecl->setType(PropertyTy, TSInfo);
2311     }
2312   }
2313 
2314   if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
2315       (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
2316       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2317         << "atomic" << "nonatomic";
2318       Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
2319   }
2320 
2321   // Warn if user supplied no assignment attribute, property is
2322   // readwrite, and this is an object type.
2323   if (!(Attributes & (ObjCDeclSpec::DQ_PR_assign | ObjCDeclSpec::DQ_PR_copy |
2324                       ObjCDeclSpec::DQ_PR_unsafe_unretained |
2325                       ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong |
2326                       ObjCDeclSpec::DQ_PR_weak)) &&
2327       PropertyTy->isObjCObjectPointerType()) {
2328       if (getLangOpts().ObjCAutoRefCount)
2329         // With arc,  @property definitions should default to (strong) when
2330         // not specified; including when property is 'readonly'.
2331         PropertyDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
2332       else if (!(Attributes & ObjCDeclSpec::DQ_PR_readonly)) {
2333         bool isAnyClassTy =
2334           (PropertyTy->isObjCClassType() ||
2335            PropertyTy->isObjCQualifiedClassType());
2336         // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2337         // issue any warning.
2338         if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2339           ;
2340         else if (propertyInPrimaryClass) {
2341           // Don't issue warning on property with no life time in class
2342           // extension as it is inherited from property in primary class.
2343           // Skip this warning in gc-only mode.
2344           if (getLangOpts().getGC() != LangOptions::GCOnly)
2345             Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2346 
2347           // If non-gc code warn that this is likely inappropriate.
2348           if (getLangOpts().getGC() == LangOptions::NonGC)
2349             Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2350         }
2351       }
2352 
2353     // FIXME: Implement warning dependent on NSCopying being
2354     // implemented. See also:
2355     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2356     // (please trim this list while you are at it).
2357   }
2358 
2359   if (!(Attributes & ObjCDeclSpec::DQ_PR_copy)
2360       &&!(Attributes & ObjCDeclSpec::DQ_PR_readonly)
2361       && getLangOpts().getGC() == LangOptions::GCOnly
2362       && PropertyTy->isBlockPointerType())
2363     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2364   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2365            !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2366            !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2367            PropertyTy->isBlockPointerType())
2368       Diag(Loc, diag::warn_objc_property_retain_of_block);
2369 
2370   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2371       (Attributes & ObjCDeclSpec::DQ_PR_setter))
2372     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2373 
2374 }
2375