lib/Sema/SemaObjCProperty.cpp

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