contrib/llvm/tools/clang/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 static bool
 818 isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
 819                                 ObjCPropertyDecl::PropertyAttributeKind Kind) {
 820   return (Attr1 & Kind) != (Attr2 & Kind);
 821 }
 822
 823 static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
 824                                               unsigned Kinds) {
 825   return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
 826 }
 827
 828 /// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
 829 /// property declaration that should be synthesised in all of the inherited
 830 /// protocols. It also diagnoses properties declared in inherited protocols with
 831 /// mismatched types or attributes, since any of them can be candidate for
 832 /// synthesis.
 833 static ObjCPropertyDecl *
 834 SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
 835                                         ObjCInterfaceDecl *ClassDecl,
 836                                         ObjCPropertyDecl *Property) {
 837   assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&
 838          "Expected a property from a protocol");
 839   ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
 840   ObjCInterfaceDecl::PropertyDeclOrder Properties;
 841   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
 842     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 843       PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 844                                                 Properties);
 845   }
 846   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
 847     while (SDecl) {
 848       for (const auto *PI : SDecl->all_referenced_protocols()) {
 849         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 850           PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 851                                                     Properties);
 852       }
 853       SDecl = SDecl->getSuperClass();
 854     }
 855   }
 856
 857   if (Properties.empty())
 858     return Property;
 859
 860   ObjCPropertyDecl *OriginalProperty = Property;
 861   size_t SelectedIndex = 0;
 862   for (const auto &Prop : llvm::enumerate(Properties)) {
 863     // Select the 'readwrite' property if such property exists.
 864     if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
 865       Property = Prop.value();
 866       SelectedIndex = Prop.index();
 867     }
 868   }
 869   if (Property != OriginalProperty) {
 870     // Check that the old property is compatible with the new one.
 871     Properties[SelectedIndex] = OriginalProperty;
 872   }
 873
 874   QualType RHSType = S.Context.getCanonicalType(Property->getType());
 875   unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
 876   enum MismatchKind {
 877     IncompatibleType = 0,
 878     HasNoExpectedAttribute,
 879     HasUnexpectedAttribute,
 880     DifferentGetter,
 881     DifferentSetter
 882   };
 883   // Represents a property from another protocol that conflicts with the
 884   // selected declaration.
 885   struct MismatchingProperty {
 886     const ObjCPropertyDecl *Prop;
 887     MismatchKind Kind;
 888     StringRef AttributeName;
 889   };
 890   SmallVector<MismatchingProperty, 4> Mismatches;
 891   for (ObjCPropertyDecl *Prop : Properties) {
 892     // Verify the property attributes.
 893     unsigned Attr = Prop->getPropertyAttributesAsWritten();
 894     if (Attr != OriginalAttributes) {
 895       auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
 896         MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
 897                                                  : HasUnexpectedAttribute;
 898         Mismatches.push_back({Prop, Kind, AttributeName});
 899       };
 900       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 901                                           ObjCPropertyDecl::OBJC_PR_copy)) {
 902         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_copy, "copy");
 903         continue;
 904       }
 905       if (areIncompatiblePropertyAttributes(
 906               OriginalAttributes, Attr, ObjCPropertyDecl::OBJC_PR_retain |
 907                                             ObjCPropertyDecl::OBJC_PR_strong)) {
 908         Diag(OriginalAttributes & (ObjCPropertyDecl::OBJC_PR_retain |
 909                                    ObjCPropertyDecl::OBJC_PR_strong),
 910              "retain (or strong)");
 911         continue;
 912       }
 913       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 914                                           ObjCPropertyDecl::OBJC_PR_atomic)) {
 915         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_atomic, "atomic");
 916         continue;
 917       }
 918     }
 919     if (Property->getGetterName() != Prop->getGetterName()) {
 920       Mismatches.push_back({Prop, DifferentGetter, ""});
 921       continue;
 922     }
 923     if (!Property->isReadOnly() && !Prop->isReadOnly() &&
 924         Property->getSetterName() != Prop->getSetterName()) {
 925       Mismatches.push_back({Prop, DifferentSetter, ""});
 926       continue;
 927     }
 928     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
 929     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
 930       bool IncompatibleObjC = false;
 931       QualType ConvertedType;
 932       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
 933           || IncompatibleObjC) {
 934         Mismatches.push_back({Prop, IncompatibleType, ""});
 935         continue;
 936       }
 937     }
 938   }
 939
 940   if (Mismatches.empty())
 941     return Property;
 942
 943   // Diagnose incompability.
 944   {
 945     bool HasIncompatibleAttributes = false;
 946     for (const auto &Note : Mismatches)
 947       HasIncompatibleAttributes =
 948           Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
 949     // Promote the warning to an error if there are incompatible attributes or
 950     // incompatible types together with readwrite/readonly incompatibility.
 951     auto Diag = S.Diag(Property->getLocation(),
 952                        Property != OriginalProperty || HasIncompatibleAttributes
 953                            ? diag::err_protocol_property_mismatch
 954                            : diag::warn_protocol_property_mismatch);
 955     Diag << Mismatches[0].Kind;
 956     switch (Mismatches[0].Kind) {
 957     case IncompatibleType:
 958       Diag << Property->getType();
 959       break;
 960     case HasNoExpectedAttribute:
 961     case HasUnexpectedAttribute:
 962       Diag << Mismatches[0].AttributeName;
 963       break;
 964     case DifferentGetter:
 965       Diag << Property->getGetterName();
 966       break;
 967     case DifferentSetter:
 968       Diag << Property->getSetterName();
 969       break;
 970     }
 971   }
 972   for (const auto &Note : Mismatches) {
 973     auto Diag =
 974         S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
 975         << Note.Kind;
 976     switch (Note.Kind) {
 977     case IncompatibleType:
 978       Diag << Note.Prop->getType();
 979       break;
 980     case HasNoExpectedAttribute:
 981     case HasUnexpectedAttribute:
 982       Diag << Note.AttributeName;
 983       break;
 984     case DifferentGetter:
 985       Diag << Note.Prop->getGetterName();
 986       break;
 987     case DifferentSetter:
 988       Diag << Note.Prop->getSetterName();
 989       break;
 990     }
 991   }
 992   if (AtLoc.isValid())
 993     S.Diag(AtLoc, diag::note_property_synthesize);
 994
 995   return Property;
 996 }
 997
 998 /// Determine whether any storage attributes were written on the property.
 999 static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
1000                                        ObjCPropertyQueryKind QueryKind) {
1001   if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;
1002
1003   // If this is a readwrite property in a class extension that refines
1004   // a readonly property in the original class definition, check it as
1005   // well.
1006
1007   // If it's a readonly property, we're not interested.
1008   if (Prop->isReadOnly()) return false;
1009
1010   // Is it declared in an extension?
1011   auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
1012   if (!Category || !Category->IsClassExtension()) return false;
1013
1014   // Find the corresponding property in the primary class definition.
1015   auto OrigClass = Category->getClassInterface();
1016   for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
1017     if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
1018       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1019   }
1020
1021   // Look through all of the protocols.
1022   for (const auto *Proto : OrigClass->all_referenced_protocols()) {
1023     if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
1024             Prop->getIdentifier(), QueryKind))
1025       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1026   }
1027
1028   return false;
1029 }
1030
1031 /// ActOnPropertyImplDecl - This routine performs semantic checks and
1032 /// builds the AST node for a property implementation declaration; declared
1033 /// as \@synthesize or \@dynamic.
1034 ///
1035 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
1036                                   SourceLocation AtLoc,
1037                                   SourceLocation PropertyLoc,
1038                                   bool Synthesize,
1039                                   IdentifierInfo *PropertyId,
1040                                   IdentifierInfo *PropertyIvar,
1041                                   SourceLocation PropertyIvarLoc,
1042                                   ObjCPropertyQueryKind QueryKind) {
1043   ObjCContainerDecl *ClassImpDecl =
1044     dyn_cast<ObjCContainerDecl>(CurContext);
1045   // Make sure we have a context for the property implementation declaration.
1046   if (!ClassImpDecl) {
1047     Diag(AtLoc, diag::err_missing_property_context);
1048     return nullptr;
1049   }
1050   if (PropertyIvarLoc.isInvalid())
1051     PropertyIvarLoc = PropertyLoc;
1052   SourceLocation PropertyDiagLoc = PropertyLoc;
1053   if (PropertyDiagLoc.isInvalid())
1054     PropertyDiagLoc = ClassImpDecl->getLocStart();
1055   ObjCPropertyDecl *property = nullptr;
1056   ObjCInterfaceDecl *IDecl = nullptr;
1057   // Find the class or category class where this property must have
1058   // a declaration.
1059   ObjCImplementationDecl *IC = nullptr;
1060   ObjCCategoryImplDecl *CatImplClass = nullptr;
1061   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
1062     IDecl = IC->getClassInterface();
1063     // We always synthesize an interface for an implementation
1064     // without an interface decl. So, IDecl is always non-zero.
1065     assert(IDecl &&
1066            "ActOnPropertyImplDecl - @implementation without @interface");
1067
1068     // Look for this property declaration in the @implementation's @interface
1069     property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
1070     if (!property) {
1071       Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
1072       return nullptr;
1073     }
1074     if (property->isClassProperty() && Synthesize) {
1075       Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
1076       return nullptr;
1077     }
1078     unsigned PIkind = property->getPropertyAttributesAsWritten();
1079     if ((PIkind & (ObjCPropertyDecl::OBJC_PR_atomic |
1080                    ObjCPropertyDecl::OBJC_PR_nonatomic) ) == 0) {
1081       if (AtLoc.isValid())
1082         Diag(AtLoc, diag::warn_implicit_atomic_property);
1083       else
1084         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
1085       Diag(property->getLocation(), diag::note_property_declare);
1086     }
1087
1088     if (const ObjCCategoryDecl *CD =
1089         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
1090       if (!CD->IsClassExtension()) {
1091         Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
1092         Diag(property->getLocation(), diag::note_property_declare);
1093         return nullptr;
1094       }
1095     }
1096     if (Synthesize&&
1097         (PIkind & ObjCPropertyDecl::OBJC_PR_readonly) &&
1098         property->hasAttr<IBOutletAttr>() &&
1099         !AtLoc.isValid()) {
1100       bool ReadWriteProperty = false;
1101       // Search into the class extensions and see if 'readonly property is
1102       // redeclared 'readwrite', then no warning is to be issued.
1103       for (auto *Ext : IDecl->known_extensions()) {
1104         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
1105         if (!R.empty())
1106           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
1107             PIkind = ExtProp->getPropertyAttributesAsWritten();
1108             if (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite) {
1109               ReadWriteProperty = true;
1110               break;
1111             }
1112           }
1113       }
1114
1115       if (!ReadWriteProperty) {
1116         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
1117             << property;
1118         SourceLocation readonlyLoc;
1119         if (LocPropertyAttribute(Context, "readonly",
1120                                  property->getLParenLoc(), readonlyLoc)) {
1121           SourceLocation endLoc =
1122             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
1123           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
1124           Diag(property->getLocation(),
1125                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
1126           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
1127         }
1128       }
1129     }
1130     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
1131       property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
1132                                                          property);
1133
1134   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
1135     if (Synthesize) {
1136       Diag(AtLoc, diag::err_synthesize_category_decl);
1137       return nullptr;
1138     }
1139     IDecl = CatImplClass->getClassInterface();
1140     if (!IDecl) {
1141       Diag(AtLoc, diag::err_missing_property_interface);
1142       return nullptr;
1143     }
1144     ObjCCategoryDecl *Category =
1145     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
1146
1147     // If category for this implementation not found, it is an error which
1148     // has already been reported eralier.
1149     if (!Category)
1150       return nullptr;
1151     // Look for this property declaration in @implementation's category
1152     property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
1153     if (!property) {
1154       Diag(PropertyLoc, diag::err_bad_category_property_decl)
1155       << Category->getDeclName();
1156       return nullptr;
1157     }
1158   } else {
1159     Diag(AtLoc, diag::err_bad_property_context);
1160     return nullptr;
1161   }
1162   ObjCIvarDecl *Ivar = nullptr;
1163   bool CompleteTypeErr = false;
1164   bool compat = true;
1165   // Check that we have a valid, previously declared ivar for @synthesize
1166   if (Synthesize) {
1167     // @synthesize
1168     if (!PropertyIvar)
1169       PropertyIvar = PropertyId;
1170     // Check that this is a previously declared 'ivar' in 'IDecl' interface
1171     ObjCInterfaceDecl *ClassDeclared;
1172     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
1173     QualType PropType = property->getType();
1174     QualType PropertyIvarType = PropType.getNonReferenceType();
1175
1176     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
1177                             diag::err_incomplete_synthesized_property,
1178                             property->getDeclName())) {
1179       Diag(property->getLocation(), diag::note_property_declare);
1180       CompleteTypeErr = true;
1181     }
1182
1183     if (getLangOpts().ObjCAutoRefCount &&
1184         (property->getPropertyAttributesAsWritten() &
1185          ObjCPropertyDecl::OBJC_PR_readonly) &&
1186         PropertyIvarType->isObjCRetainableType()) {
1187       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
1188     }
1189
1190     ObjCPropertyDecl::PropertyAttributeKind kind
1191       = property->getPropertyAttributes();
1192
1193     bool isARCWeak = false;
1194     if (kind & ObjCPropertyDecl::OBJC_PR_weak) {
1195       // Add GC __weak to the ivar type if the property is weak.
1196       if (getLangOpts().getGC() != LangOptions::NonGC) {
1197         assert(!getLangOpts().ObjCAutoRefCount);
1198         if (PropertyIvarType.isObjCGCStrong()) {
1199           Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
1200           Diag(property->getLocation(), diag::note_property_declare);
1201         } else {
1202           PropertyIvarType =
1203             Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
1204         }
1205
1206       // Otherwise, check whether ARC __weak is enabled and works with
1207       // the property type.
1208       } else {
1209         if (!getLangOpts().ObjCWeak) {
1210           // Only complain here when synthesizing an ivar.
1211           if (!Ivar) {
1212             Diag(PropertyDiagLoc,
1213                  getLangOpts().ObjCWeakRuntime
1214                    ? diag::err_synthesizing_arc_weak_property_disabled
1215                    : diag::err_synthesizing_arc_weak_property_no_runtime);
1216             Diag(property->getLocation(), diag::note_property_declare);
1217           }
1218           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1219         } else {
1220           isARCWeak = true;
1221           if (const ObjCObjectPointerType *ObjT =
1222                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1223             const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1224             if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1225               Diag(property->getLocation(),
1226                    diag::err_arc_weak_unavailable_property)
1227                 << PropertyIvarType;
1228               Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1229                 << ClassImpDecl->getName();
1230             }
1231           }
1232         }
1233       }
1234     }
1235
1236     if (AtLoc.isInvalid()) {
1237       // Check when default synthesizing a property that there is
1238       // an ivar matching property name and issue warning; since this
1239       // is the most common case of not using an ivar used for backing
1240       // property in non-default synthesis case.
1241       ObjCInterfaceDecl *ClassDeclared=nullptr;
1242       ObjCIvarDecl *originalIvar =
1243       IDecl->lookupInstanceVariable(property->getIdentifier(),
1244                                     ClassDeclared);
1245       if (originalIvar) {
1246         Diag(PropertyDiagLoc,
1247              diag::warn_autosynthesis_property_ivar_match)
1248         << PropertyId << (Ivar == nullptr) << PropertyIvar
1249         << originalIvar->getIdentifier();
1250         Diag(property->getLocation(), diag::note_property_declare);
1251         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
1252       }
1253     }
1254
1255     if (!Ivar) {
1256       // In ARC, give the ivar a lifetime qualifier based on the
1257       // property attributes.
1258       if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
1259           !PropertyIvarType.getObjCLifetime() &&
1260           PropertyIvarType->isObjCRetainableType()) {
1261
1262         // It's an error if we have to do this and the user didn't
1263         // explicitly write an ownership attribute on the property.
1264         if (!hasWrittenStorageAttribute(property, QueryKind) &&
1265             !(kind & ObjCPropertyDecl::OBJC_PR_strong)) {
1266           Diag(PropertyDiagLoc,
1267                diag::err_arc_objc_property_default_assign_on_object);
1268           Diag(property->getLocation(), diag::note_property_declare);
1269         } else {
1270           Qualifiers::ObjCLifetime lifetime =
1271             getImpliedARCOwnership(kind, PropertyIvarType);
1272           assert(lifetime && "no lifetime for property?");
1273
1274           Qualifiers qs;
1275           qs.addObjCLifetime(lifetime);
1276           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1277         }
1278       }
1279
1280       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1281                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1282                                   PropertyIvarType, /*Dinfo=*/nullptr,
1283                                   ObjCIvarDecl::Private,
1284                                   (Expr *)nullptr, true);
1285       if (RequireNonAbstractType(PropertyIvarLoc,
1286                                  PropertyIvarType,
1287                                  diag::err_abstract_type_in_decl,
1288                                  AbstractSynthesizedIvarType)) {
1289         Diag(property->getLocation(), diag::note_property_declare);
1290         // An abstract type is as bad as an incomplete type.
1291         CompleteTypeErr = true;
1292       }
1293       if (!CompleteTypeErr) {
1294         const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
1295         if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
1296           Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
1297             << PropertyIvarType;
1298           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1299         }
1300       }
1301       if (CompleteTypeErr)
1302         Ivar->setInvalidDecl();
1303       ClassImpDecl->addDecl(Ivar);
1304       IDecl->makeDeclVisibleInContext(Ivar);
1305
1306       if (getLangOpts().ObjCRuntime.isFragile())
1307         Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
1308             << PropertyId;
1309       // Note! I deliberately want it to fall thru so, we have a
1310       // a property implementation and to avoid future warnings.
1311     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1312                !declaresSameEntity(ClassDeclared, IDecl)) {
1313       Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
1314       << property->getDeclName() << Ivar->getDeclName()
1315       << ClassDeclared->getDeclName();
1316       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1317       << Ivar << Ivar->getName();
1318       // Note! I deliberately want it to fall thru so more errors are caught.
1319     }
1320     property->setPropertyIvarDecl(Ivar);
1321
1322     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1323
1324     // Check that type of property and its ivar are type compatible.
1325     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1326       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1327           && isa<ObjCObjectPointerType>(IvarType))
1328         compat =
1329           Context.canAssignObjCInterfaces(
1330                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1331                                   IvarType->getAs<ObjCObjectPointerType>());
1332       else {
1333         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1334                                              IvarType)
1335                     == Compatible);
1336       }
1337       if (!compat) {
1338         Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1339           << property->getDeclName() << PropType
1340           << Ivar->getDeclName() << IvarType;
1341         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1342         // Note! I deliberately want it to fall thru so, we have a
1343         // a property implementation and to avoid future warnings.
1344       }
1345       else {
1346         // FIXME! Rules for properties are somewhat different that those
1347         // for assignments. Use a new routine to consolidate all cases;
1348         // specifically for property redeclarations as well as for ivars.
1349         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1350         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1351         if (lhsType != rhsType &&
1352             lhsType->isArithmeticType()) {
1353           Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1354             << property->getDeclName() << PropType
1355             << Ivar->getDeclName() << IvarType;
1356           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1357           // Fall thru - see previous comment
1358         }
1359       }
1360       // __weak is explicit. So it works on Canonical type.
1361       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1362            getLangOpts().getGC() != LangOptions::NonGC)) {
1363         Diag(PropertyDiagLoc, diag::err_weak_property)
1364         << property->getDeclName() << Ivar->getDeclName();
1365         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1366         // Fall thru - see previous comment
1367       }
1368       // Fall thru - see previous comment
1369       if ((property->getType()->isObjCObjectPointerType() ||
1370            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1371           getLangOpts().getGC() != LangOptions::NonGC) {
1372         Diag(PropertyDiagLoc, diag::err_strong_property)
1373         << property->getDeclName() << Ivar->getDeclName();
1374         // Fall thru - see previous comment
1375       }
1376     }
1377     if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
1378         Ivar->getType().getObjCLifetime())
1379       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1380   } else if (PropertyIvar)
1381     // @dynamic
1382     Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);
1383
1384   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1385   ObjCPropertyImplDecl *PIDecl =
1386   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1387                                property,
1388                                (Synthesize ?
1389                                 ObjCPropertyImplDecl::Synthesize
1390                                 : ObjCPropertyImplDecl::Dynamic),
1391                                Ivar, PropertyIvarLoc);
1392
1393   if (CompleteTypeErr || !compat)
1394     PIDecl->setInvalidDecl();
1395
1396   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1397     getterMethod->createImplicitParams(Context, IDecl);
1398     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1399         Ivar->getType()->isRecordType()) {
1400       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1401       // returned by the getter as it must conform to C++'s copy-return rules.
1402       // FIXME. Eventually we want to do this for Objective-C as well.
1403       SynthesizedFunctionScope Scope(*this, getterMethod);
1404       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1405       DeclRefExpr *SelfExpr =
1406         new (Context) DeclRefExpr(SelfDecl, false, SelfDecl->getType(),
1407                                   VK_LValue, PropertyDiagLoc);
1408       MarkDeclRefReferenced(SelfExpr);
1409       Expr *LoadSelfExpr =
1410         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1411                                  CK_LValueToRValue, SelfExpr, nullptr,
1412                                  VK_RValue);
1413       Expr *IvarRefExpr =
1414         new (Context) ObjCIvarRefExpr(Ivar,
1415                                       Ivar->getUsageType(SelfDecl->getType()),
1416                                       PropertyDiagLoc,
1417                                       Ivar->getLocation(),
1418                                       LoadSelfExpr, true, true);
1419       ExprResult Res = PerformCopyInitialization(
1420           InitializedEntity::InitializeResult(PropertyDiagLoc,
1421                                               getterMethod->getReturnType(),
1422                                               /*NRVO=*/false),
1423           PropertyDiagLoc, IvarRefExpr);
1424       if (!Res.isInvalid()) {
1425         Expr *ResExpr = Res.getAs<Expr>();
1426         if (ResExpr)
1427           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1428         PIDecl->setGetterCXXConstructor(ResExpr);
1429       }
1430     }
1431     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1432         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1433       Diag(getterMethod->getLocation(),
1434            diag::warn_property_getter_owning_mismatch);
1435       Diag(property->getLocation(), diag::note_property_declare);
1436     }
1437     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1438       switch (getterMethod->getMethodFamily()) {
1439         case OMF_retain:
1440         case OMF_retainCount:
1441         case OMF_release:
1442         case OMF_autorelease:
1443           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1444             << 1 << getterMethod->getSelector();
1445           break;
1446         default:
1447           break;
1448       }
1449   }
1450   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1451     setterMethod->createImplicitParams(Context, IDecl);
1452     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1453         Ivar->getType()->isRecordType()) {
1454       // FIXME. Eventually we want to do this for Objective-C as well.
1455       SynthesizedFunctionScope Scope(*this, setterMethod);
1456       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1457       DeclRefExpr *SelfExpr =
1458         new (Context) DeclRefExpr(SelfDecl, false, SelfDecl->getType(),
1459                                   VK_LValue, PropertyDiagLoc);
1460       MarkDeclRefReferenced(SelfExpr);
1461       Expr *LoadSelfExpr =
1462         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1463                                  CK_LValueToRValue, SelfExpr, nullptr,
1464                                  VK_RValue);
1465       Expr *lhs =
1466         new (Context) ObjCIvarRefExpr(Ivar,
1467                                       Ivar->getUsageType(SelfDecl->getType()),
1468                                       PropertyDiagLoc,
1469                                       Ivar->getLocation(),
1470                                       LoadSelfExpr, true, true);
1471       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1472       ParmVarDecl *Param = (*P);
1473       QualType T = Param->getType().getNonReferenceType();
1474       DeclRefExpr *rhs = new (Context) DeclRefExpr(Param, false, T,
1475                                                    VK_LValue, PropertyDiagLoc);
1476       MarkDeclRefReferenced(rhs);
1477       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1478                                   BO_Assign, lhs, rhs);
1479       if (property->getPropertyAttributes() &
1480           ObjCPropertyDecl::OBJC_PR_atomic) {
1481         Expr *callExpr = Res.getAs<Expr>();
1482         if (const CXXOperatorCallExpr *CXXCE =
1483               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1484           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1485             if (!FuncDecl->isTrivial())
1486               if (property->getType()->isReferenceType()) {
1487                 Diag(PropertyDiagLoc,
1488                      diag::err_atomic_property_nontrivial_assign_op)
1489                     << property->getType();
1490                 Diag(FuncDecl->getLocStart(),
1491                      diag::note_callee_decl) << FuncDecl;
1492               }
1493       }
1494       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1495     }
1496   }
1497
1498   if (IC) {
1499     if (Synthesize)
1500       if (ObjCPropertyImplDecl *PPIDecl =
1501           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1502         Diag(PropertyLoc, diag::err_duplicate_ivar_use)
1503         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1504         << PropertyIvar;
1505         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1506       }
1507
1508     if (ObjCPropertyImplDecl *PPIDecl
1509         = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
1510       Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
1511       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1512       return nullptr;
1513     }
1514     IC->addPropertyImplementation(PIDecl);
1515     if (getLangOpts().ObjCDefaultSynthProperties &&
1516         getLangOpts().ObjCRuntime.isNonFragile() &&
1517         !IDecl->isObjCRequiresPropertyDefs()) {
1518       // Diagnose if an ivar was lazily synthesdized due to a previous
1519       // use and if 1) property is @dynamic or 2) property is synthesized
1520       // but it requires an ivar of different name.
1521       ObjCInterfaceDecl *ClassDeclared=nullptr;
1522       ObjCIvarDecl *Ivar = nullptr;
1523       if (!Synthesize)
1524         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1525       else {
1526         if (PropertyIvar && PropertyIvar != PropertyId)
1527           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1528       }
1529       // Issue diagnostics only if Ivar belongs to current class.
1530       if (Ivar && Ivar->getSynthesize() &&
1531           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1532         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1533         << PropertyId;
1534         Ivar->setInvalidDecl();
1535       }
1536     }
1537   } else {
1538     if (Synthesize)
1539       if (ObjCPropertyImplDecl *PPIDecl =
1540           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1541         Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
1542         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1543         << PropertyIvar;
1544         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1545       }
1546
1547     if (ObjCPropertyImplDecl *PPIDecl =
1548         CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
1549       Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
1550       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1551       return nullptr;
1552     }
1553     CatImplClass->addPropertyImplementation(PIDecl);
1554   }
1555
1556   return PIDecl;
1557 }
1558
1559 //===----------------------------------------------------------------------===//
1560 // Helper methods.
1561 //===----------------------------------------------------------------------===//
1562
1563 /// DiagnosePropertyMismatch - Compares two properties for their
1564 /// attributes and types and warns on a variety of inconsistencies.
1565 ///
1566 void
1567 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1568                                ObjCPropertyDecl *SuperProperty,
1569                                const IdentifierInfo *inheritedName,
1570                                bool OverridingProtocolProperty) {
1571   ObjCPropertyDecl::PropertyAttributeKind CAttr =
1572     Property->getPropertyAttributes();
1573   ObjCPropertyDecl::PropertyAttributeKind SAttr =
1574     SuperProperty->getPropertyAttributes();
1575
1576   // We allow readonly properties without an explicit ownership
1577   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1578   // to be overridden by a property with any explicit ownership in the subclass.
1579   if (!OverridingProtocolProperty &&
1580       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1581     ;
1582   else {
1583     if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
1584         && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
1585       Diag(Property->getLocation(), diag::warn_readonly_property)
1586         << Property->getDeclName() << inheritedName;
1587     if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
1588         != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
1589       Diag(Property->getLocation(), diag::warn_property_attribute)
1590         << Property->getDeclName() << "copy" << inheritedName;
1591     else if (!(SAttr & ObjCPropertyDecl::OBJC_PR_readonly)){
1592       unsigned CAttrRetain =
1593         (CAttr &
1594          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1595       unsigned SAttrRetain =
1596         (SAttr &
1597          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1598       bool CStrong = (CAttrRetain != 0);
1599       bool SStrong = (SAttrRetain != 0);
1600       if (CStrong != SStrong)
1601         Diag(Property->getLocation(), diag::warn_property_attribute)
1602           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1603     }
1604   }
1605
1606   // Check for nonatomic; note that nonatomic is effectively
1607   // meaningless for readonly properties, so don't diagnose if the
1608   // atomic property is 'readonly'.
1609   checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
1610   // Readonly properties from protocols can be implemented as "readwrite"
1611   // with a custom setter name.
1612   if (Property->getSetterName() != SuperProperty->getSetterName() &&
1613       !(SuperProperty->isReadOnly() &&
1614         isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
1615     Diag(Property->getLocation(), diag::warn_property_attribute)
1616       << Property->getDeclName() << "setter" << inheritedName;
1617     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1618   }
1619   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1620     Diag(Property->getLocation(), diag::warn_property_attribute)
1621       << Property->getDeclName() << "getter" << inheritedName;
1622     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1623   }
1624
1625   QualType LHSType =
1626     Context.getCanonicalType(SuperProperty->getType());
1627   QualType RHSType =
1628     Context.getCanonicalType(Property->getType());
1629
1630   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1631     // Do cases not handled in above.
1632     // FIXME. For future support of covariant property types, revisit this.
1633     bool IncompatibleObjC = false;
1634     QualType ConvertedType;
1635     if (!isObjCPointerConversion(RHSType, LHSType,
1636                                  ConvertedType, IncompatibleObjC) ||
1637         IncompatibleObjC) {
1638         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1639         << Property->getType() << SuperProperty->getType() << inheritedName;
1640       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1641     }
1642   }
1643 }
1644
1645 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1646                                             ObjCMethodDecl *GetterMethod,
1647                                             SourceLocation Loc) {
1648   if (!GetterMethod)
1649     return false;
1650   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1651   QualType PropertyRValueType =
1652       property->getType().getNonReferenceType().getAtomicUnqualifiedType();
1653   bool compat = Context.hasSameType(PropertyRValueType, GetterType);
1654   if (!compat) {
1655     const ObjCObjectPointerType *propertyObjCPtr = nullptr;
1656     const ObjCObjectPointerType *getterObjCPtr = nullptr;
1657     if ((propertyObjCPtr =
1658              PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
1659         (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
1660       compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
1661     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
1662               != Compatible) {
1663           Diag(Loc, diag::err_property_accessor_type)
1664             << property->getDeclName() << PropertyRValueType
1665             << GetterMethod->getSelector() << GetterType;
1666           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1667           return true;
1668     } else {
1669       compat = true;
1670       QualType lhsType = Context.getCanonicalType(PropertyRValueType);
1671       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1672       if (lhsType != rhsType && lhsType->isArithmeticType())
1673         compat = false;
1674     }
1675   }
1676
1677   if (!compat) {
1678     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1679     << property->getDeclName()
1680     << GetterMethod->getSelector();
1681     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1682     return true;
1683   }
1684
1685   return false;
1686 }
1687
1688 /// CollectImmediateProperties - This routine collects all properties in
1689 /// the class and its conforming protocols; but not those in its super class.
1690 static void
1691 CollectImmediateProperties(ObjCContainerDecl *CDecl,
1692                            ObjCContainerDecl::PropertyMap &PropMap,
1693                            ObjCContainerDecl::PropertyMap &SuperPropMap,
1694                            bool CollectClassPropsOnly = false,
1695                            bool IncludeProtocols = true) {
1696   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1697     for (auto *Prop : IDecl->properties()) {
1698       if (CollectClassPropsOnly && !Prop->isClassProperty())
1699         continue;
1700       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1701           Prop;
1702     }
1703
1704     // Collect the properties from visible extensions.
1705     for (auto *Ext : IDecl->visible_extensions())
1706       CollectImmediateProperties(Ext, PropMap, SuperPropMap,
1707                                  CollectClassPropsOnly, IncludeProtocols);
1708
1709     if (IncludeProtocols) {
1710       // Scan through class's protocols.
1711       for (auto *PI : IDecl->all_referenced_protocols())
1712         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1713                                    CollectClassPropsOnly);
1714     }
1715   }
1716   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1717     for (auto *Prop : CATDecl->properties()) {
1718       if (CollectClassPropsOnly && !Prop->isClassProperty())
1719         continue;
1720       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1721           Prop;
1722     }
1723     if (IncludeProtocols) {
1724       // Scan through class's protocols.
1725       for (auto *PI : CATDecl->protocols())
1726         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1727                                    CollectClassPropsOnly);
1728     }
1729   }
1730   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1731     for (auto *Prop : PDecl->properties()) {
1732       if (CollectClassPropsOnly && !Prop->isClassProperty())
1733         continue;
1734       ObjCPropertyDecl *PropertyFromSuper =
1735           SuperPropMap[std::make_pair(Prop->getIdentifier(),
1736                                       Prop->isClassProperty())];
1737       // Exclude property for protocols which conform to class's super-class,
1738       // as super-class has to implement the property.
1739       if (!PropertyFromSuper ||
1740           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1741         ObjCPropertyDecl *&PropEntry =
1742             PropMap[std::make_pair(Prop->getIdentifier(),
1743                                    Prop->isClassProperty())];
1744         if (!PropEntry)
1745           PropEntry = Prop;
1746       }
1747     }
1748     // Scan through protocol's protocols.
1749     for (auto *PI : PDecl->protocols())
1750       CollectImmediateProperties(PI, PropMap, SuperPropMap,
1751                                  CollectClassPropsOnly);
1752   }
1753 }
1754
1755 /// CollectSuperClassPropertyImplementations - This routine collects list of
1756 /// properties to be implemented in super class(s) and also coming from their
1757 /// conforming protocols.
1758 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1759                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1760   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1761     ObjCInterfaceDecl::PropertyDeclOrder PO;
1762     while (SDecl) {
1763       SDecl->collectPropertiesToImplement(PropMap, PO);
1764       SDecl = SDecl->getSuperClass();
1765     }
1766   }
1767 }
1768
1769 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1770 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1771 /// declared in class 'IFace'.
1772 bool
1773 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1774                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1775   if (!IV->getSynthesize())
1776     return false;
1777   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1778                                             Method->isInstanceMethod());
1779   if (!IMD || !IMD->isPropertyAccessor())
1780     return false;
1781
1782   // look up a property declaration whose one of its accessors is implemented
1783   // by this method.
1784   for (const auto *Property : IFace->instance_properties()) {
1785     if ((Property->getGetterName() == IMD->getSelector() ||
1786          Property->getSetterName() == IMD->getSelector()) &&
1787         (Property->getPropertyIvarDecl() == IV))
1788       return true;
1789   }
1790   // Also look up property declaration in class extension whose one of its
1791   // accessors is implemented by this method.
1792   for (const auto *Ext : IFace->known_extensions())
1793     for (const auto *Property : Ext->instance_properties())
1794       if ((Property->getGetterName() == IMD->getSelector() ||
1795            Property->getSetterName() == IMD->getSelector()) &&
1796           (Property->getPropertyIvarDecl() == IV))
1797         return true;
1798   return false;
1799 }
1800
1801 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1802                                          ObjCPropertyDecl *Prop) {
1803   bool SuperClassImplementsGetter = false;
1804   bool SuperClassImplementsSetter = false;
1805   if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1806     SuperClassImplementsSetter = true;
1807
1808   while (IDecl->getSuperClass()) {
1809     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1810     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1811       SuperClassImplementsGetter = true;
1812
1813     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1814       SuperClassImplementsSetter = true;
1815     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1816       return true;
1817     IDecl = IDecl->getSuperClass();
1818   }
1819   return false;
1820 }
1821
1822 /// \brief Default synthesizes all properties which must be synthesized
1823 /// in class's \@implementation.
1824 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
1825                                        ObjCInterfaceDecl *IDecl,
1826                                        SourceLocation AtEnd) {
1827   ObjCInterfaceDecl::PropertyMap PropMap;
1828   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1829   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1830   if (PropMap.empty())
1831     return;
1832   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1833   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1834
1835   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1836     ObjCPropertyDecl *Prop = PropertyOrder[i];
1837     // Is there a matching property synthesize/dynamic?
1838     if (Prop->isInvalidDecl() ||
1839         Prop->isClassProperty() ||
1840         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1841       continue;
1842     // Property may have been synthesized by user.
1843     if (IMPDecl->FindPropertyImplDecl(
1844             Prop->getIdentifier(), Prop->getQueryKind()))
1845       continue;
1846     if (IMPDecl->getInstanceMethod(Prop->getGetterName())) {
1847       if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1848         continue;
1849       if (IMPDecl->getInstanceMethod(Prop->getSetterName()))
1850         continue;
1851     }
1852     if (ObjCPropertyImplDecl *PID =
1853         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1854       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1855         << Prop->getIdentifier();
1856       if (PID->getLocation().isValid())
1857         Diag(PID->getLocation(), diag::note_property_synthesize);
1858       continue;
1859     }
1860     ObjCPropertyDecl *PropInSuperClass =
1861         SuperPropMap[std::make_pair(Prop->getIdentifier(),
1862                                     Prop->isClassProperty())];
1863     if (ObjCProtocolDecl *Proto =
1864           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1865       // We won't auto-synthesize properties declared in protocols.
1866       // Suppress the warning if class's superclass implements property's
1867       // getter and implements property's setter (if readwrite property).
1868       // Or, if property is going to be implemented in its super class.
1869       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1870         Diag(IMPDecl->getLocation(),
1871              diag::warn_auto_synthesizing_protocol_property)
1872           << Prop << Proto;
1873         Diag(Prop->getLocation(), diag::note_property_declare);
1874         std::string FixIt =
1875             (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
1876         Diag(AtEnd, diag::note_add_synthesize_directive)
1877             << FixItHint::CreateInsertion(AtEnd, FixIt);
1878       }
1879       continue;
1880     }
1881     // If property to be implemented in the super class, ignore.
1882     if (PropInSuperClass) {
1883       if ((Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readwrite) &&
1884           (PropInSuperClass->getPropertyAttributes() &
1885            ObjCPropertyDecl::OBJC_PR_readonly) &&
1886           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1887           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1888         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1889         << Prop->getIdentifier();
1890         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1891       }
1892       else {
1893         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1894         << Prop->getIdentifier();
1895         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1896         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1897       }
1898       continue;
1899     }
1900     // We use invalid SourceLocations for the synthesized ivars since they
1901     // aren't really synthesized at a particular location; they just exist.
1902     // Saying that they are located at the @implementation isn't really going
1903     // to help users.
1904     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1905       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1906                             true,
1907                             /* property = */ Prop->getIdentifier(),
1908                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1909                             Prop->getLocation(), Prop->getQueryKind()));
1910     if (PIDecl && !Prop->isUnavailable()) {
1911       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1912       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1913     }
1914   }
1915 }
1916
1917 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
1918                                        SourceLocation AtEnd) {
1919   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
1920     return;
1921   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
1922   if (!IC)
1923     return;
1924   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
1925     if (!IDecl->isObjCRequiresPropertyDefs())
1926       DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
1927 }
1928
1929 static void DiagnoseUnimplementedAccessor(
1930     Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
1931     ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
1932     ObjCPropertyDecl *Prop,
1933     llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
1934   // Check to see if we have a corresponding selector in SMap and with the
1935   // right method type.
1936   auto I = std::find_if(SMap.begin(), SMap.end(),
1937     [&](const ObjCMethodDecl *x) {
1938       return x->getSelector() == Method &&
1939              x->isClassMethod() == Prop->isClassProperty();
1940     });
1941   // When reporting on missing property setter/getter implementation in
1942   // categories, do not report when they are declared in primary class,
1943   // class's protocol, or one of it super classes. This is because,
1944   // the class is going to implement them.
1945   if (I == SMap.end() &&
1946       (PrimaryClass == nullptr ||
1947        !PrimaryClass->lookupPropertyAccessor(Method, C,
1948                                              Prop->isClassProperty()))) {
1949     unsigned diag =
1950         isa<ObjCCategoryDecl>(CDecl)
1951             ? (Prop->isClassProperty()
1952                    ? diag::warn_impl_required_in_category_for_class_property
1953                    : diag::warn_setter_getter_impl_required_in_category)
1954             : (Prop->isClassProperty()
1955                    ? diag::warn_impl_required_for_class_property
1956                    : diag::warn_setter_getter_impl_required);
1957     S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
1958     S.Diag(Prop->getLocation(), diag::note_property_declare);
1959     if (S.LangOpts.ObjCDefaultSynthProperties &&
1960         S.LangOpts.ObjCRuntime.isNonFragile())
1961       if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
1962         if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
1963           S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
1964   }
1965 }
1966
1967 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
1968                                            ObjCContainerDecl *CDecl,
1969                                            bool SynthesizeProperties) {
1970   ObjCContainerDecl::PropertyMap PropMap;
1971   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
1972
1973   // Since we don't synthesize class properties, we should emit diagnose even
1974   // if SynthesizeProperties is true.
1975   ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
1976   // Gather properties which need not be implemented in this class
1977   // or category.
1978   if (!IDecl)
1979     if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1980       // For categories, no need to implement properties declared in
1981       // its primary class (and its super classes) if property is
1982       // declared in one of those containers.
1983       if ((IDecl = C->getClassInterface())) {
1984         ObjCInterfaceDecl::PropertyDeclOrder PO;
1985         IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
1986       }
1987     }
1988   if (IDecl)
1989     CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
1990
1991   // When SynthesizeProperties is true, we only check class properties.
1992   CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
1993                              SynthesizeProperties/*CollectClassPropsOnly*/);
1994
1995   // Scan the @interface to see if any of the protocols it adopts
1996   // require an explicit implementation, via attribute
1997   // 'objc_protocol_requires_explicit_implementation'.
1998   if (IDecl) {
1999     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
2000
2001     for (auto *PDecl : IDecl->all_referenced_protocols()) {
2002       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2003         continue;
2004       // Lazily construct a set of all the properties in the @interface
2005       // of the class, without looking at the superclass.  We cannot
2006       // use the call to CollectImmediateProperties() above as that
2007       // utilizes information from the super class's properties as well
2008       // as scans the adopted protocols.  This work only triggers for protocols
2009       // with the attribute, which is very rare, and only occurs when
2010       // analyzing the @implementation.
2011       if (!LazyMap) {
2012         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2013         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
2014         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
2015                                    /* CollectClassPropsOnly */ false,
2016                                    /* IncludeProtocols */ false);
2017       }
2018       // Add the properties of 'PDecl' to the list of properties that
2019       // need to be implemented.
2020       for (auto *PropDecl : PDecl->properties()) {
2021         if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
2022                                       PropDecl->isClassProperty())])
2023           continue;
2024         PropMap[std::make_pair(PropDecl->getIdentifier(),
2025                                PropDecl->isClassProperty())] = PropDecl;
2026       }
2027     }
2028   }
2029
2030   if (PropMap.empty())
2031     return;
2032
2033   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
2034   for (const auto *I : IMPDecl->property_impls())
2035     PropImplMap.insert(I->getPropertyDecl());
2036
2037   llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
2038   // Collect property accessors implemented in current implementation.
2039   for (const auto *I : IMPDecl->methods())
2040     InsMap.insert(I);
2041
2042   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
2043   ObjCInterfaceDecl *PrimaryClass = nullptr;
2044   if (C && !C->IsClassExtension())
2045     if ((PrimaryClass = C->getClassInterface()))
2046       // Report unimplemented properties in the category as well.
2047       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
2048         // When reporting on missing setter/getters, do not report when
2049         // setter/getter is implemented in category's primary class
2050         // implementation.
2051         for (const auto *I : IMP->methods())
2052           InsMap.insert(I);
2053       }
2054
2055   for (ObjCContainerDecl::PropertyMap::iterator
2056        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
2057     ObjCPropertyDecl *Prop = P->second;
2058     // Is there a matching property synthesize/dynamic?
2059     if (Prop->isInvalidDecl() ||
2060         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
2061         PropImplMap.count(Prop) ||
2062         Prop->getAvailability() == AR_Unavailable)
2063       continue;
2064
2065     // Diagnose unimplemented getters and setters.
2066     DiagnoseUnimplementedAccessor(*this,
2067           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
2068     if (!Prop->isReadOnly())
2069       DiagnoseUnimplementedAccessor(*this,
2070                                     PrimaryClass, Prop->getSetterName(),
2071                                     IMPDecl, CDecl, C, Prop, InsMap);
2072   }
2073 }
2074
2075 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
2076   for (const auto *propertyImpl : impDecl->property_impls()) {
2077     const auto *property = propertyImpl->getPropertyDecl();
2078
2079     // Warn about null_resettable properties with synthesized setters,
2080     // because the setter won't properly handle nil.
2081     if (propertyImpl->getPropertyImplementation()
2082           == ObjCPropertyImplDecl::Synthesize &&
2083         (property->getPropertyAttributes() &
2084          ObjCPropertyDecl::OBJC_PR_null_resettable) &&
2085         property->getGetterMethodDecl() &&
2086         property->getSetterMethodDecl()) {
2087       auto *getterMethod = property->getGetterMethodDecl();
2088       auto *setterMethod = property->getSetterMethodDecl();
2089       if (!impDecl->getInstanceMethod(setterMethod->getSelector()) &&
2090           !impDecl->getInstanceMethod(getterMethod->getSelector())) {
2091         SourceLocation loc = propertyImpl->getLocation();
2092         if (loc.isInvalid())
2093           loc = impDecl->getLocStart();
2094
2095         Diag(loc, diag::warn_null_resettable_setter)
2096           << setterMethod->getSelector() << property->getDeclName();
2097       }
2098     }
2099   }
2100 }
2101
2102 void
2103 Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
2104                                        ObjCInterfaceDecl* IDecl) {
2105   // Rules apply in non-GC mode only
2106   if (getLangOpts().getGC() != LangOptions::NonGC)
2107     return;
2108   ObjCContainerDecl::PropertyMap PM;
2109   for (auto *Prop : IDecl->properties())
2110     PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2111   for (const auto *Ext : IDecl->known_extensions())
2112     for (auto *Prop : Ext->properties())
2113       PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2114
2115   for (ObjCContainerDecl::PropertyMap::iterator I = PM.begin(), E = PM.end();
2116        I != E; ++I) {
2117     const ObjCPropertyDecl *Property = I->second;
2118     ObjCMethodDecl *GetterMethod = nullptr;
2119     ObjCMethodDecl *SetterMethod = nullptr;
2120     bool LookedUpGetterSetter = false;
2121
2122     unsigned Attributes = Property->getPropertyAttributes();
2123     unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();
2124
2125     if (!(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic) &&
2126         !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_nonatomic)) {
2127       GetterMethod = Property->isClassProperty() ?
2128                      IMPDecl->getClassMethod(Property->getGetterName()) :
2129                      IMPDecl->getInstanceMethod(Property->getGetterName());
2130       SetterMethod = Property->isClassProperty() ?
2131                      IMPDecl->getClassMethod(Property->getSetterName()) :
2132                      IMPDecl->getInstanceMethod(Property->getSetterName());
2133       LookedUpGetterSetter = true;
2134       if (GetterMethod) {
2135         Diag(GetterMethod->getLocation(),
2136              diag::warn_default_atomic_custom_getter_setter)
2137           << Property->getIdentifier() << 0;
2138         Diag(Property->getLocation(), diag::note_property_declare);
2139       }
2140       if (SetterMethod) {
2141         Diag(SetterMethod->getLocation(),
2142              diag::warn_default_atomic_custom_getter_setter)
2143           << Property->getIdentifier() << 1;
2144         Diag(Property->getLocation(), diag::note_property_declare);
2145       }
2146     }
2147
2148     // We only care about readwrite atomic property.
2149     if ((Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
2150         !(Attributes & ObjCPropertyDecl::OBJC_PR_readwrite))
2151       continue;
2152     if (const ObjCPropertyImplDecl *PIDecl = IMPDecl->FindPropertyImplDecl(
2153             Property->getIdentifier(), Property->getQueryKind())) {
2154       if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
2155         continue;
2156       if (!LookedUpGetterSetter) {
2157         GetterMethod = Property->isClassProperty() ?
2158                        IMPDecl->getClassMethod(Property->getGetterName()) :
2159                        IMPDecl->getInstanceMethod(Property->getGetterName());
2160         SetterMethod = Property->isClassProperty() ?
2161                        IMPDecl->getClassMethod(Property->getSetterName()) :
2162                        IMPDecl->getInstanceMethod(Property->getSetterName());
2163       }
2164       if ((GetterMethod && !SetterMethod) || (!GetterMethod && SetterMethod)) {
2165         SourceLocation MethodLoc =
2166           (GetterMethod ? GetterMethod->getLocation()
2167                         : SetterMethod->getLocation());
2168         Diag(MethodLoc, diag::warn_atomic_property_rule)
2169           << Property->getIdentifier() << (GetterMethod != nullptr)
2170           << (SetterMethod != nullptr);
2171         // fixit stuff.
2172         if (Property->getLParenLoc().isValid() &&
2173             !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_atomic)) {
2174           // @property () ... case.
2175           SourceLocation AfterLParen =
2176             getLocForEndOfToken(Property->getLParenLoc());
2177           StringRef NonatomicStr = AttributesAsWritten? "nonatomic, "
2178                                                       : "nonatomic";
2179           Diag(Property->getLocation(),
2180                diag::note_atomic_property_fixup_suggest)
2181             << FixItHint::CreateInsertion(AfterLParen, NonatomicStr);
2182         } else if (Property->getLParenLoc().isInvalid()) {
2183           //@property id etc.
2184           SourceLocation startLoc =
2185             Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2186           Diag(Property->getLocation(),
2187                diag::note_atomic_property_fixup_suggest)
2188             << FixItHint::CreateInsertion(startLoc, "(nonatomic) ");
2189         }
2190         else
2191           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
2192         Diag(Property->getLocation(), diag::note_property_declare);
2193       }
2194     }
2195   }
2196 }
2197
2198 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
2199   if (getLangOpts().getGC() == LangOptions::GCOnly)
2200     return;
2201
2202   for (const auto *PID : D->property_impls()) {
2203     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2204     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
2205         !PD->isClassProperty() &&
2206         !D->getInstanceMethod(PD->getGetterName())) {
2207       ObjCMethodDecl *method = PD->getGetterMethodDecl();
2208       if (!method)
2209         continue;
2210       ObjCMethodFamily family = method->getMethodFamily();
2211       if (family == OMF_alloc || family == OMF_copy ||
2212           family == OMF_mutableCopy || family == OMF_new) {
2213         if (getLangOpts().ObjCAutoRefCount)
2214           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
2215         else
2216           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
2217
2218         // Look for a getter explicitly declared alongside the property.
2219         // If we find one, use its location for the note.
2220         SourceLocation noteLoc = PD->getLocation();
2221         SourceLocation fixItLoc;
2222         for (auto *getterRedecl : method->redecls()) {
2223           if (getterRedecl->isImplicit())
2224             continue;
2225           if (getterRedecl->getDeclContext() != PD->getDeclContext())
2226             continue;
2227           noteLoc = getterRedecl->getLocation();
2228           fixItLoc = getterRedecl->getLocEnd();
2229         }
2230
2231         Preprocessor &PP = getPreprocessor();
2232         TokenValue tokens[] = {
2233           tok::kw___attribute, tok::l_paren, tok::l_paren,
2234           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
2235           PP.getIdentifierInfo("none"), tok::r_paren,
2236           tok::r_paren, tok::r_paren
2237         };
2238         StringRef spelling = "__attribute__((objc_method_family(none)))";
2239         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
2240         if (!macroName.empty())
2241           spelling = macroName;
2242
2243         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
2244             << method->getDeclName() << spelling;
2245         if (fixItLoc.isValid()) {
2246           SmallString<64> fixItText(" ");
2247           fixItText += spelling;
2248           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
2249         }
2250       }
2251     }
2252   }
2253 }
2254
2255 void Sema::DiagnoseMissingDesignatedInitOverrides(
2256                                             const ObjCImplementationDecl *ImplD,
2257                                             const ObjCInterfaceDecl *IFD) {
2258   assert(IFD->hasDesignatedInitializers());
2259   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
2260   if (!SuperD)
2261     return;
2262
2263   SelectorSet InitSelSet;
2264   for (const auto *I : ImplD->instance_methods())
2265     if (I->getMethodFamily() == OMF_init)
2266       InitSelSet.insert(I->getSelector());
2267
2268   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
2269   SuperD->getDesignatedInitializers(DesignatedInits);
2270   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
2271          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
2272     const ObjCMethodDecl *MD = *I;
2273     if (!InitSelSet.count(MD->getSelector())) {
2274       bool Ignore = false;
2275       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
2276         Ignore = IMD->isUnavailable();
2277       }
2278       if (!Ignore) {
2279         Diag(ImplD->getLocation(),
2280              diag::warn_objc_implementation_missing_designated_init_override)
2281           << MD->getSelector();
2282         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
2283       }
2284     }
2285   }
2286 }
2287
2288 /// AddPropertyAttrs - Propagates attributes from a property to the
2289 /// implicitly-declared getter or setter for that property.
2290 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
2291                              ObjCPropertyDecl *Property) {
2292   // Should we just clone all attributes over?
2293   for (const auto *A : Property->attrs()) {
2294     if (isa<DeprecatedAttr>(A) ||
2295         isa<UnavailableAttr>(A) ||
2296         isa<AvailabilityAttr>(A))
2297       PropertyMethod->addAttr(A->clone(S.Context));
2298   }
2299 }
2300
2301 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2302 /// have the property type and issue diagnostics if they don't.
2303 /// Also synthesize a getter/setter method if none exist (and update the
2304 /// appropriate lookup tables.
2305 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
2306   ObjCMethodDecl *GetterMethod, *SetterMethod;
2307   ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
2308   if (CD->isInvalidDecl())
2309     return;
2310
2311   bool IsClassProperty = property->isClassProperty();
2312   GetterMethod = IsClassProperty ?
2313     CD->getClassMethod(property->getGetterName()) :
2314     CD->getInstanceMethod(property->getGetterName());
2315
2316   // if setter or getter is not found in class extension, it might be
2317   // in the primary class.
2318   if (!GetterMethod)
2319     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2320       if (CatDecl->IsClassExtension())
2321         GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2322                          getClassMethod(property->getGetterName()) :
2323                        CatDecl->getClassInterface()->
2324                          getInstanceMethod(property->getGetterName());
2325
2326   SetterMethod = IsClassProperty ?
2327                  CD->getClassMethod(property->getSetterName()) :
2328                  CD->getInstanceMethod(property->getSetterName());
2329   if (!SetterMethod)
2330     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2331       if (CatDecl->IsClassExtension())
2332         SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2333                           getClassMethod(property->getSetterName()) :
2334                        CatDecl->getClassInterface()->
2335                           getInstanceMethod(property->getSetterName());
2336   DiagnosePropertyAccessorMismatch(property, GetterMethod,
2337                                    property->getLocation());
2338
2339   if (!property->isReadOnly() && SetterMethod) {
2340     if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
2341         Context.VoidTy)
2342       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2343     if (SetterMethod->param_size() != 1 ||
2344         !Context.hasSameUnqualifiedType(
2345           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2346           property->getType().getNonReferenceType())) {
2347       Diag(property->getLocation(),
2348            diag::warn_accessor_property_type_mismatch)
2349         << property->getDeclName()
2350         << SetterMethod->getSelector();
2351       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2352     }
2353   }
2354
2355   // Synthesize getter/setter methods if none exist.
2356   // Find the default getter and if one not found, add one.
2357   // FIXME: The synthesized property we set here is misleading. We almost always
2358   // synthesize these methods unless the user explicitly provided prototypes
2359   // (which is odd, but allowed). Sema should be typechecking that the
2360   // declarations jive in that situation (which it is not currently).
2361   if (!GetterMethod) {
2362     // No instance/class method of same name as property getter name was found.
2363     // Declare a getter method and add it to the list of methods
2364     // for this class.
2365     SourceLocation Loc = property->getLocation();
2366
2367     // The getter returns the declared property type with all qualifiers
2368     // removed.
2369     QualType resultTy = property->getType().getAtomicUnqualifiedType();
2370
2371     // If the property is null_resettable, the getter returns nonnull.
2372     if (property->getPropertyAttributes() &
2373         ObjCPropertyDecl::OBJC_PR_null_resettable) {
2374       QualType modifiedTy = resultTy;
2375       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2376         if (*nullability == NullabilityKind::Unspecified)
2377           resultTy = Context.getAttributedType(AttributedType::attr_nonnull,
2378                                                modifiedTy, modifiedTy);
2379       }
2380     }
2381
2382     GetterMethod = ObjCMethodDecl::Create(Context, Loc, Loc,
2383                              property->getGetterName(),
2384                              resultTy, nullptr, CD,
2385                              !IsClassProperty, /*isVariadic=*/false,
2386                              /*isPropertyAccessor=*/true,
2387                              /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2388                              (property->getPropertyImplementation() ==
2389                               ObjCPropertyDecl::Optional) ?
2390                              ObjCMethodDecl::Optional :
2391                              ObjCMethodDecl::Required);
2392     CD->addDecl(GetterMethod);
2393
2394     AddPropertyAttrs(*this, GetterMethod, property);
2395
2396     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2397       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2398                                                                      Loc));
2399
2400     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2401       GetterMethod->addAttr(
2402         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2403
2404     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2405       GetterMethod->addAttr(
2406           SectionAttr::CreateImplicit(Context, SectionAttr::GNU_section,
2407                                       SA->getName(), Loc));
2408
2409     if (getLangOpts().ObjCAutoRefCount)
2410       CheckARCMethodDecl(GetterMethod);
2411   } else
2412     // A user declared getter will be synthesize when @synthesize of
2413     // the property with the same name is seen in the @implementation
2414     GetterMethod->setPropertyAccessor(true);
2415   property->setGetterMethodDecl(GetterMethod);
2416
2417   // Skip setter if property is read-only.
2418   if (!property->isReadOnly()) {
2419     // Find the default setter and if one not found, add one.
2420     if (!SetterMethod) {
2421       // No instance/class method of same name as property setter name was
2422       // found.
2423       // Declare a setter method and add it to the list of methods
2424       // for this class.
2425       SourceLocation Loc = property->getLocation();
2426
2427       SetterMethod =
2428         ObjCMethodDecl::Create(Context, Loc, Loc,
2429                                property->getSetterName(), Context.VoidTy,
2430                                nullptr, CD, !IsClassProperty,
2431                                /*isVariadic=*/false,
2432                                /*isPropertyAccessor=*/true,
2433                                /*isImplicitlyDeclared=*/true,
2434                                /*isDefined=*/false,
2435                                (property->getPropertyImplementation() ==
2436                                 ObjCPropertyDecl::Optional) ?
2437                                 ObjCMethodDecl::Optional :
2438                                 ObjCMethodDecl::Required);
2439
2440       // Remove all qualifiers from the setter's parameter type.
2441       QualType paramTy =
2442           property->getType().getUnqualifiedType().getAtomicUnqualifiedType();
2443
2444       // If the property is null_resettable, the setter accepts a
2445       // nullable value.
2446       if (property->getPropertyAttributes() &
2447           ObjCPropertyDecl::OBJC_PR_null_resettable) {
2448         QualType modifiedTy = paramTy;
2449         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2450           if (*nullability == NullabilityKind::Unspecified)
2451             paramTy = Context.getAttributedType(AttributedType::attr_nullable,
2452                                                 modifiedTy, modifiedTy);
2453         }
2454       }
2455
2456       // Invent the arguments for the setter. We don't bother making a
2457       // nice name for the argument.
2458       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2459                                                   Loc, Loc,
2460                                                   property->getIdentifier(),
2461                                                   paramTy,
2462                                                   /*TInfo=*/nullptr,
2463                                                   SC_None,
2464                                                   nullptr);
2465       SetterMethod->setMethodParams(Context, Argument, None);
2466
2467       AddPropertyAttrs(*this, SetterMethod, property);
2468
2469       CD->addDecl(SetterMethod);
2470       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2471         SetterMethod->addAttr(
2472             SectionAttr::CreateImplicit(Context, SectionAttr::GNU_section,
2473                                         SA->getName(), Loc));
2474       // It's possible for the user to have set a very odd custom
2475       // setter selector that causes it to have a method family.
2476       if (getLangOpts().ObjCAutoRefCount)
2477         CheckARCMethodDecl(SetterMethod);
2478     } else
2479       // A user declared setter will be synthesize when @synthesize of
2480       // the property with the same name is seen in the @implementation
2481       SetterMethod->setPropertyAccessor(true);
2482     property->setSetterMethodDecl(SetterMethod);
2483   }
2484   // Add any synthesized methods to the global pool. This allows us to
2485   // handle the following, which is supported by GCC (and part of the design).
2486   //
2487   // @interface Foo
2488   // @property double bar;
2489   // @end
2490   //
2491   // void thisIsUnfortunate() {
2492   //   id foo;
2493   //   double bar = [foo bar];
2494   // }
2495   //
2496   if (!IsClassProperty) {
2497     if (GetterMethod)
2498       AddInstanceMethodToGlobalPool(GetterMethod);
2499     if (SetterMethod)
2500       AddInstanceMethodToGlobalPool(SetterMethod);
2501   } else {
2502     if (GetterMethod)
2503       AddFactoryMethodToGlobalPool(GetterMethod);
2504     if (SetterMethod)
2505       AddFactoryMethodToGlobalPool(SetterMethod);
2506   }
2507
2508   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2509   if (!CurrentClass) {
2510     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2511       CurrentClass = Cat->getClassInterface();
2512     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2513       CurrentClass = Impl->getClassInterface();
2514   }
2515   if (GetterMethod)
2516     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2517   if (SetterMethod)
2518     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2519 }
2520
2521 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2522                                        SourceLocation Loc,
2523                                        unsigned &Attributes,
2524                                        bool propertyInPrimaryClass) {
2525   // FIXME: Improve the reported location.
2526   if (!PDecl || PDecl->isInvalidDecl())
2527     return;
2528
2529   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2530       (Attributes & ObjCDeclSpec::DQ_PR_readwrite))
2531     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2532     << "readonly" << "readwrite";
2533
2534   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2535   QualType PropertyTy = PropertyDecl->getType();
2536
2537   // Check for copy or retain on non-object types.
2538   if ((Attributes & (ObjCDeclSpec::DQ_PR_weak | ObjCDeclSpec::DQ_PR_copy |
2539                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong)) &&
2540       !PropertyTy->isObjCRetainableType() &&
2541       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2542     Diag(Loc, diag::err_objc_property_requires_object)
2543       << (Attributes & ObjCDeclSpec::DQ_PR_weak ? "weak" :
2544           Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain (or strong)");
2545     Attributes &= ~(ObjCDeclSpec::DQ_PR_weak   | ObjCDeclSpec::DQ_PR_copy |
2546                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong);
2547     PropertyDecl->setInvalidDecl();
2548   }
2549
2550   // Check for more than one of { assign, copy, retain }.
2551   if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
2552     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2553       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2554         << "assign" << "copy";
2555       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2556     }
2557     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2558       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2559         << "assign" << "retain";
2560       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2561     }
2562     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2563       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2564         << "assign" << "strong";
2565       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2566     }
2567     if (getLangOpts().ObjCAutoRefCount  &&
2568         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2569       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2570         << "assign" << "weak";
2571       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2572     }
2573     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2574       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2575   } else if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) {
2576     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2577       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2578         << "unsafe_unretained" << "copy";
2579       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2580     }
2581     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2582       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2583         << "unsafe_unretained" << "retain";
2584       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2585     }
2586     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2587       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2588         << "unsafe_unretained" << "strong";
2589       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2590     }
2591     if (getLangOpts().ObjCAutoRefCount  &&
2592         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2593       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2594         << "unsafe_unretained" << "weak";
2595       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2596     }
2597   } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2598     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2599       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2600         << "copy" << "retain";
2601       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2602     }
2603     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2604       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2605         << "copy" << "strong";
2606       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2607     }
2608     if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2609       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2610         << "copy" << "weak";
2611       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2612     }
2613   }
2614   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2615            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2616       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2617         << "retain" << "weak";
2618       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2619   }
2620   else if ((Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2621            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2622       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2623         << "strong" << "weak";
2624       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2625   }
2626
2627   if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2628     // 'weak' and 'nonnull' are mutually exclusive.
2629     if (auto nullability = PropertyTy->getNullability(Context)) {
2630       if (*nullability == NullabilityKind::NonNull)
2631         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2632           << "nonnull" << "weak";
2633     }
2634   }
2635
2636   if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
2637       (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
2638       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2639         << "atomic" << "nonatomic";
2640       Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
2641   }
2642
2643   // Warn if user supplied no assignment attribute, property is
2644   // readwrite, and this is an object type.
2645   if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
2646     if (Attributes & ObjCDeclSpec::DQ_PR_readonly) {
2647       // do nothing
2648     } else if (getLangOpts().ObjCAutoRefCount) {
2649       // With arc, @property definitions should default to strong when
2650       // not specified.
2651       PropertyDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
2652     } else if (PropertyTy->isObjCObjectPointerType()) {
2653         bool isAnyClassTy =
2654           (PropertyTy->isObjCClassType() ||
2655            PropertyTy->isObjCQualifiedClassType());
2656         // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2657         // issue any warning.
2658         if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2659           ;
2660         else if (propertyInPrimaryClass) {
2661           // Don't issue warning on property with no life time in class
2662           // extension as it is inherited from property in primary class.
2663           // Skip this warning in gc-only mode.
2664           if (getLangOpts().getGC() != LangOptions::GCOnly)
2665             Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2666
2667           // If non-gc code warn that this is likely inappropriate.
2668           if (getLangOpts().getGC() == LangOptions::NonGC)
2669             Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2670         }
2671     }
2672
2673     // FIXME: Implement warning dependent on NSCopying being
2674     // implemented. See also:
2675     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2676     // (please trim this list while you are at it).
2677   }
2678
2679   if (!(Attributes & ObjCDeclSpec::DQ_PR_copy)
2680       &&!(Attributes & ObjCDeclSpec::DQ_PR_readonly)
2681       && getLangOpts().getGC() == LangOptions::GCOnly
2682       && PropertyTy->isBlockPointerType())
2683     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2684   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2685            !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2686            !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2687            PropertyTy->isBlockPointerType())
2688       Diag(Loc, diag::warn_objc_property_retain_of_block);
2689
2690   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2691       (Attributes & ObjCDeclSpec::DQ_PR_setter))
2692     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2693 }