contrib/llvm-project/clang/lib/Sema/SemaObjCProperty.cpp

   1 //===--- SemaObjCProperty.cpp - Semantic Analysis for ObjC @property ------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file implements semantic analysis for Objective C @property and
  10 //  @synthesize declarations.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Sema/SemaInternal.h"
  15 #include "clang/AST/ASTMutationListener.h"
  16 #include "clang/AST/DeclObjC.h"
  17 #include "clang/AST/ExprCXX.h"
  18 #include "clang/AST/ExprObjC.h"
  19 #include "clang/Basic/SourceManager.h"
  20 #include "clang/Lex/Lexer.h"
  21 #include "clang/Lex/Preprocessor.h"
  22 #include "clang/Sema/Initialization.h"
  23 #include "llvm/ADT/DenseSet.h"
  24 #include "llvm/ADT/SmallString.h"
  25
  26 using namespace clang;
  27
  28 //===----------------------------------------------------------------------===//
  29 // Grammar actions.
  30 //===----------------------------------------------------------------------===//
  31
  32 /// getImpliedARCOwnership - Given a set of property attributes and a
  33 /// type, infer an expected lifetime.  The type's ownership qualification
  34 /// is not considered.
  35 ///
  36 /// Returns OCL_None if the attributes as stated do not imply an ownership.
  37 /// Never returns OCL_Autoreleasing.
  38 static Qualifiers::ObjCLifetime
  39 getImpliedARCOwnership(ObjCPropertyAttribute::Kind attrs, QualType type) {
  40   // retain, strong, copy, weak, and unsafe_unretained are only legal
  41   // on properties of retainable pointer type.
  42   if (attrs &
  43       (ObjCPropertyAttribute::kind_retain | ObjCPropertyAttribute::kind_strong |
  44        ObjCPropertyAttribute::kind_copy)) {
  45     return Qualifiers::OCL_Strong;
  46   } else if (attrs & ObjCPropertyAttribute::kind_weak) {
  47     return Qualifiers::OCL_Weak;
  48   } else if (attrs & ObjCPropertyAttribute::kind_unsafe_unretained) {
  49     return Qualifiers::OCL_ExplicitNone;
  50   }
  51
  52   // assign can appear on other types, so we have to check the
  53   // property type.
  54   if (attrs & ObjCPropertyAttribute::kind_assign &&
  55       type->isObjCRetainableType()) {
  56     return Qualifiers::OCL_ExplicitNone;
  57   }
  58
  59   return Qualifiers::OCL_None;
  60 }
  61
  62 /// Check the internal consistency of a property declaration with
  63 /// an explicit ownership qualifier.
  64 static void checkPropertyDeclWithOwnership(Sema &S,
  65                                            ObjCPropertyDecl *property) {
  66   if (property->isInvalidDecl()) return;
  67
  68   ObjCPropertyAttribute::Kind propertyKind = property->getPropertyAttributes();
  69   Qualifiers::ObjCLifetime propertyLifetime
  70     = property->getType().getObjCLifetime();
  71
  72   assert(propertyLifetime != Qualifiers::OCL_None);
  73
  74   Qualifiers::ObjCLifetime expectedLifetime
  75     = getImpliedARCOwnership(propertyKind, property->getType());
  76   if (!expectedLifetime) {
  77     // We have a lifetime qualifier but no dominating property
  78     // attribute.  That's okay, but restore reasonable invariants by
  79     // setting the property attribute according to the lifetime
  80     // qualifier.
  81     ObjCPropertyAttribute::Kind attr;
  82     if (propertyLifetime == Qualifiers::OCL_Strong) {
  83       attr = ObjCPropertyAttribute::kind_strong;
  84     } else if (propertyLifetime == Qualifiers::OCL_Weak) {
  85       attr = ObjCPropertyAttribute::kind_weak;
  86     } else {
  87       assert(propertyLifetime == Qualifiers::OCL_ExplicitNone);
  88       attr = ObjCPropertyAttribute::kind_unsafe_unretained;
  89     }
  90     property->setPropertyAttributes(attr);
  91     return;
  92   }
  93
  94   if (propertyLifetime == expectedLifetime) return;
  95
  96   property->setInvalidDecl();
  97   S.Diag(property->getLocation(),
  98          diag::err_arc_inconsistent_property_ownership)
  99     << property->getDeclName()
 100     << expectedLifetime
 101     << propertyLifetime;
 102 }
 103
 104 /// Check this Objective-C property against a property declared in the
 105 /// given protocol.
 106 static void
 107 CheckPropertyAgainstProtocol(Sema &S, ObjCPropertyDecl *Prop,
 108                              ObjCProtocolDecl *Proto,
 109                              llvm::SmallPtrSetImpl<ObjCProtocolDecl *> &Known) {
 110   // Have we seen this protocol before?
 111   if (!Known.insert(Proto).second)
 112     return;
 113
 114   // Look for a property with the same name.
 115   DeclContext::lookup_result R = Proto->lookup(Prop->getDeclName());
 116   for (unsigned I = 0, N = R.size(); I != N; ++I) {
 117     if (ObjCPropertyDecl *ProtoProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
 118       S.DiagnosePropertyMismatch(Prop, ProtoProp, Proto->getIdentifier(), true);
 119       return;
 120     }
 121   }
 122
 123   // Check this property against any protocols we inherit.
 124   for (auto *P : Proto->protocols())
 125     CheckPropertyAgainstProtocol(S, Prop, P, Known);
 126 }
 127
 128 static unsigned deducePropertyOwnershipFromType(Sema &S, QualType T) {
 129   // In GC mode, just look for the __weak qualifier.
 130   if (S.getLangOpts().getGC() != LangOptions::NonGC) {
 131     if (T.isObjCGCWeak())
 132       return ObjCPropertyAttribute::kind_weak;
 133
 134     // In ARC/MRC, look for an explicit ownership qualifier.
 135     // For some reason, this only applies to __weak.
 136   } else if (auto ownership = T.getObjCLifetime()) {
 137     switch (ownership) {
 138     case Qualifiers::OCL_Weak:
 139       return ObjCPropertyAttribute::kind_weak;
 140     case Qualifiers::OCL_Strong:
 141       return ObjCPropertyAttribute::kind_strong;
 142     case Qualifiers::OCL_ExplicitNone:
 143       return ObjCPropertyAttribute::kind_unsafe_unretained;
 144     case Qualifiers::OCL_Autoreleasing:
 145     case Qualifiers::OCL_None:
 146       return 0;
 147     }
 148     llvm_unreachable("bad qualifier");
 149   }
 150
 151   return 0;
 152 }
 153
 154 static const unsigned OwnershipMask =
 155     (ObjCPropertyAttribute::kind_assign | ObjCPropertyAttribute::kind_retain |
 156      ObjCPropertyAttribute::kind_copy | ObjCPropertyAttribute::kind_weak |
 157      ObjCPropertyAttribute::kind_strong |
 158      ObjCPropertyAttribute::kind_unsafe_unretained);
 159
 160 static unsigned getOwnershipRule(unsigned attr) {
 161   unsigned result = attr & OwnershipMask;
 162
 163   // From an ownership perspective, assign and unsafe_unretained are
 164   // identical; make sure one also implies the other.
 165   if (result & (ObjCPropertyAttribute::kind_assign |
 166                 ObjCPropertyAttribute::kind_unsafe_unretained)) {
 167     result |= ObjCPropertyAttribute::kind_assign |
 168               ObjCPropertyAttribute::kind_unsafe_unretained;
 169   }
 170
 171   return result;
 172 }
 173
 174 Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
 175                           SourceLocation LParenLoc,
 176                           FieldDeclarator &FD,
 177                           ObjCDeclSpec &ODS,
 178                           Selector GetterSel,
 179                           Selector SetterSel,
 180                           tok::ObjCKeywordKind MethodImplKind,
 181                           DeclContext *lexicalDC) {
 182   unsigned Attributes = ODS.getPropertyAttributes();
 183   FD.D.setObjCWeakProperty((Attributes & ObjCPropertyAttribute::kind_weak) !=
 184                            0);
 185   TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
 186   QualType T = TSI->getType();
 187   if (!getOwnershipRule(Attributes)) {
 188     Attributes |= deducePropertyOwnershipFromType(*this, T);
 189   }
 190   bool isReadWrite = ((Attributes & ObjCPropertyAttribute::kind_readwrite) ||
 191                       // default is readwrite!
 192                       !(Attributes & ObjCPropertyAttribute::kind_readonly));
 193
 194   // Proceed with constructing the ObjCPropertyDecls.
 195   ObjCContainerDecl *ClassDecl = cast<ObjCContainerDecl>(CurContext);
 196   ObjCPropertyDecl *Res = nullptr;
 197   if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
 198     if (CDecl->IsClassExtension()) {
 199       Res = HandlePropertyInClassExtension(S, AtLoc, LParenLoc,
 200                                            FD,
 201                                            GetterSel, ODS.getGetterNameLoc(),
 202                                            SetterSel, ODS.getSetterNameLoc(),
 203                                            isReadWrite, Attributes,
 204                                            ODS.getPropertyAttributes(),
 205                                            T, TSI, MethodImplKind);
 206       if (!Res)
 207         return nullptr;
 208     }
 209   }
 210
 211   if (!Res) {
 212     Res = CreatePropertyDecl(S, ClassDecl, AtLoc, LParenLoc, FD,
 213                              GetterSel, ODS.getGetterNameLoc(), SetterSel,
 214                              ODS.getSetterNameLoc(), isReadWrite, Attributes,
 215                              ODS.getPropertyAttributes(), T, TSI,
 216                              MethodImplKind);
 217     if (lexicalDC)
 218       Res->setLexicalDeclContext(lexicalDC);
 219   }
 220
 221   // Validate the attributes on the @property.
 222   CheckObjCPropertyAttributes(Res, AtLoc, Attributes,
 223                               (isa<ObjCInterfaceDecl>(ClassDecl) ||
 224                                isa<ObjCProtocolDecl>(ClassDecl)));
 225
 226   // Check consistency if the type has explicit ownership qualification.
 227   if (Res->getType().getObjCLifetime())
 228     checkPropertyDeclWithOwnership(*this, Res);
 229
 230   llvm::SmallPtrSet<ObjCProtocolDecl *, 16> KnownProtos;
 231   if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
 232     // For a class, compare the property against a property in our superclass.
 233     bool FoundInSuper = false;
 234     ObjCInterfaceDecl *CurrentInterfaceDecl = IFace;
 235     while (ObjCInterfaceDecl *Super = CurrentInterfaceDecl->getSuperClass()) {
 236       DeclContext::lookup_result R = Super->lookup(Res->getDeclName());
 237       for (unsigned I = 0, N = R.size(); I != N; ++I) {
 238         if (ObjCPropertyDecl *SuperProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
 239           DiagnosePropertyMismatch(Res, SuperProp, Super->getIdentifier(), false);
 240           FoundInSuper = true;
 241           break;
 242         }
 243       }
 244       if (FoundInSuper)
 245         break;
 246       else
 247         CurrentInterfaceDecl = Super;
 248     }
 249
 250     if (FoundInSuper) {
 251       // Also compare the property against a property in our protocols.
 252       for (auto *P : CurrentInterfaceDecl->protocols()) {
 253         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 254       }
 255     } else {
 256       // Slower path: look in all protocols we referenced.
 257       for (auto *P : IFace->all_referenced_protocols()) {
 258         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 259       }
 260     }
 261   } else if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
 262     // We don't check if class extension. Because properties in class extension
 263     // are meant to override some of the attributes and checking has already done
 264     // when property in class extension is constructed.
 265     if (!Cat->IsClassExtension())
 266       for (auto *P : Cat->protocols())
 267         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 268   } else {
 269     ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(ClassDecl);
 270     for (auto *P : Proto->protocols())
 271       CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 272   }
 273
 274   ActOnDocumentableDecl(Res);
 275   return Res;
 276 }
 277
 278 static ObjCPropertyAttribute::Kind
 279 makePropertyAttributesAsWritten(unsigned Attributes) {
 280   unsigned attributesAsWritten = 0;
 281   if (Attributes & ObjCPropertyAttribute::kind_readonly)
 282     attributesAsWritten |= ObjCPropertyAttribute::kind_readonly;
 283   if (Attributes & ObjCPropertyAttribute::kind_readwrite)
 284     attributesAsWritten |= ObjCPropertyAttribute::kind_readwrite;
 285   if (Attributes & ObjCPropertyAttribute::kind_getter)
 286     attributesAsWritten |= ObjCPropertyAttribute::kind_getter;
 287   if (Attributes & ObjCPropertyAttribute::kind_setter)
 288     attributesAsWritten |= ObjCPropertyAttribute::kind_setter;
 289   if (Attributes & ObjCPropertyAttribute::kind_assign)
 290     attributesAsWritten |= ObjCPropertyAttribute::kind_assign;
 291   if (Attributes & ObjCPropertyAttribute::kind_retain)
 292     attributesAsWritten |= ObjCPropertyAttribute::kind_retain;
 293   if (Attributes & ObjCPropertyAttribute::kind_strong)
 294     attributesAsWritten |= ObjCPropertyAttribute::kind_strong;
 295   if (Attributes & ObjCPropertyAttribute::kind_weak)
 296     attributesAsWritten |= ObjCPropertyAttribute::kind_weak;
 297   if (Attributes & ObjCPropertyAttribute::kind_copy)
 298     attributesAsWritten |= ObjCPropertyAttribute::kind_copy;
 299   if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
 300     attributesAsWritten |= ObjCPropertyAttribute::kind_unsafe_unretained;
 301   if (Attributes & ObjCPropertyAttribute::kind_nonatomic)
 302     attributesAsWritten |= ObjCPropertyAttribute::kind_nonatomic;
 303   if (Attributes & ObjCPropertyAttribute::kind_atomic)
 304     attributesAsWritten |= ObjCPropertyAttribute::kind_atomic;
 305   if (Attributes & ObjCPropertyAttribute::kind_class)
 306     attributesAsWritten |= ObjCPropertyAttribute::kind_class;
 307   if (Attributes & ObjCPropertyAttribute::kind_direct)
 308     attributesAsWritten |= ObjCPropertyAttribute::kind_direct;
 309
 310   return (ObjCPropertyAttribute::Kind)attributesAsWritten;
 311 }
 312
 313 static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
 314                                  SourceLocation LParenLoc, SourceLocation &Loc) {
 315   if (LParenLoc.isMacroID())
 316     return false;
 317
 318   SourceManager &SM = Context.getSourceManager();
 319   std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
 320   // Try to load the file buffer.
 321   bool invalidTemp = false;
 322   StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
 323   if (invalidTemp)
 324     return false;
 325   const char *tokenBegin = file.data() + locInfo.second;
 326
 327   // Lex from the start of the given location.
 328   Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
 329               Context.getLangOpts(),
 330               file.begin(), tokenBegin, file.end());
 331   Token Tok;
 332   do {
 333     lexer.LexFromRawLexer(Tok);
 334     if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
 335       Loc = Tok.getLocation();
 336       return true;
 337     }
 338   } while (Tok.isNot(tok::r_paren));
 339   return false;
 340 }
 341
 342 /// Check for a mismatch in the atomicity of the given properties.
 343 static void checkAtomicPropertyMismatch(Sema &S,
 344                                         ObjCPropertyDecl *OldProperty,
 345                                         ObjCPropertyDecl *NewProperty,
 346                                         bool PropagateAtomicity) {
 347   // If the atomicity of both matches, we're done.
 348   bool OldIsAtomic = (OldProperty->getPropertyAttributes() &
 349                       ObjCPropertyAttribute::kind_nonatomic) == 0;
 350   bool NewIsAtomic = (NewProperty->getPropertyAttributes() &
 351                       ObjCPropertyAttribute::kind_nonatomic) == 0;
 352   if (OldIsAtomic == NewIsAtomic) return;
 353
 354   // Determine whether the given property is readonly and implicitly
 355   // atomic.
 356   auto isImplicitlyReadonlyAtomic = [](ObjCPropertyDecl *Property) -> bool {
 357     // Is it readonly?
 358     auto Attrs = Property->getPropertyAttributes();
 359     if ((Attrs & ObjCPropertyAttribute::kind_readonly) == 0)
 360       return false;
 361
 362     // Is it nonatomic?
 363     if (Attrs & ObjCPropertyAttribute::kind_nonatomic)
 364       return false;
 365
 366     // Was 'atomic' specified directly?
 367     if (Property->getPropertyAttributesAsWritten() &
 368         ObjCPropertyAttribute::kind_atomic)
 369       return false;
 370
 371     return true;
 372   };
 373
 374   // If we're allowed to propagate atomicity, and the new property did
 375   // not specify atomicity at all, propagate.
 376   const unsigned AtomicityMask = (ObjCPropertyAttribute::kind_atomic |
 377                                   ObjCPropertyAttribute::kind_nonatomic);
 378   if (PropagateAtomicity &&
 379       ((NewProperty->getPropertyAttributesAsWritten() & AtomicityMask) == 0)) {
 380     unsigned Attrs = NewProperty->getPropertyAttributes();
 381     Attrs = Attrs & ~AtomicityMask;
 382     if (OldIsAtomic)
 383       Attrs |= ObjCPropertyAttribute::kind_atomic;
 384     else
 385       Attrs |= ObjCPropertyAttribute::kind_nonatomic;
 386
 387     NewProperty->overwritePropertyAttributes(Attrs);
 388     return;
 389   }
 390
 391   // One of the properties is atomic; if it's a readonly property, and
 392   // 'atomic' wasn't explicitly specified, we're okay.
 393   if ((OldIsAtomic && isImplicitlyReadonlyAtomic(OldProperty)) ||
 394       (NewIsAtomic && isImplicitlyReadonlyAtomic(NewProperty)))
 395     return;
 396
 397   // Diagnose the conflict.
 398   const IdentifierInfo *OldContextName;
 399   auto *OldDC = OldProperty->getDeclContext();
 400   if (auto Category = dyn_cast<ObjCCategoryDecl>(OldDC))
 401     OldContextName = Category->getClassInterface()->getIdentifier();
 402   else
 403     OldContextName = cast<ObjCContainerDecl>(OldDC)->getIdentifier();
 404
 405   S.Diag(NewProperty->getLocation(), diag::warn_property_attribute)
 406     << NewProperty->getDeclName() << "atomic"
 407     << OldContextName;
 408   S.Diag(OldProperty->getLocation(), diag::note_property_declare);
 409 }
 410
 411 ObjCPropertyDecl *
 412 Sema::HandlePropertyInClassExtension(Scope *S,
 413                                      SourceLocation AtLoc,
 414                                      SourceLocation LParenLoc,
 415                                      FieldDeclarator &FD,
 416                                      Selector GetterSel,
 417                                      SourceLocation GetterNameLoc,
 418                                      Selector SetterSel,
 419                                      SourceLocation SetterNameLoc,
 420                                      const bool isReadWrite,
 421                                      unsigned &Attributes,
 422                                      const unsigned AttributesAsWritten,
 423                                      QualType T,
 424                                      TypeSourceInfo *TSI,
 425                                      tok::ObjCKeywordKind MethodImplKind) {
 426   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
 427   // Diagnose if this property is already in continuation class.
 428   DeclContext *DC = CurContext;
 429   IdentifierInfo *PropertyId = FD.D.getIdentifier();
 430   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
 431
 432   // We need to look in the @interface to see if the @property was
 433   // already declared.
 434   if (!CCPrimary) {
 435     Diag(CDecl->getLocation(), diag::err_continuation_class);
 436     return nullptr;
 437   }
 438
 439   bool isClassProperty =
 440       (AttributesAsWritten & ObjCPropertyAttribute::kind_class) ||
 441       (Attributes & ObjCPropertyAttribute::kind_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 & ObjCPropertyAttribute::kind_readwrite) &&
 467                   (PIDecl->getPropertyAttributesAsWritten() &
 468                    ObjCPropertyAttribute::kind_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 & ObjCPropertyAttribute::kind_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 |= ObjCPropertyAttribute::kind_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 & ObjCPropertyAttribute::kind_weak) &&
 508         !(PIDecl->getPropertyAttributesAsWritten() &
 509           ObjCPropertyAttribute::kind_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 & (ObjCPropertyAttribute::kind_assign |
 587                     ObjCPropertyAttribute::kind_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 && isAssign &&
 599       !(Attributes & ObjCPropertyAttribute::kind_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().getEndLoc();
 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().getBeginLoc();
 618     TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
 619   }
 620
 621   DeclContext *DC = CDecl;
 622   ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
 623                                                      FD.D.getIdentifierLoc(),
 624                                                      PropertyId, AtLoc,
 625                                                      LParenLoc, T, TInfo);
 626
 627   bool isClassProperty =
 628       (AttributesAsWritten & ObjCPropertyAttribute::kind_class) ||
 629       (Attributes & ObjCPropertyAttribute::kind_class);
 630   // Class property and instance property can have the same name.
 631   if (ObjCPropertyDecl *prevDecl = ObjCPropertyDecl::findPropertyDecl(
 632           DC, PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty))) {
 633     Diag(PDecl->getLocation(), diag::err_duplicate_property);
 634     Diag(prevDecl->getLocation(), diag::note_property_declare);
 635     PDecl->setInvalidDecl();
 636   }
 637   else {
 638     DC->addDecl(PDecl);
 639     if (lexicalDC)
 640       PDecl->setLexicalDeclContext(lexicalDC);
 641   }
 642
 643   if (T->isArrayType() || T->isFunctionType()) {
 644     Diag(AtLoc, diag::err_property_type) << T;
 645     PDecl->setInvalidDecl();
 646   }
 647
 648   ProcessDeclAttributes(S, PDecl, FD.D);
 649
 650   // Regardless of setter/getter attribute, we save the default getter/setter
 651   // selector names in anticipation of declaration of setter/getter methods.
 652   PDecl->setGetterName(GetterSel, GetterNameLoc);
 653   PDecl->setSetterName(SetterSel, SetterNameLoc);
 654   PDecl->setPropertyAttributesAsWritten(
 655                           makePropertyAttributesAsWritten(AttributesAsWritten));
 656
 657   if (Attributes & ObjCPropertyAttribute::kind_readonly)
 658     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_readonly);
 659
 660   if (Attributes & ObjCPropertyAttribute::kind_getter)
 661     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_getter);
 662
 663   if (Attributes & ObjCPropertyAttribute::kind_setter)
 664     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_setter);
 665
 666   if (isReadWrite)
 667     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_readwrite);
 668
 669   if (Attributes & ObjCPropertyAttribute::kind_retain)
 670     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_retain);
 671
 672   if (Attributes & ObjCPropertyAttribute::kind_strong)
 673     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
 674
 675   if (Attributes & ObjCPropertyAttribute::kind_weak)
 676     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_weak);
 677
 678   if (Attributes & ObjCPropertyAttribute::kind_copy)
 679     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_copy);
 680
 681   if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
 682     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_unsafe_unretained);
 683
 684   if (isAssign)
 685     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_assign);
 686
 687   // In the semantic attributes, one of nonatomic or atomic is always set.
 688   if (Attributes & ObjCPropertyAttribute::kind_nonatomic)
 689     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_nonatomic);
 690   else
 691     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_atomic);
 692
 693   // 'unsafe_unretained' is alias for 'assign'.
 694   if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
 695     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_assign);
 696   if (isAssign)
 697     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_unsafe_unretained);
 698
 699   if (MethodImplKind == tok::objc_required)
 700     PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
 701   else if (MethodImplKind == tok::objc_optional)
 702     PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
 703
 704   if (Attributes & ObjCPropertyAttribute::kind_nullability)
 705     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_nullability);
 706
 707   if (Attributes & ObjCPropertyAttribute::kind_null_resettable)
 708     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_null_resettable);
 709
 710   if (Attributes & ObjCPropertyAttribute::kind_class)
 711     PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_class);
 712
 713   if ((Attributes & ObjCPropertyAttribute::kind_direct) ||
 714       CDecl->hasAttr<ObjCDirectMembersAttr>()) {
 715     if (isa<ObjCProtocolDecl>(CDecl)) {
 716       Diag(PDecl->getLocation(), diag::err_objc_direct_on_protocol) << true;
 717     } else if (getLangOpts().ObjCRuntime.allowsDirectDispatch()) {
 718       PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_direct);
 719     } else {
 720       Diag(PDecl->getLocation(), diag::warn_objc_direct_property_ignored)
 721           << PDecl->getDeclName();
 722     }
 723   }
 724
 725   return PDecl;
 726 }
 727
 728 static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
 729                                  ObjCPropertyDecl *property,
 730                                  ObjCIvarDecl *ivar) {
 731   if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;
 732
 733   QualType ivarType = ivar->getType();
 734   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
 735
 736   // The lifetime implied by the property's attributes.
 737   Qualifiers::ObjCLifetime propertyLifetime =
 738     getImpliedARCOwnership(property->getPropertyAttributes(),
 739                            property->getType());
 740
 741   // We're fine if they match.
 742   if (propertyLifetime == ivarLifetime) return;
 743
 744   // None isn't a valid lifetime for an object ivar in ARC, and
 745   // __autoreleasing is never valid; don't diagnose twice.
 746   if ((ivarLifetime == Qualifiers::OCL_None &&
 747        S.getLangOpts().ObjCAutoRefCount) ||
 748       ivarLifetime == Qualifiers::OCL_Autoreleasing)
 749     return;
 750
 751   // If the ivar is private, and it's implicitly __unsafe_unretained
 752   // because of its type, then pretend it was actually implicitly
 753   // __strong.  This is only sound because we're processing the
 754   // property implementation before parsing any method bodies.
 755   if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
 756       propertyLifetime == Qualifiers::OCL_Strong &&
 757       ivar->getAccessControl() == ObjCIvarDecl::Private) {
 758     SplitQualType split = ivarType.split();
 759     if (split.Quals.hasObjCLifetime()) {
 760       assert(ivarType->isObjCARCImplicitlyUnretainedType());
 761       split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
 762       ivarType = S.Context.getQualifiedType(split);
 763       ivar->setType(ivarType);
 764       return;
 765     }
 766   }
 767
 768   switch (propertyLifetime) {
 769   case Qualifiers::OCL_Strong:
 770     S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
 771       << property->getDeclName()
 772       << ivar->getDeclName()
 773       << ivarLifetime;
 774     break;
 775
 776   case Qualifiers::OCL_Weak:
 777     S.Diag(ivar->getLocation(), diag::err_weak_property)
 778       << property->getDeclName()
 779       << ivar->getDeclName();
 780     break;
 781
 782   case Qualifiers::OCL_ExplicitNone:
 783     S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
 784         << property->getDeclName() << ivar->getDeclName()
 785         << ((property->getPropertyAttributesAsWritten() &
 786              ObjCPropertyAttribute::kind_assign) != 0);
 787     break;
 788
 789   case Qualifiers::OCL_Autoreleasing:
 790     llvm_unreachable("properties cannot be autoreleasing");
 791
 792   case Qualifiers::OCL_None:
 793     // Any other property should be ignored.
 794     return;
 795   }
 796
 797   S.Diag(property->getLocation(), diag::note_property_declare);
 798   if (propertyImplLoc.isValid())
 799     S.Diag(propertyImplLoc, diag::note_property_synthesize);
 800 }
 801
 802 /// setImpliedPropertyAttributeForReadOnlyProperty -
 803 /// This routine evaludates life-time attributes for a 'readonly'
 804 /// property with no known lifetime of its own, using backing
 805 /// 'ivar's attribute, if any. If no backing 'ivar', property's
 806 /// life-time is assumed 'strong'.
 807 static void setImpliedPropertyAttributeForReadOnlyProperty(
 808               ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
 809   Qualifiers::ObjCLifetime propertyLifetime =
 810     getImpliedARCOwnership(property->getPropertyAttributes(),
 811                            property->getType());
 812   if (propertyLifetime != Qualifiers::OCL_None)
 813     return;
 814
 815   if (!ivar) {
 816     // if no backing ivar, make property 'strong'.
 817     property->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
 818     return;
 819   }
 820   // property assumes owenership of backing ivar.
 821   QualType ivarType = ivar->getType();
 822   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
 823   if (ivarLifetime == Qualifiers::OCL_Strong)
 824     property->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
 825   else if (ivarLifetime == Qualifiers::OCL_Weak)
 826     property->setPropertyAttributes(ObjCPropertyAttribute::kind_weak);
 827 }
 828
 829 static bool isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
 830                                             ObjCPropertyAttribute::Kind Kind) {
 831   return (Attr1 & Kind) != (Attr2 & Kind);
 832 }
 833
 834 static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
 835                                               unsigned Kinds) {
 836   return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
 837 }
 838
 839 /// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
 840 /// property declaration that should be synthesised in all of the inherited
 841 /// protocols. It also diagnoses properties declared in inherited protocols with
 842 /// mismatched types or attributes, since any of them can be candidate for
 843 /// synthesis.
 844 static ObjCPropertyDecl *
 845 SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
 846                                         ObjCInterfaceDecl *ClassDecl,
 847                                         ObjCPropertyDecl *Property) {
 848   assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&
 849          "Expected a property from a protocol");
 850   ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
 851   ObjCInterfaceDecl::PropertyDeclOrder Properties;
 852   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
 853     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 854       PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 855                                                 Properties);
 856   }
 857   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
 858     while (SDecl) {
 859       for (const auto *PI : SDecl->all_referenced_protocols()) {
 860         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 861           PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 862                                                     Properties);
 863       }
 864       SDecl = SDecl->getSuperClass();
 865     }
 866   }
 867
 868   if (Properties.empty())
 869     return Property;
 870
 871   ObjCPropertyDecl *OriginalProperty = Property;
 872   size_t SelectedIndex = 0;
 873   for (const auto &Prop : llvm::enumerate(Properties)) {
 874     // Select the 'readwrite' property if such property exists.
 875     if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
 876       Property = Prop.value();
 877       SelectedIndex = Prop.index();
 878     }
 879   }
 880   if (Property != OriginalProperty) {
 881     // Check that the old property is compatible with the new one.
 882     Properties[SelectedIndex] = OriginalProperty;
 883   }
 884
 885   QualType RHSType = S.Context.getCanonicalType(Property->getType());
 886   unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
 887   enum MismatchKind {
 888     IncompatibleType = 0,
 889     HasNoExpectedAttribute,
 890     HasUnexpectedAttribute,
 891     DifferentGetter,
 892     DifferentSetter
 893   };
 894   // Represents a property from another protocol that conflicts with the
 895   // selected declaration.
 896   struct MismatchingProperty {
 897     const ObjCPropertyDecl *Prop;
 898     MismatchKind Kind;
 899     StringRef AttributeName;
 900   };
 901   SmallVector<MismatchingProperty, 4> Mismatches;
 902   for (ObjCPropertyDecl *Prop : Properties) {
 903     // Verify the property attributes.
 904     unsigned Attr = Prop->getPropertyAttributesAsWritten();
 905     if (Attr != OriginalAttributes) {
 906       auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
 907         MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
 908                                                  : HasUnexpectedAttribute;
 909         Mismatches.push_back({Prop, Kind, AttributeName});
 910       };
 911       // The ownership might be incompatible unless the property has no explicit
 912       // ownership.
 913       bool HasOwnership =
 914           (Attr & (ObjCPropertyAttribute::kind_retain |
 915                    ObjCPropertyAttribute::kind_strong |
 916                    ObjCPropertyAttribute::kind_copy |
 917                    ObjCPropertyAttribute::kind_assign |
 918                    ObjCPropertyAttribute::kind_unsafe_unretained |
 919                    ObjCPropertyAttribute::kind_weak)) != 0;
 920       if (HasOwnership &&
 921           isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 922                                           ObjCPropertyAttribute::kind_copy)) {
 923         Diag(OriginalAttributes & ObjCPropertyAttribute::kind_copy, "copy");
 924         continue;
 925       }
 926       if (HasOwnership && areIncompatiblePropertyAttributes(
 927                               OriginalAttributes, Attr,
 928                               ObjCPropertyAttribute::kind_retain |
 929                                   ObjCPropertyAttribute::kind_strong)) {
 930         Diag(OriginalAttributes & (ObjCPropertyAttribute::kind_retain |
 931                                    ObjCPropertyAttribute::kind_strong),
 932              "retain (or strong)");
 933         continue;
 934       }
 935       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 936                                           ObjCPropertyAttribute::kind_atomic)) {
 937         Diag(OriginalAttributes & ObjCPropertyAttribute::kind_atomic, "atomic");
 938         continue;
 939       }
 940     }
 941     if (Property->getGetterName() != Prop->getGetterName()) {
 942       Mismatches.push_back({Prop, DifferentGetter, ""});
 943       continue;
 944     }
 945     if (!Property->isReadOnly() && !Prop->isReadOnly() &&
 946         Property->getSetterName() != Prop->getSetterName()) {
 947       Mismatches.push_back({Prop, DifferentSetter, ""});
 948       continue;
 949     }
 950     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
 951     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
 952       bool IncompatibleObjC = false;
 953       QualType ConvertedType;
 954       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
 955           || IncompatibleObjC) {
 956         Mismatches.push_back({Prop, IncompatibleType, ""});
 957         continue;
 958       }
 959     }
 960   }
 961
 962   if (Mismatches.empty())
 963     return Property;
 964
 965   // Diagnose incompability.
 966   {
 967     bool HasIncompatibleAttributes = false;
 968     for (const auto &Note : Mismatches)
 969       HasIncompatibleAttributes =
 970           Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
 971     // Promote the warning to an error if there are incompatible attributes or
 972     // incompatible types together with readwrite/readonly incompatibility.
 973     auto Diag = S.Diag(Property->getLocation(),
 974                        Property != OriginalProperty || HasIncompatibleAttributes
 975                            ? diag::err_protocol_property_mismatch
 976                            : diag::warn_protocol_property_mismatch);
 977     Diag << Mismatches[0].Kind;
 978     switch (Mismatches[0].Kind) {
 979     case IncompatibleType:
 980       Diag << Property->getType();
 981       break;
 982     case HasNoExpectedAttribute:
 983     case HasUnexpectedAttribute:
 984       Diag << Mismatches[0].AttributeName;
 985       break;
 986     case DifferentGetter:
 987       Diag << Property->getGetterName();
 988       break;
 989     case DifferentSetter:
 990       Diag << Property->getSetterName();
 991       break;
 992     }
 993   }
 994   for (const auto &Note : Mismatches) {
 995     auto Diag =
 996         S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
 997         << Note.Kind;
 998     switch (Note.Kind) {
 999     case IncompatibleType:
1000       Diag << Note.Prop->getType();
1001       break;
1002     case HasNoExpectedAttribute:
1003     case HasUnexpectedAttribute:
1004       Diag << Note.AttributeName;
1005       break;
1006     case DifferentGetter:
1007       Diag << Note.Prop->getGetterName();
1008       break;
1009     case DifferentSetter:
1010       Diag << Note.Prop->getSetterName();
1011       break;
1012     }
1013   }
1014   if (AtLoc.isValid())
1015     S.Diag(AtLoc, diag::note_property_synthesize);
1016
1017   return Property;
1018 }
1019
1020 /// Determine whether any storage attributes were written on the property.
1021 static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
1022                                        ObjCPropertyQueryKind QueryKind) {
1023   if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;
1024
1025   // If this is a readwrite property in a class extension that refines
1026   // a readonly property in the original class definition, check it as
1027   // well.
1028
1029   // If it's a readonly property, we're not interested.
1030   if (Prop->isReadOnly()) return false;
1031
1032   // Is it declared in an extension?
1033   auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
1034   if (!Category || !Category->IsClassExtension()) return false;
1035
1036   // Find the corresponding property in the primary class definition.
1037   auto OrigClass = Category->getClassInterface();
1038   for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
1039     if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
1040       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1041   }
1042
1043   // Look through all of the protocols.
1044   for (const auto *Proto : OrigClass->all_referenced_protocols()) {
1045     if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
1046             Prop->getIdentifier(), QueryKind))
1047       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1048   }
1049
1050   return false;
1051 }
1052
1053 /// Create a synthesized property accessor stub inside the \@implementation.
1054 static ObjCMethodDecl *
1055 RedeclarePropertyAccessor(ASTContext &Context, ObjCImplementationDecl *Impl,
1056                           ObjCMethodDecl *AccessorDecl, SourceLocation AtLoc,
1057                           SourceLocation PropertyLoc) {
1058   ObjCMethodDecl *Decl = AccessorDecl;
1059   ObjCMethodDecl *ImplDecl = ObjCMethodDecl::Create(
1060       Context, AtLoc.isValid() ? AtLoc : Decl->getBeginLoc(),
1061       PropertyLoc.isValid() ? PropertyLoc : Decl->getEndLoc(),
1062       Decl->getSelector(), Decl->getReturnType(),
1063       Decl->getReturnTypeSourceInfo(), Impl, Decl->isInstanceMethod(),
1064       Decl->isVariadic(), Decl->isPropertyAccessor(),
1065       /* isSynthesized*/ true, Decl->isImplicit(), Decl->isDefined(),
1066       Decl->getImplementationControl(), Decl->hasRelatedResultType());
1067   ImplDecl->getMethodFamily();
1068   if (Decl->hasAttrs())
1069     ImplDecl->setAttrs(Decl->getAttrs());
1070   ImplDecl->setSelfDecl(Decl->getSelfDecl());
1071   ImplDecl->setCmdDecl(Decl->getCmdDecl());
1072   SmallVector<SourceLocation, 1> SelLocs;
1073   Decl->getSelectorLocs(SelLocs);
1074   ImplDecl->setMethodParams(Context, Decl->parameters(), SelLocs);
1075   ImplDecl->setLexicalDeclContext(Impl);
1076   ImplDecl->setDefined(false);
1077   return ImplDecl;
1078 }
1079
1080 /// ActOnPropertyImplDecl - This routine performs semantic checks and
1081 /// builds the AST node for a property implementation declaration; declared
1082 /// as \@synthesize or \@dynamic.
1083 ///
1084 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
1085                                   SourceLocation AtLoc,
1086                                   SourceLocation PropertyLoc,
1087                                   bool Synthesize,
1088                                   IdentifierInfo *PropertyId,
1089                                   IdentifierInfo *PropertyIvar,
1090                                   SourceLocation PropertyIvarLoc,
1091                                   ObjCPropertyQueryKind QueryKind) {
1092   ObjCContainerDecl *ClassImpDecl =
1093     dyn_cast<ObjCContainerDecl>(CurContext);
1094   // Make sure we have a context for the property implementation declaration.
1095   if (!ClassImpDecl) {
1096     Diag(AtLoc, diag::err_missing_property_context);
1097     return nullptr;
1098   }
1099   if (PropertyIvarLoc.isInvalid())
1100     PropertyIvarLoc = PropertyLoc;
1101   SourceLocation PropertyDiagLoc = PropertyLoc;
1102   if (PropertyDiagLoc.isInvalid())
1103     PropertyDiagLoc = ClassImpDecl->getBeginLoc();
1104   ObjCPropertyDecl *property = nullptr;
1105   ObjCInterfaceDecl *IDecl = nullptr;
1106   // Find the class or category class where this property must have
1107   // a declaration.
1108   ObjCImplementationDecl *IC = nullptr;
1109   ObjCCategoryImplDecl *CatImplClass = nullptr;
1110   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
1111     IDecl = IC->getClassInterface();
1112     // We always synthesize an interface for an implementation
1113     // without an interface decl. So, IDecl is always non-zero.
1114     assert(IDecl &&
1115            "ActOnPropertyImplDecl - @implementation without @interface");
1116
1117     // Look for this property declaration in the @implementation's @interface
1118     property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
1119     if (!property) {
1120       Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
1121       return nullptr;
1122     }
1123     if (property->isClassProperty() && Synthesize) {
1124       Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
1125       return nullptr;
1126     }
1127     unsigned PIkind = property->getPropertyAttributesAsWritten();
1128     if ((PIkind & (ObjCPropertyAttribute::kind_atomic |
1129                    ObjCPropertyAttribute::kind_nonatomic)) == 0) {
1130       if (AtLoc.isValid())
1131         Diag(AtLoc, diag::warn_implicit_atomic_property);
1132       else
1133         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
1134       Diag(property->getLocation(), diag::note_property_declare);
1135     }
1136
1137     if (const ObjCCategoryDecl *CD =
1138         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
1139       if (!CD->IsClassExtension()) {
1140         Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
1141         Diag(property->getLocation(), diag::note_property_declare);
1142         return nullptr;
1143       }
1144     }
1145     if (Synthesize && (PIkind & ObjCPropertyAttribute::kind_readonly) &&
1146         property->hasAttr<IBOutletAttr>() && !AtLoc.isValid()) {
1147       bool ReadWriteProperty = false;
1148       // Search into the class extensions and see if 'readonly property is
1149       // redeclared 'readwrite', then no warning is to be issued.
1150       for (auto *Ext : IDecl->known_extensions()) {
1151         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
1152         if (!R.empty())
1153           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
1154             PIkind = ExtProp->getPropertyAttributesAsWritten();
1155             if (PIkind & ObjCPropertyAttribute::kind_readwrite) {
1156               ReadWriteProperty = true;
1157               break;
1158             }
1159           }
1160       }
1161
1162       if (!ReadWriteProperty) {
1163         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
1164             << property;
1165         SourceLocation readonlyLoc;
1166         if (LocPropertyAttribute(Context, "readonly",
1167                                  property->getLParenLoc(), readonlyLoc)) {
1168           SourceLocation endLoc =
1169             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
1170           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
1171           Diag(property->getLocation(),
1172                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
1173           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
1174         }
1175       }
1176     }
1177     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
1178       property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
1179                                                          property);
1180
1181   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
1182     if (Synthesize) {
1183       Diag(AtLoc, diag::err_synthesize_category_decl);
1184       return nullptr;
1185     }
1186     IDecl = CatImplClass->getClassInterface();
1187     if (!IDecl) {
1188       Diag(AtLoc, diag::err_missing_property_interface);
1189       return nullptr;
1190     }
1191     ObjCCategoryDecl *Category =
1192     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
1193
1194     // If category for this implementation not found, it is an error which
1195     // has already been reported eralier.
1196     if (!Category)
1197       return nullptr;
1198     // Look for this property declaration in @implementation's category
1199     property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
1200     if (!property) {
1201       Diag(PropertyLoc, diag::err_bad_category_property_decl)
1202       << Category->getDeclName();
1203       return nullptr;
1204     }
1205   } else {
1206     Diag(AtLoc, diag::err_bad_property_context);
1207     return nullptr;
1208   }
1209   ObjCIvarDecl *Ivar = nullptr;
1210   bool CompleteTypeErr = false;
1211   bool compat = true;
1212   // Check that we have a valid, previously declared ivar for @synthesize
1213   if (Synthesize) {
1214     // @synthesize
1215     if (!PropertyIvar)
1216       PropertyIvar = PropertyId;
1217     // Check that this is a previously declared 'ivar' in 'IDecl' interface
1218     ObjCInterfaceDecl *ClassDeclared;
1219     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
1220     QualType PropType = property->getType();
1221     QualType PropertyIvarType = PropType.getNonReferenceType();
1222
1223     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
1224                             diag::err_incomplete_synthesized_property,
1225                             property->getDeclName())) {
1226       Diag(property->getLocation(), diag::note_property_declare);
1227       CompleteTypeErr = true;
1228     }
1229
1230     if (getLangOpts().ObjCAutoRefCount &&
1231         (property->getPropertyAttributesAsWritten() &
1232          ObjCPropertyAttribute::kind_readonly) &&
1233         PropertyIvarType->isObjCRetainableType()) {
1234       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
1235     }
1236
1237     ObjCPropertyAttribute::Kind kind = property->getPropertyAttributes();
1238
1239     bool isARCWeak = false;
1240     if (kind & ObjCPropertyAttribute::kind_weak) {
1241       // Add GC __weak to the ivar type if the property is weak.
1242       if (getLangOpts().getGC() != LangOptions::NonGC) {
1243         assert(!getLangOpts().ObjCAutoRefCount);
1244         if (PropertyIvarType.isObjCGCStrong()) {
1245           Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
1246           Diag(property->getLocation(), diag::note_property_declare);
1247         } else {
1248           PropertyIvarType =
1249             Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
1250         }
1251
1252       // Otherwise, check whether ARC __weak is enabled and works with
1253       // the property type.
1254       } else {
1255         if (!getLangOpts().ObjCWeak) {
1256           // Only complain here when synthesizing an ivar.
1257           if (!Ivar) {
1258             Diag(PropertyDiagLoc,
1259                  getLangOpts().ObjCWeakRuntime
1260                    ? diag::err_synthesizing_arc_weak_property_disabled
1261                    : diag::err_synthesizing_arc_weak_property_no_runtime);
1262             Diag(property->getLocation(), diag::note_property_declare);
1263           }
1264           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1265         } else {
1266           isARCWeak = true;
1267           if (const ObjCObjectPointerType *ObjT =
1268                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1269             const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1270             if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1271               Diag(property->getLocation(),
1272                    diag::err_arc_weak_unavailable_property)
1273                 << PropertyIvarType;
1274               Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1275                 << ClassImpDecl->getName();
1276             }
1277           }
1278         }
1279       }
1280     }
1281
1282     if (AtLoc.isInvalid()) {
1283       // Check when default synthesizing a property that there is
1284       // an ivar matching property name and issue warning; since this
1285       // is the most common case of not using an ivar used for backing
1286       // property in non-default synthesis case.
1287       ObjCInterfaceDecl *ClassDeclared=nullptr;
1288       ObjCIvarDecl *originalIvar =
1289       IDecl->lookupInstanceVariable(property->getIdentifier(),
1290                                     ClassDeclared);
1291       if (originalIvar) {
1292         Diag(PropertyDiagLoc,
1293              diag::warn_autosynthesis_property_ivar_match)
1294         << PropertyId << (Ivar == nullptr) << PropertyIvar
1295         << originalIvar->getIdentifier();
1296         Diag(property->getLocation(), diag::note_property_declare);
1297         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
1298       }
1299     }
1300
1301     if (!Ivar) {
1302       // In ARC, give the ivar a lifetime qualifier based on the
1303       // property attributes.
1304       if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
1305           !PropertyIvarType.getObjCLifetime() &&
1306           PropertyIvarType->isObjCRetainableType()) {
1307
1308         // It's an error if we have to do this and the user didn't
1309         // explicitly write an ownership attribute on the property.
1310         if (!hasWrittenStorageAttribute(property, QueryKind) &&
1311             !(kind & ObjCPropertyAttribute::kind_strong)) {
1312           Diag(PropertyDiagLoc,
1313                diag::err_arc_objc_property_default_assign_on_object);
1314           Diag(property->getLocation(), diag::note_property_declare);
1315         } else {
1316           Qualifiers::ObjCLifetime lifetime =
1317             getImpliedARCOwnership(kind, PropertyIvarType);
1318           assert(lifetime && "no lifetime for property?");
1319
1320           Qualifiers qs;
1321           qs.addObjCLifetime(lifetime);
1322           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1323         }
1324       }
1325
1326       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1327                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1328                                   PropertyIvarType, /*TInfo=*/nullptr,
1329                                   ObjCIvarDecl::Private,
1330                                   (Expr *)nullptr, true);
1331       if (RequireNonAbstractType(PropertyIvarLoc,
1332                                  PropertyIvarType,
1333                                  diag::err_abstract_type_in_decl,
1334                                  AbstractSynthesizedIvarType)) {
1335         Diag(property->getLocation(), diag::note_property_declare);
1336         // An abstract type is as bad as an incomplete type.
1337         CompleteTypeErr = true;
1338       }
1339       if (!CompleteTypeErr) {
1340         const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
1341         if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
1342           Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
1343             << PropertyIvarType;
1344           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1345         }
1346       }
1347       if (CompleteTypeErr)
1348         Ivar->setInvalidDecl();
1349       ClassImpDecl->addDecl(Ivar);
1350       IDecl->makeDeclVisibleInContext(Ivar);
1351
1352       if (getLangOpts().ObjCRuntime.isFragile())
1353         Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
1354             << PropertyId;
1355       // Note! I deliberately want it to fall thru so, we have a
1356       // a property implementation and to avoid future warnings.
1357     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1358                !declaresSameEntity(ClassDeclared, IDecl)) {
1359       Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
1360       << property->getDeclName() << Ivar->getDeclName()
1361       << ClassDeclared->getDeclName();
1362       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1363       << Ivar << Ivar->getName();
1364       // Note! I deliberately want it to fall thru so more errors are caught.
1365     }
1366     property->setPropertyIvarDecl(Ivar);
1367
1368     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1369
1370     // Check that type of property and its ivar are type compatible.
1371     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1372       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1373           && isa<ObjCObjectPointerType>(IvarType))
1374         compat =
1375           Context.canAssignObjCInterfaces(
1376                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1377                                   IvarType->getAs<ObjCObjectPointerType>());
1378       else {
1379         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1380                                              IvarType)
1381                     == Compatible);
1382       }
1383       if (!compat) {
1384         Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1385           << property->getDeclName() << PropType
1386           << Ivar->getDeclName() << IvarType;
1387         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1388         // Note! I deliberately want it to fall thru so, we have a
1389         // a property implementation and to avoid future warnings.
1390       }
1391       else {
1392         // FIXME! Rules for properties are somewhat different that those
1393         // for assignments. Use a new routine to consolidate all cases;
1394         // specifically for property redeclarations as well as for ivars.
1395         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1396         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1397         if (lhsType != rhsType &&
1398             lhsType->isArithmeticType()) {
1399           Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1400             << property->getDeclName() << PropType
1401             << Ivar->getDeclName() << IvarType;
1402           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1403           // Fall thru - see previous comment
1404         }
1405       }
1406       // __weak is explicit. So it works on Canonical type.
1407       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1408            getLangOpts().getGC() != LangOptions::NonGC)) {
1409         Diag(PropertyDiagLoc, diag::err_weak_property)
1410         << property->getDeclName() << Ivar->getDeclName();
1411         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1412         // Fall thru - see previous comment
1413       }
1414       // Fall thru - see previous comment
1415       if ((property->getType()->isObjCObjectPointerType() ||
1416            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1417           getLangOpts().getGC() != LangOptions::NonGC) {
1418         Diag(PropertyDiagLoc, diag::err_strong_property)
1419         << property->getDeclName() << Ivar->getDeclName();
1420         // Fall thru - see previous comment
1421       }
1422     }
1423     if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
1424         Ivar->getType().getObjCLifetime())
1425       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1426   } else if (PropertyIvar)
1427     // @dynamic
1428     Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);
1429
1430   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1431   ObjCPropertyImplDecl *PIDecl =
1432   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1433                                property,
1434                                (Synthesize ?
1435                                 ObjCPropertyImplDecl::Synthesize
1436                                 : ObjCPropertyImplDecl::Dynamic),
1437                                Ivar, PropertyIvarLoc);
1438
1439   if (CompleteTypeErr || !compat)
1440     PIDecl->setInvalidDecl();
1441
1442   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1443     getterMethod->createImplicitParams(Context, IDecl);
1444
1445     // Redeclare the getter within the implementation as DeclContext.
1446     if (Synthesize) {
1447       // If the method hasn't been overridden, create a synthesized implementation.
1448       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1449           getterMethod->getSelector(), getterMethod->isInstanceMethod());
1450       if (!OMD)
1451         OMD = RedeclarePropertyAccessor(Context, IC, getterMethod, AtLoc,
1452                                         PropertyLoc);
1453       PIDecl->setGetterMethodDecl(OMD);
1454     }
1455
1456     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1457         Ivar->getType()->isRecordType()) {
1458       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1459       // returned by the getter as it must conform to C++'s copy-return rules.
1460       // FIXME. Eventually we want to do this for Objective-C as well.
1461       SynthesizedFunctionScope Scope(*this, getterMethod);
1462       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1463       DeclRefExpr *SelfExpr = new (Context)
1464           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1465                       PropertyDiagLoc);
1466       MarkDeclRefReferenced(SelfExpr);
1467       Expr *LoadSelfExpr =
1468         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1469                                  CK_LValueToRValue, SelfExpr, nullptr,
1470                                  VK_RValue);
1471       Expr *IvarRefExpr =
1472         new (Context) ObjCIvarRefExpr(Ivar,
1473                                       Ivar->getUsageType(SelfDecl->getType()),
1474                                       PropertyDiagLoc,
1475                                       Ivar->getLocation(),
1476                                       LoadSelfExpr, true, true);
1477       ExprResult Res = PerformCopyInitialization(
1478           InitializedEntity::InitializeResult(PropertyDiagLoc,
1479                                               getterMethod->getReturnType(),
1480                                               /*NRVO=*/false),
1481           PropertyDiagLoc, IvarRefExpr);
1482       if (!Res.isInvalid()) {
1483         Expr *ResExpr = Res.getAs<Expr>();
1484         if (ResExpr)
1485           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1486         PIDecl->setGetterCXXConstructor(ResExpr);
1487       }
1488     }
1489     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1490         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1491       Diag(getterMethod->getLocation(),
1492            diag::warn_property_getter_owning_mismatch);
1493       Diag(property->getLocation(), diag::note_property_declare);
1494     }
1495     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1496       switch (getterMethod->getMethodFamily()) {
1497         case OMF_retain:
1498         case OMF_retainCount:
1499         case OMF_release:
1500         case OMF_autorelease:
1501           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1502             << 1 << getterMethod->getSelector();
1503           break;
1504         default:
1505           break;
1506       }
1507   }
1508
1509   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1510     setterMethod->createImplicitParams(Context, IDecl);
1511
1512     // Redeclare the setter within the implementation as DeclContext.
1513     if (Synthesize) {
1514       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1515           setterMethod->getSelector(), setterMethod->isInstanceMethod());
1516       if (!OMD)
1517         OMD = RedeclarePropertyAccessor(Context, IC, setterMethod,
1518                                         AtLoc, PropertyLoc);
1519       PIDecl->setSetterMethodDecl(OMD);
1520     }
1521
1522     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1523         Ivar->getType()->isRecordType()) {
1524       // FIXME. Eventually we want to do this for Objective-C as well.
1525       SynthesizedFunctionScope Scope(*this, setterMethod);
1526       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1527       DeclRefExpr *SelfExpr = new (Context)
1528           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1529                       PropertyDiagLoc);
1530       MarkDeclRefReferenced(SelfExpr);
1531       Expr *LoadSelfExpr =
1532         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1533                                  CK_LValueToRValue, SelfExpr, nullptr,
1534                                  VK_RValue);
1535       Expr *lhs =
1536         new (Context) ObjCIvarRefExpr(Ivar,
1537                                       Ivar->getUsageType(SelfDecl->getType()),
1538                                       PropertyDiagLoc,
1539                                       Ivar->getLocation(),
1540                                       LoadSelfExpr, true, true);
1541       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1542       ParmVarDecl *Param = (*P);
1543       QualType T = Param->getType().getNonReferenceType();
1544       DeclRefExpr *rhs = new (Context)
1545           DeclRefExpr(Context, Param, false, T, VK_LValue, PropertyDiagLoc);
1546       MarkDeclRefReferenced(rhs);
1547       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1548                                   BO_Assign, lhs, rhs);
1549       if (property->getPropertyAttributes() &
1550           ObjCPropertyAttribute::kind_atomic) {
1551         Expr *callExpr = Res.getAs<Expr>();
1552         if (const CXXOperatorCallExpr *CXXCE =
1553               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1554           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1555             if (!FuncDecl->isTrivial())
1556               if (property->getType()->isReferenceType()) {
1557                 Diag(PropertyDiagLoc,
1558                      diag::err_atomic_property_nontrivial_assign_op)
1559                     << property->getType();
1560                 Diag(FuncDecl->getBeginLoc(), diag::note_callee_decl)
1561                     << FuncDecl;
1562               }
1563       }
1564       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1565     }
1566   }
1567
1568   if (IC) {
1569     if (Synthesize)
1570       if (ObjCPropertyImplDecl *PPIDecl =
1571           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1572         Diag(PropertyLoc, diag::err_duplicate_ivar_use)
1573         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1574         << PropertyIvar;
1575         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1576       }
1577
1578     if (ObjCPropertyImplDecl *PPIDecl
1579         = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
1580       Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
1581       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1582       return nullptr;
1583     }
1584     IC->addPropertyImplementation(PIDecl);
1585     if (getLangOpts().ObjCDefaultSynthProperties &&
1586         getLangOpts().ObjCRuntime.isNonFragile() &&
1587         !IDecl->isObjCRequiresPropertyDefs()) {
1588       // Diagnose if an ivar was lazily synthesdized due to a previous
1589       // use and if 1) property is @dynamic or 2) property is synthesized
1590       // but it requires an ivar of different name.
1591       ObjCInterfaceDecl *ClassDeclared=nullptr;
1592       ObjCIvarDecl *Ivar = nullptr;
1593       if (!Synthesize)
1594         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1595       else {
1596         if (PropertyIvar && PropertyIvar != PropertyId)
1597           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1598       }
1599       // Issue diagnostics only if Ivar belongs to current class.
1600       if (Ivar && Ivar->getSynthesize() &&
1601           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1602         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1603         << PropertyId;
1604         Ivar->setInvalidDecl();
1605       }
1606     }
1607   } else {
1608     if (Synthesize)
1609       if (ObjCPropertyImplDecl *PPIDecl =
1610           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1611         Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
1612         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1613         << PropertyIvar;
1614         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1615       }
1616
1617     if (ObjCPropertyImplDecl *PPIDecl =
1618         CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
1619       Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
1620       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1621       return nullptr;
1622     }
1623     CatImplClass->addPropertyImplementation(PIDecl);
1624   }
1625
1626   if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic &&
1627       PIDecl->getPropertyDecl() &&
1628       PIDecl->getPropertyDecl()->isDirectProperty()) {
1629     Diag(PropertyLoc, diag::err_objc_direct_dynamic_property);
1630     Diag(PIDecl->getPropertyDecl()->getLocation(),
1631          diag::note_previous_declaration);
1632     return nullptr;
1633   }
1634
1635   return PIDecl;
1636 }
1637
1638 //===----------------------------------------------------------------------===//
1639 // Helper methods.
1640 //===----------------------------------------------------------------------===//
1641
1642 /// DiagnosePropertyMismatch - Compares two properties for their
1643 /// attributes and types and warns on a variety of inconsistencies.
1644 ///
1645 void
1646 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1647                                ObjCPropertyDecl *SuperProperty,
1648                                const IdentifierInfo *inheritedName,
1649                                bool OverridingProtocolProperty) {
1650   ObjCPropertyAttribute::Kind CAttr = Property->getPropertyAttributes();
1651   ObjCPropertyAttribute::Kind SAttr = SuperProperty->getPropertyAttributes();
1652
1653   // We allow readonly properties without an explicit ownership
1654   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1655   // to be overridden by a property with any explicit ownership in the subclass.
1656   if (!OverridingProtocolProperty &&
1657       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1658     ;
1659   else {
1660     if ((CAttr & ObjCPropertyAttribute::kind_readonly) &&
1661         (SAttr & ObjCPropertyAttribute::kind_readwrite))
1662       Diag(Property->getLocation(), diag::warn_readonly_property)
1663         << Property->getDeclName() << inheritedName;
1664     if ((CAttr & ObjCPropertyAttribute::kind_copy) !=
1665         (SAttr & ObjCPropertyAttribute::kind_copy))
1666       Diag(Property->getLocation(), diag::warn_property_attribute)
1667         << Property->getDeclName() << "copy" << inheritedName;
1668     else if (!(SAttr & ObjCPropertyAttribute::kind_readonly)) {
1669       unsigned CAttrRetain = (CAttr & (ObjCPropertyAttribute::kind_retain |
1670                                        ObjCPropertyAttribute::kind_strong));
1671       unsigned SAttrRetain = (SAttr & (ObjCPropertyAttribute::kind_retain |
1672                                        ObjCPropertyAttribute::kind_strong));
1673       bool CStrong = (CAttrRetain != 0);
1674       bool SStrong = (SAttrRetain != 0);
1675       if (CStrong != SStrong)
1676         Diag(Property->getLocation(), diag::warn_property_attribute)
1677           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1678     }
1679   }
1680
1681   // Check for nonatomic; note that nonatomic is effectively
1682   // meaningless for readonly properties, so don't diagnose if the
1683   // atomic property is 'readonly'.
1684   checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
1685   // Readonly properties from protocols can be implemented as "readwrite"
1686   // with a custom setter name.
1687   if (Property->getSetterName() != SuperProperty->getSetterName() &&
1688       !(SuperProperty->isReadOnly() &&
1689         isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
1690     Diag(Property->getLocation(), diag::warn_property_attribute)
1691       << Property->getDeclName() << "setter" << inheritedName;
1692     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1693   }
1694   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1695     Diag(Property->getLocation(), diag::warn_property_attribute)
1696       << Property->getDeclName() << "getter" << inheritedName;
1697     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1698   }
1699
1700   QualType LHSType =
1701     Context.getCanonicalType(SuperProperty->getType());
1702   QualType RHSType =
1703     Context.getCanonicalType(Property->getType());
1704
1705   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1706     // Do cases not handled in above.
1707     // FIXME. For future support of covariant property types, revisit this.
1708     bool IncompatibleObjC = false;
1709     QualType ConvertedType;
1710     if (!isObjCPointerConversion(RHSType, LHSType,
1711                                  ConvertedType, IncompatibleObjC) ||
1712         IncompatibleObjC) {
1713         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1714         << Property->getType() << SuperProperty->getType() << inheritedName;
1715       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1716     }
1717   }
1718 }
1719
1720 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1721                                             ObjCMethodDecl *GetterMethod,
1722                                             SourceLocation Loc) {
1723   if (!GetterMethod)
1724     return false;
1725   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1726   QualType PropertyRValueType =
1727       property->getType().getNonReferenceType().getAtomicUnqualifiedType();
1728   bool compat = Context.hasSameType(PropertyRValueType, GetterType);
1729   if (!compat) {
1730     const ObjCObjectPointerType *propertyObjCPtr = nullptr;
1731     const ObjCObjectPointerType *getterObjCPtr = nullptr;
1732     if ((propertyObjCPtr =
1733              PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
1734         (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
1735       compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
1736     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
1737               != Compatible) {
1738           Diag(Loc, diag::err_property_accessor_type)
1739             << property->getDeclName() << PropertyRValueType
1740             << GetterMethod->getSelector() << GetterType;
1741           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1742           return true;
1743     } else {
1744       compat = true;
1745       QualType lhsType = Context.getCanonicalType(PropertyRValueType);
1746       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1747       if (lhsType != rhsType && lhsType->isArithmeticType())
1748         compat = false;
1749     }
1750   }
1751
1752   if (!compat) {
1753     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1754     << property->getDeclName()
1755     << GetterMethod->getSelector();
1756     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1757     return true;
1758   }
1759
1760   return false;
1761 }
1762
1763 /// CollectImmediateProperties - This routine collects all properties in
1764 /// the class and its conforming protocols; but not those in its super class.
1765 static void
1766 CollectImmediateProperties(ObjCContainerDecl *CDecl,
1767                            ObjCContainerDecl::PropertyMap &PropMap,
1768                            ObjCContainerDecl::PropertyMap &SuperPropMap,
1769                            bool CollectClassPropsOnly = false,
1770                            bool IncludeProtocols = true) {
1771   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1772     for (auto *Prop : IDecl->properties()) {
1773       if (CollectClassPropsOnly && !Prop->isClassProperty())
1774         continue;
1775       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1776           Prop;
1777     }
1778
1779     // Collect the properties from visible extensions.
1780     for (auto *Ext : IDecl->visible_extensions())
1781       CollectImmediateProperties(Ext, PropMap, SuperPropMap,
1782                                  CollectClassPropsOnly, IncludeProtocols);
1783
1784     if (IncludeProtocols) {
1785       // Scan through class's protocols.
1786       for (auto *PI : IDecl->all_referenced_protocols())
1787         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1788                                    CollectClassPropsOnly);
1789     }
1790   }
1791   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1792     for (auto *Prop : CATDecl->properties()) {
1793       if (CollectClassPropsOnly && !Prop->isClassProperty())
1794         continue;
1795       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1796           Prop;
1797     }
1798     if (IncludeProtocols) {
1799       // Scan through class's protocols.
1800       for (auto *PI : CATDecl->protocols())
1801         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1802                                    CollectClassPropsOnly);
1803     }
1804   }
1805   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1806     for (auto *Prop : PDecl->properties()) {
1807       if (CollectClassPropsOnly && !Prop->isClassProperty())
1808         continue;
1809       ObjCPropertyDecl *PropertyFromSuper =
1810           SuperPropMap[std::make_pair(Prop->getIdentifier(),
1811                                       Prop->isClassProperty())];
1812       // Exclude property for protocols which conform to class's super-class,
1813       // as super-class has to implement the property.
1814       if (!PropertyFromSuper ||
1815           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1816         ObjCPropertyDecl *&PropEntry =
1817             PropMap[std::make_pair(Prop->getIdentifier(),
1818                                    Prop->isClassProperty())];
1819         if (!PropEntry)
1820           PropEntry = Prop;
1821       }
1822     }
1823     // Scan through protocol's protocols.
1824     for (auto *PI : PDecl->protocols())
1825       CollectImmediateProperties(PI, PropMap, SuperPropMap,
1826                                  CollectClassPropsOnly);
1827   }
1828 }
1829
1830 /// CollectSuperClassPropertyImplementations - This routine collects list of
1831 /// properties to be implemented in super class(s) and also coming from their
1832 /// conforming protocols.
1833 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1834                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1835   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1836     ObjCInterfaceDecl::PropertyDeclOrder PO;
1837     while (SDecl) {
1838       SDecl->collectPropertiesToImplement(PropMap, PO);
1839       SDecl = SDecl->getSuperClass();
1840     }
1841   }
1842 }
1843
1844 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1845 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1846 /// declared in class 'IFace'.
1847 bool
1848 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1849                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1850   if (!IV->getSynthesize())
1851     return false;
1852   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1853                                             Method->isInstanceMethod());
1854   if (!IMD || !IMD->isPropertyAccessor())
1855     return false;
1856
1857   // look up a property declaration whose one of its accessors is implemented
1858   // by this method.
1859   for (const auto *Property : IFace->instance_properties()) {
1860     if ((Property->getGetterName() == IMD->getSelector() ||
1861          Property->getSetterName() == IMD->getSelector()) &&
1862         (Property->getPropertyIvarDecl() == IV))
1863       return true;
1864   }
1865   // Also look up property declaration in class extension whose one of its
1866   // accessors is implemented by this method.
1867   for (const auto *Ext : IFace->known_extensions())
1868     for (const auto *Property : Ext->instance_properties())
1869       if ((Property->getGetterName() == IMD->getSelector() ||
1870            Property->getSetterName() == IMD->getSelector()) &&
1871           (Property->getPropertyIvarDecl() == IV))
1872         return true;
1873   return false;
1874 }
1875
1876 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1877                                          ObjCPropertyDecl *Prop) {
1878   bool SuperClassImplementsGetter = false;
1879   bool SuperClassImplementsSetter = false;
1880   if (Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_readonly)
1881     SuperClassImplementsSetter = true;
1882
1883   while (IDecl->getSuperClass()) {
1884     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1885     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1886       SuperClassImplementsGetter = true;
1887
1888     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1889       SuperClassImplementsSetter = true;
1890     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1891       return true;
1892     IDecl = IDecl->getSuperClass();
1893   }
1894   return false;
1895 }
1896
1897 /// Default synthesizes all properties which must be synthesized
1898 /// in class's \@implementation.
1899 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
1900                                        ObjCInterfaceDecl *IDecl,
1901                                        SourceLocation AtEnd) {
1902   ObjCInterfaceDecl::PropertyMap PropMap;
1903   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1904   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1905   if (PropMap.empty())
1906     return;
1907   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1908   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1909
1910   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1911     ObjCPropertyDecl *Prop = PropertyOrder[i];
1912     // Is there a matching property synthesize/dynamic?
1913     if (Prop->isInvalidDecl() ||
1914         Prop->isClassProperty() ||
1915         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1916       continue;
1917     // Property may have been synthesized by user.
1918     if (IMPDecl->FindPropertyImplDecl(
1919             Prop->getIdentifier(), Prop->getQueryKind()))
1920       continue;
1921     ObjCMethodDecl *ImpMethod = IMPDecl->getInstanceMethod(Prop->getGetterName());
1922     if (ImpMethod && !ImpMethod->getBody()) {
1923       if (Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_readonly)
1924         continue;
1925       ImpMethod = IMPDecl->getInstanceMethod(Prop->getSetterName());
1926       if (ImpMethod && !ImpMethod->getBody())
1927         continue;
1928     }
1929     if (ObjCPropertyImplDecl *PID =
1930         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1931       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1932         << Prop->getIdentifier();
1933       if (PID->getLocation().isValid())
1934         Diag(PID->getLocation(), diag::note_property_synthesize);
1935       continue;
1936     }
1937     ObjCPropertyDecl *PropInSuperClass =
1938         SuperPropMap[std::make_pair(Prop->getIdentifier(),
1939                                     Prop->isClassProperty())];
1940     if (ObjCProtocolDecl *Proto =
1941           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1942       // We won't auto-synthesize properties declared in protocols.
1943       // Suppress the warning if class's superclass implements property's
1944       // getter and implements property's setter (if readwrite property).
1945       // Or, if property is going to be implemented in its super class.
1946       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1947         Diag(IMPDecl->getLocation(),
1948              diag::warn_auto_synthesizing_protocol_property)
1949           << Prop << Proto;
1950         Diag(Prop->getLocation(), diag::note_property_declare);
1951         std::string FixIt =
1952             (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
1953         Diag(AtEnd, diag::note_add_synthesize_directive)
1954             << FixItHint::CreateInsertion(AtEnd, FixIt);
1955       }
1956       continue;
1957     }
1958     // If property to be implemented in the super class, ignore.
1959     if (PropInSuperClass) {
1960       if ((Prop->getPropertyAttributes() &
1961            ObjCPropertyAttribute::kind_readwrite) &&
1962           (PropInSuperClass->getPropertyAttributes() &
1963            ObjCPropertyAttribute::kind_readonly) &&
1964           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1965           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1966         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1967         << Prop->getIdentifier();
1968         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1969       } else {
1970         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1971         << Prop->getIdentifier();
1972         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1973         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1974       }
1975       continue;
1976     }
1977     // We use invalid SourceLocations for the synthesized ivars since they
1978     // aren't really synthesized at a particular location; they just exist.
1979     // Saying that they are located at the @implementation isn't really going
1980     // to help users.
1981     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1982       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1983                             true,
1984                             /* property = */ Prop->getIdentifier(),
1985                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1986                             Prop->getLocation(), Prop->getQueryKind()));
1987     if (PIDecl && !Prop->isUnavailable()) {
1988       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1989       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1990     }
1991   }
1992 }
1993
1994 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
1995                                        SourceLocation AtEnd) {
1996   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
1997     return;
1998   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
1999   if (!IC)
2000     return;
2001   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
2002     if (!IDecl->isObjCRequiresPropertyDefs())
2003       DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
2004 }
2005
2006 static void DiagnoseUnimplementedAccessor(
2007     Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
2008     ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
2009     ObjCPropertyDecl *Prop,
2010     llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
2011   // Check to see if we have a corresponding selector in SMap and with the
2012   // right method type.
2013   auto I = llvm::find_if(SMap, [&](const ObjCMethodDecl *x) {
2014     return x->getSelector() == Method &&
2015            x->isClassMethod() == Prop->isClassProperty();
2016   });
2017   // When reporting on missing property setter/getter implementation in
2018   // categories, do not report when they are declared in primary class,
2019   // class's protocol, or one of it super classes. This is because,
2020   // the class is going to implement them.
2021   if (I == SMap.end() &&
2022       (PrimaryClass == nullptr ||
2023        !PrimaryClass->lookupPropertyAccessor(Method, C,
2024                                              Prop->isClassProperty()))) {
2025     unsigned diag =
2026         isa<ObjCCategoryDecl>(CDecl)
2027             ? (Prop->isClassProperty()
2028                    ? diag::warn_impl_required_in_category_for_class_property
2029                    : diag::warn_setter_getter_impl_required_in_category)
2030             : (Prop->isClassProperty()
2031                    ? diag::warn_impl_required_for_class_property
2032                    : diag::warn_setter_getter_impl_required);
2033     S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
2034     S.Diag(Prop->getLocation(), diag::note_property_declare);
2035     if (S.LangOpts.ObjCDefaultSynthProperties &&
2036         S.LangOpts.ObjCRuntime.isNonFragile())
2037       if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
2038         if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
2039           S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
2040   }
2041 }
2042
2043 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
2044                                            ObjCContainerDecl *CDecl,
2045                                            bool SynthesizeProperties) {
2046   ObjCContainerDecl::PropertyMap PropMap;
2047   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
2048
2049   // Since we don't synthesize class properties, we should emit diagnose even
2050   // if SynthesizeProperties is true.
2051   ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2052   // Gather properties which need not be implemented in this class
2053   // or category.
2054   if (!IDecl)
2055     if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
2056       // For categories, no need to implement properties declared in
2057       // its primary class (and its super classes) if property is
2058       // declared in one of those containers.
2059       if ((IDecl = C->getClassInterface())) {
2060         ObjCInterfaceDecl::PropertyDeclOrder PO;
2061         IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
2062       }
2063     }
2064   if (IDecl)
2065     CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
2066
2067   // When SynthesizeProperties is true, we only check class properties.
2068   CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
2069                              SynthesizeProperties/*CollectClassPropsOnly*/);
2070
2071   // Scan the @interface to see if any of the protocols it adopts
2072   // require an explicit implementation, via attribute
2073   // 'objc_protocol_requires_explicit_implementation'.
2074   if (IDecl) {
2075     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
2076
2077     for (auto *PDecl : IDecl->all_referenced_protocols()) {
2078       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2079         continue;
2080       // Lazily construct a set of all the properties in the @interface
2081       // of the class, without looking at the superclass.  We cannot
2082       // use the call to CollectImmediateProperties() above as that
2083       // utilizes information from the super class's properties as well
2084       // as scans the adopted protocols.  This work only triggers for protocols
2085       // with the attribute, which is very rare, and only occurs when
2086       // analyzing the @implementation.
2087       if (!LazyMap) {
2088         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2089         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
2090         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
2091                                    /* CollectClassPropsOnly */ false,
2092                                    /* IncludeProtocols */ false);
2093       }
2094       // Add the properties of 'PDecl' to the list of properties that
2095       // need to be implemented.
2096       for (auto *PropDecl : PDecl->properties()) {
2097         if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
2098                                       PropDecl->isClassProperty())])
2099           continue;
2100         PropMap[std::make_pair(PropDecl->getIdentifier(),
2101                                PropDecl->isClassProperty())] = PropDecl;
2102       }
2103     }
2104   }
2105
2106   if (PropMap.empty())
2107     return;
2108
2109   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
2110   for (const auto *I : IMPDecl->property_impls())
2111     PropImplMap.insert(I->getPropertyDecl());
2112
2113   llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
2114   // Collect property accessors implemented in current implementation.
2115   for (const auto *I : IMPDecl->methods())
2116     InsMap.insert(I);
2117
2118   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
2119   ObjCInterfaceDecl *PrimaryClass = nullptr;
2120   if (C && !C->IsClassExtension())
2121     if ((PrimaryClass = C->getClassInterface()))
2122       // Report unimplemented properties in the category as well.
2123       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
2124         // When reporting on missing setter/getters, do not report when
2125         // setter/getter is implemented in category's primary class
2126         // implementation.
2127         for (const auto *I : IMP->methods())
2128           InsMap.insert(I);
2129       }
2130
2131   for (ObjCContainerDecl::PropertyMap::iterator
2132        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
2133     ObjCPropertyDecl *Prop = P->second;
2134     // Is there a matching property synthesize/dynamic?
2135     if (Prop->isInvalidDecl() ||
2136         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
2137         PropImplMap.count(Prop) ||
2138         Prop->getAvailability() == AR_Unavailable)
2139       continue;
2140
2141     // Diagnose unimplemented getters and setters.
2142     DiagnoseUnimplementedAccessor(*this,
2143           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
2144     if (!Prop->isReadOnly())
2145       DiagnoseUnimplementedAccessor(*this,
2146                                     PrimaryClass, Prop->getSetterName(),
2147                                     IMPDecl, CDecl, C, Prop, InsMap);
2148   }
2149 }
2150
2151 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
2152   for (const auto *propertyImpl : impDecl->property_impls()) {
2153     const auto *property = propertyImpl->getPropertyDecl();
2154     // Warn about null_resettable properties with synthesized setters,
2155     // because the setter won't properly handle nil.
2156     if (propertyImpl->getPropertyImplementation() ==
2157             ObjCPropertyImplDecl::Synthesize &&
2158         (property->getPropertyAttributes() &
2159          ObjCPropertyAttribute::kind_null_resettable) &&
2160         property->getGetterMethodDecl() && property->getSetterMethodDecl()) {
2161       auto *getterImpl = propertyImpl->getGetterMethodDecl();
2162       auto *setterImpl = propertyImpl->getSetterMethodDecl();
2163       if ((!getterImpl || getterImpl->isSynthesizedAccessorStub()) &&
2164           (!setterImpl || setterImpl->isSynthesizedAccessorStub())) {
2165         SourceLocation loc = propertyImpl->getLocation();
2166         if (loc.isInvalid())
2167           loc = impDecl->getBeginLoc();
2168
2169         Diag(loc, diag::warn_null_resettable_setter)
2170           << setterImpl->getSelector() << property->getDeclName();
2171       }
2172     }
2173   }
2174 }
2175
2176 void
2177 Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
2178                                        ObjCInterfaceDecl* IDecl) {
2179   // Rules apply in non-GC mode only
2180   if (getLangOpts().getGC() != LangOptions::NonGC)
2181     return;
2182   ObjCContainerDecl::PropertyMap PM;
2183   for (auto *Prop : IDecl->properties())
2184     PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2185   for (const auto *Ext : IDecl->known_extensions())
2186     for (auto *Prop : Ext->properties())
2187       PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
2188
2189   for (ObjCContainerDecl::PropertyMap::iterator I = PM.begin(), E = PM.end();
2190        I != E; ++I) {
2191     const ObjCPropertyDecl *Property = I->second;
2192     ObjCMethodDecl *GetterMethod = nullptr;
2193     ObjCMethodDecl *SetterMethod = nullptr;
2194
2195     unsigned Attributes = Property->getPropertyAttributes();
2196     unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();
2197
2198     if (!(AttributesAsWritten & ObjCPropertyAttribute::kind_atomic) &&
2199         !(AttributesAsWritten & ObjCPropertyAttribute::kind_nonatomic)) {
2200       GetterMethod = Property->isClassProperty() ?
2201                      IMPDecl->getClassMethod(Property->getGetterName()) :
2202                      IMPDecl->getInstanceMethod(Property->getGetterName());
2203       SetterMethod = Property->isClassProperty() ?
2204                      IMPDecl->getClassMethod(Property->getSetterName()) :
2205                      IMPDecl->getInstanceMethod(Property->getSetterName());
2206       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2207         GetterMethod = nullptr;
2208       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2209         SetterMethod = nullptr;
2210       if (GetterMethod) {
2211         Diag(GetterMethod->getLocation(),
2212              diag::warn_default_atomic_custom_getter_setter)
2213           << Property->getIdentifier() << 0;
2214         Diag(Property->getLocation(), diag::note_property_declare);
2215       }
2216       if (SetterMethod) {
2217         Diag(SetterMethod->getLocation(),
2218              diag::warn_default_atomic_custom_getter_setter)
2219           << Property->getIdentifier() << 1;
2220         Diag(Property->getLocation(), diag::note_property_declare);
2221       }
2222     }
2223
2224     // We only care about readwrite atomic property.
2225     if ((Attributes & ObjCPropertyAttribute::kind_nonatomic) ||
2226         !(Attributes & ObjCPropertyAttribute::kind_readwrite))
2227       continue;
2228     if (const ObjCPropertyImplDecl *PIDecl = IMPDecl->FindPropertyImplDecl(
2229             Property->getIdentifier(), Property->getQueryKind())) {
2230       if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
2231         continue;
2232       GetterMethod = PIDecl->getGetterMethodDecl();
2233       SetterMethod = PIDecl->getSetterMethodDecl();
2234       if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
2235         GetterMethod = nullptr;
2236       if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
2237         SetterMethod = nullptr;
2238       if ((bool)GetterMethod ^ (bool)SetterMethod) {
2239         SourceLocation MethodLoc =
2240           (GetterMethod ? GetterMethod->getLocation()
2241                         : SetterMethod->getLocation());
2242         Diag(MethodLoc, diag::warn_atomic_property_rule)
2243           << Property->getIdentifier() << (GetterMethod != nullptr)
2244           << (SetterMethod != nullptr);
2245         // fixit stuff.
2246         if (Property->getLParenLoc().isValid() &&
2247             !(AttributesAsWritten & ObjCPropertyAttribute::kind_atomic)) {
2248           // @property () ... case.
2249           SourceLocation AfterLParen =
2250             getLocForEndOfToken(Property->getLParenLoc());
2251           StringRef NonatomicStr = AttributesAsWritten? "nonatomic, "
2252                                                       : "nonatomic";
2253           Diag(Property->getLocation(),
2254                diag::note_atomic_property_fixup_suggest)
2255             << FixItHint::CreateInsertion(AfterLParen, NonatomicStr);
2256         } else if (Property->getLParenLoc().isInvalid()) {
2257           //@property id etc.
2258           SourceLocation startLoc =
2259             Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2260           Diag(Property->getLocation(),
2261                diag::note_atomic_property_fixup_suggest)
2262             << FixItHint::CreateInsertion(startLoc, "(nonatomic) ");
2263         } else
2264           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
2265         Diag(Property->getLocation(), diag::note_property_declare);
2266       }
2267     }
2268   }
2269 }
2270
2271 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
2272   if (getLangOpts().getGC() == LangOptions::GCOnly)
2273     return;
2274
2275   for (const auto *PID : D->property_impls()) {
2276     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2277     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
2278         !PD->isClassProperty()) {
2279       ObjCMethodDecl *IM = PID->getGetterMethodDecl();
2280       if (IM && !IM->isSynthesizedAccessorStub())
2281         continue;
2282       ObjCMethodDecl *method = PD->getGetterMethodDecl();
2283       if (!method)
2284         continue;
2285       ObjCMethodFamily family = method->getMethodFamily();
2286       if (family == OMF_alloc || family == OMF_copy ||
2287           family == OMF_mutableCopy || family == OMF_new) {
2288         if (getLangOpts().ObjCAutoRefCount)
2289           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
2290         else
2291           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
2292
2293         // Look for a getter explicitly declared alongside the property.
2294         // If we find one, use its location for the note.
2295         SourceLocation noteLoc = PD->getLocation();
2296         SourceLocation fixItLoc;
2297         for (auto *getterRedecl : method->redecls()) {
2298           if (getterRedecl->isImplicit())
2299             continue;
2300           if (getterRedecl->getDeclContext() != PD->getDeclContext())
2301             continue;
2302           noteLoc = getterRedecl->getLocation();
2303           fixItLoc = getterRedecl->getEndLoc();
2304         }
2305
2306         Preprocessor &PP = getPreprocessor();
2307         TokenValue tokens[] = {
2308           tok::kw___attribute, tok::l_paren, tok::l_paren,
2309           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
2310           PP.getIdentifierInfo("none"), tok::r_paren,
2311           tok::r_paren, tok::r_paren
2312         };
2313         StringRef spelling = "__attribute__((objc_method_family(none)))";
2314         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
2315         if (!macroName.empty())
2316           spelling = macroName;
2317
2318         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
2319             << method->getDeclName() << spelling;
2320         if (fixItLoc.isValid()) {
2321           SmallString<64> fixItText(" ");
2322           fixItText += spelling;
2323           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
2324         }
2325       }
2326     }
2327   }
2328 }
2329
2330 void Sema::DiagnoseMissingDesignatedInitOverrides(
2331                                             const ObjCImplementationDecl *ImplD,
2332                                             const ObjCInterfaceDecl *IFD) {
2333   assert(IFD->hasDesignatedInitializers());
2334   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
2335   if (!SuperD)
2336     return;
2337
2338   SelectorSet InitSelSet;
2339   for (const auto *I : ImplD->instance_methods())
2340     if (I->getMethodFamily() == OMF_init)
2341       InitSelSet.insert(I->getSelector());
2342
2343   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
2344   SuperD->getDesignatedInitializers(DesignatedInits);
2345   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
2346          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
2347     const ObjCMethodDecl *MD = *I;
2348     if (!InitSelSet.count(MD->getSelector())) {
2349       // Don't emit a diagnostic if the overriding method in the subclass is
2350       // marked as unavailable.
2351       bool Ignore = false;
2352       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
2353         Ignore = IMD->isUnavailable();
2354       } else {
2355         // Check the methods declared in the class extensions too.
2356         for (auto *Ext : IFD->visible_extensions())
2357           if (auto *IMD = Ext->getInstanceMethod(MD->getSelector())) {
2358             Ignore = IMD->isUnavailable();
2359             break;
2360           }
2361       }
2362       if (!Ignore) {
2363         Diag(ImplD->getLocation(),
2364              diag::warn_objc_implementation_missing_designated_init_override)
2365           << MD->getSelector();
2366         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
2367       }
2368     }
2369   }
2370 }
2371
2372 /// AddPropertyAttrs - Propagates attributes from a property to the
2373 /// implicitly-declared getter or setter for that property.
2374 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
2375                              ObjCPropertyDecl *Property) {
2376   // Should we just clone all attributes over?
2377   for (const auto *A : Property->attrs()) {
2378     if (isa<DeprecatedAttr>(A) ||
2379         isa<UnavailableAttr>(A) ||
2380         isa<AvailabilityAttr>(A))
2381       PropertyMethod->addAttr(A->clone(S.Context));
2382   }
2383 }
2384
2385 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2386 /// have the property type and issue diagnostics if they don't.
2387 /// Also synthesize a getter/setter method if none exist (and update the
2388 /// appropriate lookup tables.
2389 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
2390   ObjCMethodDecl *GetterMethod, *SetterMethod;
2391   ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
2392   if (CD->isInvalidDecl())
2393     return;
2394
2395   bool IsClassProperty = property->isClassProperty();
2396   GetterMethod = IsClassProperty ?
2397     CD->getClassMethod(property->getGetterName()) :
2398     CD->getInstanceMethod(property->getGetterName());
2399
2400   // if setter or getter is not found in class extension, it might be
2401   // in the primary class.
2402   if (!GetterMethod)
2403     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2404       if (CatDecl->IsClassExtension())
2405         GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2406                          getClassMethod(property->getGetterName()) :
2407                        CatDecl->getClassInterface()->
2408                          getInstanceMethod(property->getGetterName());
2409
2410   SetterMethod = IsClassProperty ?
2411                  CD->getClassMethod(property->getSetterName()) :
2412                  CD->getInstanceMethod(property->getSetterName());
2413   if (!SetterMethod)
2414     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2415       if (CatDecl->IsClassExtension())
2416         SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2417                           getClassMethod(property->getSetterName()) :
2418                        CatDecl->getClassInterface()->
2419                           getInstanceMethod(property->getSetterName());
2420   DiagnosePropertyAccessorMismatch(property, GetterMethod,
2421                                    property->getLocation());
2422
2423   // synthesizing accessors must not result in a direct method that is not
2424   // monomorphic
2425   if (!GetterMethod) {
2426     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
2427       auto *ExistingGetter = CatDecl->getClassInterface()->lookupMethod(
2428           property->getGetterName(), !IsClassProperty, true, false, CatDecl);
2429       if (ExistingGetter) {
2430         if (ExistingGetter->isDirectMethod() || property->isDirectProperty()) {
2431           Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
2432               << property->isDirectProperty() << 1 /* property */
2433               << ExistingGetter->isDirectMethod()
2434               << ExistingGetter->getDeclName();
2435           Diag(ExistingGetter->getLocation(), diag::note_previous_declaration);
2436         }
2437       }
2438     }
2439   }
2440
2441   if (!property->isReadOnly() && !SetterMethod) {
2442     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
2443       auto *ExistingSetter = CatDecl->getClassInterface()->lookupMethod(
2444           property->getSetterName(), !IsClassProperty, true, false, CatDecl);
2445       if (ExistingSetter) {
2446         if (ExistingSetter->isDirectMethod() || property->isDirectProperty()) {
2447           Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
2448               << property->isDirectProperty() << 1 /* property */
2449               << ExistingSetter->isDirectMethod()
2450               << ExistingSetter->getDeclName();
2451           Diag(ExistingSetter->getLocation(), diag::note_previous_declaration);
2452         }
2453       }
2454     }
2455   }
2456
2457   if (!property->isReadOnly() && SetterMethod) {
2458     if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
2459         Context.VoidTy)
2460       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2461     if (SetterMethod->param_size() != 1 ||
2462         !Context.hasSameUnqualifiedType(
2463           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2464           property->getType().getNonReferenceType())) {
2465       Diag(property->getLocation(),
2466            diag::warn_accessor_property_type_mismatch)
2467         << property->getDeclName()
2468         << SetterMethod->getSelector();
2469       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2470     }
2471   }
2472
2473   // Synthesize getter/setter methods if none exist.
2474   // Find the default getter and if one not found, add one.
2475   // FIXME: The synthesized property we set here is misleading. We almost always
2476   // synthesize these methods unless the user explicitly provided prototypes
2477   // (which is odd, but allowed). Sema should be typechecking that the
2478   // declarations jive in that situation (which it is not currently).
2479   if (!GetterMethod) {
2480     // No instance/class method of same name as property getter name was found.
2481     // Declare a getter method and add it to the list of methods
2482     // for this class.
2483     SourceLocation Loc = property->getLocation();
2484
2485     // The getter returns the declared property type with all qualifiers
2486     // removed.
2487     QualType resultTy = property->getType().getAtomicUnqualifiedType();
2488
2489     // If the property is null_resettable, the getter returns nonnull.
2490     if (property->getPropertyAttributes() &
2491         ObjCPropertyAttribute::kind_null_resettable) {
2492       QualType modifiedTy = resultTy;
2493       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2494         if (*nullability == NullabilityKind::Unspecified)
2495           resultTy = Context.getAttributedType(attr::TypeNonNull,
2496                                                modifiedTy, modifiedTy);
2497       }
2498     }
2499
2500     GetterMethod = ObjCMethodDecl::Create(
2501         Context, Loc, Loc, property->getGetterName(), resultTy, nullptr, CD,
2502         !IsClassProperty, /*isVariadic=*/false,
2503         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
2504         /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2505         (property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
2506             ? ObjCMethodDecl::Optional
2507             : ObjCMethodDecl::Required);
2508     CD->addDecl(GetterMethod);
2509
2510     AddPropertyAttrs(*this, GetterMethod, property);
2511
2512     if (property->isDirectProperty())
2513       GetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2514
2515     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2516       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2517                                                                      Loc));
2518
2519     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2520       GetterMethod->addAttr(
2521         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2522
2523     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2524       GetterMethod->addAttr(SectionAttr::CreateImplicit(
2525           Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2526           SectionAttr::GNU_section));
2527
2528     if (getLangOpts().ObjCAutoRefCount)
2529       CheckARCMethodDecl(GetterMethod);
2530   } else
2531     // A user declared getter will be synthesize when @synthesize of
2532     // the property with the same name is seen in the @implementation
2533     GetterMethod->setPropertyAccessor(true);
2534
2535   GetterMethod->createImplicitParams(Context,
2536                                      GetterMethod->getClassInterface());
2537   property->setGetterMethodDecl(GetterMethod);
2538
2539   // Skip setter if property is read-only.
2540   if (!property->isReadOnly()) {
2541     // Find the default setter and if one not found, add one.
2542     if (!SetterMethod) {
2543       // No instance/class method of same name as property setter name was
2544       // found.
2545       // Declare a setter method and add it to the list of methods
2546       // for this class.
2547       SourceLocation Loc = property->getLocation();
2548
2549       SetterMethod =
2550         ObjCMethodDecl::Create(Context, Loc, Loc,
2551                                property->getSetterName(), Context.VoidTy,
2552                                nullptr, CD, !IsClassProperty,
2553                                /*isVariadic=*/false,
2554                                /*isPropertyAccessor=*/true,
2555                                /*isSynthesizedAccessorStub=*/false,
2556                                /*isImplicitlyDeclared=*/true,
2557                                /*isDefined=*/false,
2558                                (property->getPropertyImplementation() ==
2559                                 ObjCPropertyDecl::Optional) ?
2560                                 ObjCMethodDecl::Optional :
2561                                 ObjCMethodDecl::Required);
2562
2563       // Remove all qualifiers from the setter's parameter type.
2564       QualType paramTy =
2565           property->getType().getUnqualifiedType().getAtomicUnqualifiedType();
2566
2567       // If the property is null_resettable, the setter accepts a
2568       // nullable value.
2569       if (property->getPropertyAttributes() &
2570           ObjCPropertyAttribute::kind_null_resettable) {
2571         QualType modifiedTy = paramTy;
2572         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2573           if (*nullability == NullabilityKind::Unspecified)
2574             paramTy = Context.getAttributedType(attr::TypeNullable,
2575                                                 modifiedTy, modifiedTy);
2576         }
2577       }
2578
2579       // Invent the arguments for the setter. We don't bother making a
2580       // nice name for the argument.
2581       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2582                                                   Loc, Loc,
2583                                                   property->getIdentifier(),
2584                                                   paramTy,
2585                                                   /*TInfo=*/nullptr,
2586                                                   SC_None,
2587                                                   nullptr);
2588       SetterMethod->setMethodParams(Context, Argument, None);
2589
2590       AddPropertyAttrs(*this, SetterMethod, property);
2591
2592       if (property->isDirectProperty())
2593         SetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2594
2595       CD->addDecl(SetterMethod);
2596       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2597         SetterMethod->addAttr(SectionAttr::CreateImplicit(
2598             Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2599             SectionAttr::GNU_section));
2600       // It's possible for the user to have set a very odd custom
2601       // setter selector that causes it to have a method family.
2602       if (getLangOpts().ObjCAutoRefCount)
2603         CheckARCMethodDecl(SetterMethod);
2604     } else
2605       // A user declared setter will be synthesize when @synthesize of
2606       // the property with the same name is seen in the @implementation
2607       SetterMethod->setPropertyAccessor(true);
2608
2609     SetterMethod->createImplicitParams(Context,
2610                                        SetterMethod->getClassInterface());
2611     property->setSetterMethodDecl(SetterMethod);
2612   }
2613   // Add any synthesized methods to the global pool. This allows us to
2614   // handle the following, which is supported by GCC (and part of the design).
2615   //
2616   // @interface Foo
2617   // @property double bar;
2618   // @end
2619   //
2620   // void thisIsUnfortunate() {
2621   //   id foo;
2622   //   double bar = [foo bar];
2623   // }
2624   //
2625   if (!IsClassProperty) {
2626     if (GetterMethod)
2627       AddInstanceMethodToGlobalPool(GetterMethod);
2628     if (SetterMethod)
2629       AddInstanceMethodToGlobalPool(SetterMethod);
2630   } else {
2631     if (GetterMethod)
2632       AddFactoryMethodToGlobalPool(GetterMethod);
2633     if (SetterMethod)
2634       AddFactoryMethodToGlobalPool(SetterMethod);
2635   }
2636
2637   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2638   if (!CurrentClass) {
2639     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2640       CurrentClass = Cat->getClassInterface();
2641     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2642       CurrentClass = Impl->getClassInterface();
2643   }
2644   if (GetterMethod)
2645     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2646   if (SetterMethod)
2647     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2648 }
2649
2650 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2651                                        SourceLocation Loc,
2652                                        unsigned &Attributes,
2653                                        bool propertyInPrimaryClass) {
2654   // FIXME: Improve the reported location.
2655   if (!PDecl || PDecl->isInvalidDecl())
2656     return;
2657
2658   if ((Attributes & ObjCPropertyAttribute::kind_readonly) &&
2659       (Attributes & ObjCPropertyAttribute::kind_readwrite))
2660     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2661     << "readonly" << "readwrite";
2662
2663   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2664   QualType PropertyTy = PropertyDecl->getType();
2665
2666   // Check for copy or retain on non-object types.
2667   if ((Attributes &
2668        (ObjCPropertyAttribute::kind_weak | ObjCPropertyAttribute::kind_copy |
2669         ObjCPropertyAttribute::kind_retain |
2670         ObjCPropertyAttribute::kind_strong)) &&
2671       !PropertyTy->isObjCRetainableType() &&
2672       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2673     Diag(Loc, diag::err_objc_property_requires_object)
2674         << (Attributes & ObjCPropertyAttribute::kind_weak
2675                 ? "weak"
2676                 : Attributes & ObjCPropertyAttribute::kind_copy
2677                       ? "copy"
2678                       : "retain (or strong)");
2679     Attributes &=
2680         ~(ObjCPropertyAttribute::kind_weak | ObjCPropertyAttribute::kind_copy |
2681           ObjCPropertyAttribute::kind_retain |
2682           ObjCPropertyAttribute::kind_strong);
2683     PropertyDecl->setInvalidDecl();
2684   }
2685
2686   // Check for assign on object types.
2687   if ((Attributes & ObjCPropertyAttribute::kind_assign) &&
2688       !(Attributes & ObjCPropertyAttribute::kind_unsafe_unretained) &&
2689       PropertyTy->isObjCRetainableType() &&
2690       !PropertyTy->isObjCARCImplicitlyUnretainedType()) {
2691     Diag(Loc, diag::warn_objc_property_assign_on_object);
2692   }
2693
2694   // Check for more than one of { assign, copy, retain }.
2695   if (Attributes & ObjCPropertyAttribute::kind_assign) {
2696     if (Attributes & ObjCPropertyAttribute::kind_copy) {
2697       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2698         << "assign" << "copy";
2699       Attributes &= ~ObjCPropertyAttribute::kind_copy;
2700     }
2701     if (Attributes & ObjCPropertyAttribute::kind_retain) {
2702       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2703         << "assign" << "retain";
2704       Attributes &= ~ObjCPropertyAttribute::kind_retain;
2705     }
2706     if (Attributes & ObjCPropertyAttribute::kind_strong) {
2707       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2708         << "assign" << "strong";
2709       Attributes &= ~ObjCPropertyAttribute::kind_strong;
2710     }
2711     if (getLangOpts().ObjCAutoRefCount &&
2712         (Attributes & ObjCPropertyAttribute::kind_weak)) {
2713       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2714         << "assign" << "weak";
2715       Attributes &= ~ObjCPropertyAttribute::kind_weak;
2716     }
2717     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2718       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2719   } else if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained) {
2720     if (Attributes & ObjCPropertyAttribute::kind_copy) {
2721       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2722         << "unsafe_unretained" << "copy";
2723       Attributes &= ~ObjCPropertyAttribute::kind_copy;
2724     }
2725     if (Attributes & ObjCPropertyAttribute::kind_retain) {
2726       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2727         << "unsafe_unretained" << "retain";
2728       Attributes &= ~ObjCPropertyAttribute::kind_retain;
2729     }
2730     if (Attributes & ObjCPropertyAttribute::kind_strong) {
2731       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2732         << "unsafe_unretained" << "strong";
2733       Attributes &= ~ObjCPropertyAttribute::kind_strong;
2734     }
2735     if (getLangOpts().ObjCAutoRefCount &&
2736         (Attributes & ObjCPropertyAttribute::kind_weak)) {
2737       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2738         << "unsafe_unretained" << "weak";
2739       Attributes &= ~ObjCPropertyAttribute::kind_weak;
2740     }
2741   } else if (Attributes & ObjCPropertyAttribute::kind_copy) {
2742     if (Attributes & ObjCPropertyAttribute::kind_retain) {
2743       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2744         << "copy" << "retain";
2745       Attributes &= ~ObjCPropertyAttribute::kind_retain;
2746     }
2747     if (Attributes & ObjCPropertyAttribute::kind_strong) {
2748       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2749         << "copy" << "strong";
2750       Attributes &= ~ObjCPropertyAttribute::kind_strong;
2751     }
2752     if (Attributes & ObjCPropertyAttribute::kind_weak) {
2753       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2754         << "copy" << "weak";
2755       Attributes &= ~ObjCPropertyAttribute::kind_weak;
2756     }
2757   } else if ((Attributes & ObjCPropertyAttribute::kind_retain) &&
2758              (Attributes & ObjCPropertyAttribute::kind_weak)) {
2759     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "retain"
2760                                                                << "weak";
2761     Attributes &= ~ObjCPropertyAttribute::kind_retain;
2762   } else if ((Attributes & ObjCPropertyAttribute::kind_strong) &&
2763              (Attributes & ObjCPropertyAttribute::kind_weak)) {
2764     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "strong"
2765                                                                << "weak";
2766     Attributes &= ~ObjCPropertyAttribute::kind_weak;
2767   }
2768
2769   if (Attributes & ObjCPropertyAttribute::kind_weak) {
2770     // 'weak' and 'nonnull' are mutually exclusive.
2771     if (auto nullability = PropertyTy->getNullability(Context)) {
2772       if (*nullability == NullabilityKind::NonNull)
2773         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2774           << "nonnull" << "weak";
2775     }
2776   }
2777
2778   if ((Attributes & ObjCPropertyAttribute::kind_atomic) &&
2779       (Attributes & ObjCPropertyAttribute::kind_nonatomic)) {
2780     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "atomic"
2781                                                                << "nonatomic";
2782     Attributes &= ~ObjCPropertyAttribute::kind_atomic;
2783   }
2784
2785   // Warn if user supplied no assignment attribute, property is
2786   // readwrite, and this is an object type.
2787   if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
2788     if (Attributes & ObjCPropertyAttribute::kind_readonly) {
2789       // do nothing
2790     } else if (getLangOpts().ObjCAutoRefCount) {
2791       // With arc, @property definitions should default to strong when
2792       // not specified.
2793       PropertyDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
2794     } else if (PropertyTy->isObjCObjectPointerType()) {
2795       bool isAnyClassTy = (PropertyTy->isObjCClassType() ||
2796                            PropertyTy->isObjCQualifiedClassType());
2797       // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2798       // issue any warning.
2799       if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2800         ;
2801       else if (propertyInPrimaryClass) {
2802         // Don't issue warning on property with no life time in class
2803         // extension as it is inherited from property in primary class.
2804         // Skip this warning in gc-only mode.
2805         if (getLangOpts().getGC() != LangOptions::GCOnly)
2806           Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2807
2808         // If non-gc code warn that this is likely inappropriate.
2809         if (getLangOpts().getGC() == LangOptions::NonGC)
2810           Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2811       }
2812     }
2813
2814     // FIXME: Implement warning dependent on NSCopying being
2815     // implemented. See also:
2816     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2817     // (please trim this list while you are at it).
2818   }
2819
2820   if (!(Attributes & ObjCPropertyAttribute::kind_copy) &&
2821       !(Attributes & ObjCPropertyAttribute::kind_readonly) &&
2822       getLangOpts().getGC() == LangOptions::GCOnly &&
2823       PropertyTy->isBlockPointerType())
2824     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2825   else if ((Attributes & ObjCPropertyAttribute::kind_retain) &&
2826            !(Attributes & ObjCPropertyAttribute::kind_readonly) &&
2827            !(Attributes & ObjCPropertyAttribute::kind_strong) &&
2828            PropertyTy->isBlockPointerType())
2829     Diag(Loc, diag::warn_objc_property_retain_of_block);
2830
2831   if ((Attributes & ObjCPropertyAttribute::kind_readonly) &&
2832       (Attributes & ObjCPropertyAttribute::kind_setter))
2833     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2834 }