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 getImpliedARCOwnership(
  39                                ObjCPropertyDecl::PropertyAttributeKind attrs,
  40                                                 QualType type) {
  41   // retain, strong, copy, weak, and unsafe_unretained are only legal
  42   // on properties of retainable pointer type.
  43   if (attrs & (ObjCPropertyDecl::OBJC_PR_retain |
  44                ObjCPropertyDecl::OBJC_PR_strong |
  45                ObjCPropertyDecl::OBJC_PR_copy)) {
  46     return Qualifiers::OCL_Strong;
  47   } else if (attrs & ObjCPropertyDecl::OBJC_PR_weak) {
  48     return Qualifiers::OCL_Weak;
  49   } else if (attrs & ObjCPropertyDecl::OBJC_PR_unsafe_unretained) {
  50     return Qualifiers::OCL_ExplicitNone;
  51   }
  52
  53   // assign can appear on other types, so we have to check the
  54   // property type.
  55   if (attrs & ObjCPropertyDecl::OBJC_PR_assign &&
  56       type->isObjCRetainableType()) {
  57     return Qualifiers::OCL_ExplicitNone;
  58   }
  59
  60   return Qualifiers::OCL_None;
  61 }
  62
  63 /// Check the internal consistency of a property declaration with
  64 /// an explicit ownership qualifier.
  65 static void checkPropertyDeclWithOwnership(Sema &S,
  66                                            ObjCPropertyDecl *property) {
  67   if (property->isInvalidDecl()) return;
  68
  69   ObjCPropertyDecl::PropertyAttributeKind propertyKind
  70     = property->getPropertyAttributes();
  71   Qualifiers::ObjCLifetime propertyLifetime
  72     = property->getType().getObjCLifetime();
  73
  74   assert(propertyLifetime != Qualifiers::OCL_None);
  75
  76   Qualifiers::ObjCLifetime expectedLifetime
  77     = getImpliedARCOwnership(propertyKind, property->getType());
  78   if (!expectedLifetime) {
  79     // We have a lifetime qualifier but no dominating property
  80     // attribute.  That's okay, but restore reasonable invariants by
  81     // setting the property attribute according to the lifetime
  82     // qualifier.
  83     ObjCPropertyDecl::PropertyAttributeKind attr;
  84     if (propertyLifetime == Qualifiers::OCL_Strong) {
  85       attr = ObjCPropertyDecl::OBJC_PR_strong;
  86     } else if (propertyLifetime == Qualifiers::OCL_Weak) {
  87       attr = ObjCPropertyDecl::OBJC_PR_weak;
  88     } else {
  89       assert(propertyLifetime == Qualifiers::OCL_ExplicitNone);
  90       attr = ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
  91     }
  92     property->setPropertyAttributes(attr);
  93     return;
  94   }
  95
  96   if (propertyLifetime == expectedLifetime) return;
  97
  98   property->setInvalidDecl();
  99   S.Diag(property->getLocation(),
 100          diag::err_arc_inconsistent_property_ownership)
 101     << property->getDeclName()
 102     << expectedLifetime
 103     << propertyLifetime;
 104 }
 105
 106 /// Check this Objective-C property against a property declared in the
 107 /// given protocol.
 108 static void
 109 CheckPropertyAgainstProtocol(Sema &S, ObjCPropertyDecl *Prop,
 110                              ObjCProtocolDecl *Proto,
 111                              llvm::SmallPtrSetImpl<ObjCProtocolDecl *> &Known) {
 112   // Have we seen this protocol before?
 113   if (!Known.insert(Proto).second)
 114     return;
 115
 116   // Look for a property with the same name.
 117   DeclContext::lookup_result R = Proto->lookup(Prop->getDeclName());
 118   for (unsigned I = 0, N = R.size(); I != N; ++I) {
 119     if (ObjCPropertyDecl *ProtoProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
 120       S.DiagnosePropertyMismatch(Prop, ProtoProp, Proto->getIdentifier(), true);
 121       return;
 122     }
 123   }
 124
 125   // Check this property against any protocols we inherit.
 126   for (auto *P : Proto->protocols())
 127     CheckPropertyAgainstProtocol(S, Prop, P, Known);
 128 }
 129
 130 static unsigned deducePropertyOwnershipFromType(Sema &S, QualType T) {
 131   // In GC mode, just look for the __weak qualifier.
 132   if (S.getLangOpts().getGC() != LangOptions::NonGC) {
 133     if (T.isObjCGCWeak()) return ObjCDeclSpec::DQ_PR_weak;
 134
 135   // In ARC/MRC, look for an explicit ownership qualifier.
 136   // For some reason, this only applies to __weak.
 137   } else if (auto ownership = T.getObjCLifetime()) {
 138     switch (ownership) {
 139     case Qualifiers::OCL_Weak:
 140       return ObjCDeclSpec::DQ_PR_weak;
 141     case Qualifiers::OCL_Strong:
 142       return ObjCDeclSpec::DQ_PR_strong;
 143     case Qualifiers::OCL_ExplicitNone:
 144       return ObjCDeclSpec::DQ_PR_unsafe_unretained;
 145     case Qualifiers::OCL_Autoreleasing:
 146     case Qualifiers::OCL_None:
 147       return 0;
 148     }
 149     llvm_unreachable("bad qualifier");
 150   }
 151
 152   return 0;
 153 }
 154
 155 static const unsigned OwnershipMask =
 156   (ObjCPropertyDecl::OBJC_PR_assign |
 157    ObjCPropertyDecl::OBJC_PR_retain |
 158    ObjCPropertyDecl::OBJC_PR_copy   |
 159    ObjCPropertyDecl::OBJC_PR_weak   |
 160    ObjCPropertyDecl::OBJC_PR_strong |
 161    ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
 162
 163 static unsigned getOwnershipRule(unsigned attr) {
 164   unsigned result = attr & OwnershipMask;
 165
 166   // From an ownership perspective, assign and unsafe_unretained are
 167   // identical; make sure one also implies the other.
 168   if (result & (ObjCPropertyDecl::OBJC_PR_assign |
 169                 ObjCPropertyDecl::OBJC_PR_unsafe_unretained)) {
 170     result |= ObjCPropertyDecl::OBJC_PR_assign |
 171               ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
 172   }
 173
 174   return result;
 175 }
 176
 177 Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
 178                           SourceLocation LParenLoc,
 179                           FieldDeclarator &FD,
 180                           ObjCDeclSpec &ODS,
 181                           Selector GetterSel,
 182                           Selector SetterSel,
 183                           tok::ObjCKeywordKind MethodImplKind,
 184                           DeclContext *lexicalDC) {
 185   unsigned Attributes = ODS.getPropertyAttributes();
 186   FD.D.setObjCWeakProperty((Attributes & ObjCDeclSpec::DQ_PR_weak) != 0);
 187   TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
 188   QualType T = TSI->getType();
 189   if (!getOwnershipRule(Attributes)) {
 190     Attributes |= deducePropertyOwnershipFromType(*this, T);
 191   }
 192   bool isReadWrite = ((Attributes & ObjCDeclSpec::DQ_PR_readwrite) ||
 193                       // default is readwrite!
 194                       !(Attributes & ObjCDeclSpec::DQ_PR_readonly));
 195
 196   // Proceed with constructing the ObjCPropertyDecls.
 197   ObjCContainerDecl *ClassDecl = cast<ObjCContainerDecl>(CurContext);
 198   ObjCPropertyDecl *Res = nullptr;
 199   if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
 200     if (CDecl->IsClassExtension()) {
 201       Res = HandlePropertyInClassExtension(S, AtLoc, LParenLoc,
 202                                            FD,
 203                                            GetterSel, ODS.getGetterNameLoc(),
 204                                            SetterSel, ODS.getSetterNameLoc(),
 205                                            isReadWrite, Attributes,
 206                                            ODS.getPropertyAttributes(),
 207                                            T, TSI, MethodImplKind);
 208       if (!Res)
 209         return nullptr;
 210     }
 211   }
 212
 213   if (!Res) {
 214     Res = CreatePropertyDecl(S, ClassDecl, AtLoc, LParenLoc, FD,
 215                              GetterSel, ODS.getGetterNameLoc(), SetterSel,
 216                              ODS.getSetterNameLoc(), isReadWrite, Attributes,
 217                              ODS.getPropertyAttributes(), T, TSI,
 218                              MethodImplKind);
 219     if (lexicalDC)
 220       Res->setLexicalDeclContext(lexicalDC);
 221   }
 222
 223   // Validate the attributes on the @property.
 224   CheckObjCPropertyAttributes(Res, AtLoc, Attributes,
 225                               (isa<ObjCInterfaceDecl>(ClassDecl) ||
 226                                isa<ObjCProtocolDecl>(ClassDecl)));
 227
 228   // Check consistency if the type has explicit ownership qualification.
 229   if (Res->getType().getObjCLifetime())
 230     checkPropertyDeclWithOwnership(*this, Res);
 231
 232   llvm::SmallPtrSet<ObjCProtocolDecl *, 16> KnownProtos;
 233   if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
 234     // For a class, compare the property against a property in our superclass.
 235     bool FoundInSuper = false;
 236     ObjCInterfaceDecl *CurrentInterfaceDecl = IFace;
 237     while (ObjCInterfaceDecl *Super = CurrentInterfaceDecl->getSuperClass()) {
 238       DeclContext::lookup_result R = Super->lookup(Res->getDeclName());
 239       for (unsigned I = 0, N = R.size(); I != N; ++I) {
 240         if (ObjCPropertyDecl *SuperProp = dyn_cast<ObjCPropertyDecl>(R[I])) {
 241           DiagnosePropertyMismatch(Res, SuperProp, Super->getIdentifier(), false);
 242           FoundInSuper = true;
 243           break;
 244         }
 245       }
 246       if (FoundInSuper)
 247         break;
 248       else
 249         CurrentInterfaceDecl = Super;
 250     }
 251
 252     if (FoundInSuper) {
 253       // Also compare the property against a property in our protocols.
 254       for (auto *P : CurrentInterfaceDecl->protocols()) {
 255         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 256       }
 257     } else {
 258       // Slower path: look in all protocols we referenced.
 259       for (auto *P : IFace->all_referenced_protocols()) {
 260         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 261       }
 262     }
 263   } else if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
 264     // We don't check if class extension. Because properties in class extension
 265     // are meant to override some of the attributes and checking has already done
 266     // when property in class extension is constructed.
 267     if (!Cat->IsClassExtension())
 268       for (auto *P : Cat->protocols())
 269         CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 270   } else {
 271     ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(ClassDecl);
 272     for (auto *P : Proto->protocols())
 273       CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
 274   }
 275
 276   ActOnDocumentableDecl(Res);
 277   return Res;
 278 }
 279
 280 static ObjCPropertyDecl::PropertyAttributeKind
 281 makePropertyAttributesAsWritten(unsigned Attributes) {
 282   unsigned attributesAsWritten = 0;
 283   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
 284     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readonly;
 285   if (Attributes & ObjCDeclSpec::DQ_PR_readwrite)
 286     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_readwrite;
 287   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
 288     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_getter;
 289   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
 290     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_setter;
 291   if (Attributes & ObjCDeclSpec::DQ_PR_assign)
 292     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_assign;
 293   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
 294     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_retain;
 295   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
 296     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_strong;
 297   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
 298     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_weak;
 299   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
 300     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_copy;
 301   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
 302     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_unsafe_unretained;
 303   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
 304     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_nonatomic;
 305   if (Attributes & ObjCDeclSpec::DQ_PR_atomic)
 306     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_atomic;
 307   if (Attributes & ObjCDeclSpec::DQ_PR_class)
 308     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_class;
 309   if (Attributes & ObjCDeclSpec::DQ_PR_direct)
 310     attributesAsWritten |= ObjCPropertyDecl::OBJC_PR_direct;
 311
 312   return (ObjCPropertyDecl::PropertyAttributeKind)attributesAsWritten;
 313 }
 314
 315 static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
 316                                  SourceLocation LParenLoc, SourceLocation &Loc) {
 317   if (LParenLoc.isMacroID())
 318     return false;
 319
 320   SourceManager &SM = Context.getSourceManager();
 321   std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
 322   // Try to load the file buffer.
 323   bool invalidTemp = false;
 324   StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
 325   if (invalidTemp)
 326     return false;
 327   const char *tokenBegin = file.data() + locInfo.second;
 328
 329   // Lex from the start of the given location.
 330   Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
 331               Context.getLangOpts(),
 332               file.begin(), tokenBegin, file.end());
 333   Token Tok;
 334   do {
 335     lexer.LexFromRawLexer(Tok);
 336     if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
 337       Loc = Tok.getLocation();
 338       return true;
 339     }
 340   } while (Tok.isNot(tok::r_paren));
 341   return false;
 342 }
 343
 344 /// Check for a mismatch in the atomicity of the given properties.
 345 static void checkAtomicPropertyMismatch(Sema &S,
 346                                         ObjCPropertyDecl *OldProperty,
 347                                         ObjCPropertyDecl *NewProperty,
 348                                         bool PropagateAtomicity) {
 349   // If the atomicity of both matches, we're done.
 350   bool OldIsAtomic =
 351     (OldProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
 352       == 0;
 353   bool NewIsAtomic =
 354     (NewProperty->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_nonatomic)
 355       == 0;
 356   if (OldIsAtomic == NewIsAtomic) return;
 357
 358   // Determine whether the given property is readonly and implicitly
 359   // atomic.
 360   auto isImplicitlyReadonlyAtomic = [](ObjCPropertyDecl *Property) -> bool {
 361     // Is it readonly?
 362     auto Attrs = Property->getPropertyAttributes();
 363     if ((Attrs & ObjCPropertyDecl::OBJC_PR_readonly) == 0) return false;
 364
 365     // Is it nonatomic?
 366     if (Attrs & ObjCPropertyDecl::OBJC_PR_nonatomic) return false;
 367
 368     // Was 'atomic' specified directly?
 369     if (Property->getPropertyAttributesAsWritten() &
 370           ObjCPropertyDecl::OBJC_PR_atomic)
 371       return false;
 372
 373     return true;
 374   };
 375
 376   // If we're allowed to propagate atomicity, and the new property did
 377   // not specify atomicity at all, propagate.
 378   const unsigned AtomicityMask =
 379     (ObjCPropertyDecl::OBJC_PR_atomic | ObjCPropertyDecl::OBJC_PR_nonatomic);
 380   if (PropagateAtomicity &&
 381       ((NewProperty->getPropertyAttributesAsWritten() & AtomicityMask) == 0)) {
 382     unsigned Attrs = NewProperty->getPropertyAttributes();
 383     Attrs = Attrs & ~AtomicityMask;
 384     if (OldIsAtomic)
 385       Attrs |= ObjCPropertyDecl::OBJC_PR_atomic;
 386     else
 387       Attrs |= ObjCPropertyDecl::OBJC_PR_nonatomic;
 388
 389     NewProperty->overwritePropertyAttributes(Attrs);
 390     return;
 391   }
 392
 393   // One of the properties is atomic; if it's a readonly property, and
 394   // 'atomic' wasn't explicitly specified, we're okay.
 395   if ((OldIsAtomic && isImplicitlyReadonlyAtomic(OldProperty)) ||
 396       (NewIsAtomic && isImplicitlyReadonlyAtomic(NewProperty)))
 397     return;
 398
 399   // Diagnose the conflict.
 400   const IdentifierInfo *OldContextName;
 401   auto *OldDC = OldProperty->getDeclContext();
 402   if (auto Category = dyn_cast<ObjCCategoryDecl>(OldDC))
 403     OldContextName = Category->getClassInterface()->getIdentifier();
 404   else
 405     OldContextName = cast<ObjCContainerDecl>(OldDC)->getIdentifier();
 406
 407   S.Diag(NewProperty->getLocation(), diag::warn_property_attribute)
 408     << NewProperty->getDeclName() << "atomic"
 409     << OldContextName;
 410   S.Diag(OldProperty->getLocation(), diag::note_property_declare);
 411 }
 412
 413 ObjCPropertyDecl *
 414 Sema::HandlePropertyInClassExtension(Scope *S,
 415                                      SourceLocation AtLoc,
 416                                      SourceLocation LParenLoc,
 417                                      FieldDeclarator &FD,
 418                                      Selector GetterSel,
 419                                      SourceLocation GetterNameLoc,
 420                                      Selector SetterSel,
 421                                      SourceLocation SetterNameLoc,
 422                                      const bool isReadWrite,
 423                                      unsigned &Attributes,
 424                                      const unsigned AttributesAsWritten,
 425                                      QualType T,
 426                                      TypeSourceInfo *TSI,
 427                                      tok::ObjCKeywordKind MethodImplKind) {
 428   ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
 429   // Diagnose if this property is already in continuation class.
 430   DeclContext *DC = CurContext;
 431   IdentifierInfo *PropertyId = FD.D.getIdentifier();
 432   ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();
 433
 434   // We need to look in the @interface to see if the @property was
 435   // already declared.
 436   if (!CCPrimary) {
 437     Diag(CDecl->getLocation(), diag::err_continuation_class);
 438     return nullptr;
 439   }
 440
 441   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
 442                          (Attributes & ObjCDeclSpec::DQ_PR_class);
 443
 444   // Find the property in the extended class's primary class or
 445   // extensions.
 446   ObjCPropertyDecl *PIDecl = CCPrimary->FindPropertyVisibleInPrimaryClass(
 447       PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty));
 448
 449   // If we found a property in an extension, complain.
 450   if (PIDecl && isa<ObjCCategoryDecl>(PIDecl->getDeclContext())) {
 451     Diag(AtLoc, diag::err_duplicate_property);
 452     Diag(PIDecl->getLocation(), diag::note_property_declare);
 453     return nullptr;
 454   }
 455
 456   // Check for consistency with the previous declaration, if there is one.
 457   if (PIDecl) {
 458     // A readonly property declared in the primary class can be refined
 459     // by adding a readwrite property within an extension.
 460     // Anything else is an error.
 461     if (!(PIDecl->isReadOnly() && isReadWrite)) {
 462       // Tailor the diagnostics for the common case where a readwrite
 463       // property is declared both in the @interface and the continuation.
 464       // This is a common error where the user often intended the original
 465       // declaration to be readonly.
 466       unsigned diag =
 467         (Attributes & ObjCDeclSpec::DQ_PR_readwrite) &&
 468         (PIDecl->getPropertyAttributesAsWritten() &
 469            ObjCPropertyDecl::OBJC_PR_readwrite)
 470         ? diag::err_use_continuation_class_redeclaration_readwrite
 471         : diag::err_use_continuation_class;
 472       Diag(AtLoc, diag)
 473         << CCPrimary->getDeclName();
 474       Diag(PIDecl->getLocation(), diag::note_property_declare);
 475       return nullptr;
 476     }
 477
 478     // Check for consistency of getters.
 479     if (PIDecl->getGetterName() != GetterSel) {
 480      // If the getter was written explicitly, complain.
 481       if (AttributesAsWritten & ObjCDeclSpec::DQ_PR_getter) {
 482         Diag(AtLoc, diag::warn_property_redecl_getter_mismatch)
 483           << PIDecl->getGetterName() << GetterSel;
 484         Diag(PIDecl->getLocation(), diag::note_property_declare);
 485       }
 486
 487       // Always adopt the getter from the original declaration.
 488       GetterSel = PIDecl->getGetterName();
 489       Attributes |= ObjCDeclSpec::DQ_PR_getter;
 490     }
 491
 492     // Check consistency of ownership.
 493     unsigned ExistingOwnership
 494       = getOwnershipRule(PIDecl->getPropertyAttributes());
 495     unsigned NewOwnership = getOwnershipRule(Attributes);
 496     if (ExistingOwnership && NewOwnership != ExistingOwnership) {
 497       // If the ownership was written explicitly, complain.
 498       if (getOwnershipRule(AttributesAsWritten)) {
 499         Diag(AtLoc, diag::warn_property_attr_mismatch);
 500         Diag(PIDecl->getLocation(), diag::note_property_declare);
 501       }
 502
 503       // Take the ownership from the original property.
 504       Attributes = (Attributes & ~OwnershipMask) | ExistingOwnership;
 505     }
 506
 507     // If the redeclaration is 'weak' but the original property is not,
 508     if ((Attributes & ObjCPropertyDecl::OBJC_PR_weak) &&
 509         !(PIDecl->getPropertyAttributesAsWritten()
 510             & ObjCPropertyDecl::OBJC_PR_weak) &&
 511         PIDecl->getType()->getAs<ObjCObjectPointerType>() &&
 512         PIDecl->getType().getObjCLifetime() == Qualifiers::OCL_None) {
 513       Diag(AtLoc, diag::warn_property_implicitly_mismatched);
 514       Diag(PIDecl->getLocation(), diag::note_property_declare);
 515     }
 516   }
 517
 518   // Create a new ObjCPropertyDecl with the DeclContext being
 519   // the class extension.
 520   ObjCPropertyDecl *PDecl = CreatePropertyDecl(S, CDecl, AtLoc, LParenLoc,
 521                                                FD, GetterSel, GetterNameLoc,
 522                                                SetterSel, SetterNameLoc,
 523                                                isReadWrite,
 524                                                Attributes, AttributesAsWritten,
 525                                                T, TSI, MethodImplKind, DC);
 526
 527   // If there was no declaration of a property with the same name in
 528   // the primary class, we're done.
 529   if (!PIDecl) {
 530     ProcessPropertyDecl(PDecl);
 531     return PDecl;
 532   }
 533
 534   if (!Context.hasSameType(PIDecl->getType(), PDecl->getType())) {
 535     bool IncompatibleObjC = false;
 536     QualType ConvertedType;
 537     // Relax the strict type matching for property type in continuation class.
 538     // Allow property object type of continuation class to be different as long
 539     // as it narrows the object type in its primary class property. Note that
 540     // this conversion is safe only because the wider type is for a 'readonly'
 541     // property in primary class and 'narrowed' type for a 'readwrite' property
 542     // in continuation class.
 543     QualType PrimaryClassPropertyT = Context.getCanonicalType(PIDecl->getType());
 544     QualType ClassExtPropertyT = Context.getCanonicalType(PDecl->getType());
 545     if (!isa<ObjCObjectPointerType>(PrimaryClassPropertyT) ||
 546         !isa<ObjCObjectPointerType>(ClassExtPropertyT) ||
 547         (!isObjCPointerConversion(ClassExtPropertyT, PrimaryClassPropertyT,
 548                                   ConvertedType, IncompatibleObjC))
 549         || IncompatibleObjC) {
 550       Diag(AtLoc,
 551           diag::err_type_mismatch_continuation_class) << PDecl->getType();
 552       Diag(PIDecl->getLocation(), diag::note_property_declare);
 553       return nullptr;
 554     }
 555   }
 556
 557   // Check that atomicity of property in class extension matches the previous
 558   // declaration.
 559   checkAtomicPropertyMismatch(*this, PIDecl, PDecl, true);
 560
 561   // Make sure getter/setter are appropriately synthesized.
 562   ProcessPropertyDecl(PDecl);
 563   return PDecl;
 564 }
 565
 566 ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
 567                                            ObjCContainerDecl *CDecl,
 568                                            SourceLocation AtLoc,
 569                                            SourceLocation LParenLoc,
 570                                            FieldDeclarator &FD,
 571                                            Selector GetterSel,
 572                                            SourceLocation GetterNameLoc,
 573                                            Selector SetterSel,
 574                                            SourceLocation SetterNameLoc,
 575                                            const bool isReadWrite,
 576                                            const unsigned Attributes,
 577                                            const unsigned AttributesAsWritten,
 578                                            QualType T,
 579                                            TypeSourceInfo *TInfo,
 580                                            tok::ObjCKeywordKind MethodImplKind,
 581                                            DeclContext *lexicalDC){
 582   IdentifierInfo *PropertyId = FD.D.getIdentifier();
 583
 584   // Property defaults to 'assign' if it is readwrite, unless this is ARC
 585   // and the type is retainable.
 586   bool isAssign;
 587   if (Attributes & (ObjCDeclSpec::DQ_PR_assign |
 588                     ObjCDeclSpec::DQ_PR_unsafe_unretained)) {
 589     isAssign = true;
 590   } else if (getOwnershipRule(Attributes) || !isReadWrite) {
 591     isAssign = false;
 592   } else {
 593     isAssign = (!getLangOpts().ObjCAutoRefCount ||
 594                 !T->isObjCRetainableType());
 595   }
 596
 597   // Issue a warning if property is 'assign' as default and its
 598   // object, which is gc'able conforms to NSCopying protocol
 599   if (getLangOpts().getGC() != LangOptions::NonGC &&
 600       isAssign && !(Attributes & ObjCDeclSpec::DQ_PR_assign)) {
 601     if (const ObjCObjectPointerType *ObjPtrTy =
 602           T->getAs<ObjCObjectPointerType>()) {
 603       ObjCInterfaceDecl *IDecl = ObjPtrTy->getObjectType()->getInterface();
 604       if (IDecl)
 605         if (ObjCProtocolDecl* PNSCopying =
 606             LookupProtocol(&Context.Idents.get("NSCopying"), AtLoc))
 607           if (IDecl->ClassImplementsProtocol(PNSCopying, true))
 608             Diag(AtLoc, diag::warn_implements_nscopying) << PropertyId;
 609     }
 610   }
 611
 612   if (T->isObjCObjectType()) {
 613     SourceLocation StarLoc = TInfo->getTypeLoc().getEndLoc();
 614     StarLoc = getLocForEndOfToken(StarLoc);
 615     Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object)
 616       << FixItHint::CreateInsertion(StarLoc, "*");
 617     T = Context.getObjCObjectPointerType(T);
 618     SourceLocation TLoc = TInfo->getTypeLoc().getBeginLoc();
 619     TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
 620   }
 621
 622   DeclContext *DC = CDecl;
 623   ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
 624                                                      FD.D.getIdentifierLoc(),
 625                                                      PropertyId, AtLoc,
 626                                                      LParenLoc, T, TInfo);
 627
 628   bool isClassProperty = (AttributesAsWritten & ObjCDeclSpec::DQ_PR_class) ||
 629                          (Attributes & ObjCDeclSpec::DQ_PR_class);
 630   // Class property and instance property can have the same name.
 631   if (ObjCPropertyDecl *prevDecl = ObjCPropertyDecl::findPropertyDecl(
 632           DC, PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty))) {
 633     Diag(PDecl->getLocation(), diag::err_duplicate_property);
 634     Diag(prevDecl->getLocation(), diag::note_property_declare);
 635     PDecl->setInvalidDecl();
 636   }
 637   else {
 638     DC->addDecl(PDecl);
 639     if (lexicalDC)
 640       PDecl->setLexicalDeclContext(lexicalDC);
 641   }
 642
 643   if (T->isArrayType() || T->isFunctionType()) {
 644     Diag(AtLoc, diag::err_property_type) << T;
 645     PDecl->setInvalidDecl();
 646   }
 647
 648   ProcessDeclAttributes(S, PDecl, FD.D);
 649
 650   // Regardless of setter/getter attribute, we save the default getter/setter
 651   // selector names in anticipation of declaration of setter/getter methods.
 652   PDecl->setGetterName(GetterSel, GetterNameLoc);
 653   PDecl->setSetterName(SetterSel, SetterNameLoc);
 654   PDecl->setPropertyAttributesAsWritten(
 655                           makePropertyAttributesAsWritten(AttributesAsWritten));
 656
 657   if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
 658     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
 659
 660   if (Attributes & ObjCDeclSpec::DQ_PR_getter)
 661     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_getter);
 662
 663   if (Attributes & ObjCDeclSpec::DQ_PR_setter)
 664     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_setter);
 665
 666   if (isReadWrite)
 667     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
 668
 669   if (Attributes & ObjCDeclSpec::DQ_PR_retain)
 670     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
 671
 672   if (Attributes & ObjCDeclSpec::DQ_PR_strong)
 673     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
 674
 675   if (Attributes & ObjCDeclSpec::DQ_PR_weak)
 676     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
 677
 678   if (Attributes & ObjCDeclSpec::DQ_PR_copy)
 679     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
 680
 681   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
 682     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
 683
 684   if (isAssign)
 685     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
 686
 687   // In the semantic attributes, one of nonatomic or atomic is always set.
 688   if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
 689     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
 690   else
 691     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_atomic);
 692
 693   // 'unsafe_unretained' is alias for 'assign'.
 694   if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained)
 695     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
 696   if (isAssign)
 697     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_unsafe_unretained);
 698
 699   if (MethodImplKind == tok::objc_required)
 700     PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
 701   else if (MethodImplKind == tok::objc_optional)
 702     PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
 703
 704   if (Attributes & ObjCDeclSpec::DQ_PR_nullability)
 705     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nullability);
 706
 707   if (Attributes & ObjCDeclSpec::DQ_PR_null_resettable)
 708     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_null_resettable);
 709
 710   if (Attributes & ObjCDeclSpec::DQ_PR_class)
 711     PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_class);
 712
 713   if ((Attributes & ObjCDeclSpec::DQ_PR_direct) ||
 714       CDecl->hasAttr<ObjCDirectMembersAttr>()) {
 715     if (isa<ObjCProtocolDecl>(CDecl)) {
 716       Diag(PDecl->getLocation(), diag::err_objc_direct_on_protocol) << true;
 717     } else if (getLangOpts().ObjCRuntime.allowsDirectDispatch()) {
 718       PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_direct);
 719     } else {
 720       Diag(PDecl->getLocation(), diag::warn_objc_direct_property_ignored)
 721           << PDecl->getDeclName();
 722     }
 723   }
 724
 725   return PDecl;
 726 }
 727
 728 static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
 729                                  ObjCPropertyDecl *property,
 730                                  ObjCIvarDecl *ivar) {
 731   if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;
 732
 733   QualType ivarType = ivar->getType();
 734   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
 735
 736   // The lifetime implied by the property's attributes.
 737   Qualifiers::ObjCLifetime propertyLifetime =
 738     getImpliedARCOwnership(property->getPropertyAttributes(),
 739                            property->getType());
 740
 741   // We're fine if they match.
 742   if (propertyLifetime == ivarLifetime) return;
 743
 744   // None isn't a valid lifetime for an object ivar in ARC, and
 745   // __autoreleasing is never valid; don't diagnose twice.
 746   if ((ivarLifetime == Qualifiers::OCL_None &&
 747        S.getLangOpts().ObjCAutoRefCount) ||
 748       ivarLifetime == Qualifiers::OCL_Autoreleasing)
 749     return;
 750
 751   // If the ivar is private, and it's implicitly __unsafe_unretained
 752   // because of its type, then pretend it was actually implicitly
 753   // __strong.  This is only sound because we're processing the
 754   // property implementation before parsing any method bodies.
 755   if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
 756       propertyLifetime == Qualifiers::OCL_Strong &&
 757       ivar->getAccessControl() == ObjCIvarDecl::Private) {
 758     SplitQualType split = ivarType.split();
 759     if (split.Quals.hasObjCLifetime()) {
 760       assert(ivarType->isObjCARCImplicitlyUnretainedType());
 761       split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
 762       ivarType = S.Context.getQualifiedType(split);
 763       ivar->setType(ivarType);
 764       return;
 765     }
 766   }
 767
 768   switch (propertyLifetime) {
 769   case Qualifiers::OCL_Strong:
 770     S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
 771       << property->getDeclName()
 772       << ivar->getDeclName()
 773       << ivarLifetime;
 774     break;
 775
 776   case Qualifiers::OCL_Weak:
 777     S.Diag(ivar->getLocation(), diag::err_weak_property)
 778       << property->getDeclName()
 779       << ivar->getDeclName();
 780     break;
 781
 782   case Qualifiers::OCL_ExplicitNone:
 783     S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
 784       << property->getDeclName()
 785       << ivar->getDeclName()
 786       << ((property->getPropertyAttributesAsWritten()
 787            & ObjCPropertyDecl::OBJC_PR_assign) != 0);
 788     break;
 789
 790   case Qualifiers::OCL_Autoreleasing:
 791     llvm_unreachable("properties cannot be autoreleasing");
 792
 793   case Qualifiers::OCL_None:
 794     // Any other property should be ignored.
 795     return;
 796   }
 797
 798   S.Diag(property->getLocation(), diag::note_property_declare);
 799   if (propertyImplLoc.isValid())
 800     S.Diag(propertyImplLoc, diag::note_property_synthesize);
 801 }
 802
 803 /// setImpliedPropertyAttributeForReadOnlyProperty -
 804 /// This routine evaludates life-time attributes for a 'readonly'
 805 /// property with no known lifetime of its own, using backing
 806 /// 'ivar's attribute, if any. If no backing 'ivar', property's
 807 /// life-time is assumed 'strong'.
 808 static void setImpliedPropertyAttributeForReadOnlyProperty(
 809               ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
 810   Qualifiers::ObjCLifetime propertyLifetime =
 811     getImpliedARCOwnership(property->getPropertyAttributes(),
 812                            property->getType());
 813   if (propertyLifetime != Qualifiers::OCL_None)
 814     return;
 815
 816   if (!ivar) {
 817     // if no backing ivar, make property 'strong'.
 818     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
 819     return;
 820   }
 821   // property assumes owenership of backing ivar.
 822   QualType ivarType = ivar->getType();
 823   Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
 824   if (ivarLifetime == Qualifiers::OCL_Strong)
 825     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
 826   else if (ivarLifetime == Qualifiers::OCL_Weak)
 827     property->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_weak);
 828 }
 829
 830 static bool
 831 isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
 832                                 ObjCPropertyDecl::PropertyAttributeKind Kind) {
 833   return (Attr1 & Kind) != (Attr2 & Kind);
 834 }
 835
 836 static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
 837                                               unsigned Kinds) {
 838   return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
 839 }
 840
 841 /// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
 842 /// property declaration that should be synthesised in all of the inherited
 843 /// protocols. It also diagnoses properties declared in inherited protocols with
 844 /// mismatched types or attributes, since any of them can be candidate for
 845 /// synthesis.
 846 static ObjCPropertyDecl *
 847 SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
 848                                         ObjCInterfaceDecl *ClassDecl,
 849                                         ObjCPropertyDecl *Property) {
 850   assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&
 851          "Expected a property from a protocol");
 852   ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
 853   ObjCInterfaceDecl::PropertyDeclOrder Properties;
 854   for (const auto *PI : ClassDecl->all_referenced_protocols()) {
 855     if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 856       PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 857                                                 Properties);
 858   }
 859   if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
 860     while (SDecl) {
 861       for (const auto *PI : SDecl->all_referenced_protocols()) {
 862         if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
 863           PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
 864                                                     Properties);
 865       }
 866       SDecl = SDecl->getSuperClass();
 867     }
 868   }
 869
 870   if (Properties.empty())
 871     return Property;
 872
 873   ObjCPropertyDecl *OriginalProperty = Property;
 874   size_t SelectedIndex = 0;
 875   for (const auto &Prop : llvm::enumerate(Properties)) {
 876     // Select the 'readwrite' property if such property exists.
 877     if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
 878       Property = Prop.value();
 879       SelectedIndex = Prop.index();
 880     }
 881   }
 882   if (Property != OriginalProperty) {
 883     // Check that the old property is compatible with the new one.
 884     Properties[SelectedIndex] = OriginalProperty;
 885   }
 886
 887   QualType RHSType = S.Context.getCanonicalType(Property->getType());
 888   unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
 889   enum MismatchKind {
 890     IncompatibleType = 0,
 891     HasNoExpectedAttribute,
 892     HasUnexpectedAttribute,
 893     DifferentGetter,
 894     DifferentSetter
 895   };
 896   // Represents a property from another protocol that conflicts with the
 897   // selected declaration.
 898   struct MismatchingProperty {
 899     const ObjCPropertyDecl *Prop;
 900     MismatchKind Kind;
 901     StringRef AttributeName;
 902   };
 903   SmallVector<MismatchingProperty, 4> Mismatches;
 904   for (ObjCPropertyDecl *Prop : Properties) {
 905     // Verify the property attributes.
 906     unsigned Attr = Prop->getPropertyAttributesAsWritten();
 907     if (Attr != OriginalAttributes) {
 908       auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
 909         MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
 910                                                  : HasUnexpectedAttribute;
 911         Mismatches.push_back({Prop, Kind, AttributeName});
 912       };
 913       // The ownership might be incompatible unless the property has no explicit
 914       // ownership.
 915       bool HasOwnership = (Attr & (ObjCPropertyDecl::OBJC_PR_retain |
 916                                    ObjCPropertyDecl::OBJC_PR_strong |
 917                                    ObjCPropertyDecl::OBJC_PR_copy |
 918                                    ObjCPropertyDecl::OBJC_PR_assign |
 919                                    ObjCPropertyDecl::OBJC_PR_unsafe_unretained |
 920                                    ObjCPropertyDecl::OBJC_PR_weak)) != 0;
 921       if (HasOwnership &&
 922           isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 923                                           ObjCPropertyDecl::OBJC_PR_copy)) {
 924         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_copy, "copy");
 925         continue;
 926       }
 927       if (HasOwnership && areIncompatiblePropertyAttributes(
 928                               OriginalAttributes, Attr,
 929                               ObjCPropertyDecl::OBJC_PR_retain |
 930                                   ObjCPropertyDecl::OBJC_PR_strong)) {
 931         Diag(OriginalAttributes & (ObjCPropertyDecl::OBJC_PR_retain |
 932                                    ObjCPropertyDecl::OBJC_PR_strong),
 933              "retain (or strong)");
 934         continue;
 935       }
 936       if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
 937                                           ObjCPropertyDecl::OBJC_PR_atomic)) {
 938         Diag(OriginalAttributes & ObjCPropertyDecl::OBJC_PR_atomic, "atomic");
 939         continue;
 940       }
 941     }
 942     if (Property->getGetterName() != Prop->getGetterName()) {
 943       Mismatches.push_back({Prop, DifferentGetter, ""});
 944       continue;
 945     }
 946     if (!Property->isReadOnly() && !Prop->isReadOnly() &&
 947         Property->getSetterName() != Prop->getSetterName()) {
 948       Mismatches.push_back({Prop, DifferentSetter, ""});
 949       continue;
 950     }
 951     QualType LHSType = S.Context.getCanonicalType(Prop->getType());
 952     if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
 953       bool IncompatibleObjC = false;
 954       QualType ConvertedType;
 955       if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
 956           || IncompatibleObjC) {
 957         Mismatches.push_back({Prop, IncompatibleType, ""});
 958         continue;
 959       }
 960     }
 961   }
 962
 963   if (Mismatches.empty())
 964     return Property;
 965
 966   // Diagnose incompability.
 967   {
 968     bool HasIncompatibleAttributes = false;
 969     for (const auto &Note : Mismatches)
 970       HasIncompatibleAttributes =
 971           Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
 972     // Promote the warning to an error if there are incompatible attributes or
 973     // incompatible types together with readwrite/readonly incompatibility.
 974     auto Diag = S.Diag(Property->getLocation(),
 975                        Property != OriginalProperty || HasIncompatibleAttributes
 976                            ? diag::err_protocol_property_mismatch
 977                            : diag::warn_protocol_property_mismatch);
 978     Diag << Mismatches[0].Kind;
 979     switch (Mismatches[0].Kind) {
 980     case IncompatibleType:
 981       Diag << Property->getType();
 982       break;
 983     case HasNoExpectedAttribute:
 984     case HasUnexpectedAttribute:
 985       Diag << Mismatches[0].AttributeName;
 986       break;
 987     case DifferentGetter:
 988       Diag << Property->getGetterName();
 989       break;
 990     case DifferentSetter:
 991       Diag << Property->getSetterName();
 992       break;
 993     }
 994   }
 995   for (const auto &Note : Mismatches) {
 996     auto Diag =
 997         S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
 998         << Note.Kind;
 999     switch (Note.Kind) {
1000     case IncompatibleType:
1001       Diag << Note.Prop->getType();
1002       break;
1003     case HasNoExpectedAttribute:
1004     case HasUnexpectedAttribute:
1005       Diag << Note.AttributeName;
1006       break;
1007     case DifferentGetter:
1008       Diag << Note.Prop->getGetterName();
1009       break;
1010     case DifferentSetter:
1011       Diag << Note.Prop->getSetterName();
1012       break;
1013     }
1014   }
1015   if (AtLoc.isValid())
1016     S.Diag(AtLoc, diag::note_property_synthesize);
1017
1018   return Property;
1019 }
1020
1021 /// Determine whether any storage attributes were written on the property.
1022 static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
1023                                        ObjCPropertyQueryKind QueryKind) {
1024   if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;
1025
1026   // If this is a readwrite property in a class extension that refines
1027   // a readonly property in the original class definition, check it as
1028   // well.
1029
1030   // If it's a readonly property, we're not interested.
1031   if (Prop->isReadOnly()) return false;
1032
1033   // Is it declared in an extension?
1034   auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
1035   if (!Category || !Category->IsClassExtension()) return false;
1036
1037   // Find the corresponding property in the primary class definition.
1038   auto OrigClass = Category->getClassInterface();
1039   for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
1040     if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
1041       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1042   }
1043
1044   // Look through all of the protocols.
1045   for (const auto *Proto : OrigClass->all_referenced_protocols()) {
1046     if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
1047             Prop->getIdentifier(), QueryKind))
1048       return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
1049   }
1050
1051   return false;
1052 }
1053
1054 /// Create a synthesized property accessor stub inside the \@implementation.
1055 static ObjCMethodDecl *
1056 RedeclarePropertyAccessor(ASTContext &Context, ObjCImplementationDecl *Impl,
1057                           ObjCMethodDecl *AccessorDecl, SourceLocation AtLoc,
1058                           SourceLocation PropertyLoc) {
1059   ObjCMethodDecl *Decl = AccessorDecl;
1060   ObjCMethodDecl *ImplDecl = ObjCMethodDecl::Create(
1061       Context, AtLoc.isValid() ? AtLoc : Decl->getBeginLoc(),
1062       PropertyLoc.isValid() ? PropertyLoc : Decl->getEndLoc(),
1063       Decl->getSelector(), Decl->getReturnType(),
1064       Decl->getReturnTypeSourceInfo(), Impl, Decl->isInstanceMethod(),
1065       Decl->isVariadic(), Decl->isPropertyAccessor(),
1066       /* isSynthesized*/ true, Decl->isImplicit(), Decl->isDefined(),
1067       Decl->getImplementationControl(), Decl->hasRelatedResultType());
1068   ImplDecl->getMethodFamily();
1069   if (Decl->hasAttrs())
1070     ImplDecl->setAttrs(Decl->getAttrs());
1071   ImplDecl->setSelfDecl(Decl->getSelfDecl());
1072   ImplDecl->setCmdDecl(Decl->getCmdDecl());
1073   SmallVector<SourceLocation, 1> SelLocs;
1074   Decl->getSelectorLocs(SelLocs);
1075   ImplDecl->setMethodParams(Context, Decl->parameters(), SelLocs);
1076   ImplDecl->setLexicalDeclContext(Impl);
1077   ImplDecl->setDefined(false);
1078   return ImplDecl;
1079 }
1080
1081 /// ActOnPropertyImplDecl - This routine performs semantic checks and
1082 /// builds the AST node for a property implementation declaration; declared
1083 /// as \@synthesize or \@dynamic.
1084 ///
1085 Decl *Sema::ActOnPropertyImplDecl(Scope *S,
1086                                   SourceLocation AtLoc,
1087                                   SourceLocation PropertyLoc,
1088                                   bool Synthesize,
1089                                   IdentifierInfo *PropertyId,
1090                                   IdentifierInfo *PropertyIvar,
1091                                   SourceLocation PropertyIvarLoc,
1092                                   ObjCPropertyQueryKind QueryKind) {
1093   ObjCContainerDecl *ClassImpDecl =
1094     dyn_cast<ObjCContainerDecl>(CurContext);
1095   // Make sure we have a context for the property implementation declaration.
1096   if (!ClassImpDecl) {
1097     Diag(AtLoc, diag::err_missing_property_context);
1098     return nullptr;
1099   }
1100   if (PropertyIvarLoc.isInvalid())
1101     PropertyIvarLoc = PropertyLoc;
1102   SourceLocation PropertyDiagLoc = PropertyLoc;
1103   if (PropertyDiagLoc.isInvalid())
1104     PropertyDiagLoc = ClassImpDecl->getBeginLoc();
1105   ObjCPropertyDecl *property = nullptr;
1106   ObjCInterfaceDecl *IDecl = nullptr;
1107   // Find the class or category class where this property must have
1108   // a declaration.
1109   ObjCImplementationDecl *IC = nullptr;
1110   ObjCCategoryImplDecl *CatImplClass = nullptr;
1111   if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
1112     IDecl = IC->getClassInterface();
1113     // We always synthesize an interface for an implementation
1114     // without an interface decl. So, IDecl is always non-zero.
1115     assert(IDecl &&
1116            "ActOnPropertyImplDecl - @implementation without @interface");
1117
1118     // Look for this property declaration in the @implementation's @interface
1119     property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
1120     if (!property) {
1121       Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
1122       return nullptr;
1123     }
1124     if (property->isClassProperty() && Synthesize) {
1125       Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
1126       return nullptr;
1127     }
1128     unsigned PIkind = property->getPropertyAttributesAsWritten();
1129     if ((PIkind & (ObjCPropertyDecl::OBJC_PR_atomic |
1130                    ObjCPropertyDecl::OBJC_PR_nonatomic) ) == 0) {
1131       if (AtLoc.isValid())
1132         Diag(AtLoc, diag::warn_implicit_atomic_property);
1133       else
1134         Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
1135       Diag(property->getLocation(), diag::note_property_declare);
1136     }
1137
1138     if (const ObjCCategoryDecl *CD =
1139         dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
1140       if (!CD->IsClassExtension()) {
1141         Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
1142         Diag(property->getLocation(), diag::note_property_declare);
1143         return nullptr;
1144       }
1145     }
1146     if (Synthesize&&
1147         (PIkind & ObjCPropertyDecl::OBJC_PR_readonly) &&
1148         property->hasAttr<IBOutletAttr>() &&
1149         !AtLoc.isValid()) {
1150       bool ReadWriteProperty = false;
1151       // Search into the class extensions and see if 'readonly property is
1152       // redeclared 'readwrite', then no warning is to be issued.
1153       for (auto *Ext : IDecl->known_extensions()) {
1154         DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
1155         if (!R.empty())
1156           if (ObjCPropertyDecl *ExtProp = dyn_cast<ObjCPropertyDecl>(R[0])) {
1157             PIkind = ExtProp->getPropertyAttributesAsWritten();
1158             if (PIkind & ObjCPropertyDecl::OBJC_PR_readwrite) {
1159               ReadWriteProperty = true;
1160               break;
1161             }
1162           }
1163       }
1164
1165       if (!ReadWriteProperty) {
1166         Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
1167             << property;
1168         SourceLocation readonlyLoc;
1169         if (LocPropertyAttribute(Context, "readonly",
1170                                  property->getLParenLoc(), readonlyLoc)) {
1171           SourceLocation endLoc =
1172             readonlyLoc.getLocWithOffset(strlen("readonly")-1);
1173           SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
1174           Diag(property->getLocation(),
1175                diag::note_auto_readonly_iboutlet_fixup_suggest) <<
1176           FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
1177         }
1178       }
1179     }
1180     if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
1181       property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
1182                                                          property);
1183
1184   } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
1185     if (Synthesize) {
1186       Diag(AtLoc, diag::err_synthesize_category_decl);
1187       return nullptr;
1188     }
1189     IDecl = CatImplClass->getClassInterface();
1190     if (!IDecl) {
1191       Diag(AtLoc, diag::err_missing_property_interface);
1192       return nullptr;
1193     }
1194     ObjCCategoryDecl *Category =
1195     IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());
1196
1197     // If category for this implementation not found, it is an error which
1198     // has already been reported eralier.
1199     if (!Category)
1200       return nullptr;
1201     // Look for this property declaration in @implementation's category
1202     property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
1203     if (!property) {
1204       Diag(PropertyLoc, diag::err_bad_category_property_decl)
1205       << Category->getDeclName();
1206       return nullptr;
1207     }
1208   } else {
1209     Diag(AtLoc, diag::err_bad_property_context);
1210     return nullptr;
1211   }
1212   ObjCIvarDecl *Ivar = nullptr;
1213   bool CompleteTypeErr = false;
1214   bool compat = true;
1215   // Check that we have a valid, previously declared ivar for @synthesize
1216   if (Synthesize) {
1217     // @synthesize
1218     if (!PropertyIvar)
1219       PropertyIvar = PropertyId;
1220     // Check that this is a previously declared 'ivar' in 'IDecl' interface
1221     ObjCInterfaceDecl *ClassDeclared;
1222     Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
1223     QualType PropType = property->getType();
1224     QualType PropertyIvarType = PropType.getNonReferenceType();
1225
1226     if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
1227                             diag::err_incomplete_synthesized_property,
1228                             property->getDeclName())) {
1229       Diag(property->getLocation(), diag::note_property_declare);
1230       CompleteTypeErr = true;
1231     }
1232
1233     if (getLangOpts().ObjCAutoRefCount &&
1234         (property->getPropertyAttributesAsWritten() &
1235          ObjCPropertyDecl::OBJC_PR_readonly) &&
1236         PropertyIvarType->isObjCRetainableType()) {
1237       setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
1238     }
1239
1240     ObjCPropertyDecl::PropertyAttributeKind kind
1241       = property->getPropertyAttributes();
1242
1243     bool isARCWeak = false;
1244     if (kind & ObjCPropertyDecl::OBJC_PR_weak) {
1245       // Add GC __weak to the ivar type if the property is weak.
1246       if (getLangOpts().getGC() != LangOptions::NonGC) {
1247         assert(!getLangOpts().ObjCAutoRefCount);
1248         if (PropertyIvarType.isObjCGCStrong()) {
1249           Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
1250           Diag(property->getLocation(), diag::note_property_declare);
1251         } else {
1252           PropertyIvarType =
1253             Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
1254         }
1255
1256       // Otherwise, check whether ARC __weak is enabled and works with
1257       // the property type.
1258       } else {
1259         if (!getLangOpts().ObjCWeak) {
1260           // Only complain here when synthesizing an ivar.
1261           if (!Ivar) {
1262             Diag(PropertyDiagLoc,
1263                  getLangOpts().ObjCWeakRuntime
1264                    ? diag::err_synthesizing_arc_weak_property_disabled
1265                    : diag::err_synthesizing_arc_weak_property_no_runtime);
1266             Diag(property->getLocation(), diag::note_property_declare);
1267           }
1268           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1269         } else {
1270           isARCWeak = true;
1271           if (const ObjCObjectPointerType *ObjT =
1272                 PropertyIvarType->getAs<ObjCObjectPointerType>()) {
1273             const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
1274             if (ObjI && ObjI->isArcWeakrefUnavailable()) {
1275               Diag(property->getLocation(),
1276                    diag::err_arc_weak_unavailable_property)
1277                 << PropertyIvarType;
1278               Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
1279                 << ClassImpDecl->getName();
1280             }
1281           }
1282         }
1283       }
1284     }
1285
1286     if (AtLoc.isInvalid()) {
1287       // Check when default synthesizing a property that there is
1288       // an ivar matching property name and issue warning; since this
1289       // is the most common case of not using an ivar used for backing
1290       // property in non-default synthesis case.
1291       ObjCInterfaceDecl *ClassDeclared=nullptr;
1292       ObjCIvarDecl *originalIvar =
1293       IDecl->lookupInstanceVariable(property->getIdentifier(),
1294                                     ClassDeclared);
1295       if (originalIvar) {
1296         Diag(PropertyDiagLoc,
1297              diag::warn_autosynthesis_property_ivar_match)
1298         << PropertyId << (Ivar == nullptr) << PropertyIvar
1299         << originalIvar->getIdentifier();
1300         Diag(property->getLocation(), diag::note_property_declare);
1301         Diag(originalIvar->getLocation(), diag::note_ivar_decl);
1302       }
1303     }
1304
1305     if (!Ivar) {
1306       // In ARC, give the ivar a lifetime qualifier based on the
1307       // property attributes.
1308       if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
1309           !PropertyIvarType.getObjCLifetime() &&
1310           PropertyIvarType->isObjCRetainableType()) {
1311
1312         // It's an error if we have to do this and the user didn't
1313         // explicitly write an ownership attribute on the property.
1314         if (!hasWrittenStorageAttribute(property, QueryKind) &&
1315             !(kind & ObjCPropertyDecl::OBJC_PR_strong)) {
1316           Diag(PropertyDiagLoc,
1317                diag::err_arc_objc_property_default_assign_on_object);
1318           Diag(property->getLocation(), diag::note_property_declare);
1319         } else {
1320           Qualifiers::ObjCLifetime lifetime =
1321             getImpliedARCOwnership(kind, PropertyIvarType);
1322           assert(lifetime && "no lifetime for property?");
1323
1324           Qualifiers qs;
1325           qs.addObjCLifetime(lifetime);
1326           PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
1327         }
1328       }
1329
1330       Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
1331                                   PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
1332                                   PropertyIvarType, /*TInfo=*/nullptr,
1333                                   ObjCIvarDecl::Private,
1334                                   (Expr *)nullptr, true);
1335       if (RequireNonAbstractType(PropertyIvarLoc,
1336                                  PropertyIvarType,
1337                                  diag::err_abstract_type_in_decl,
1338                                  AbstractSynthesizedIvarType)) {
1339         Diag(property->getLocation(), diag::note_property_declare);
1340         // An abstract type is as bad as an incomplete type.
1341         CompleteTypeErr = true;
1342       }
1343       if (!CompleteTypeErr) {
1344         const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
1345         if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
1346           Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
1347             << PropertyIvarType;
1348           CompleteTypeErr = true; // suppress later diagnostics about the ivar
1349         }
1350       }
1351       if (CompleteTypeErr)
1352         Ivar->setInvalidDecl();
1353       ClassImpDecl->addDecl(Ivar);
1354       IDecl->makeDeclVisibleInContext(Ivar);
1355
1356       if (getLangOpts().ObjCRuntime.isFragile())
1357         Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
1358             << PropertyId;
1359       // Note! I deliberately want it to fall thru so, we have a
1360       // a property implementation and to avoid future warnings.
1361     } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
1362                !declaresSameEntity(ClassDeclared, IDecl)) {
1363       Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
1364       << property->getDeclName() << Ivar->getDeclName()
1365       << ClassDeclared->getDeclName();
1366       Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
1367       << Ivar << Ivar->getName();
1368       // Note! I deliberately want it to fall thru so more errors are caught.
1369     }
1370     property->setPropertyIvarDecl(Ivar);
1371
1372     QualType IvarType = Context.getCanonicalType(Ivar->getType());
1373
1374     // Check that type of property and its ivar are type compatible.
1375     if (!Context.hasSameType(PropertyIvarType, IvarType)) {
1376       if (isa<ObjCObjectPointerType>(PropertyIvarType)
1377           && isa<ObjCObjectPointerType>(IvarType))
1378         compat =
1379           Context.canAssignObjCInterfaces(
1380                                   PropertyIvarType->getAs<ObjCObjectPointerType>(),
1381                                   IvarType->getAs<ObjCObjectPointerType>());
1382       else {
1383         compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
1384                                              IvarType)
1385                     == Compatible);
1386       }
1387       if (!compat) {
1388         Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1389           << property->getDeclName() << PropType
1390           << Ivar->getDeclName() << IvarType;
1391         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1392         // Note! I deliberately want it to fall thru so, we have a
1393         // a property implementation and to avoid future warnings.
1394       }
1395       else {
1396         // FIXME! Rules for properties are somewhat different that those
1397         // for assignments. Use a new routine to consolidate all cases;
1398         // specifically for property redeclarations as well as for ivars.
1399         QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
1400         QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
1401         if (lhsType != rhsType &&
1402             lhsType->isArithmeticType()) {
1403           Diag(PropertyDiagLoc, diag::err_property_ivar_type)
1404             << property->getDeclName() << PropType
1405             << Ivar->getDeclName() << IvarType;
1406           Diag(Ivar->getLocation(), diag::note_ivar_decl);
1407           // Fall thru - see previous comment
1408         }
1409       }
1410       // __weak is explicit. So it works on Canonical type.
1411       if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
1412            getLangOpts().getGC() != LangOptions::NonGC)) {
1413         Diag(PropertyDiagLoc, diag::err_weak_property)
1414         << property->getDeclName() << Ivar->getDeclName();
1415         Diag(Ivar->getLocation(), diag::note_ivar_decl);
1416         // Fall thru - see previous comment
1417       }
1418       // Fall thru - see previous comment
1419       if ((property->getType()->isObjCObjectPointerType() ||
1420            PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
1421           getLangOpts().getGC() != LangOptions::NonGC) {
1422         Diag(PropertyDiagLoc, diag::err_strong_property)
1423         << property->getDeclName() << Ivar->getDeclName();
1424         // Fall thru - see previous comment
1425       }
1426     }
1427     if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
1428         Ivar->getType().getObjCLifetime())
1429       checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
1430   } else if (PropertyIvar)
1431     // @dynamic
1432     Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);
1433
1434   assert (property && "ActOnPropertyImplDecl - property declaration missing");
1435   ObjCPropertyImplDecl *PIDecl =
1436   ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
1437                                property,
1438                                (Synthesize ?
1439                                 ObjCPropertyImplDecl::Synthesize
1440                                 : ObjCPropertyImplDecl::Dynamic),
1441                                Ivar, PropertyIvarLoc);
1442
1443   if (CompleteTypeErr || !compat)
1444     PIDecl->setInvalidDecl();
1445
1446   if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
1447     getterMethod->createImplicitParams(Context, IDecl);
1448
1449     // Redeclare the getter within the implementation as DeclContext.
1450     if (Synthesize) {
1451       // If the method hasn't been overridden, create a synthesized implementation.
1452       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1453           getterMethod->getSelector(), getterMethod->isInstanceMethod());
1454       if (!OMD)
1455         OMD = RedeclarePropertyAccessor(Context, IC, getterMethod, AtLoc,
1456                                         PropertyLoc);
1457       PIDecl->setGetterMethodDecl(OMD);
1458     }
1459
1460     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1461         Ivar->getType()->isRecordType()) {
1462       // For Objective-C++, need to synthesize the AST for the IVAR object to be
1463       // returned by the getter as it must conform to C++'s copy-return rules.
1464       // FIXME. Eventually we want to do this for Objective-C as well.
1465       SynthesizedFunctionScope Scope(*this, getterMethod);
1466       ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
1467       DeclRefExpr *SelfExpr = new (Context)
1468           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1469                       PropertyDiagLoc);
1470       MarkDeclRefReferenced(SelfExpr);
1471       Expr *LoadSelfExpr =
1472         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1473                                  CK_LValueToRValue, SelfExpr, nullptr,
1474                                  VK_RValue);
1475       Expr *IvarRefExpr =
1476         new (Context) ObjCIvarRefExpr(Ivar,
1477                                       Ivar->getUsageType(SelfDecl->getType()),
1478                                       PropertyDiagLoc,
1479                                       Ivar->getLocation(),
1480                                       LoadSelfExpr, true, true);
1481       ExprResult Res = PerformCopyInitialization(
1482           InitializedEntity::InitializeResult(PropertyDiagLoc,
1483                                               getterMethod->getReturnType(),
1484                                               /*NRVO=*/false),
1485           PropertyDiagLoc, IvarRefExpr);
1486       if (!Res.isInvalid()) {
1487         Expr *ResExpr = Res.getAs<Expr>();
1488         if (ResExpr)
1489           ResExpr = MaybeCreateExprWithCleanups(ResExpr);
1490         PIDecl->setGetterCXXConstructor(ResExpr);
1491       }
1492     }
1493     if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
1494         !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
1495       Diag(getterMethod->getLocation(),
1496            diag::warn_property_getter_owning_mismatch);
1497       Diag(property->getLocation(), diag::note_property_declare);
1498     }
1499     if (getLangOpts().ObjCAutoRefCount && Synthesize)
1500       switch (getterMethod->getMethodFamily()) {
1501         case OMF_retain:
1502         case OMF_retainCount:
1503         case OMF_release:
1504         case OMF_autorelease:
1505           Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
1506             << 1 << getterMethod->getSelector();
1507           break;
1508         default:
1509           break;
1510       }
1511   }
1512
1513   if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
1514     setterMethod->createImplicitParams(Context, IDecl);
1515
1516     // Redeclare the setter within the implementation as DeclContext.
1517     if (Synthesize) {
1518       ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
1519           setterMethod->getSelector(), setterMethod->isInstanceMethod());
1520       if (!OMD)
1521         OMD = RedeclarePropertyAccessor(Context, IC, setterMethod,
1522                                         AtLoc, PropertyLoc);
1523       PIDecl->setSetterMethodDecl(OMD);
1524     }
1525
1526     if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
1527         Ivar->getType()->isRecordType()) {
1528       // FIXME. Eventually we want to do this for Objective-C as well.
1529       SynthesizedFunctionScope Scope(*this, setterMethod);
1530       ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
1531       DeclRefExpr *SelfExpr = new (Context)
1532           DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
1533                       PropertyDiagLoc);
1534       MarkDeclRefReferenced(SelfExpr);
1535       Expr *LoadSelfExpr =
1536         ImplicitCastExpr::Create(Context, SelfDecl->getType(),
1537                                  CK_LValueToRValue, SelfExpr, nullptr,
1538                                  VK_RValue);
1539       Expr *lhs =
1540         new (Context) ObjCIvarRefExpr(Ivar,
1541                                       Ivar->getUsageType(SelfDecl->getType()),
1542                                       PropertyDiagLoc,
1543                                       Ivar->getLocation(),
1544                                       LoadSelfExpr, true, true);
1545       ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
1546       ParmVarDecl *Param = (*P);
1547       QualType T = Param->getType().getNonReferenceType();
1548       DeclRefExpr *rhs = new (Context)
1549           DeclRefExpr(Context, Param, false, T, VK_LValue, PropertyDiagLoc);
1550       MarkDeclRefReferenced(rhs);
1551       ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
1552                                   BO_Assign, lhs, rhs);
1553       if (property->getPropertyAttributes() &
1554           ObjCPropertyDecl::OBJC_PR_atomic) {
1555         Expr *callExpr = Res.getAs<Expr>();
1556         if (const CXXOperatorCallExpr *CXXCE =
1557               dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
1558           if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
1559             if (!FuncDecl->isTrivial())
1560               if (property->getType()->isReferenceType()) {
1561                 Diag(PropertyDiagLoc,
1562                      diag::err_atomic_property_nontrivial_assign_op)
1563                     << property->getType();
1564                 Diag(FuncDecl->getBeginLoc(), diag::note_callee_decl)
1565                     << FuncDecl;
1566               }
1567       }
1568       PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
1569     }
1570   }
1571
1572   if (IC) {
1573     if (Synthesize)
1574       if (ObjCPropertyImplDecl *PPIDecl =
1575           IC->FindPropertyImplIvarDecl(PropertyIvar)) {
1576         Diag(PropertyLoc, diag::err_duplicate_ivar_use)
1577         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1578         << PropertyIvar;
1579         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1580       }
1581
1582     if (ObjCPropertyImplDecl *PPIDecl
1583         = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
1584       Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
1585       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1586       return nullptr;
1587     }
1588     IC->addPropertyImplementation(PIDecl);
1589     if (getLangOpts().ObjCDefaultSynthProperties &&
1590         getLangOpts().ObjCRuntime.isNonFragile() &&
1591         !IDecl->isObjCRequiresPropertyDefs()) {
1592       // Diagnose if an ivar was lazily synthesdized due to a previous
1593       // use and if 1) property is @dynamic or 2) property is synthesized
1594       // but it requires an ivar of different name.
1595       ObjCInterfaceDecl *ClassDeclared=nullptr;
1596       ObjCIvarDecl *Ivar = nullptr;
1597       if (!Synthesize)
1598         Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1599       else {
1600         if (PropertyIvar && PropertyIvar != PropertyId)
1601           Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
1602       }
1603       // Issue diagnostics only if Ivar belongs to current class.
1604       if (Ivar && Ivar->getSynthesize() &&
1605           declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
1606         Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
1607         << PropertyId;
1608         Ivar->setInvalidDecl();
1609       }
1610     }
1611   } else {
1612     if (Synthesize)
1613       if (ObjCPropertyImplDecl *PPIDecl =
1614           CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
1615         Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
1616         << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
1617         << PropertyIvar;
1618         Diag(PPIDecl->getLocation(), diag::note_previous_use);
1619       }
1620
1621     if (ObjCPropertyImplDecl *PPIDecl =
1622         CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
1623       Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
1624       Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
1625       return nullptr;
1626     }
1627     CatImplClass->addPropertyImplementation(PIDecl);
1628   }
1629
1630   return PIDecl;
1631 }
1632
1633 //===----------------------------------------------------------------------===//
1634 // Helper methods.
1635 //===----------------------------------------------------------------------===//
1636
1637 /// DiagnosePropertyMismatch - Compares two properties for their
1638 /// attributes and types and warns on a variety of inconsistencies.
1639 ///
1640 void
1641 Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
1642                                ObjCPropertyDecl *SuperProperty,
1643                                const IdentifierInfo *inheritedName,
1644                                bool OverridingProtocolProperty) {
1645   ObjCPropertyDecl::PropertyAttributeKind CAttr =
1646     Property->getPropertyAttributes();
1647   ObjCPropertyDecl::PropertyAttributeKind SAttr =
1648     SuperProperty->getPropertyAttributes();
1649
1650   // We allow readonly properties without an explicit ownership
1651   // (assign/unsafe_unretained/weak/retain/strong/copy) in super class
1652   // to be overridden by a property with any explicit ownership in the subclass.
1653   if (!OverridingProtocolProperty &&
1654       !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
1655     ;
1656   else {
1657     if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
1658         && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
1659       Diag(Property->getLocation(), diag::warn_readonly_property)
1660         << Property->getDeclName() << inheritedName;
1661     if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
1662         != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
1663       Diag(Property->getLocation(), diag::warn_property_attribute)
1664         << Property->getDeclName() << "copy" << inheritedName;
1665     else if (!(SAttr & ObjCPropertyDecl::OBJC_PR_readonly)){
1666       unsigned CAttrRetain =
1667         (CAttr &
1668          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1669       unsigned SAttrRetain =
1670         (SAttr &
1671          (ObjCPropertyDecl::OBJC_PR_retain | ObjCPropertyDecl::OBJC_PR_strong));
1672       bool CStrong = (CAttrRetain != 0);
1673       bool SStrong = (SAttrRetain != 0);
1674       if (CStrong != SStrong)
1675         Diag(Property->getLocation(), diag::warn_property_attribute)
1676           << Property->getDeclName() << "retain (or strong)" << inheritedName;
1677     }
1678   }
1679
1680   // Check for nonatomic; note that nonatomic is effectively
1681   // meaningless for readonly properties, so don't diagnose if the
1682   // atomic property is 'readonly'.
1683   checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
1684   // Readonly properties from protocols can be implemented as "readwrite"
1685   // with a custom setter name.
1686   if (Property->getSetterName() != SuperProperty->getSetterName() &&
1687       !(SuperProperty->isReadOnly() &&
1688         isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
1689     Diag(Property->getLocation(), diag::warn_property_attribute)
1690       << Property->getDeclName() << "setter" << inheritedName;
1691     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1692   }
1693   if (Property->getGetterName() != SuperProperty->getGetterName()) {
1694     Diag(Property->getLocation(), diag::warn_property_attribute)
1695       << Property->getDeclName() << "getter" << inheritedName;
1696     Diag(SuperProperty->getLocation(), diag::note_property_declare);
1697   }
1698
1699   QualType LHSType =
1700     Context.getCanonicalType(SuperProperty->getType());
1701   QualType RHSType =
1702     Context.getCanonicalType(Property->getType());
1703
1704   if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
1705     // Do cases not handled in above.
1706     // FIXME. For future support of covariant property types, revisit this.
1707     bool IncompatibleObjC = false;
1708     QualType ConvertedType;
1709     if (!isObjCPointerConversion(RHSType, LHSType,
1710                                  ConvertedType, IncompatibleObjC) ||
1711         IncompatibleObjC) {
1712         Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
1713         << Property->getType() << SuperProperty->getType() << inheritedName;
1714       Diag(SuperProperty->getLocation(), diag::note_property_declare);
1715     }
1716   }
1717 }
1718
1719 bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
1720                                             ObjCMethodDecl *GetterMethod,
1721                                             SourceLocation Loc) {
1722   if (!GetterMethod)
1723     return false;
1724   QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
1725   QualType PropertyRValueType =
1726       property->getType().getNonReferenceType().getAtomicUnqualifiedType();
1727   bool compat = Context.hasSameType(PropertyRValueType, GetterType);
1728   if (!compat) {
1729     const ObjCObjectPointerType *propertyObjCPtr = nullptr;
1730     const ObjCObjectPointerType *getterObjCPtr = nullptr;
1731     if ((propertyObjCPtr =
1732              PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
1733         (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
1734       compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
1735     else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
1736               != Compatible) {
1737           Diag(Loc, diag::err_property_accessor_type)
1738             << property->getDeclName() << PropertyRValueType
1739             << GetterMethod->getSelector() << GetterType;
1740           Diag(GetterMethod->getLocation(), diag::note_declared_at);
1741           return true;
1742     } else {
1743       compat = true;
1744       QualType lhsType = Context.getCanonicalType(PropertyRValueType);
1745       QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
1746       if (lhsType != rhsType && lhsType->isArithmeticType())
1747         compat = false;
1748     }
1749   }
1750
1751   if (!compat) {
1752     Diag(Loc, diag::warn_accessor_property_type_mismatch)
1753     << property->getDeclName()
1754     << GetterMethod->getSelector();
1755     Diag(GetterMethod->getLocation(), diag::note_declared_at);
1756     return true;
1757   }
1758
1759   return false;
1760 }
1761
1762 /// CollectImmediateProperties - This routine collects all properties in
1763 /// the class and its conforming protocols; but not those in its super class.
1764 static void
1765 CollectImmediateProperties(ObjCContainerDecl *CDecl,
1766                            ObjCContainerDecl::PropertyMap &PropMap,
1767                            ObjCContainerDecl::PropertyMap &SuperPropMap,
1768                            bool CollectClassPropsOnly = false,
1769                            bool IncludeProtocols = true) {
1770   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
1771     for (auto *Prop : IDecl->properties()) {
1772       if (CollectClassPropsOnly && !Prop->isClassProperty())
1773         continue;
1774       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1775           Prop;
1776     }
1777
1778     // Collect the properties from visible extensions.
1779     for (auto *Ext : IDecl->visible_extensions())
1780       CollectImmediateProperties(Ext, PropMap, SuperPropMap,
1781                                  CollectClassPropsOnly, IncludeProtocols);
1782
1783     if (IncludeProtocols) {
1784       // Scan through class's protocols.
1785       for (auto *PI : IDecl->all_referenced_protocols())
1786         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1787                                    CollectClassPropsOnly);
1788     }
1789   }
1790   if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
1791     for (auto *Prop : CATDecl->properties()) {
1792       if (CollectClassPropsOnly && !Prop->isClassProperty())
1793         continue;
1794       PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
1795           Prop;
1796     }
1797     if (IncludeProtocols) {
1798       // Scan through class's protocols.
1799       for (auto *PI : CATDecl->protocols())
1800         CollectImmediateProperties(PI, PropMap, SuperPropMap,
1801                                    CollectClassPropsOnly);
1802     }
1803   }
1804   else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
1805     for (auto *Prop : PDecl->properties()) {
1806       if (CollectClassPropsOnly && !Prop->isClassProperty())
1807         continue;
1808       ObjCPropertyDecl *PropertyFromSuper =
1809           SuperPropMap[std::make_pair(Prop->getIdentifier(),
1810                                       Prop->isClassProperty())];
1811       // Exclude property for protocols which conform to class's super-class,
1812       // as super-class has to implement the property.
1813       if (!PropertyFromSuper ||
1814           PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
1815         ObjCPropertyDecl *&PropEntry =
1816             PropMap[std::make_pair(Prop->getIdentifier(),
1817                                    Prop->isClassProperty())];
1818         if (!PropEntry)
1819           PropEntry = Prop;
1820       }
1821     }
1822     // Scan through protocol's protocols.
1823     for (auto *PI : PDecl->protocols())
1824       CollectImmediateProperties(PI, PropMap, SuperPropMap,
1825                                  CollectClassPropsOnly);
1826   }
1827 }
1828
1829 /// CollectSuperClassPropertyImplementations - This routine collects list of
1830 /// properties to be implemented in super class(s) and also coming from their
1831 /// conforming protocols.
1832 static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
1833                                     ObjCInterfaceDecl::PropertyMap &PropMap) {
1834   if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
1835     ObjCInterfaceDecl::PropertyDeclOrder PO;
1836     while (SDecl) {
1837       SDecl->collectPropertiesToImplement(PropMap, PO);
1838       SDecl = SDecl->getSuperClass();
1839     }
1840   }
1841 }
1842
1843 /// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1844 /// an ivar synthesized for 'Method' and 'Method' is a property accessor
1845 /// declared in class 'IFace'.
1846 bool
1847 Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
1848                                      ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
1849   if (!IV->getSynthesize())
1850     return false;
1851   ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
1852                                             Method->isInstanceMethod());
1853   if (!IMD || !IMD->isPropertyAccessor())
1854     return false;
1855
1856   // look up a property declaration whose one of its accessors is implemented
1857   // by this method.
1858   for (const auto *Property : IFace->instance_properties()) {
1859     if ((Property->getGetterName() == IMD->getSelector() ||
1860          Property->getSetterName() == IMD->getSelector()) &&
1861         (Property->getPropertyIvarDecl() == IV))
1862       return true;
1863   }
1864   // Also look up property declaration in class extension whose one of its
1865   // accessors is implemented by this method.
1866   for (const auto *Ext : IFace->known_extensions())
1867     for (const auto *Property : Ext->instance_properties())
1868       if ((Property->getGetterName() == IMD->getSelector() ||
1869            Property->getSetterName() == IMD->getSelector()) &&
1870           (Property->getPropertyIvarDecl() == IV))
1871         return true;
1872   return false;
1873 }
1874
1875 static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
1876                                          ObjCPropertyDecl *Prop) {
1877   bool SuperClassImplementsGetter = false;
1878   bool SuperClassImplementsSetter = false;
1879   if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1880     SuperClassImplementsSetter = true;
1881
1882   while (IDecl->getSuperClass()) {
1883     ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
1884     if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
1885       SuperClassImplementsGetter = true;
1886
1887     if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
1888       SuperClassImplementsSetter = true;
1889     if (SuperClassImplementsGetter && SuperClassImplementsSetter)
1890       return true;
1891     IDecl = IDecl->getSuperClass();
1892   }
1893   return false;
1894 }
1895
1896 /// Default synthesizes all properties which must be synthesized
1897 /// in class's \@implementation.
1898 void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
1899                                        ObjCInterfaceDecl *IDecl,
1900                                        SourceLocation AtEnd) {
1901   ObjCInterfaceDecl::PropertyMap PropMap;
1902   ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
1903   IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
1904   if (PropMap.empty())
1905     return;
1906   ObjCInterfaceDecl::PropertyMap SuperPropMap;
1907   CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);
1908
1909   for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
1910     ObjCPropertyDecl *Prop = PropertyOrder[i];
1911     // Is there a matching property synthesize/dynamic?
1912     if (Prop->isInvalidDecl() ||
1913         Prop->isClassProperty() ||
1914         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
1915       continue;
1916     // Property may have been synthesized by user.
1917     if (IMPDecl->FindPropertyImplDecl(
1918             Prop->getIdentifier(), Prop->getQueryKind()))
1919       continue;
1920     ObjCMethodDecl *ImpMethod = IMPDecl->getInstanceMethod(Prop->getGetterName());
1921     if (ImpMethod && !ImpMethod->getBody()) {
1922       if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readonly)
1923         continue;
1924       ImpMethod = IMPDecl->getInstanceMethod(Prop->getSetterName());
1925       if (ImpMethod && !ImpMethod->getBody())
1926         continue;
1927     }
1928     if (ObjCPropertyImplDecl *PID =
1929         IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
1930       Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
1931         << Prop->getIdentifier();
1932       if (PID->getLocation().isValid())
1933         Diag(PID->getLocation(), diag::note_property_synthesize);
1934       continue;
1935     }
1936     ObjCPropertyDecl *PropInSuperClass =
1937         SuperPropMap[std::make_pair(Prop->getIdentifier(),
1938                                     Prop->isClassProperty())];
1939     if (ObjCProtocolDecl *Proto =
1940           dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
1941       // We won't auto-synthesize properties declared in protocols.
1942       // Suppress the warning if class's superclass implements property's
1943       // getter and implements property's setter (if readwrite property).
1944       // Or, if property is going to be implemented in its super class.
1945       if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
1946         Diag(IMPDecl->getLocation(),
1947              diag::warn_auto_synthesizing_protocol_property)
1948           << Prop << Proto;
1949         Diag(Prop->getLocation(), diag::note_property_declare);
1950         std::string FixIt =
1951             (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
1952         Diag(AtEnd, diag::note_add_synthesize_directive)
1953             << FixItHint::CreateInsertion(AtEnd, FixIt);
1954       }
1955       continue;
1956     }
1957     // If property to be implemented in the super class, ignore.
1958     if (PropInSuperClass) {
1959       if ((Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_readwrite) &&
1960           (PropInSuperClass->getPropertyAttributes() &
1961            ObjCPropertyDecl::OBJC_PR_readonly) &&
1962           !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
1963           !IDecl->HasUserDeclaredSetterMethod(Prop)) {
1964         Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
1965         << Prop->getIdentifier();
1966         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1967       }
1968       else {
1969         Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
1970         << Prop->getIdentifier();
1971         Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
1972         Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1973       }
1974       continue;
1975     }
1976     // We use invalid SourceLocations for the synthesized ivars since they
1977     // aren't really synthesized at a particular location; they just exist.
1978     // Saying that they are located at the @implementation isn't really going
1979     // to help users.
1980     ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
1981       ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
1982                             true,
1983                             /* property = */ Prop->getIdentifier(),
1984                             /* ivar = */ Prop->getDefaultSynthIvarName(Context),
1985                             Prop->getLocation(), Prop->getQueryKind()));
1986     if (PIDecl && !Prop->isUnavailable()) {
1987       Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
1988       Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
1989     }
1990   }
1991 }
1992
1993 void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
1994                                        SourceLocation AtEnd) {
1995   if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
1996     return;
1997   ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
1998   if (!IC)
1999     return;
2000   if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
2001     if (!IDecl->isObjCRequiresPropertyDefs())
2002       DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
2003 }
2004
2005 static void DiagnoseUnimplementedAccessor(
2006     Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
2007     ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
2008     ObjCPropertyDecl *Prop,
2009     llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
2010   // Check to see if we have a corresponding selector in SMap and with the
2011   // right method type.
2012   auto I = llvm::find_if(SMap, [&](const ObjCMethodDecl *x) {
2013     return x->getSelector() == Method &&
2014            x->isClassMethod() == Prop->isClassProperty();
2015   });
2016   // When reporting on missing property setter/getter implementation in
2017   // categories, do not report when they are declared in primary class,
2018   // class's protocol, or one of it super classes. This is because,
2019   // the class is going to implement them.
2020   if (I == SMap.end() &&
2021       (PrimaryClass == nullptr ||
2022        !PrimaryClass->lookupPropertyAccessor(Method, C,
2023                                              Prop->isClassProperty()))) {
2024     unsigned diag =
2025         isa<ObjCCategoryDecl>(CDecl)
2026             ? (Prop->isClassProperty()
2027                    ? diag::warn_impl_required_in_category_for_class_property
2028                    : diag::warn_setter_getter_impl_required_in_category)
2029             : (Prop->isClassProperty()
2030                    ? diag::warn_impl_required_for_class_property
2031                    : diag::warn_setter_getter_impl_required);
2032     S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
2033     S.Diag(Prop->getLocation(), diag::note_property_declare);
2034     if (S.LangOpts.ObjCDefaultSynthProperties &&
2035         S.LangOpts.ObjCRuntime.isNonFragile())
2036       if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
2037         if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
2038           S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
2039   }
2040 }
2041
2042 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
2043                                            ObjCContainerDecl *CDecl,
2044                                            bool SynthesizeProperties) {
2045   ObjCContainerDecl::PropertyMap PropMap;
2046   ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);
2047
2048   // Since we don't synthesize class properties, we should emit diagnose even
2049   // if SynthesizeProperties is true.
2050   ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2051   // Gather properties which need not be implemented in this class
2052   // or category.
2053   if (!IDecl)
2054     if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
2055       // For categories, no need to implement properties declared in
2056       // its primary class (and its super classes) if property is
2057       // declared in one of those containers.
2058       if ((IDecl = C->getClassInterface())) {
2059         ObjCInterfaceDecl::PropertyDeclOrder PO;
2060         IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
2061       }
2062     }
2063   if (IDecl)
2064     CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);
2065
2066   // When SynthesizeProperties is true, we only check class properties.
2067   CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
2068                              SynthesizeProperties/*CollectClassPropsOnly*/);
2069
2070   // Scan the @interface to see if any of the protocols it adopts
2071   // require an explicit implementation, via attribute
2072   // 'objc_protocol_requires_explicit_implementation'.
2073   if (IDecl) {
2074     std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;
2075
2076     for (auto *PDecl : IDecl->all_referenced_protocols()) {
2077       if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
2078         continue;
2079       // Lazily construct a set of all the properties in the @interface
2080       // of the class, without looking at the superclass.  We cannot
2081       // use the call to CollectImmediateProperties() above as that
2082       // utilizes information from the super class's properties as well
2083       // as scans the adopted protocols.  This work only triggers for protocols
2084       // with the attribute, which is very rare, and only occurs when
2085       // analyzing the @implementation.
2086       if (!LazyMap) {
2087         ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
2088         LazyMap.reset(new ObjCContainerDecl::PropertyMap());
2089         CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
2090                                    /* CollectClassPropsOnly */ false,
2091                                    /* IncludeProtocols */ false);
2092       }
2093       // Add the properties of 'PDecl' to the list of properties that
2094       // need to be implemented.
2095       for (auto *PropDecl : PDecl->properties()) {
2096         if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
2097                                       PropDecl->isClassProperty())])
2098           continue;
2099         PropMap[std::make_pair(PropDecl->getIdentifier(),
2100                                PropDecl->isClassProperty())] = PropDecl;
2101       }
2102     }
2103   }
2104
2105   if (PropMap.empty())
2106     return;
2107
2108   llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
2109   for (const auto *I : IMPDecl->property_impls())
2110     PropImplMap.insert(I->getPropertyDecl());
2111
2112   llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
2113   // Collect property accessors implemented in current implementation.
2114   for (const auto *I : IMPDecl->methods())
2115     InsMap.insert(I);
2116
2117   ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
2118   ObjCInterfaceDecl *PrimaryClass = nullptr;
2119   if (C && !C->IsClassExtension())
2120     if ((PrimaryClass = C->getClassInterface()))
2121       // Report unimplemented properties in the category as well.
2122       if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
2123         // When reporting on missing setter/getters, do not report when
2124         // setter/getter is implemented in category's primary class
2125         // implementation.
2126         for (const auto *I : IMP->methods())
2127           InsMap.insert(I);
2128       }
2129
2130   for (ObjCContainerDecl::PropertyMap::iterator
2131        P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
2132     ObjCPropertyDecl *Prop = P->second;
2133     // Is there a matching property synthesize/dynamic?
2134     if (Prop->isInvalidDecl() ||
2135         Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
2136         PropImplMap.count(Prop) ||
2137         Prop->getAvailability() == AR_Unavailable)
2138       continue;
2139
2140     // Diagnose unimplemented getters and setters.
2141     DiagnoseUnimplementedAccessor(*this,
2142           PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
2143     if (!Prop->isReadOnly())
2144       DiagnoseUnimplementedAccessor(*this,
2145                                     PrimaryClass, Prop->getSetterName(),
2146                                     IMPDecl, CDecl, C, Prop, InsMap);
2147   }
2148 }
2149
2150 void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
2151   for (const auto *propertyImpl : impDecl->property_impls()) {
2152     const auto *property = propertyImpl->getPropertyDecl();
2153     // Warn about null_resettable properties with synthesized setters,
2154     // because the setter won't properly handle nil.
2155     if (propertyImpl->getPropertyImplementation()
2156           == ObjCPropertyImplDecl::Synthesize &&
2157         (property->getPropertyAttributes() &
2158          ObjCPropertyDecl::OBJC_PR_null_resettable) &&
2159         property->getGetterMethodDecl() &&
2160         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 & ObjCPropertyDecl::OBJC_PR_atomic) &&
2199         !(AttributesAsWritten & ObjCPropertyDecl::OBJC_PR_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 & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
2226         !(Attributes & ObjCPropertyDecl::OBJC_PR_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 & ObjCPropertyDecl::OBJC_PR_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         }
2264         else
2265           Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
2266         Diag(Property->getLocation(), diag::note_property_declare);
2267       }
2268     }
2269   }
2270 }
2271
2272 void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
2273   if (getLangOpts().getGC() == LangOptions::GCOnly)
2274     return;
2275
2276   for (const auto *PID : D->property_impls()) {
2277     const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2278     if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
2279         !PD->isClassProperty()) {
2280       ObjCMethodDecl *IM = PID->getGetterMethodDecl();
2281       if (IM && !IM->isSynthesizedAccessorStub())
2282         continue;
2283       ObjCMethodDecl *method = PD->getGetterMethodDecl();
2284       if (!method)
2285         continue;
2286       ObjCMethodFamily family = method->getMethodFamily();
2287       if (family == OMF_alloc || family == OMF_copy ||
2288           family == OMF_mutableCopy || family == OMF_new) {
2289         if (getLangOpts().ObjCAutoRefCount)
2290           Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
2291         else
2292           Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);
2293
2294         // Look for a getter explicitly declared alongside the property.
2295         // If we find one, use its location for the note.
2296         SourceLocation noteLoc = PD->getLocation();
2297         SourceLocation fixItLoc;
2298         for (auto *getterRedecl : method->redecls()) {
2299           if (getterRedecl->isImplicit())
2300             continue;
2301           if (getterRedecl->getDeclContext() != PD->getDeclContext())
2302             continue;
2303           noteLoc = getterRedecl->getLocation();
2304           fixItLoc = getterRedecl->getEndLoc();
2305         }
2306
2307         Preprocessor &PP = getPreprocessor();
2308         TokenValue tokens[] = {
2309           tok::kw___attribute, tok::l_paren, tok::l_paren,
2310           PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
2311           PP.getIdentifierInfo("none"), tok::r_paren,
2312           tok::r_paren, tok::r_paren
2313         };
2314         StringRef spelling = "__attribute__((objc_method_family(none)))";
2315         StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
2316         if (!macroName.empty())
2317           spelling = macroName;
2318
2319         auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
2320             << method->getDeclName() << spelling;
2321         if (fixItLoc.isValid()) {
2322           SmallString<64> fixItText(" ");
2323           fixItText += spelling;
2324           noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
2325         }
2326       }
2327     }
2328   }
2329 }
2330
2331 void Sema::DiagnoseMissingDesignatedInitOverrides(
2332                                             const ObjCImplementationDecl *ImplD,
2333                                             const ObjCInterfaceDecl *IFD) {
2334   assert(IFD->hasDesignatedInitializers());
2335   const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
2336   if (!SuperD)
2337     return;
2338
2339   SelectorSet InitSelSet;
2340   for (const auto *I : ImplD->instance_methods())
2341     if (I->getMethodFamily() == OMF_init)
2342       InitSelSet.insert(I->getSelector());
2343
2344   SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
2345   SuperD->getDesignatedInitializers(DesignatedInits);
2346   for (SmallVector<const ObjCMethodDecl *, 8>::iterator
2347          I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
2348     const ObjCMethodDecl *MD = *I;
2349     if (!InitSelSet.count(MD->getSelector())) {
2350       // Don't emit a diagnostic if the overriding method in the subclass is
2351       // marked as unavailable.
2352       bool Ignore = false;
2353       if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
2354         Ignore = IMD->isUnavailable();
2355       } else {
2356         // Check the methods declared in the class extensions too.
2357         for (auto *Ext : IFD->visible_extensions())
2358           if (auto *IMD = Ext->getInstanceMethod(MD->getSelector())) {
2359             Ignore = IMD->isUnavailable();
2360             break;
2361           }
2362       }
2363       if (!Ignore) {
2364         Diag(ImplD->getLocation(),
2365              diag::warn_objc_implementation_missing_designated_init_override)
2366           << MD->getSelector();
2367         Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
2368       }
2369     }
2370   }
2371 }
2372
2373 /// AddPropertyAttrs - Propagates attributes from a property to the
2374 /// implicitly-declared getter or setter for that property.
2375 static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
2376                              ObjCPropertyDecl *Property) {
2377   // Should we just clone all attributes over?
2378   for (const auto *A : Property->attrs()) {
2379     if (isa<DeprecatedAttr>(A) ||
2380         isa<UnavailableAttr>(A) ||
2381         isa<AvailabilityAttr>(A))
2382       PropertyMethod->addAttr(A->clone(S.Context));
2383   }
2384 }
2385
2386 /// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2387 /// have the property type and issue diagnostics if they don't.
2388 /// Also synthesize a getter/setter method if none exist (and update the
2389 /// appropriate lookup tables.
2390 void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
2391   ObjCMethodDecl *GetterMethod, *SetterMethod;
2392   ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
2393   if (CD->isInvalidDecl())
2394     return;
2395
2396   bool IsClassProperty = property->isClassProperty();
2397   GetterMethod = IsClassProperty ?
2398     CD->getClassMethod(property->getGetterName()) :
2399     CD->getInstanceMethod(property->getGetterName());
2400
2401   // if setter or getter is not found in class extension, it might be
2402   // in the primary class.
2403   if (!GetterMethod)
2404     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2405       if (CatDecl->IsClassExtension())
2406         GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2407                          getClassMethod(property->getGetterName()) :
2408                        CatDecl->getClassInterface()->
2409                          getInstanceMethod(property->getGetterName());
2410
2411   SetterMethod = IsClassProperty ?
2412                  CD->getClassMethod(property->getSetterName()) :
2413                  CD->getInstanceMethod(property->getSetterName());
2414   if (!SetterMethod)
2415     if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
2416       if (CatDecl->IsClassExtension())
2417         SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
2418                           getClassMethod(property->getSetterName()) :
2419                        CatDecl->getClassInterface()->
2420                           getInstanceMethod(property->getSetterName());
2421   DiagnosePropertyAccessorMismatch(property, GetterMethod,
2422                                    property->getLocation());
2423
2424   if (!property->isReadOnly() && SetterMethod) {
2425     if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
2426         Context.VoidTy)
2427       Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
2428     if (SetterMethod->param_size() != 1 ||
2429         !Context.hasSameUnqualifiedType(
2430           (*SetterMethod->param_begin())->getType().getNonReferenceType(),
2431           property->getType().getNonReferenceType())) {
2432       Diag(property->getLocation(),
2433            diag::warn_accessor_property_type_mismatch)
2434         << property->getDeclName()
2435         << SetterMethod->getSelector();
2436       Diag(SetterMethod->getLocation(), diag::note_declared_at);
2437     }
2438   }
2439
2440   // Synthesize getter/setter methods if none exist.
2441   // Find the default getter and if one not found, add one.
2442   // FIXME: The synthesized property we set here is misleading. We almost always
2443   // synthesize these methods unless the user explicitly provided prototypes
2444   // (which is odd, but allowed). Sema should be typechecking that the
2445   // declarations jive in that situation (which it is not currently).
2446   if (!GetterMethod) {
2447     // No instance/class method of same name as property getter name was found.
2448     // Declare a getter method and add it to the list of methods
2449     // for this class.
2450     SourceLocation Loc = property->getLocation();
2451
2452     // The getter returns the declared property type with all qualifiers
2453     // removed.
2454     QualType resultTy = property->getType().getAtomicUnqualifiedType();
2455
2456     // If the property is null_resettable, the getter returns nonnull.
2457     if (property->getPropertyAttributes() &
2458         ObjCPropertyDecl::OBJC_PR_null_resettable) {
2459       QualType modifiedTy = resultTy;
2460       if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
2461         if (*nullability == NullabilityKind::Unspecified)
2462           resultTy = Context.getAttributedType(attr::TypeNonNull,
2463                                                modifiedTy, modifiedTy);
2464       }
2465     }
2466
2467     GetterMethod = ObjCMethodDecl::Create(
2468         Context, Loc, Loc, property->getGetterName(), resultTy, nullptr, CD,
2469         !IsClassProperty, /*isVariadic=*/false,
2470         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
2471         /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
2472         (property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
2473             ? ObjCMethodDecl::Optional
2474             : ObjCMethodDecl::Required);
2475     CD->addDecl(GetterMethod);
2476
2477     AddPropertyAttrs(*this, GetterMethod, property);
2478
2479     if (property->isDirectProperty())
2480       GetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2481
2482     if (property->hasAttr<NSReturnsNotRetainedAttr>())
2483       GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
2484                                                                      Loc));
2485
2486     if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
2487       GetterMethod->addAttr(
2488         ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));
2489
2490     if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2491       GetterMethod->addAttr(SectionAttr::CreateImplicit(
2492           Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2493           SectionAttr::GNU_section));
2494
2495     if (getLangOpts().ObjCAutoRefCount)
2496       CheckARCMethodDecl(GetterMethod);
2497   } else
2498     // A user declared getter will be synthesize when @synthesize of
2499     // the property with the same name is seen in the @implementation
2500     GetterMethod->setPropertyAccessor(true);
2501
2502   GetterMethod->createImplicitParams(Context,
2503                                      GetterMethod->getClassInterface());
2504   property->setGetterMethodDecl(GetterMethod);
2505
2506   // Skip setter if property is read-only.
2507   if (!property->isReadOnly()) {
2508     // Find the default setter and if one not found, add one.
2509     if (!SetterMethod) {
2510       // No instance/class method of same name as property setter name was
2511       // found.
2512       // Declare a setter method and add it to the list of methods
2513       // for this class.
2514       SourceLocation Loc = property->getLocation();
2515
2516       SetterMethod =
2517         ObjCMethodDecl::Create(Context, Loc, Loc,
2518                                property->getSetterName(), Context.VoidTy,
2519                                nullptr, CD, !IsClassProperty,
2520                                /*isVariadic=*/false,
2521                                /*isPropertyAccessor=*/true,
2522                                /*isSynthesizedAccessorStub=*/false,
2523                                /*isImplicitlyDeclared=*/true,
2524                                /*isDefined=*/false,
2525                                (property->getPropertyImplementation() ==
2526                                 ObjCPropertyDecl::Optional) ?
2527                                 ObjCMethodDecl::Optional :
2528                                 ObjCMethodDecl::Required);
2529
2530       // Remove all qualifiers from the setter's parameter type.
2531       QualType paramTy =
2532           property->getType().getUnqualifiedType().getAtomicUnqualifiedType();
2533
2534       // If the property is null_resettable, the setter accepts a
2535       // nullable value.
2536       if (property->getPropertyAttributes() &
2537           ObjCPropertyDecl::OBJC_PR_null_resettable) {
2538         QualType modifiedTy = paramTy;
2539         if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
2540           if (*nullability == NullabilityKind::Unspecified)
2541             paramTy = Context.getAttributedType(attr::TypeNullable,
2542                                                 modifiedTy, modifiedTy);
2543         }
2544       }
2545
2546       // Invent the arguments for the setter. We don't bother making a
2547       // nice name for the argument.
2548       ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
2549                                                   Loc, Loc,
2550                                                   property->getIdentifier(),
2551                                                   paramTy,
2552                                                   /*TInfo=*/nullptr,
2553                                                   SC_None,
2554                                                   nullptr);
2555       SetterMethod->setMethodParams(Context, Argument, None);
2556
2557       AddPropertyAttrs(*this, SetterMethod, property);
2558
2559       if (property->isDirectProperty())
2560         SetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));
2561
2562       CD->addDecl(SetterMethod);
2563       if (const SectionAttr *SA = property->getAttr<SectionAttr>())
2564         SetterMethod->addAttr(SectionAttr::CreateImplicit(
2565             Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
2566             SectionAttr::GNU_section));
2567       // It's possible for the user to have set a very odd custom
2568       // setter selector that causes it to have a method family.
2569       if (getLangOpts().ObjCAutoRefCount)
2570         CheckARCMethodDecl(SetterMethod);
2571     } else
2572       // A user declared setter will be synthesize when @synthesize of
2573       // the property with the same name is seen in the @implementation
2574       SetterMethod->setPropertyAccessor(true);
2575
2576     SetterMethod->createImplicitParams(Context,
2577                                        SetterMethod->getClassInterface());
2578     property->setSetterMethodDecl(SetterMethod);
2579   }
2580   // Add any synthesized methods to the global pool. This allows us to
2581   // handle the following, which is supported by GCC (and part of the design).
2582   //
2583   // @interface Foo
2584   // @property double bar;
2585   // @end
2586   //
2587   // void thisIsUnfortunate() {
2588   //   id foo;
2589   //   double bar = [foo bar];
2590   // }
2591   //
2592   if (!IsClassProperty) {
2593     if (GetterMethod)
2594       AddInstanceMethodToGlobalPool(GetterMethod);
2595     if (SetterMethod)
2596       AddInstanceMethodToGlobalPool(SetterMethod);
2597   } else {
2598     if (GetterMethod)
2599       AddFactoryMethodToGlobalPool(GetterMethod);
2600     if (SetterMethod)
2601       AddFactoryMethodToGlobalPool(SetterMethod);
2602   }
2603
2604   ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
2605   if (!CurrentClass) {
2606     if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
2607       CurrentClass = Cat->getClassInterface();
2608     else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
2609       CurrentClass = Impl->getClassInterface();
2610   }
2611   if (GetterMethod)
2612     CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
2613   if (SetterMethod)
2614     CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2615 }
2616
2617 void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
2618                                        SourceLocation Loc,
2619                                        unsigned &Attributes,
2620                                        bool propertyInPrimaryClass) {
2621   // FIXME: Improve the reported location.
2622   if (!PDecl || PDecl->isInvalidDecl())
2623     return;
2624
2625   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2626       (Attributes & ObjCDeclSpec::DQ_PR_readwrite))
2627     Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2628     << "readonly" << "readwrite";
2629
2630   ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
2631   QualType PropertyTy = PropertyDecl->getType();
2632
2633   // Check for copy or retain on non-object types.
2634   if ((Attributes & (ObjCDeclSpec::DQ_PR_weak | ObjCDeclSpec::DQ_PR_copy |
2635                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong)) &&
2636       !PropertyTy->isObjCRetainableType() &&
2637       !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
2638     Diag(Loc, diag::err_objc_property_requires_object)
2639       << (Attributes & ObjCDeclSpec::DQ_PR_weak ? "weak" :
2640           Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain (or strong)");
2641     Attributes &= ~(ObjCDeclSpec::DQ_PR_weak   | ObjCDeclSpec::DQ_PR_copy |
2642                     ObjCDeclSpec::DQ_PR_retain | ObjCDeclSpec::DQ_PR_strong);
2643     PropertyDecl->setInvalidDecl();
2644   }
2645
2646   // Check for assign on object types.
2647   if ((Attributes & ObjCDeclSpec::DQ_PR_assign) &&
2648       !(Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) &&
2649       PropertyTy->isObjCRetainableType() &&
2650       !PropertyTy->isObjCARCImplicitlyUnretainedType()) {
2651     Diag(Loc, diag::warn_objc_property_assign_on_object);
2652   }
2653
2654   // Check for more than one of { assign, copy, retain }.
2655   if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
2656     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2657       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2658         << "assign" << "copy";
2659       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2660     }
2661     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2662       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2663         << "assign" << "retain";
2664       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2665     }
2666     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2667       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2668         << "assign" << "strong";
2669       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2670     }
2671     if (getLangOpts().ObjCAutoRefCount  &&
2672         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2673       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2674         << "assign" << "weak";
2675       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2676     }
2677     if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
2678       Diag(Loc, diag::warn_iboutletcollection_property_assign);
2679   } else if (Attributes & ObjCDeclSpec::DQ_PR_unsafe_unretained) {
2680     if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2681       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2682         << "unsafe_unretained" << "copy";
2683       Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
2684     }
2685     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2686       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2687         << "unsafe_unretained" << "retain";
2688       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2689     }
2690     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2691       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2692         << "unsafe_unretained" << "strong";
2693       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2694     }
2695     if (getLangOpts().ObjCAutoRefCount  &&
2696         (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2697       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2698         << "unsafe_unretained" << "weak";
2699       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2700     }
2701   } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
2702     if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
2703       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2704         << "copy" << "retain";
2705       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2706     }
2707     if (Attributes & ObjCDeclSpec::DQ_PR_strong) {
2708       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2709         << "copy" << "strong";
2710       Attributes &= ~ObjCDeclSpec::DQ_PR_strong;
2711     }
2712     if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2713       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2714         << "copy" << "weak";
2715       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2716     }
2717   }
2718   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2719            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2720       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2721         << "retain" << "weak";
2722       Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
2723   }
2724   else if ((Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2725            (Attributes & ObjCDeclSpec::DQ_PR_weak)) {
2726       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2727         << "strong" << "weak";
2728       Attributes &= ~ObjCDeclSpec::DQ_PR_weak;
2729   }
2730
2731   if (Attributes & ObjCDeclSpec::DQ_PR_weak) {
2732     // 'weak' and 'nonnull' are mutually exclusive.
2733     if (auto nullability = PropertyTy->getNullability(Context)) {
2734       if (*nullability == NullabilityKind::NonNull)
2735         Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2736           << "nonnull" << "weak";
2737     }
2738   }
2739
2740   if ((Attributes & ObjCDeclSpec::DQ_PR_atomic) &&
2741       (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)) {
2742       Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
2743         << "atomic" << "nonatomic";
2744       Attributes &= ~ObjCDeclSpec::DQ_PR_atomic;
2745   }
2746
2747   // Warn if user supplied no assignment attribute, property is
2748   // readwrite, and this is an object type.
2749   if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
2750     if (Attributes & ObjCDeclSpec::DQ_PR_readonly) {
2751       // do nothing
2752     } else if (getLangOpts().ObjCAutoRefCount) {
2753       // With arc, @property definitions should default to strong when
2754       // not specified.
2755       PropertyDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_strong);
2756     } else if (PropertyTy->isObjCObjectPointerType()) {
2757         bool isAnyClassTy =
2758           (PropertyTy->isObjCClassType() ||
2759            PropertyTy->isObjCQualifiedClassType());
2760         // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
2761         // issue any warning.
2762         if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
2763           ;
2764         else if (propertyInPrimaryClass) {
2765           // Don't issue warning on property with no life time in class
2766           // extension as it is inherited from property in primary class.
2767           // Skip this warning in gc-only mode.
2768           if (getLangOpts().getGC() != LangOptions::GCOnly)
2769             Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
2770
2771           // If non-gc code warn that this is likely inappropriate.
2772           if (getLangOpts().getGC() == LangOptions::NonGC)
2773             Diag(Loc, diag::warn_objc_property_default_assign_on_object);
2774         }
2775     }
2776
2777     // FIXME: Implement warning dependent on NSCopying being
2778     // implemented. See also:
2779     // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
2780     // (please trim this list while you are at it).
2781   }
2782
2783   if (!(Attributes & ObjCDeclSpec::DQ_PR_copy)
2784       &&!(Attributes & ObjCDeclSpec::DQ_PR_readonly)
2785       && getLangOpts().getGC() == LangOptions::GCOnly
2786       && PropertyTy->isBlockPointerType())
2787     Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
2788   else if ((Attributes & ObjCDeclSpec::DQ_PR_retain) &&
2789            !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2790            !(Attributes & ObjCDeclSpec::DQ_PR_strong) &&
2791            PropertyTy->isBlockPointerType())
2792       Diag(Loc, diag::warn_objc_property_retain_of_block);
2793
2794   if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
2795       (Attributes & ObjCDeclSpec::DQ_PR_setter))
2796     Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2797 }