/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaObjCProperty.cpp

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaObjCProperty.cpp
Warning:	line 2159, column 14 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaObjCProperty.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include/clang/Sema -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../include -I /usr/src/gnu/usr.bin/clang/libclangSema/obj -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/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//===----------------------------------------------------------------------===//

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"

26using namespace clang;

28//===----------------------------------------------------------------------===//
29// Grammar actions.
30//===----------------------------------------------------------------------===//

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.
38static Qualifiers::ObjCLifetime
39getImpliedARCOwnership(ObjCPropertyAttribute::Kind attrs, QualType type) {
// retain, strong, copy, weak, and unsafe_unretained are only legal
// on properties of retainable pointer type.
if (attrs &
    (ObjCPropertyAttribute::kind_retain | ObjCPropertyAttribute::kind_strong |
     ObjCPropertyAttribute::kind_copy)) {
  return Qualifiers::OCL_Strong;
} else if (attrs & ObjCPropertyAttribute::kind_weak) {
  return Qualifiers::OCL_Weak;
} else if (attrs & ObjCPropertyAttribute::kind_unsafe_unretained) {
  return Qualifiers::OCL_ExplicitNone;
}

// assign can appear on other types, so we have to check the
// property type.
if (attrs & ObjCPropertyAttribute::kind_assign &&
    type->isObjCRetainableType()) {
  return Qualifiers::OCL_ExplicitNone;
}

return Qualifiers::OCL_None;
60}

62/// Check the internal consistency of a property declaration with
63/// an explicit ownership qualifier.
64static void checkPropertyDeclWithOwnership(Sema &S,
                                         ObjCPropertyDecl *property) {
if (property->isInvalidDecl()) return;

ObjCPropertyAttribute::Kind propertyKind = property->getPropertyAttributes();
Qualifiers::ObjCLifetime propertyLifetime
  = property->getType().getObjCLifetime();

assert(propertyLifetime != Qualifiers::OCL_None)((void)0);

Qualifiers::ObjCLifetime expectedLifetime
  = getImpliedARCOwnership(propertyKind, property->getType());
if (!expectedLifetime) {
  // We have a lifetime qualifier but no dominating property
  // attribute.  That's okay, but restore reasonable invariants by
  // setting the property attribute according to the lifetime
  // qualifier.
  ObjCPropertyAttribute::Kind attr;
  if (propertyLifetime == Qualifiers::OCL_Strong) {
    attr = ObjCPropertyAttribute::kind_strong;
  } else if (propertyLifetime == Qualifiers::OCL_Weak) {
    attr = ObjCPropertyAttribute::kind_weak;
  } else {
    assert(propertyLifetime == Qualifiers::OCL_ExplicitNone)((void)0);
    attr = ObjCPropertyAttribute::kind_unsafe_unretained;
  }
  property->setPropertyAttributes(attr);
  return;
}

if (propertyLifetime == expectedLifetime) return;

property->setInvalidDecl();
S.Diag(property->getLocation(),
       diag::err_arc_inconsistent_property_ownership)
  << property->getDeclName()
  << expectedLifetime
  << propertyLifetime;
102}

104/// Check this Objective-C property against a property declared in the
105/// given protocol.
106static void
107CheckPropertyAgainstProtocol(Sema &S, ObjCPropertyDecl *Prop,
                           ObjCProtocolDecl *Proto,
                           llvm::SmallPtrSetImpl<ObjCProtocolDecl *> &Known) {
// Have we seen this protocol before?
if (!Known.insert(Proto).second)
  return;

// Look for a property with the same name.
if (ObjCPropertyDecl *ProtoProp =
    Proto->lookup(Prop->getDeclName()).find_first<ObjCPropertyDecl>()) {
  S.DiagnosePropertyMismatch(Prop, ProtoProp, Proto->getIdentifier(), true);
  return;
}

// Check this property against any protocols we inherit.
for (auto *P : Proto->protocols())
  CheckPropertyAgainstProtocol(S, Prop, P, Known);
124}

126static unsigned deducePropertyOwnershipFromType(Sema &S, QualType T) {
// In GC mode, just look for the __weak qualifier.
if (S.getLangOpts().getGC() != LangOptions::NonGC) {
  if (T.isObjCGCWeak())
    return ObjCPropertyAttribute::kind_weak;

  // In ARC/MRC, look for an explicit ownership qualifier.
  // For some reason, this only applies to __weak.
} else if (auto ownership = T.getObjCLifetime()) {
  switch (ownership) {
  case Qualifiers::OCL_Weak:
    return ObjCPropertyAttribute::kind_weak;
  case Qualifiers::OCL_Strong:
    return ObjCPropertyAttribute::kind_strong;
  case Qualifiers::OCL_ExplicitNone:
    return ObjCPropertyAttribute::kind_unsafe_unretained;
  case Qualifiers::OCL_Autoreleasing:
  case Qualifiers::OCL_None:
    return 0;
  }
  llvm_unreachable("bad qualifier")__builtin_unreachable();
}

return 0;
150}

152static const unsigned OwnershipMask =
  (ObjCPropertyAttribute::kind_assign | ObjCPropertyAttribute::kind_retain |
   ObjCPropertyAttribute::kind_copy | ObjCPropertyAttribute::kind_weak |
   ObjCPropertyAttribute::kind_strong |
   ObjCPropertyAttribute::kind_unsafe_unretained);

158static unsigned getOwnershipRule(unsigned attr) {
unsigned result = attr & OwnershipMask;

// From an ownership perspective, assign and unsafe_unretained are
// identical; make sure one also implies the other.
if (result & (ObjCPropertyAttribute::kind_assign |
              ObjCPropertyAttribute::kind_unsafe_unretained)) {
  result |= ObjCPropertyAttribute::kind_assign |
            ObjCPropertyAttribute::kind_unsafe_unretained;
}

return result;
170}

172Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
                        SourceLocation LParenLoc,
                        FieldDeclarator &FD,
                        ObjCDeclSpec &ODS,
                        Selector GetterSel,
                        Selector SetterSel,
                        tok::ObjCKeywordKind MethodImplKind,
                        DeclContext *lexicalDC) {
unsigned Attributes = ODS.getPropertyAttributes();
FD.D.setObjCWeakProperty((Attributes & ObjCPropertyAttribute::kind_weak) !=
                         0);
TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
QualType T = TSI->getType();
if (!getOwnershipRule(Attributes)) {
  Attributes |= deducePropertyOwnershipFromType(*this, T);
}
bool isReadWrite = ((Attributes & ObjCPropertyAttribute::kind_readwrite) ||
                    // default is readwrite!
                    !(Attributes & ObjCPropertyAttribute::kind_readonly));

// Proceed with constructing the ObjCPropertyDecls.
ObjCContainerDecl *ClassDecl = cast<ObjCContainerDecl>(CurContext);
ObjCPropertyDecl *Res = nullptr;
if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
  if (CDecl->IsClassExtension()) {
    Res = HandlePropertyInClassExtension(S, AtLoc, LParenLoc,
                                         FD,
                                         GetterSel, ODS.getGetterNameLoc(),
                                         SetterSel, ODS.getSetterNameLoc(),
                                         isReadWrite, Attributes,
                                         ODS.getPropertyAttributes(),
                                         T, TSI, MethodImplKind);
    if (!Res)
      return nullptr;
  }
}

if (!Res) {
  Res = CreatePropertyDecl(S, ClassDecl, AtLoc, LParenLoc, FD,
                           GetterSel, ODS.getGetterNameLoc(), SetterSel,
                           ODS.getSetterNameLoc(), isReadWrite, Attributes,
                           ODS.getPropertyAttributes(), T, TSI,
                           MethodImplKind);
  if (lexicalDC)
    Res->setLexicalDeclContext(lexicalDC);
}

// Validate the attributes on the @property.
CheckObjCPropertyAttributes(Res, AtLoc, Attributes,
                            (isa<ObjCInterfaceDecl>(ClassDecl) ||
                             isa<ObjCProtocolDecl>(ClassDecl)));

// Check consistency if the type has explicit ownership qualification.
if (Res->getType().getObjCLifetime())
  checkPropertyDeclWithOwnership(*this, Res);

llvm::SmallPtrSet<ObjCProtocolDecl *, 16> KnownProtos;
if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
  // For a class, compare the property against a property in our superclass.
  bool FoundInSuper = false;
  ObjCInterfaceDecl *CurrentInterfaceDecl = IFace;
  while (ObjCInterfaceDecl *Super = CurrentInterfaceDecl->getSuperClass()) {
    if (ObjCPropertyDecl *SuperProp =
        Super->lookup(Res->getDeclName()).find_first<ObjCPropertyDecl>()) {
      DiagnosePropertyMismatch(Res, SuperProp, Super->getIdentifier(), false);
      FoundInSuper = true;
      break;
    }
    CurrentInterfaceDecl = Super;
  }

  if (FoundInSuper) {
    // Also compare the property against a property in our protocols.
    for (auto *P : CurrentInterfaceDecl->protocols()) {
      CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
    }
  } else {
    // Slower path: look in all protocols we referenced.
    for (auto *P : IFace->all_referenced_protocols()) {
      CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
    }
  }
} else if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
  // We don't check if class extension. Because properties in class extension
  // are meant to override some of the attributes and checking has already done
  // when property in class extension is constructed.
  if (!Cat->IsClassExtension())
    for (auto *P : Cat->protocols())
      CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
} else {
  ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(ClassDecl);
  for (auto *P : Proto->protocols())
    CheckPropertyAgainstProtocol(*this, Res, P, KnownProtos);
}

ActOnDocumentableDecl(Res);
return Res;
269}

271static ObjCPropertyAttribute::Kind
272makePropertyAttributesAsWritten(unsigned Attributes) {
unsigned attributesAsWritten = 0;
if (Attributes & ObjCPropertyAttribute::kind_readonly)
  attributesAsWritten |= ObjCPropertyAttribute::kind_readonly;
if (Attributes & ObjCPropertyAttribute::kind_readwrite)
  attributesAsWritten |= ObjCPropertyAttribute::kind_readwrite;
if (Attributes & ObjCPropertyAttribute::kind_getter)
  attributesAsWritten |= ObjCPropertyAttribute::kind_getter;
if (Attributes & ObjCPropertyAttribute::kind_setter)
  attributesAsWritten |= ObjCPropertyAttribute::kind_setter;
if (Attributes & ObjCPropertyAttribute::kind_assign)
  attributesAsWritten |= ObjCPropertyAttribute::kind_assign;
if (Attributes & ObjCPropertyAttribute::kind_retain)
  attributesAsWritten |= ObjCPropertyAttribute::kind_retain;
if (Attributes & ObjCPropertyAttribute::kind_strong)
  attributesAsWritten |= ObjCPropertyAttribute::kind_strong;
if (Attributes & ObjCPropertyAttribute::kind_weak)
  attributesAsWritten |= ObjCPropertyAttribute::kind_weak;
if (Attributes & ObjCPropertyAttribute::kind_copy)
  attributesAsWritten |= ObjCPropertyAttribute::kind_copy;
if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
  attributesAsWritten |= ObjCPropertyAttribute::kind_unsafe_unretained;
if (Attributes & ObjCPropertyAttribute::kind_nonatomic)
  attributesAsWritten |= ObjCPropertyAttribute::kind_nonatomic;
if (Attributes & ObjCPropertyAttribute::kind_atomic)
  attributesAsWritten |= ObjCPropertyAttribute::kind_atomic;
if (Attributes & ObjCPropertyAttribute::kind_class)
  attributesAsWritten |= ObjCPropertyAttribute::kind_class;
if (Attributes & ObjCPropertyAttribute::kind_direct)
  attributesAsWritten |= ObjCPropertyAttribute::kind_direct;

return (ObjCPropertyAttribute::Kind)attributesAsWritten;
304}

306static bool LocPropertyAttribute( ASTContext &Context, const char *attrName,
                               SourceLocation LParenLoc, SourceLocation &Loc) {
if (LParenLoc.isMacroID())
  return false;

SourceManager &SM = Context.getSourceManager();
std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(LParenLoc);
// Try to load the file buffer.
bool invalidTemp = false;
StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
if (invalidTemp)
  return false;
const char *tokenBegin = file.data() + locInfo.second;

// Lex from the start of the given location.
Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
            Context.getLangOpts(),
            file.begin(), tokenBegin, file.end());
Token Tok;
do {
  lexer.LexFromRawLexer(Tok);
  if (Tok.is(tok::raw_identifier) && Tok.getRawIdentifier() == attrName) {
    Loc = Tok.getLocation();
    return true;
  }
} while (Tok.isNot(tok::r_paren));
return false;
333}

335/// Check for a mismatch in the atomicity of the given properties.
336static void checkAtomicPropertyMismatch(Sema &S,
                                      ObjCPropertyDecl *OldProperty,
                                      ObjCPropertyDecl *NewProperty,
                                      bool PropagateAtomicity) {
// If the atomicity of both matches, we're done.
bool OldIsAtomic = (OldProperty->getPropertyAttributes() &
                    ObjCPropertyAttribute::kind_nonatomic) == 0;
bool NewIsAtomic = (NewProperty->getPropertyAttributes() &
                    ObjCPropertyAttribute::kind_nonatomic) == 0;
if (OldIsAtomic == NewIsAtomic) return;

// Determine whether the given property is readonly and implicitly
// atomic.
auto isImplicitlyReadonlyAtomic = [](ObjCPropertyDecl *Property) -> bool {
  // Is it readonly?
  auto Attrs = Property->getPropertyAttributes();
  if ((Attrs & ObjCPropertyAttribute::kind_readonly) == 0)
    return false;

  // Is it nonatomic?
  if (Attrs & ObjCPropertyAttribute::kind_nonatomic)
    return false;

  // Was 'atomic' specified directly?
  if (Property->getPropertyAttributesAsWritten() &
      ObjCPropertyAttribute::kind_atomic)
    return false;

  return true;
};

// If we're allowed to propagate atomicity, and the new property did
// not specify atomicity at all, propagate.
const unsigned AtomicityMask = (ObjCPropertyAttribute::kind_atomic |
                                ObjCPropertyAttribute::kind_nonatomic);
if (PropagateAtomicity &&
    ((NewProperty->getPropertyAttributesAsWritten() & AtomicityMask) == 0)) {
  unsigned Attrs = NewProperty->getPropertyAttributes();
  Attrs = Attrs & ~AtomicityMask;
  if (OldIsAtomic)
    Attrs |= ObjCPropertyAttribute::kind_atomic;
  else
    Attrs |= ObjCPropertyAttribute::kind_nonatomic;

  NewProperty->overwritePropertyAttributes(Attrs);
  return;
}

// One of the properties is atomic; if it's a readonly property, and
// 'atomic' wasn't explicitly specified, we're okay.
if ((OldIsAtomic && isImplicitlyReadonlyAtomic(OldProperty)) ||
    (NewIsAtomic && isImplicitlyReadonlyAtomic(NewProperty)))
  return;

// Diagnose the conflict.
const IdentifierInfo *OldContextName;
auto *OldDC = OldProperty->getDeclContext();
if (auto Category = dyn_cast<ObjCCategoryDecl>(OldDC))
  OldContextName = Category->getClassInterface()->getIdentifier();
else
  OldContextName = cast<ObjCContainerDecl>(OldDC)->getIdentifier();

S.Diag(NewProperty->getLocation(), diag::warn_property_attribute)
  << NewProperty->getDeclName() << "atomic"
  << OldContextName;
S.Diag(OldProperty->getLocation(), diag::note_property_declare);
402}

404ObjCPropertyDecl *
405Sema::HandlePropertyInClassExtension(Scope *S,
                                   SourceLocation AtLoc,
                                   SourceLocation LParenLoc,
                                   FieldDeclarator &FD,
                                   Selector GetterSel,
                                   SourceLocation GetterNameLoc,
                                   Selector SetterSel,
                                   SourceLocation SetterNameLoc,
                                   const bool isReadWrite,
                                   unsigned &Attributes,
                                   const unsigned AttributesAsWritten,
                                   QualType T,
                                   TypeSourceInfo *TSI,
                                   tok::ObjCKeywordKind MethodImplKind) {
ObjCCategoryDecl *CDecl = cast<ObjCCategoryDecl>(CurContext);
// Diagnose if this property is already in continuation class.
DeclContext *DC = CurContext;
IdentifierInfo *PropertyId = FD.D.getIdentifier();
ObjCInterfaceDecl *CCPrimary = CDecl->getClassInterface();

// We need to look in the @interface to see if the @property was
// already declared.
if (!CCPrimary) {
  Diag(CDecl->getLocation(), diag::err_continuation_class);
  return nullptr;
}

bool isClassProperty =
    (AttributesAsWritten & ObjCPropertyAttribute::kind_class) ||
    (Attributes & ObjCPropertyAttribute::kind_class);

// Find the property in the extended class's primary class or
// extensions.
ObjCPropertyDecl *PIDecl = CCPrimary->FindPropertyVisibleInPrimaryClass(
    PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty));

// If we found a property in an extension, complain.
if (PIDecl && isa<ObjCCategoryDecl>(PIDecl->getDeclContext())) {
  Diag(AtLoc, diag::err_duplicate_property);
  Diag(PIDecl->getLocation(), diag::note_property_declare);
  return nullptr;
}

// Check for consistency with the previous declaration, if there is one.
if (PIDecl) {
  // A readonly property declared in the primary class can be refined
  // by adding a readwrite property within an extension.
  // Anything else is an error.
  if (!(PIDecl->isReadOnly() && isReadWrite)) {
    // Tailor the diagnostics for the common case where a readwrite
    // property is declared both in the @interface and the continuation.
    // This is a common error where the user often intended the original
    // declaration to be readonly.
    unsigned diag =
        (Attributes & ObjCPropertyAttribute::kind_readwrite) &&
                (PIDecl->getPropertyAttributesAsWritten() &
                 ObjCPropertyAttribute::kind_readwrite)
            ? diag::err_use_continuation_class_redeclaration_readwrite
            : diag::err_use_continuation_class;
    Diag(AtLoc, diag)
      << CCPrimary->getDeclName();
    Diag(PIDecl->getLocation(), diag::note_property_declare);
    return nullptr;
  }

  // Check for consistency of getters.
  if (PIDecl->getGetterName() != GetterSel) {
   // If the getter was written explicitly, complain.
   if (AttributesAsWritten & ObjCPropertyAttribute::kind_getter) {
     Diag(AtLoc, diag::warn_property_redecl_getter_mismatch)
         << PIDecl->getGetterName() << GetterSel;
     Diag(PIDecl->getLocation(), diag::note_property_declare);
   }

    // Always adopt the getter from the original declaration.
    GetterSel = PIDecl->getGetterName();
    Attributes |= ObjCPropertyAttribute::kind_getter;
  }

  // Check consistency of ownership.
  unsigned ExistingOwnership
    = getOwnershipRule(PIDecl->getPropertyAttributes());
  unsigned NewOwnership = getOwnershipRule(Attributes);
  if (ExistingOwnership && NewOwnership != ExistingOwnership) {
    // If the ownership was written explicitly, complain.
    if (getOwnershipRule(AttributesAsWritten)) {
      Diag(AtLoc, diag::warn_property_attr_mismatch);
      Diag(PIDecl->getLocation(), diag::note_property_declare);
    }

    // Take the ownership from the original property.
    Attributes = (Attributes & ~OwnershipMask) | ExistingOwnership;
  }

  // If the redeclaration is 'weak' but the original property is not,
  if ((Attributes & ObjCPropertyAttribute::kind_weak) &&
      !(PIDecl->getPropertyAttributesAsWritten() &
        ObjCPropertyAttribute::kind_weak) &&
      PIDecl->getType()->getAs<ObjCObjectPointerType>() &&
      PIDecl->getType().getObjCLifetime() == Qualifiers::OCL_None) {
    Diag(AtLoc, diag::warn_property_implicitly_mismatched);
    Diag(PIDecl->getLocation(), diag::note_property_declare);
  }
}

// Create a new ObjCPropertyDecl with the DeclContext being
// the class extension.
ObjCPropertyDecl *PDecl = CreatePropertyDecl(S, CDecl, AtLoc, LParenLoc,
                                             FD, GetterSel, GetterNameLoc,
                                             SetterSel, SetterNameLoc,
                                             isReadWrite,
                                             Attributes, AttributesAsWritten,
                                             T, TSI, MethodImplKind, DC);

// If there was no declaration of a property with the same name in
// the primary class, we're done.
if (!PIDecl) {
  ProcessPropertyDecl(PDecl);
  return PDecl;
}

if (!Context.hasSameType(PIDecl->getType(), PDecl->getType())) {
  bool IncompatibleObjC = false;
  QualType ConvertedType;
  // Relax the strict type matching for property type in continuation class.
  // Allow property object type of continuation class to be different as long
  // as it narrows the object type in its primary class property. Note that
  // this conversion is safe only because the wider type is for a 'readonly'
  // property in primary class and 'narrowed' type for a 'readwrite' property
  // in continuation class.
  QualType PrimaryClassPropertyT = Context.getCanonicalType(PIDecl->getType());
  QualType ClassExtPropertyT = Context.getCanonicalType(PDecl->getType());
  if (!isa<ObjCObjectPointerType>(PrimaryClassPropertyT) ||
      !isa<ObjCObjectPointerType>(ClassExtPropertyT) ||
      (!isObjCPointerConversion(ClassExtPropertyT, PrimaryClassPropertyT,
                                ConvertedType, IncompatibleObjC))
      || IncompatibleObjC) {
    Diag(AtLoc,
        diag::err_type_mismatch_continuation_class) << PDecl->getType();
    Diag(PIDecl->getLocation(), diag::note_property_declare);
    return nullptr;
  }
}

// Check that atomicity of property in class extension matches the previous
// declaration.
checkAtomicPropertyMismatch(*this, PIDecl, PDecl, true);

// Make sure getter/setter are appropriately synthesized.
ProcessPropertyDecl(PDecl);
return PDecl;
556}

558ObjCPropertyDecl *Sema::CreatePropertyDecl(Scope *S,
                                         ObjCContainerDecl *CDecl,
                                         SourceLocation AtLoc,
                                         SourceLocation LParenLoc,
                                         FieldDeclarator &FD,
                                         Selector GetterSel,
                                         SourceLocation GetterNameLoc,
                                         Selector SetterSel,
                                         SourceLocation SetterNameLoc,
                                         const bool isReadWrite,
                                         const unsigned Attributes,
                                         const unsigned AttributesAsWritten,
                                         QualType T,
                                         TypeSourceInfo *TInfo,
                                         tok::ObjCKeywordKind MethodImplKind,
                                         DeclContext *lexicalDC){
IdentifierInfo *PropertyId = FD.D.getIdentifier();

// Property defaults to 'assign' if it is readwrite, unless this is ARC
// and the type is retainable.
bool isAssign;
if (Attributes & (ObjCPropertyAttribute::kind_assign |
                  ObjCPropertyAttribute::kind_unsafe_unretained)) {
  isAssign = true;
} else if (getOwnershipRule(Attributes) || !isReadWrite) {
  isAssign = false;
} else {
  isAssign = (!getLangOpts().ObjCAutoRefCount ||
              !T->isObjCRetainableType());
}

// Issue a warning if property is 'assign' as default and its
// object, which is gc'able conforms to NSCopying protocol
if (getLangOpts().getGC() != LangOptions::NonGC && isAssign &&
    !(Attributes & ObjCPropertyAttribute::kind_assign)) {
  if (const ObjCObjectPointerType *ObjPtrTy =
        T->getAs<ObjCObjectPointerType>()) {
    ObjCInterfaceDecl *IDecl = ObjPtrTy->getObjectType()->getInterface();
    if (IDecl)
      if (ObjCProtocolDecl* PNSCopying =
          LookupProtocol(&Context.Idents.get("NSCopying"), AtLoc))
        if (IDecl->ClassImplementsProtocol(PNSCopying, true))
          Diag(AtLoc, diag::warn_implements_nscopying) << PropertyId;
  }
}

if (T->isObjCObjectType()) {
  SourceLocation StarLoc = TInfo->getTypeLoc().getEndLoc();
  StarLoc = getLocForEndOfToken(StarLoc);
  Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object)
    << FixItHint::CreateInsertion(StarLoc, "*");
  T = Context.getObjCObjectPointerType(T);
  SourceLocation TLoc = TInfo->getTypeLoc().getBeginLoc();
  TInfo = Context.getTrivialTypeSourceInfo(T, TLoc);
}

DeclContext *DC = CDecl;
ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
                                                   FD.D.getIdentifierLoc(),
                                                   PropertyId, AtLoc,
                                                   LParenLoc, T, TInfo);

bool isClassProperty =
    (AttributesAsWritten & ObjCPropertyAttribute::kind_class) ||
    (Attributes & ObjCPropertyAttribute::kind_class);
// Class property and instance property can have the same name.
if (ObjCPropertyDecl *prevDecl = ObjCPropertyDecl::findPropertyDecl(
        DC, PropertyId, ObjCPropertyDecl::getQueryKind(isClassProperty))) {
  Diag(PDecl->getLocation(), diag::err_duplicate_property);
  Diag(prevDecl->getLocation(), diag::note_property_declare);
  PDecl->setInvalidDecl();
}
else {
  DC->addDecl(PDecl);
  if (lexicalDC)
    PDecl->setLexicalDeclContext(lexicalDC);
}

if (T->isArrayType() || T->isFunctionType()) {
  Diag(AtLoc, diag::err_property_type) << T;
  PDecl->setInvalidDecl();
}

ProcessDeclAttributes(S, PDecl, FD.D);

// Regardless of setter/getter attribute, we save the default getter/setter
// selector names in anticipation of declaration of setter/getter methods.
PDecl->setGetterName(GetterSel, GetterNameLoc);
PDecl->setSetterName(SetterSel, SetterNameLoc);
PDecl->setPropertyAttributesAsWritten(
                        makePropertyAttributesAsWritten(AttributesAsWritten));

if (Attributes & ObjCPropertyAttribute::kind_readonly)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_readonly);

if (Attributes & ObjCPropertyAttribute::kind_getter)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_getter);

if (Attributes & ObjCPropertyAttribute::kind_setter)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_setter);

if (isReadWrite)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_readwrite);

if (Attributes & ObjCPropertyAttribute::kind_retain)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_retain);

if (Attributes & ObjCPropertyAttribute::kind_strong)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);

if (Attributes & ObjCPropertyAttribute::kind_weak)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_weak);

if (Attributes & ObjCPropertyAttribute::kind_copy)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_copy);

if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_unsafe_unretained);

if (isAssign)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_assign);

// In the semantic attributes, one of nonatomic or atomic is always set.
if (Attributes & ObjCPropertyAttribute::kind_nonatomic)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_nonatomic);
else
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_atomic);

// 'unsafe_unretained' is alias for 'assign'.
if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_assign);
if (isAssign)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_unsafe_unretained);

if (MethodImplKind == tok::objc_required)
  PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
else if (MethodImplKind == tok::objc_optional)
  PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);

if (Attributes & ObjCPropertyAttribute::kind_nullability)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_nullability);

if (Attributes & ObjCPropertyAttribute::kind_null_resettable)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_null_resettable);

if (Attributes & ObjCPropertyAttribute::kind_class)
  PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_class);

if ((Attributes & ObjCPropertyAttribute::kind_direct) ||
    CDecl->hasAttr<ObjCDirectMembersAttr>()) {
  if (isa<ObjCProtocolDecl>(CDecl)) {
    Diag(PDecl->getLocation(), diag::err_objc_direct_on_protocol) << true;
  } else if (getLangOpts().ObjCRuntime.allowsDirectDispatch()) {
    PDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_direct);
  } else {
    Diag(PDecl->getLocation(), diag::warn_objc_direct_property_ignored)
        << PDecl->getDeclName();
  }
}

return PDecl;
719}

721static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
                               ObjCPropertyDecl *property,
                               ObjCIvarDecl *ivar) {
if (property->isInvalidDecl() || ivar->isInvalidDecl()) return;

QualType ivarType = ivar->getType();
Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();

// The lifetime implied by the property's attributes.
Qualifiers::ObjCLifetime propertyLifetime =
  getImpliedARCOwnership(property->getPropertyAttributes(),
                         property->getType());

// We're fine if they match.
if (propertyLifetime == ivarLifetime) return;

// None isn't a valid lifetime for an object ivar in ARC, and
// __autoreleasing is never valid; don't diagnose twice.
if ((ivarLifetime == Qualifiers::OCL_None &&
     S.getLangOpts().ObjCAutoRefCount) ||
    ivarLifetime == Qualifiers::OCL_Autoreleasing)
  return;

// If the ivar is private, and it's implicitly __unsafe_unretained
// because of its type, then pretend it was actually implicitly
// __strong.  This is only sound because we're processing the
// property implementation before parsing any method bodies.
if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
    propertyLifetime == Qualifiers::OCL_Strong &&
    ivar->getAccessControl() == ObjCIvarDecl::Private) {
  SplitQualType split = ivarType.split();
  if (split.Quals.hasObjCLifetime()) {
    assert(ivarType->isObjCARCImplicitlyUnretainedType())((void)0);
    split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
    ivarType = S.Context.getQualifiedType(split);
    ivar->setType(ivarType);
    return;
  }
}

switch (propertyLifetime) {
case Qualifiers::OCL_Strong:
  S.Diag(ivar->getLocation(), diag::err_arc_strong_property_ownership)
    << property->getDeclName()
    << ivar->getDeclName()
    << ivarLifetime;
  break;

case Qualifiers::OCL_Weak:
  S.Diag(ivar->getLocation(), diag::err_weak_property)
    << property->getDeclName()
    << ivar->getDeclName();
  break;

case Qualifiers::OCL_ExplicitNone:
  S.Diag(ivar->getLocation(), diag::err_arc_assign_property_ownership)
      << property->getDeclName() << ivar->getDeclName()
      << ((property->getPropertyAttributesAsWritten() &
           ObjCPropertyAttribute::kind_assign) != 0);
  break;

case Qualifiers::OCL_Autoreleasing:
  llvm_unreachable("properties cannot be autoreleasing")__builtin_unreachable();

case Qualifiers::OCL_None:
  // Any other property should be ignored.
  return;
}

S.Diag(property->getLocation(), diag::note_property_declare);
if (propertyImplLoc.isValid())
  S.Diag(propertyImplLoc, diag::note_property_synthesize);
793}

795/// setImpliedPropertyAttributeForReadOnlyProperty -
796/// This routine evaludates life-time attributes for a 'readonly'
797/// property with no known lifetime of its own, using backing
798/// 'ivar's attribute, if any. If no backing 'ivar', property's
799/// life-time is assumed 'strong'.
800static void setImpliedPropertyAttributeForReadOnlyProperty(
            ObjCPropertyDecl *property, ObjCIvarDecl *ivar) {
Qualifiers::ObjCLifetime propertyLifetime =
  getImpliedARCOwnership(property->getPropertyAttributes(),
                         property->getType());
if (propertyLifetime != Qualifiers::OCL_None)
  return;

if (!ivar) {
  // if no backing ivar, make property 'strong'.
  property->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
  return;
}
// property assumes owenership of backing ivar.
QualType ivarType = ivar->getType();
Qualifiers::ObjCLifetime ivarLifetime = ivarType.getObjCLifetime();
if (ivarLifetime == Qualifiers::OCL_Strong)
  property->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
else if (ivarLifetime == Qualifiers::OCL_Weak)
  property->setPropertyAttributes(ObjCPropertyAttribute::kind_weak);
820}

822static bool isIncompatiblePropertyAttribute(unsigned Attr1, unsigned Attr2,
                                          ObjCPropertyAttribute::Kind Kind) {
return (Attr1 & Kind) != (Attr2 & Kind);
825}

827static bool areIncompatiblePropertyAttributes(unsigned Attr1, unsigned Attr2,
                                            unsigned Kinds) {
return ((Attr1 & Kinds) != 0) != ((Attr2 & Kinds) != 0);
830}

832/// SelectPropertyForSynthesisFromProtocols - Finds the most appropriate
833/// property declaration that should be synthesised in all of the inherited
834/// protocols. It also diagnoses properties declared in inherited protocols with
835/// mismatched types or attributes, since any of them can be candidate for
836/// synthesis.
837static ObjCPropertyDecl *
838SelectPropertyForSynthesisFromProtocols(Sema &S, SourceLocation AtLoc,
                                      ObjCInterfaceDecl *ClassDecl,
                                      ObjCPropertyDecl *Property) {
assert(isa<ObjCProtocolDecl>(Property->getDeclContext()) &&((void)0)
       "Expected a property from a protocol")((void)0);
ObjCInterfaceDecl::ProtocolPropertySet ProtocolSet;
ObjCInterfaceDecl::PropertyDeclOrder Properties;
for (const auto *PI : ClassDecl->all_referenced_protocols()) {
  if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
    PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
                                              Properties);
}
if (ObjCInterfaceDecl *SDecl = ClassDecl->getSuperClass()) {
  while (SDecl) {
    for (const auto *PI : SDecl->all_referenced_protocols()) {
      if (const ObjCProtocolDecl *PDecl = PI->getDefinition())
        PDecl->collectInheritedProtocolProperties(Property, ProtocolSet,
                                                  Properties);
    }
    SDecl = SDecl->getSuperClass();
  }
}

if (Properties.empty())
  return Property;

ObjCPropertyDecl *OriginalProperty = Property;
size_t SelectedIndex = 0;
for (const auto &Prop : llvm::enumerate(Properties)) {
  // Select the 'readwrite' property if such property exists.
  if (Property->isReadOnly() && !Prop.value()->isReadOnly()) {
    Property = Prop.value();
    SelectedIndex = Prop.index();
  }
}
if (Property != OriginalProperty) {
  // Check that the old property is compatible with the new one.
  Properties[SelectedIndex] = OriginalProperty;
}

QualType RHSType = S.Context.getCanonicalType(Property->getType());
unsigned OriginalAttributes = Property->getPropertyAttributesAsWritten();
enum MismatchKind {
  IncompatibleType = 0,
  HasNoExpectedAttribute,
  HasUnexpectedAttribute,
  DifferentGetter,
  DifferentSetter
};
// Represents a property from another protocol that conflicts with the
// selected declaration.
struct MismatchingProperty {
  const ObjCPropertyDecl *Prop;
  MismatchKind Kind;
  StringRef AttributeName;
};
SmallVector<MismatchingProperty, 4> Mismatches;
for (ObjCPropertyDecl *Prop : Properties) {
  // Verify the property attributes.
  unsigned Attr = Prop->getPropertyAttributesAsWritten();
  if (Attr != OriginalAttributes) {
    auto Diag = [&](bool OriginalHasAttribute, StringRef AttributeName) {
      MismatchKind Kind = OriginalHasAttribute ? HasNoExpectedAttribute
                                               : HasUnexpectedAttribute;
      Mismatches.push_back({Prop, Kind, AttributeName});
    };
    // The ownership might be incompatible unless the property has no explicit
    // ownership.
    bool HasOwnership =
        (Attr & (ObjCPropertyAttribute::kind_retain |
                 ObjCPropertyAttribute::kind_strong |
                 ObjCPropertyAttribute::kind_copy |
                 ObjCPropertyAttribute::kind_assign |
                 ObjCPropertyAttribute::kind_unsafe_unretained |
                 ObjCPropertyAttribute::kind_weak)) != 0;
    if (HasOwnership &&
        isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
                                        ObjCPropertyAttribute::kind_copy)) {
      Diag(OriginalAttributes & ObjCPropertyAttribute::kind_copy, "copy");
      continue;
    }
    if (HasOwnership && areIncompatiblePropertyAttributes(
                            OriginalAttributes, Attr,
                            ObjCPropertyAttribute::kind_retain |
                                ObjCPropertyAttribute::kind_strong)) {
      Diag(OriginalAttributes & (ObjCPropertyAttribute::kind_retain |
                                 ObjCPropertyAttribute::kind_strong),
           "retain (or strong)");
      continue;
    }
    if (isIncompatiblePropertyAttribute(OriginalAttributes, Attr,
                                        ObjCPropertyAttribute::kind_atomic)) {
      Diag(OriginalAttributes & ObjCPropertyAttribute::kind_atomic, "atomic");
      continue;
    }
  }
  if (Property->getGetterName() != Prop->getGetterName()) {
    Mismatches.push_back({Prop, DifferentGetter, ""});
    continue;
  }
  if (!Property->isReadOnly() && !Prop->isReadOnly() &&
      Property->getSetterName() != Prop->getSetterName()) {
    Mismatches.push_back({Prop, DifferentSetter, ""});
    continue;
  }
  QualType LHSType = S.Context.getCanonicalType(Prop->getType());
  if (!S.Context.propertyTypesAreCompatible(LHSType, RHSType)) {
    bool IncompatibleObjC = false;
    QualType ConvertedType;
    if (!S.isObjCPointerConversion(RHSType, LHSType, ConvertedType, IncompatibleObjC)
        || IncompatibleObjC) {
      Mismatches.push_back({Prop, IncompatibleType, ""});
      continue;
    }
  }
}

if (Mismatches.empty())
  return Property;

// Diagnose incompability.
{
  bool HasIncompatibleAttributes = false;
  for (const auto &Note : Mismatches)
    HasIncompatibleAttributes =
        Note.Kind != IncompatibleType ? true : HasIncompatibleAttributes;
  // Promote the warning to an error if there are incompatible attributes or
  // incompatible types together with readwrite/readonly incompatibility.
  auto Diag = S.Diag(Property->getLocation(),
                     Property != OriginalProperty || HasIncompatibleAttributes
                         ? diag::err_protocol_property_mismatch
                         : diag::warn_protocol_property_mismatch);
  Diag << Mismatches[0].Kind;
  switch (Mismatches[0].Kind) {
  case IncompatibleType:
    Diag << Property->getType();
    break;
  case HasNoExpectedAttribute:
  case HasUnexpectedAttribute:
    Diag << Mismatches[0].AttributeName;
    break;
  case DifferentGetter:
    Diag << Property->getGetterName();
    break;
  case DifferentSetter:
    Diag << Property->getSetterName();
    break;
  }
}
for (const auto &Note : Mismatches) {
  auto Diag =
      S.Diag(Note.Prop->getLocation(), diag::note_protocol_property_declare)
      << Note.Kind;
  switch (Note.Kind) {
  case IncompatibleType:
    Diag << Note.Prop->getType();
    break;
  case HasNoExpectedAttribute:
  case HasUnexpectedAttribute:
    Diag << Note.AttributeName;
    break;
  case DifferentGetter:
    Diag << Note.Prop->getGetterName();
    break;
  case DifferentSetter:
    Diag << Note.Prop->getSetterName();
    break;
  }
}
if (AtLoc.isValid())
  S.Diag(AtLoc, diag::note_property_synthesize);

return Property;
1011}

1013/// Determine whether any storage attributes were written on the property.
1014static bool hasWrittenStorageAttribute(ObjCPropertyDecl *Prop,
                                     ObjCPropertyQueryKind QueryKind) {
if (Prop->getPropertyAttributesAsWritten() & OwnershipMask) return true;

// If this is a readwrite property in a class extension that refines
// a readonly property in the original class definition, check it as
// well.

// If it's a readonly property, we're not interested.
if (Prop->isReadOnly()) return false;

// Is it declared in an extension?
auto Category = dyn_cast<ObjCCategoryDecl>(Prop->getDeclContext());
if (!Category || !Category->IsClassExtension()) return false;

// Find the corresponding property in the primary class definition.
auto OrigClass = Category->getClassInterface();
for (auto Found : OrigClass->lookup(Prop->getDeclName())) {
  if (ObjCPropertyDecl *OrigProp = dyn_cast<ObjCPropertyDecl>(Found))
    return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
}

// Look through all of the protocols.
for (const auto *Proto : OrigClass->all_referenced_protocols()) {
  if (ObjCPropertyDecl *OrigProp = Proto->FindPropertyDeclaration(
          Prop->getIdentifier(), QueryKind))
    return OrigProp->getPropertyAttributesAsWritten() & OwnershipMask;
}

return false;
1044}

1046/// Create a synthesized property accessor stub inside the \@implementation.
1047static ObjCMethodDecl *
1048RedeclarePropertyAccessor(ASTContext &Context, ObjCImplementationDecl *Impl,
                        ObjCMethodDecl *AccessorDecl, SourceLocation AtLoc,
                        SourceLocation PropertyLoc) {
ObjCMethodDecl *Decl = AccessorDecl;
ObjCMethodDecl *ImplDecl = ObjCMethodDecl::Create(
    Context, AtLoc.isValid() ? AtLoc : Decl->getBeginLoc(),
    PropertyLoc.isValid() ? PropertyLoc : Decl->getEndLoc(),
    Decl->getSelector(), Decl->getReturnType(),
    Decl->getReturnTypeSourceInfo(), Impl, Decl->isInstanceMethod(),
    Decl->isVariadic(), Decl->isPropertyAccessor(),
    /* isSynthesized*/ true, Decl->isImplicit(), Decl->isDefined(),
    Decl->getImplementationControl(), Decl->hasRelatedResultType());
ImplDecl->getMethodFamily();
if (Decl->hasAttrs())
  ImplDecl->setAttrs(Decl->getAttrs());
ImplDecl->setSelfDecl(Decl->getSelfDecl());
ImplDecl->setCmdDecl(Decl->getCmdDecl());
SmallVector<SourceLocation, 1> SelLocs;
Decl->getSelectorLocs(SelLocs);
ImplDecl->setMethodParams(Context, Decl->parameters(), SelLocs);
ImplDecl->setLexicalDeclContext(Impl);
ImplDecl->setDefined(false);
return ImplDecl;
1071}

1073/// ActOnPropertyImplDecl - This routine performs semantic checks and
1074/// builds the AST node for a property implementation declaration; declared
1075/// as \@synthesize or \@dynamic.
1076///
1077Decl *Sema::ActOnPropertyImplDecl(Scope *S,
                                SourceLocation AtLoc,
                                SourceLocation PropertyLoc,
                                bool Synthesize,
                                IdentifierInfo *PropertyId,
                                IdentifierInfo *PropertyIvar,
                                SourceLocation PropertyIvarLoc,
                                ObjCPropertyQueryKind QueryKind) {
ObjCContainerDecl *ClassImpDecl =
  dyn_cast<ObjCContainerDecl>(CurContext);
// Make sure we have a context for the property implementation declaration.
if (!ClassImpDecl) {
  Diag(AtLoc, diag::err_missing_property_context);
  return nullptr;
}
if (PropertyIvarLoc.isInvalid())
  PropertyIvarLoc = PropertyLoc;
SourceLocation PropertyDiagLoc = PropertyLoc;
if (PropertyDiagLoc.isInvalid())
  PropertyDiagLoc = ClassImpDecl->getBeginLoc();
ObjCPropertyDecl *property = nullptr;
ObjCInterfaceDecl *IDecl = nullptr;
// Find the class or category class where this property must have
// a declaration.
ObjCImplementationDecl *IC = nullptr;
ObjCCategoryImplDecl *CatImplClass = nullptr;
if ((IC = dyn_cast<ObjCImplementationDecl>(ClassImpDecl))) {
  IDecl = IC->getClassInterface();
  // We always synthesize an interface for an implementation
  // without an interface decl. So, IDecl is always non-zero.
  assert(IDecl &&((void)0)
         "ActOnPropertyImplDecl - @implementation without @interface")((void)0);

  // Look for this property declaration in the @implementation's @interface
  property = IDecl->FindPropertyDeclaration(PropertyId, QueryKind);
  if (!property) {
    Diag(PropertyLoc, diag::err_bad_property_decl) << IDecl->getDeclName();
    return nullptr;
  }
  if (property->isClassProperty() && Synthesize) {
    Diag(PropertyLoc, diag::err_synthesize_on_class_property) << PropertyId;
    return nullptr;
  }
  unsigned PIkind = property->getPropertyAttributesAsWritten();
  if ((PIkind & (ObjCPropertyAttribute::kind_atomic |
                 ObjCPropertyAttribute::kind_nonatomic)) == 0) {
    if (AtLoc.isValid())
      Diag(AtLoc, diag::warn_implicit_atomic_property);
    else
      Diag(IC->getLocation(), diag::warn_auto_implicit_atomic_property);
    Diag(property->getLocation(), diag::note_property_declare);
  }

  if (const ObjCCategoryDecl *CD =
      dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
    if (!CD->IsClassExtension()) {
      Diag(PropertyLoc, diag::err_category_property) << CD->getDeclName();
      Diag(property->getLocation(), diag::note_property_declare);
      return nullptr;
    }
  }
  if (Synthesize && (PIkind & ObjCPropertyAttribute::kind_readonly) &&
      property->hasAttr<IBOutletAttr>() && !AtLoc.isValid()) {
    bool ReadWriteProperty = false;
    // Search into the class extensions and see if 'readonly property is
    // redeclared 'readwrite', then no warning is to be issued.
    for (auto *Ext : IDecl->known_extensions()) {
      DeclContext::lookup_result R = Ext->lookup(property->getDeclName());
      if (auto *ExtProp = R.find_first<ObjCPropertyDecl>()) {
        PIkind = ExtProp->getPropertyAttributesAsWritten();
        if (PIkind & ObjCPropertyAttribute::kind_readwrite) {
          ReadWriteProperty = true;
          break;
        }
      }
    }

    if (!ReadWriteProperty) {
      Diag(property->getLocation(), diag::warn_auto_readonly_iboutlet_property)
          << property;
      SourceLocation readonlyLoc;
      if (LocPropertyAttribute(Context, "readonly",
                               property->getLParenLoc(), readonlyLoc)) {
        SourceLocation endLoc =
          readonlyLoc.getLocWithOffset(strlen("readonly")-1);
        SourceRange ReadonlySourceRange(readonlyLoc, endLoc);
        Diag(property->getLocation(),
             diag::note_auto_readonly_iboutlet_fixup_suggest) <<
        FixItHint::CreateReplacement(ReadonlySourceRange, "readwrite");
      }
    }
  }
  if (Synthesize && isa<ObjCProtocolDecl>(property->getDeclContext()))
    property = SelectPropertyForSynthesisFromProtocols(*this, AtLoc, IDecl,
                                                       property);

} else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
  if (Synthesize) {
    Diag(AtLoc, diag::err_synthesize_category_decl);
    return nullptr;
  }
  IDecl = CatImplClass->getClassInterface();
  if (!IDecl) {
    Diag(AtLoc, diag::err_missing_property_interface);
    return nullptr;
  }
  ObjCCategoryDecl *Category =
  IDecl->FindCategoryDeclaration(CatImplClass->getIdentifier());

  // If category for this implementation not found, it is an error which
  // has already been reported eralier.
  if (!Category)
    return nullptr;
  // Look for this property declaration in @implementation's category
  property = Category->FindPropertyDeclaration(PropertyId, QueryKind);
  if (!property) {
    Diag(PropertyLoc, diag::err_bad_category_property_decl)
    << Category->getDeclName();
    return nullptr;
  }
} else {
  Diag(AtLoc, diag::err_bad_property_context);
  return nullptr;
}
ObjCIvarDecl *Ivar = nullptr;
bool CompleteTypeErr = false;
bool compat = true;
// Check that we have a valid, previously declared ivar for @synthesize
if (Synthesize) {
  // @synthesize
  if (!PropertyIvar)
    PropertyIvar = PropertyId;
  // Check that this is a previously declared 'ivar' in 'IDecl' interface
  ObjCInterfaceDecl *ClassDeclared;
  Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
  QualType PropType = property->getType();
  QualType PropertyIvarType = PropType.getNonReferenceType();

  if (RequireCompleteType(PropertyDiagLoc, PropertyIvarType,
                          diag::err_incomplete_synthesized_property,
                          property->getDeclName())) {
    Diag(property->getLocation(), diag::note_property_declare);
    CompleteTypeErr = true;
  }

  if (getLangOpts().ObjCAutoRefCount &&
      (property->getPropertyAttributesAsWritten() &
       ObjCPropertyAttribute::kind_readonly) &&
      PropertyIvarType->isObjCRetainableType()) {
    setImpliedPropertyAttributeForReadOnlyProperty(property, Ivar);
  }

  ObjCPropertyAttribute::Kind kind = property->getPropertyAttributes();

  bool isARCWeak = false;
  if (kind & ObjCPropertyAttribute::kind_weak) {
    // Add GC __weak to the ivar type if the property is weak.
    if (getLangOpts().getGC() != LangOptions::NonGC) {
      assert(!getLangOpts().ObjCAutoRefCount)((void)0);
      if (PropertyIvarType.isObjCGCStrong()) {
        Diag(PropertyDiagLoc, diag::err_gc_weak_property_strong_type);
        Diag(property->getLocation(), diag::note_property_declare);
      } else {
        PropertyIvarType =
          Context.getObjCGCQualType(PropertyIvarType, Qualifiers::Weak);
      }

    // Otherwise, check whether ARC __weak is enabled and works with
    // the property type.
    } else {
      if (!getLangOpts().ObjCWeak) {
        // Only complain here when synthesizing an ivar.
        if (!Ivar) {
          Diag(PropertyDiagLoc,
               getLangOpts().ObjCWeakRuntime
                 ? diag::err_synthesizing_arc_weak_property_disabled
                 : diag::err_synthesizing_arc_weak_property_no_runtime);
          Diag(property->getLocation(), diag::note_property_declare);
        }
        CompleteTypeErr = true; // suppress later diagnostics about the ivar
      } else {
        isARCWeak = true;
        if (const ObjCObjectPointerType *ObjT =
              PropertyIvarType->getAs<ObjCObjectPointerType>()) {
          const ObjCInterfaceDecl *ObjI = ObjT->getInterfaceDecl();
          if (ObjI && ObjI->isArcWeakrefUnavailable()) {
            Diag(property->getLocation(),
                 diag::err_arc_weak_unavailable_property)
              << PropertyIvarType;
            Diag(ClassImpDecl->getLocation(), diag::note_implemented_by_class)
              << ClassImpDecl->getName();
          }
        }
      }
    }
  }

  if (AtLoc.isInvalid()) {
    // Check when default synthesizing a property that there is
    // an ivar matching property name and issue warning; since this
    // is the most common case of not using an ivar used for backing
    // property in non-default synthesis case.
    ObjCInterfaceDecl *ClassDeclared=nullptr;
    ObjCIvarDecl *originalIvar =
    IDecl->lookupInstanceVariable(property->getIdentifier(),
                                  ClassDeclared);
    if (originalIvar) {
      Diag(PropertyDiagLoc,
           diag::warn_autosynthesis_property_ivar_match)
      << PropertyId << (Ivar == nullptr) << PropertyIvar
      << originalIvar->getIdentifier();
      Diag(property->getLocation(), diag::note_property_declare);
      Diag(originalIvar->getLocation(), diag::note_ivar_decl);
    }
  }

  if (!Ivar) {
    // In ARC, give the ivar a lifetime qualifier based on the
    // property attributes.
    if ((getLangOpts().ObjCAutoRefCount || isARCWeak) &&
        !PropertyIvarType.getObjCLifetime() &&
        PropertyIvarType->isObjCRetainableType()) {

      // It's an error if we have to do this and the user didn't
      // explicitly write an ownership attribute on the property.
      if (!hasWrittenStorageAttribute(property, QueryKind) &&
          !(kind & ObjCPropertyAttribute::kind_strong)) {
        Diag(PropertyDiagLoc,
             diag::err_arc_objc_property_default_assign_on_object);
        Diag(property->getLocation(), diag::note_property_declare);
      } else {
        Qualifiers::ObjCLifetime lifetime =
          getImpliedARCOwnership(kind, PropertyIvarType);
        assert(lifetime && "no lifetime for property?")((void)0);

        Qualifiers qs;
        qs.addObjCLifetime(lifetime);
        PropertyIvarType = Context.getQualifiedType(PropertyIvarType, qs);
      }
    }

    Ivar = ObjCIvarDecl::Create(Context, ClassImpDecl,
                                PropertyIvarLoc,PropertyIvarLoc, PropertyIvar,
                                PropertyIvarType, /*TInfo=*/nullptr,
                                ObjCIvarDecl::Private,
                                (Expr *)nullptr, true);
    if (RequireNonAbstractType(PropertyIvarLoc,
                               PropertyIvarType,
                               diag::err_abstract_type_in_decl,
                               AbstractSynthesizedIvarType)) {
      Diag(property->getLocation(), diag::note_property_declare);
      // An abstract type is as bad as an incomplete type.
      CompleteTypeErr = true;
    }
    if (!CompleteTypeErr) {
      const RecordType *RecordTy = PropertyIvarType->getAs<RecordType>();
      if (RecordTy && RecordTy->getDecl()->hasFlexibleArrayMember()) {
        Diag(PropertyIvarLoc, diag::err_synthesize_variable_sized_ivar)
          << PropertyIvarType;
        CompleteTypeErr = true; // suppress later diagnostics about the ivar
      }
    }
    if (CompleteTypeErr)
      Ivar->setInvalidDecl();
    ClassImpDecl->addDecl(Ivar);
    IDecl->makeDeclVisibleInContext(Ivar);

    if (getLangOpts().ObjCRuntime.isFragile())
      Diag(PropertyDiagLoc, diag::err_missing_property_ivar_decl)
          << PropertyId;
    // Note! I deliberately want it to fall thru so, we have a
    // a property implementation and to avoid future warnings.
  } else if (getLangOpts().ObjCRuntime.isNonFragile() &&
             !declaresSameEntity(ClassDeclared, IDecl)) {
    Diag(PropertyDiagLoc, diag::err_ivar_in_superclass_use)
    << property->getDeclName() << Ivar->getDeclName()
    << ClassDeclared->getDeclName();
    Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
    << Ivar << Ivar->getName();
    // Note! I deliberately want it to fall thru so more errors are caught.
  }
  property->setPropertyIvarDecl(Ivar);

  QualType IvarType = Context.getCanonicalType(Ivar->getType());

  // Check that type of property and its ivar are type compatible.
  if (!Context.hasSameType(PropertyIvarType, IvarType)) {
    if (isa<ObjCObjectPointerType>(PropertyIvarType)
        && isa<ObjCObjectPointerType>(IvarType))
      compat =
        Context.canAssignObjCInterfaces(
                                PropertyIvarType->getAs<ObjCObjectPointerType>(),
                                IvarType->getAs<ObjCObjectPointerType>());
    else {
      compat = (CheckAssignmentConstraints(PropertyIvarLoc, PropertyIvarType,
                                           IvarType)
                  == Compatible);
    }
    if (!compat) {
      Diag(PropertyDiagLoc, diag::err_property_ivar_type)
        << property->getDeclName() << PropType
        << Ivar->getDeclName() << IvarType;
      Diag(Ivar->getLocation(), diag::note_ivar_decl);
      // Note! I deliberately want it to fall thru so, we have a
      // a property implementation and to avoid future warnings.
    }
    else {
      // FIXME! Rules for properties are somewhat different that those
      // for assignments. Use a new routine to consolidate all cases;
      // specifically for property redeclarations as well as for ivars.
      QualType lhsType =Context.getCanonicalType(PropertyIvarType).getUnqualifiedType();
      QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
      if (lhsType != rhsType &&
          lhsType->isArithmeticType()) {
        Diag(PropertyDiagLoc, diag::err_property_ivar_type)
          << property->getDeclName() << PropType
          << Ivar->getDeclName() << IvarType;
        Diag(Ivar->getLocation(), diag::note_ivar_decl);
        // Fall thru - see previous comment
      }
    }
    // __weak is explicit. So it works on Canonical type.
    if ((PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
         getLangOpts().getGC() != LangOptions::NonGC)) {
      Diag(PropertyDiagLoc, diag::err_weak_property)
      << property->getDeclName() << Ivar->getDeclName();
      Diag(Ivar->getLocation(), diag::note_ivar_decl);
      // Fall thru - see previous comment
    }
    // Fall thru - see previous comment
    if ((property->getType()->isObjCObjectPointerType() ||
         PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
        getLangOpts().getGC() != LangOptions::NonGC) {
      Diag(PropertyDiagLoc, diag::err_strong_property)
      << property->getDeclName() << Ivar->getDeclName();
      // Fall thru - see previous comment
    }
  }
  if (getLangOpts().ObjCAutoRefCount || isARCWeak ||
      Ivar->getType().getObjCLifetime())
    checkARCPropertyImpl(*this, PropertyLoc, property, Ivar);
} else if (PropertyIvar)
  // @dynamic
  Diag(PropertyDiagLoc, diag::err_dynamic_property_ivar_decl);

assert (property && "ActOnPropertyImplDecl - property declaration missing")((void)0);
ObjCPropertyImplDecl *PIDecl =
ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
                             property,
                             (Synthesize ?
                              ObjCPropertyImplDecl::Synthesize
                              : ObjCPropertyImplDecl::Dynamic),
                             Ivar, PropertyIvarLoc);

if (CompleteTypeErr || !compat)
  PIDecl->setInvalidDecl();

if (ObjCMethodDecl *getterMethod = property->getGetterMethodDecl()) {
  getterMethod->createImplicitParams(Context, IDecl);

  // Redeclare the getter within the implementation as DeclContext.
  if (Synthesize) {
    // If the method hasn't been overridden, create a synthesized implementation.
    ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
        getterMethod->getSelector(), getterMethod->isInstanceMethod());
    if (!OMD)
      OMD = RedeclarePropertyAccessor(Context, IC, getterMethod, AtLoc,
                                      PropertyLoc);
    PIDecl->setGetterMethodDecl(OMD);
  }

  if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
      Ivar->getType()->isRecordType()) {
    // For Objective-C++, need to synthesize the AST for the IVAR object to be
    // returned by the getter as it must conform to C++'s copy-return rules.
    // FIXME. Eventually we want to do this for Objective-C as well.
    SynthesizedFunctionScope Scope(*this, getterMethod);
    ImplicitParamDecl *SelfDecl = getterMethod->getSelfDecl();
    DeclRefExpr *SelfExpr = new (Context)
        DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
                    PropertyDiagLoc);
    MarkDeclRefReferenced(SelfExpr);
    Expr *LoadSelfExpr = ImplicitCastExpr::Create(
        Context, SelfDecl->getType(), CK_LValueToRValue, SelfExpr, nullptr,
        VK_PRValue, FPOptionsOverride());
    Expr *IvarRefExpr =
      new (Context) ObjCIvarRefExpr(Ivar,
                                    Ivar->getUsageType(SelfDecl->getType()),
                                    PropertyDiagLoc,
                                    Ivar->getLocation(),
                                    LoadSelfExpr, true, true);
    ExprResult Res = PerformCopyInitialization(
        InitializedEntity::InitializeResult(PropertyDiagLoc,
                                            getterMethod->getReturnType()),
        PropertyDiagLoc, IvarRefExpr);
    if (!Res.isInvalid()) {
      Expr *ResExpr = Res.getAs<Expr>();
      if (ResExpr)
        ResExpr = MaybeCreateExprWithCleanups(ResExpr);
      PIDecl->setGetterCXXConstructor(ResExpr);
    }
  }
  if (property->hasAttr<NSReturnsNotRetainedAttr>() &&
      !getterMethod->hasAttr<NSReturnsNotRetainedAttr>()) {
    Diag(getterMethod->getLocation(),
         diag::warn_property_getter_owning_mismatch);
    Diag(property->getLocation(), diag::note_property_declare);
  }
  if (getLangOpts().ObjCAutoRefCount && Synthesize)
    switch (getterMethod->getMethodFamily()) {
      case OMF_retain:
      case OMF_retainCount:
      case OMF_release:
      case OMF_autorelease:
        Diag(getterMethod->getLocation(), diag::err_arc_illegal_method_def)
          << 1 << getterMethod->getSelector();
        break;
      default:
        break;
    }
}

if (ObjCMethodDecl *setterMethod = property->getSetterMethodDecl()) {
  setterMethod->createImplicitParams(Context, IDecl);

  // Redeclare the setter within the implementation as DeclContext.
  if (Synthesize) {
    ObjCMethodDecl *OMD = ClassImpDecl->getMethod(
        setterMethod->getSelector(), setterMethod->isInstanceMethod());
    if (!OMD)
      OMD = RedeclarePropertyAccessor(Context, IC, setterMethod,
                                      AtLoc, PropertyLoc);
    PIDecl->setSetterMethodDecl(OMD);
  }

  if (getLangOpts().CPlusPlus && Synthesize && !CompleteTypeErr &&
      Ivar->getType()->isRecordType()) {
    // FIXME. Eventually we want to do this for Objective-C as well.
    SynthesizedFunctionScope Scope(*this, setterMethod);
    ImplicitParamDecl *SelfDecl = setterMethod->getSelfDecl();
    DeclRefExpr *SelfExpr = new (Context)
        DeclRefExpr(Context, SelfDecl, false, SelfDecl->getType(), VK_LValue,
                    PropertyDiagLoc);
    MarkDeclRefReferenced(SelfExpr);
    Expr *LoadSelfExpr = ImplicitCastExpr::Create(
        Context, SelfDecl->getType(), CK_LValueToRValue, SelfExpr, nullptr,
        VK_PRValue, FPOptionsOverride());
    Expr *lhs =
      new (Context) ObjCIvarRefExpr(Ivar,
                                    Ivar->getUsageType(SelfDecl->getType()),
                                    PropertyDiagLoc,
                                    Ivar->getLocation(),
                                    LoadSelfExpr, true, true);
    ObjCMethodDecl::param_iterator P = setterMethod->param_begin();
    ParmVarDecl *Param = (*P);
    QualType T = Param->getType().getNonReferenceType();
    DeclRefExpr *rhs = new (Context)
        DeclRefExpr(Context, Param, false, T, VK_LValue, PropertyDiagLoc);
    MarkDeclRefReferenced(rhs);
    ExprResult Res = BuildBinOp(S, PropertyDiagLoc,
                                BO_Assign, lhs, rhs);
    if (property->getPropertyAttributes() &
        ObjCPropertyAttribute::kind_atomic) {
      Expr *callExpr = Res.getAs<Expr>();
      if (const CXXOperatorCallExpr *CXXCE =
            dyn_cast_or_null<CXXOperatorCallExpr>(callExpr))
        if (const FunctionDecl *FuncDecl = CXXCE->getDirectCallee())
          if (!FuncDecl->isTrivial())
            if (property->getType()->isReferenceType()) {
              Diag(PropertyDiagLoc,
                   diag::err_atomic_property_nontrivial_assign_op)
                  << property->getType();
              Diag(FuncDecl->getBeginLoc(), diag::note_callee_decl)
                  << FuncDecl;
            }
    }
    PIDecl->setSetterCXXAssignment(Res.getAs<Expr>());
  }
}

if (IC) {
  if (Synthesize)
    if (ObjCPropertyImplDecl *PPIDecl =
        IC->FindPropertyImplIvarDecl(PropertyIvar)) {
      Diag(PropertyLoc, diag::err_duplicate_ivar_use)
      << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
      << PropertyIvar;
      Diag(PPIDecl->getLocation(), diag::note_previous_use);
    }

  if (ObjCPropertyImplDecl *PPIDecl
      = IC->FindPropertyImplDecl(PropertyId, QueryKind)) {
    Diag(PropertyLoc, diag::err_property_implemented) << PropertyId;
    Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
    return nullptr;
  }
  IC->addPropertyImplementation(PIDecl);
  if (getLangOpts().ObjCDefaultSynthProperties &&
      getLangOpts().ObjCRuntime.isNonFragile() &&
      !IDecl->isObjCRequiresPropertyDefs()) {
    // Diagnose if an ivar was lazily synthesdized due to a previous
    // use and if 1) property is @dynamic or 2) property is synthesized
    // but it requires an ivar of different name.
    ObjCInterfaceDecl *ClassDeclared=nullptr;
    ObjCIvarDecl *Ivar = nullptr;
    if (!Synthesize)
      Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
    else {
      if (PropertyIvar && PropertyIvar != PropertyId)
        Ivar = IDecl->lookupInstanceVariable(PropertyId, ClassDeclared);
    }
    // Issue diagnostics only if Ivar belongs to current class.
    if (Ivar && Ivar->getSynthesize() &&
        declaresSameEntity(IC->getClassInterface(), ClassDeclared)) {
      Diag(Ivar->getLocation(), diag::err_undeclared_var_use)
      << PropertyId;
      Ivar->setInvalidDecl();
    }
  }
} else {
  if (Synthesize)
    if (ObjCPropertyImplDecl *PPIDecl =
        CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
      Diag(PropertyDiagLoc, diag::err_duplicate_ivar_use)
      << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
      << PropertyIvar;
      Diag(PPIDecl->getLocation(), diag::note_previous_use);
    }

  if (ObjCPropertyImplDecl *PPIDecl =
      CatImplClass->FindPropertyImplDecl(PropertyId, QueryKind)) {
    Diag(PropertyDiagLoc, diag::err_property_implemented) << PropertyId;
    Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
    return nullptr;
  }
  CatImplClass->addPropertyImplementation(PIDecl);
}

if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic &&
    PIDecl->getPropertyDecl() &&
    PIDecl->getPropertyDecl()->isDirectProperty()) {
  Diag(PropertyLoc, diag::err_objc_direct_dynamic_property);
  Diag(PIDecl->getPropertyDecl()->getLocation(),
       diag::note_previous_declaration);
  return nullptr;
}

return PIDecl;
1625}

1627//===----------------------------------------------------------------------===//
1628// Helper methods.
1629//===----------------------------------------------------------------------===//

1631/// DiagnosePropertyMismatch - Compares two properties for their
1632/// attributes and types and warns on a variety of inconsistencies.
1633///
1634void
1635Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
                             ObjCPropertyDecl *SuperProperty,
                             const IdentifierInfo *inheritedName,
                             bool OverridingProtocolProperty) {
ObjCPropertyAttribute::Kind CAttr = Property->getPropertyAttributes();
ObjCPropertyAttribute::Kind SAttr = SuperProperty->getPropertyAttributes();

// We allow readonly properties without an explicit ownership
// (assign/unsafe_unretained/weak/retain/strong/copy) in super class
// to be overridden by a property with any explicit ownership in the subclass.
if (!OverridingProtocolProperty &&
    !getOwnershipRule(SAttr) && getOwnershipRule(CAttr))
  ;
else {
  if ((CAttr & ObjCPropertyAttribute::kind_readonly) &&
      (SAttr & ObjCPropertyAttribute::kind_readwrite))
    Diag(Property->getLocation(), diag::warn_readonly_property)
      << Property->getDeclName() << inheritedName;
  if ((CAttr & ObjCPropertyAttribute::kind_copy) !=
      (SAttr & ObjCPropertyAttribute::kind_copy))
    Diag(Property->getLocation(), diag::warn_property_attribute)
      << Property->getDeclName() << "copy" << inheritedName;
  else if (!(SAttr & ObjCPropertyAttribute::kind_readonly)) {
    unsigned CAttrRetain = (CAttr & (ObjCPropertyAttribute::kind_retain |
                                     ObjCPropertyAttribute::kind_strong));
    unsigned SAttrRetain = (SAttr & (ObjCPropertyAttribute::kind_retain |
                                     ObjCPropertyAttribute::kind_strong));
    bool CStrong = (CAttrRetain != 0);
    bool SStrong = (SAttrRetain != 0);
    if (CStrong != SStrong)
      Diag(Property->getLocation(), diag::warn_property_attribute)
        << Property->getDeclName() << "retain (or strong)" << inheritedName;
  }
}

// Check for nonatomic; note that nonatomic is effectively
// meaningless for readonly properties, so don't diagnose if the
// atomic property is 'readonly'.
checkAtomicPropertyMismatch(*this, SuperProperty, Property, false);
// Readonly properties from protocols can be implemented as "readwrite"
// with a custom setter name.
if (Property->getSetterName() != SuperProperty->getSetterName() &&
    !(SuperProperty->isReadOnly() &&
      isa<ObjCProtocolDecl>(SuperProperty->getDeclContext()))) {
  Diag(Property->getLocation(), diag::warn_property_attribute)
    << Property->getDeclName() << "setter" << inheritedName;
  Diag(SuperProperty->getLocation(), diag::note_property_declare);
}
if (Property->getGetterName() != SuperProperty->getGetterName()) {
  Diag(Property->getLocation(), diag::warn_property_attribute)
    << Property->getDeclName() << "getter" << inheritedName;
  Diag(SuperProperty->getLocation(), diag::note_property_declare);
}

QualType LHSType =
  Context.getCanonicalType(SuperProperty->getType());
QualType RHSType =
  Context.getCanonicalType(Property->getType());

if (!Context.propertyTypesAreCompatible(LHSType, RHSType)) {
  // Do cases not handled in above.
  // FIXME. For future support of covariant property types, revisit this.
  bool IncompatibleObjC = false;
  QualType ConvertedType;
  if (!isObjCPointerConversion(RHSType, LHSType,
                               ConvertedType, IncompatibleObjC) ||
      IncompatibleObjC) {
      Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
      << Property->getType() << SuperProperty->getType() << inheritedName;
    Diag(SuperProperty->getLocation(), diag::note_property_declare);
  }
}
1707}

1709bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
                                          ObjCMethodDecl *GetterMethod,
                                          SourceLocation Loc) {
if (!GetterMethod)
  return false;
QualType GetterType = GetterMethod->getReturnType().getNonReferenceType();
QualType PropertyRValueType =
    property->getType().getNonReferenceType().getAtomicUnqualifiedType();
bool compat = Context.hasSameType(PropertyRValueType, GetterType);
if (!compat) {
  const ObjCObjectPointerType *propertyObjCPtr = nullptr;
  const ObjCObjectPointerType *getterObjCPtr = nullptr;
  if ((propertyObjCPtr =
           PropertyRValueType->getAs<ObjCObjectPointerType>()) &&
      (getterObjCPtr = GetterType->getAs<ObjCObjectPointerType>()))
    compat = Context.canAssignObjCInterfaces(getterObjCPtr, propertyObjCPtr);
  else if (CheckAssignmentConstraints(Loc, GetterType, PropertyRValueType)
            != Compatible) {
        Diag(Loc, diag::err_property_accessor_type)
          << property->getDeclName() << PropertyRValueType
          << GetterMethod->getSelector() << GetterType;
        Diag(GetterMethod->getLocation(), diag::note_declared_at);
        return true;
  } else {
    compat = true;
    QualType lhsType = Context.getCanonicalType(PropertyRValueType);
    QualType rhsType =Context.getCanonicalType(GetterType).getUnqualifiedType();
    if (lhsType != rhsType && lhsType->isArithmeticType())
      compat = false;
  }
}

if (!compat) {
  Diag(Loc, diag::warn_accessor_property_type_mismatch)
  << property->getDeclName()
  << GetterMethod->getSelector();
  Diag(GetterMethod->getLocation(), diag::note_declared_at);
  return true;
}

return false;
1750}

1752/// CollectImmediateProperties - This routine collects all properties in
1753/// the class and its conforming protocols; but not those in its super class.
1754static void
1755CollectImmediateProperties(ObjCContainerDecl *CDecl,
                         ObjCContainerDecl::PropertyMap &PropMap,
                         ObjCContainerDecl::PropertyMap &SuperPropMap,
                         bool CollectClassPropsOnly = false,
                         bool IncludeProtocols = true) {
if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
  for (auto *Prop : IDecl->properties()) {
    if (CollectClassPropsOnly && !Prop->isClassProperty())
      continue;
    PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
        Prop;
  }

  // Collect the properties from visible extensions.
  for (auto *Ext : IDecl->visible_extensions())
    CollectImmediateProperties(Ext, PropMap, SuperPropMap,
                               CollectClassPropsOnly, IncludeProtocols);

  if (IncludeProtocols) {
    // Scan through class's protocols.
    for (auto *PI : IDecl->all_referenced_protocols())
      CollectImmediateProperties(PI, PropMap, SuperPropMap,
                                 CollectClassPropsOnly);
  }
}
if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
  for (auto *Prop : CATDecl->properties()) {
    if (CollectClassPropsOnly && !Prop->isClassProperty())
      continue;
    PropMap[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] =
        Prop;
  }
  if (IncludeProtocols) {
    // Scan through class's protocols.
    for (auto *PI : CATDecl->protocols())
      CollectImmediateProperties(PI, PropMap, SuperPropMap,
                                 CollectClassPropsOnly);
  }
}
else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
  for (auto *Prop : PDecl->properties()) {
    if (CollectClassPropsOnly && !Prop->isClassProperty())
      continue;
    ObjCPropertyDecl *PropertyFromSuper =
        SuperPropMap[std::make_pair(Prop->getIdentifier(),
                                    Prop->isClassProperty())];
    // Exclude property for protocols which conform to class's super-class,
    // as super-class has to implement the property.
    if (!PropertyFromSuper ||
        PropertyFromSuper->getIdentifier() != Prop->getIdentifier()) {
      ObjCPropertyDecl *&PropEntry =
          PropMap[std::make_pair(Prop->getIdentifier(),
                                 Prop->isClassProperty())];
      if (!PropEntry)
        PropEntry = Prop;
    }
  }
  // Scan through protocol's protocols.
  for (auto *PI : PDecl->protocols())
    CollectImmediateProperties(PI, PropMap, SuperPropMap,
                               CollectClassPropsOnly);
}
1817}

1819/// CollectSuperClassPropertyImplementations - This routine collects list of
1820/// properties to be implemented in super class(s) and also coming from their
1821/// conforming protocols.
1822static void CollectSuperClassPropertyImplementations(ObjCInterfaceDecl *CDecl,
                                  ObjCInterfaceDecl::PropertyMap &PropMap) {
if (ObjCInterfaceDecl *SDecl = CDecl->getSuperClass()) {
  ObjCInterfaceDecl::PropertyDeclOrder PO;
  while (SDecl) {
    SDecl->collectPropertiesToImplement(PropMap, PO);
    SDecl = SDecl->getSuperClass();
  }
}
1831}

1833/// IvarBacksCurrentMethodAccessor - This routine returns 'true' if 'IV' is
1834/// an ivar synthesized for 'Method' and 'Method' is a property accessor
1835/// declared in class 'IFace'.
1836bool
1837Sema::IvarBacksCurrentMethodAccessor(ObjCInterfaceDecl *IFace,
                                   ObjCMethodDecl *Method, ObjCIvarDecl *IV) {
if (!IV->getSynthesize())
  return false;
ObjCMethodDecl *IMD = IFace->lookupMethod(Method->getSelector(),
                                          Method->isInstanceMethod());
if (!IMD || !IMD->isPropertyAccessor())
  return false;

// look up a property declaration whose one of its accessors is implemented
// by this method.
for (const auto *Property : IFace->instance_properties()) {
  if ((Property->getGetterName() == IMD->getSelector() ||
       Property->getSetterName() == IMD->getSelector()) &&
      (Property->getPropertyIvarDecl() == IV))
    return true;
}
// Also look up property declaration in class extension whose one of its
// accessors is implemented by this method.
for (const auto *Ext : IFace->known_extensions())
  for (const auto *Property : Ext->instance_properties())
    if ((Property->getGetterName() == IMD->getSelector() ||
         Property->getSetterName() == IMD->getSelector()) &&
        (Property->getPropertyIvarDecl() == IV))
      return true;
return false;
1863}

1865static bool SuperClassImplementsProperty(ObjCInterfaceDecl *IDecl,
                                       ObjCPropertyDecl *Prop) {
bool SuperClassImplementsGetter = false;
bool SuperClassImplementsSetter = false;
if (Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_readonly)
  SuperClassImplementsSetter = true;

while (IDecl->getSuperClass()) {
  ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
  if (!SuperClassImplementsGetter && SDecl->getInstanceMethod(Prop->getGetterName()))
    SuperClassImplementsGetter = true;

  if (!SuperClassImplementsSetter && SDecl->getInstanceMethod(Prop->getSetterName()))
    SuperClassImplementsSetter = true;
  if (SuperClassImplementsGetter && SuperClassImplementsSetter)
    return true;
  IDecl = IDecl->getSuperClass();
}
return false;
1884}

1886/// Default synthesizes all properties which must be synthesized
1887/// in class's \@implementation.
1888void Sema::DefaultSynthesizeProperties(Scope *S, ObjCImplDecl *IMPDecl,
                                     ObjCInterfaceDecl *IDecl,
                                     SourceLocation AtEnd) {
ObjCInterfaceDecl::PropertyMap PropMap;
ObjCInterfaceDecl::PropertyDeclOrder PropertyOrder;
IDecl->collectPropertiesToImplement(PropMap, PropertyOrder);
if (PropMap.empty())
  return;
ObjCInterfaceDecl::PropertyMap SuperPropMap;
CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);

for (unsigned i = 0, e = PropertyOrder.size(); i != e; i++) {
  ObjCPropertyDecl *Prop = PropertyOrder[i];
  // Is there a matching property synthesize/dynamic?
  if (Prop->isInvalidDecl() ||
      Prop->isClassProperty() ||
      Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional)
    continue;
  // Property may have been synthesized by user.
  if (IMPDecl->FindPropertyImplDecl(
          Prop->getIdentifier(), Prop->getQueryKind()))
    continue;
  ObjCMethodDecl *ImpMethod = IMPDecl->getInstanceMethod(Prop->getGetterName());
  if (ImpMethod && !ImpMethod->getBody()) {
    if (Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_readonly)
      continue;
    ImpMethod = IMPDecl->getInstanceMethod(Prop->getSetterName());
    if (ImpMethod && !ImpMethod->getBody())
      continue;
  }
  if (ObjCPropertyImplDecl *PID =
      IMPDecl->FindPropertyImplIvarDecl(Prop->getIdentifier())) {
    Diag(Prop->getLocation(), diag::warn_no_autosynthesis_shared_ivar_property)
      << Prop->getIdentifier();
    if (PID->getLocation().isValid())
      Diag(PID->getLocation(), diag::note_property_synthesize);
    continue;
  }
  ObjCPropertyDecl *PropInSuperClass =
      SuperPropMap[std::make_pair(Prop->getIdentifier(),
                                  Prop->isClassProperty())];
  if (ObjCProtocolDecl *Proto =
        dyn_cast<ObjCProtocolDecl>(Prop->getDeclContext())) {
    // We won't auto-synthesize properties declared in protocols.
    // Suppress the warning if class's superclass implements property's
    // getter and implements property's setter (if readwrite property).
    // Or, if property is going to be implemented in its super class.
    if (!SuperClassImplementsProperty(IDecl, Prop) && !PropInSuperClass) {
      Diag(IMPDecl->getLocation(),
           diag::warn_auto_synthesizing_protocol_property)
        << Prop << Proto;
      Diag(Prop->getLocation(), diag::note_property_declare);
      std::string FixIt =
          (Twine("@synthesize ") + Prop->getName() + ";\n\n").str();
      Diag(AtEnd, diag::note_add_synthesize_directive)
          << FixItHint::CreateInsertion(AtEnd, FixIt);
    }
    continue;
  }
  // If property to be implemented in the super class, ignore.
  if (PropInSuperClass) {
    if ((Prop->getPropertyAttributes() &
         ObjCPropertyAttribute::kind_readwrite) &&
        (PropInSuperClass->getPropertyAttributes() &
         ObjCPropertyAttribute::kind_readonly) &&
        !IMPDecl->getInstanceMethod(Prop->getSetterName()) &&
        !IDecl->HasUserDeclaredSetterMethod(Prop)) {
      Diag(Prop->getLocation(), diag::warn_no_autosynthesis_property)
      << Prop->getIdentifier();
      Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
    } else {
      Diag(Prop->getLocation(), diag::warn_autosynthesis_property_in_superclass)
      << Prop->getIdentifier();
      Diag(PropInSuperClass->getLocation(), diag::note_property_declare);
      Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
    }
    continue;
  }
  // We use invalid SourceLocations for the synthesized ivars since they
  // aren't really synthesized at a particular location; they just exist.
  // Saying that they are located at the @implementation isn't really going
  // to help users.
  ObjCPropertyImplDecl *PIDecl = dyn_cast_or_null<ObjCPropertyImplDecl>(
    ActOnPropertyImplDecl(S, SourceLocation(), SourceLocation(),
                          true,
                          /* property = */ Prop->getIdentifier(),
                          /* ivar = */ Prop->getDefaultSynthIvarName(Context),
                          Prop->getLocation(), Prop->getQueryKind()));
  if (PIDecl && !Prop->isUnavailable()) {
    Diag(Prop->getLocation(), diag::warn_missing_explicit_synthesis);
    Diag(IMPDecl->getLocation(), diag::note_while_in_implementation);
  }
}
1981}

1983void Sema::DefaultSynthesizeProperties(Scope *S, Decl *D,
                                     SourceLocation AtEnd) {
if (!LangOpts.ObjCDefaultSynthProperties || LangOpts.ObjCRuntime.isFragile())
  return;
ObjCImplementationDecl *IC=dyn_cast_or_null<ObjCImplementationDecl>(D);
if (!IC)
  return;
if (ObjCInterfaceDecl* IDecl = IC->getClassInterface())
  if (!IDecl->isObjCRequiresPropertyDefs())
    DefaultSynthesizeProperties(S, IC, IDecl, AtEnd);
1993}

1995static void DiagnoseUnimplementedAccessor(
  Sema &S, ObjCInterfaceDecl *PrimaryClass, Selector Method,
  ObjCImplDecl *IMPDecl, ObjCContainerDecl *CDecl, ObjCCategoryDecl *C,
  ObjCPropertyDecl *Prop,
  llvm::SmallPtrSet<const ObjCMethodDecl *, 8> &SMap) {
// Check to see if we have a corresponding selector in SMap and with the
// right method type.
auto I = llvm::find_if(SMap, [&](const ObjCMethodDecl *x) {
  return x->getSelector() == Method &&
         x->isClassMethod() == Prop->isClassProperty();
});
// When reporting on missing property setter/getter implementation in
// categories, do not report when they are declared in primary class,
// class's protocol, or one of it super classes. This is because,
// the class is going to implement them.
if (I == SMap.end() &&
    (PrimaryClass == nullptr ||
     !PrimaryClass->lookupPropertyAccessor(Method, C,
                                           Prop->isClassProperty()))) {
  unsigned diag =
      isa<ObjCCategoryDecl>(CDecl)
          ? (Prop->isClassProperty()
                 ? diag::warn_impl_required_in_category_for_class_property
                 : diag::warn_setter_getter_impl_required_in_category)
          : (Prop->isClassProperty()
                 ? diag::warn_impl_required_for_class_property
                 : diag::warn_setter_getter_impl_required);
  S.Diag(IMPDecl->getLocation(), diag) << Prop->getDeclName() << Method;
  S.Diag(Prop->getLocation(), diag::note_property_declare);
  if (S.LangOpts.ObjCDefaultSynthProperties &&
      S.LangOpts.ObjCRuntime.isNonFragile())
    if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CDecl))
      if (const ObjCInterfaceDecl *RID = ID->isObjCRequiresPropertyDefs())
        S.Diag(RID->getLocation(), diag::note_suppressed_class_declare);
}
2030}

2032void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                         ObjCContainerDecl *CDecl,
                                         bool SynthesizeProperties) {
ObjCContainerDecl::PropertyMap PropMap;
ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl);

// Since we don't synthesize class properties, we should emit diagnose even
// if SynthesizeProperties is true.
ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
// Gather properties which need not be implemented in this class
// or category.
if (!IDecl)
  if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
    // For categories, no need to implement properties declared in
    // its primary class (and its super classes) if property is
    // declared in one of those containers.
    if ((IDecl = C->getClassInterface())) {
      ObjCInterfaceDecl::PropertyDeclOrder PO;
      IDecl->collectPropertiesToImplement(NoNeedToImplPropMap, PO);
    }
  }
if (IDecl)
  CollectSuperClassPropertyImplementations(IDecl, NoNeedToImplPropMap);

// When SynthesizeProperties is true, we only check class properties.
CollectImmediateProperties(CDecl, PropMap, NoNeedToImplPropMap,
                           SynthesizeProperties/*CollectClassPropsOnly*/);

// Scan the @interface to see if any of the protocols it adopts
// require an explicit implementation, via attribute
// 'objc_protocol_requires_explicit_implementation'.
if (IDecl) {
  std::unique_ptr<ObjCContainerDecl::PropertyMap> LazyMap;

  for (auto *PDecl : IDecl->all_referenced_protocols()) {
    if (!PDecl->hasAttr<ObjCExplicitProtocolImplAttr>())
      continue;
    // Lazily construct a set of all the properties in the @interface
    // of the class, without looking at the superclass.  We cannot
    // use the call to CollectImmediateProperties() above as that
    // utilizes information from the super class's properties as well
    // as scans the adopted protocols.  This work only triggers for protocols
    // with the attribute, which is very rare, and only occurs when
    // analyzing the @implementation.
    if (!LazyMap) {
      ObjCContainerDecl::PropertyMap NoNeedToImplPropMap;
      LazyMap.reset(new ObjCContainerDecl::PropertyMap());
      CollectImmediateProperties(CDecl, *LazyMap, NoNeedToImplPropMap,
                                 /* CollectClassPropsOnly */ false,
                                 /* IncludeProtocols */ false);
    }
    // Add the properties of 'PDecl' to the list of properties that
    // need to be implemented.
    for (auto *PropDecl : PDecl->properties()) {
      if ((*LazyMap)[std::make_pair(PropDecl->getIdentifier(),
                                    PropDecl->isClassProperty())])
        continue;
      PropMap[std::make_pair(PropDecl->getIdentifier(),
                             PropDecl->isClassProperty())] = PropDecl;
    }
  }
}

if (PropMap.empty())
  return;

llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
for (const auto *I : IMPDecl->property_impls())
  PropImplMap.insert(I->getPropertyDecl());

llvm::SmallPtrSet<const ObjCMethodDecl *, 8> InsMap;
// Collect property accessors implemented in current implementation.
for (const auto *I : IMPDecl->methods())
  InsMap.insert(I);

ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl);
ObjCInterfaceDecl *PrimaryClass = nullptr;
if (C && !C->IsClassExtension())
  if ((PrimaryClass = C->getClassInterface()))
    // Report unimplemented properties in the category as well.
    if (ObjCImplDecl *IMP = PrimaryClass->getImplementation()) {
      // When reporting on missing setter/getters, do not report when
      // setter/getter is implemented in category's primary class
      // implementation.
      for (const auto *I : IMP->methods())
        InsMap.insert(I);
    }

for (ObjCContainerDecl::PropertyMap::iterator
     P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
  ObjCPropertyDecl *Prop = P->second;
  // Is there a matching property synthesize/dynamic?
  if (Prop->isInvalidDecl() ||
      Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
      PropImplMap.count(Prop) ||
      Prop->getAvailability() == AR_Unavailable)
    continue;

  // Diagnose unimplemented getters and setters.
  DiagnoseUnimplementedAccessor(*this,
        PrimaryClass, Prop->getGetterName(), IMPDecl, CDecl, C, Prop, InsMap);
  if (!Prop->isReadOnly())
    DiagnoseUnimplementedAccessor(*this,
                                  PrimaryClass, Prop->getSetterName(),
                                  IMPDecl, CDecl, C, Prop, InsMap);
}
2138}

2140void Sema::diagnoseNullResettableSynthesizedSetters(const ObjCImplDecl *impDecl) {
for (const auto *propertyImpl : impDecl->property_impls()) {
  const auto *property = propertyImpl->getPropertyDecl();
  // Warn about null_resettable properties with synthesized setters,
  // because the setter won't properly handle nil.
  if (propertyImpl->getPropertyImplementation() ==
4
←
Taking true branch→
          ObjCPropertyImplDecl::Synthesize &&
      (property->getPropertyAttributes() &
1
Assuming the condition is true→
       ObjCPropertyAttribute::kind_null_resettable) &&
      property->getGetterMethodDecl() && property->getSetterMethodDecl()) {
2
←
Assuming the condition is true→
3
←
Assuming the condition is true→
    auto *getterImpl = propertyImpl->getGetterMethodDecl();
    auto *setterImpl = propertyImpl->getSetterMethodDecl();
5
←
'setterImpl' initialized here→
    if ((!getterImpl || getterImpl->isSynthesizedAccessorStub()) &&
6
←
Assuming 'getterImpl' is null→
        (!setterImpl || setterImpl->isSynthesizedAccessorStub())) {
7
←
Assuming 'setterImpl' is null→
      SourceLocation loc = propertyImpl->getLocation();
      if (loc.isInvalid())
8
←
Taking false branch→
        loc = impDecl->getBeginLoc();

      Diag(loc, diag::warn_null_resettable_setter)
        << setterImpl->getSelector() << property->getDeclName();
9
←
Called C++ object pointer is null
    }
  }
}
2163}

2165void
2166Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
                                     ObjCInterfaceDecl* IDecl) {
// Rules apply in non-GC mode only
if (getLangOpts().getGC() != LangOptions::NonGC)
  return;
ObjCContainerDecl::PropertyMap PM;
for (auto *Prop : IDecl->properties())
  PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;
for (const auto *Ext : IDecl->known_extensions())
  for (auto *Prop : Ext->properties())
    PM[std::make_pair(Prop->getIdentifier(), Prop->isClassProperty())] = Prop;

for (ObjCContainerDecl::PropertyMap::iterator I = PM.begin(), E = PM.end();
     I != E; ++I) {
  const ObjCPropertyDecl *Property = I->second;
  ObjCMethodDecl *GetterMethod = nullptr;
  ObjCMethodDecl *SetterMethod = nullptr;

  unsigned Attributes = Property->getPropertyAttributes();
  unsigned AttributesAsWritten = Property->getPropertyAttributesAsWritten();

  if (!(AttributesAsWritten & ObjCPropertyAttribute::kind_atomic) &&
      !(AttributesAsWritten & ObjCPropertyAttribute::kind_nonatomic)) {
    GetterMethod = Property->isClassProperty() ?
                   IMPDecl->getClassMethod(Property->getGetterName()) :
                   IMPDecl->getInstanceMethod(Property->getGetterName());
    SetterMethod = Property->isClassProperty() ?
                   IMPDecl->getClassMethod(Property->getSetterName()) :
                   IMPDecl->getInstanceMethod(Property->getSetterName());
    if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
      GetterMethod = nullptr;
    if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
      SetterMethod = nullptr;
    if (GetterMethod) {
      Diag(GetterMethod->getLocation(),
           diag::warn_default_atomic_custom_getter_setter)
        << Property->getIdentifier() << 0;
      Diag(Property->getLocation(), diag::note_property_declare);
    }
    if (SetterMethod) {
      Diag(SetterMethod->getLocation(),
           diag::warn_default_atomic_custom_getter_setter)
        << Property->getIdentifier() << 1;
      Diag(Property->getLocation(), diag::note_property_declare);
    }
  }

  // We only care about readwrite atomic property.
  if ((Attributes & ObjCPropertyAttribute::kind_nonatomic) ||
      !(Attributes & ObjCPropertyAttribute::kind_readwrite))
    continue;
  if (const ObjCPropertyImplDecl *PIDecl = IMPDecl->FindPropertyImplDecl(
          Property->getIdentifier(), Property->getQueryKind())) {
    if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
      continue;
    GetterMethod = PIDecl->getGetterMethodDecl();
    SetterMethod = PIDecl->getSetterMethodDecl();
    if (GetterMethod && GetterMethod->isSynthesizedAccessorStub())
      GetterMethod = nullptr;
    if (SetterMethod && SetterMethod->isSynthesizedAccessorStub())
      SetterMethod = nullptr;
    if ((bool)GetterMethod ^ (bool)SetterMethod) {
      SourceLocation MethodLoc =
        (GetterMethod ? GetterMethod->getLocation()
                      : SetterMethod->getLocation());
      Diag(MethodLoc, diag::warn_atomic_property_rule)
        << Property->getIdentifier() << (GetterMethod != nullptr)
        << (SetterMethod != nullptr);
      // fixit stuff.
      if (Property->getLParenLoc().isValid() &&
          !(AttributesAsWritten & ObjCPropertyAttribute::kind_atomic)) {
        // @property () ... case.
        SourceLocation AfterLParen =
          getLocForEndOfToken(Property->getLParenLoc());
        StringRef NonatomicStr = AttributesAsWritten? "nonatomic, "
                                                    : "nonatomic";
        Diag(Property->getLocation(),
             diag::note_atomic_property_fixup_suggest)
          << FixItHint::CreateInsertion(AfterLParen, NonatomicStr);
      } else if (Property->getLParenLoc().isInvalid()) {
        //@property id etc.
        SourceLocation startLoc =
          Property->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
        Diag(Property->getLocation(),
             diag::note_atomic_property_fixup_suggest)
          << FixItHint::CreateInsertion(startLoc, "(nonatomic) ");
      } else
        Diag(MethodLoc, diag::note_atomic_property_fixup_suggest);
      Diag(Property->getLocation(), diag::note_property_declare);
    }
  }
}
2258}

2260void Sema::DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D) {
if (getLangOpts().getGC() == LangOptions::GCOnly)
  return;

for (const auto *PID : D->property_impls()) {
  const ObjCPropertyDecl *PD = PID->getPropertyDecl();
  if (PD && !PD->hasAttr<NSReturnsNotRetainedAttr>() &&
      !PD->isClassProperty()) {
    ObjCMethodDecl *IM = PID->getGetterMethodDecl();
    if (IM && !IM->isSynthesizedAccessorStub())
      continue;
    ObjCMethodDecl *method = PD->getGetterMethodDecl();
    if (!method)
      continue;
    ObjCMethodFamily family = method->getMethodFamily();
    if (family == OMF_alloc || family == OMF_copy ||
        family == OMF_mutableCopy || family == OMF_new) {
      if (getLangOpts().ObjCAutoRefCount)
        Diag(PD->getLocation(), diag::err_cocoa_naming_owned_rule);
      else
        Diag(PD->getLocation(), diag::warn_cocoa_naming_owned_rule);

      // Look for a getter explicitly declared alongside the property.
      // If we find one, use its location for the note.
      SourceLocation noteLoc = PD->getLocation();
      SourceLocation fixItLoc;
      for (auto *getterRedecl : method->redecls()) {
        if (getterRedecl->isImplicit())
          continue;
        if (getterRedecl->getDeclContext() != PD->getDeclContext())
          continue;
        noteLoc = getterRedecl->getLocation();
        fixItLoc = getterRedecl->getEndLoc();
      }

      Preprocessor &PP = getPreprocessor();
      TokenValue tokens[] = {
        tok::kw___attribute, tok::l_paren, tok::l_paren,
        PP.getIdentifierInfo("objc_method_family"), tok::l_paren,
        PP.getIdentifierInfo("none"), tok::r_paren,
        tok::r_paren, tok::r_paren
      };
      StringRef spelling = "__attribute__((objc_method_family(none)))";
      StringRef macroName = PP.getLastMacroWithSpelling(noteLoc, tokens);
      if (!macroName.empty())
        spelling = macroName;

      auto noteDiag = Diag(noteLoc, diag::note_cocoa_naming_declare_family)
          << method->getDeclName() << spelling;
      if (fixItLoc.isValid()) {
        SmallString<64> fixItText(" ");
        fixItText += spelling;
        noteDiag << FixItHint::CreateInsertion(fixItLoc, fixItText);
      }
    }
  }
}
2317}

2319void Sema::DiagnoseMissingDesignatedInitOverrides(
                                          const ObjCImplementationDecl *ImplD,
                                          const ObjCInterfaceDecl *IFD) {
assert(IFD->hasDesignatedInitializers())((void)0);
const ObjCInterfaceDecl *SuperD = IFD->getSuperClass();
if (!SuperD)
  return;

SelectorSet InitSelSet;
for (const auto *I : ImplD->instance_methods())
  if (I->getMethodFamily() == OMF_init)
    InitSelSet.insert(I->getSelector());

SmallVector<const ObjCMethodDecl *, 8> DesignatedInits;
SuperD->getDesignatedInitializers(DesignatedInits);
for (SmallVector<const ObjCMethodDecl *, 8>::iterator
       I = DesignatedInits.begin(), E = DesignatedInits.end(); I != E; ++I) {
  const ObjCMethodDecl *MD = *I;
  if (!InitSelSet.count(MD->getSelector())) {
    // Don't emit a diagnostic if the overriding method in the subclass is
    // marked as unavailable.
    bool Ignore = false;
    if (auto *IMD = IFD->getInstanceMethod(MD->getSelector())) {
      Ignore = IMD->isUnavailable();
    } else {
      // Check the methods declared in the class extensions too.
      for (auto *Ext : IFD->visible_extensions())
        if (auto *IMD = Ext->getInstanceMethod(MD->getSelector())) {
          Ignore = IMD->isUnavailable();
          break;
        }
    }
    if (!Ignore) {
      Diag(ImplD->getLocation(),
           diag::warn_objc_implementation_missing_designated_init_override)
        << MD->getSelector();
      Diag(MD->getLocation(), diag::note_objc_designated_init_marked_here);
    }
  }
}
2359}

2361/// AddPropertyAttrs - Propagates attributes from a property to the
2362/// implicitly-declared getter or setter for that property.
2363static void AddPropertyAttrs(Sema &S, ObjCMethodDecl *PropertyMethod,
                           ObjCPropertyDecl *Property) {
// Should we just clone all attributes over?
for (const auto *A : Property->attrs()) {
  if (isa<DeprecatedAttr>(A) ||
      isa<UnavailableAttr>(A) ||
      isa<AvailabilityAttr>(A))
    PropertyMethod->addAttr(A->clone(S.Context));
}
2372}

2374/// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
2375/// have the property type and issue diagnostics if they don't.
2376/// Also synthesize a getter/setter method if none exist (and update the
2377/// appropriate lookup tables.
2378void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property) {
ObjCMethodDecl *GetterMethod, *SetterMethod;
ObjCContainerDecl *CD = cast<ObjCContainerDecl>(property->getDeclContext());
if (CD->isInvalidDecl())
  return;

bool IsClassProperty = property->isClassProperty();
GetterMethod = IsClassProperty ?
  CD->getClassMethod(property->getGetterName()) :
  CD->getInstanceMethod(property->getGetterName());

// if setter or getter is not found in class extension, it might be
// in the primary class.
if (!GetterMethod)
  if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
    if (CatDecl->IsClassExtension())
      GetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
                       getClassMethod(property->getGetterName()) :
                     CatDecl->getClassInterface()->
                       getInstanceMethod(property->getGetterName());

SetterMethod = IsClassProperty ?
               CD->getClassMethod(property->getSetterName()) :
               CD->getInstanceMethod(property->getSetterName());
if (!SetterMethod)
  if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD))
    if (CatDecl->IsClassExtension())
      SetterMethod = IsClassProperty ? CatDecl->getClassInterface()->
                        getClassMethod(property->getSetterName()) :
                     CatDecl->getClassInterface()->
                        getInstanceMethod(property->getSetterName());
DiagnosePropertyAccessorMismatch(property, GetterMethod,
                                 property->getLocation());

// synthesizing accessors must not result in a direct method that is not
// monomorphic
if (!GetterMethod) {
  if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
    auto *ExistingGetter = CatDecl->getClassInterface()->lookupMethod(
        property->getGetterName(), !IsClassProperty, true, false, CatDecl);
    if (ExistingGetter) {
      if (ExistingGetter->isDirectMethod() || property->isDirectProperty()) {
        Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
            << property->isDirectProperty() << 1 /* property */
            << ExistingGetter->isDirectMethod()
            << ExistingGetter->getDeclName();
        Diag(ExistingGetter->getLocation(), diag::note_previous_declaration);
      }
    }
  }
}

if (!property->isReadOnly() && !SetterMethod) {
  if (const ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CD)) {
    auto *ExistingSetter = CatDecl->getClassInterface()->lookupMethod(
        property->getSetterName(), !IsClassProperty, true, false, CatDecl);
    if (ExistingSetter) {
      if (ExistingSetter->isDirectMethod() || property->isDirectProperty()) {
        Diag(property->getLocation(), diag::err_objc_direct_duplicate_decl)
            << property->isDirectProperty() << 1 /* property */
            << ExistingSetter->isDirectMethod()
            << ExistingSetter->getDeclName();
        Diag(ExistingSetter->getLocation(), diag::note_previous_declaration);
      }
    }
  }
}

if (!property->isReadOnly() && SetterMethod) {
  if (Context.getCanonicalType(SetterMethod->getReturnType()) !=
      Context.VoidTy)
    Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
  if (SetterMethod->param_size() != 1 ||
      !Context.hasSameUnqualifiedType(
        (*SetterMethod->param_begin())->getType().getNonReferenceType(),
        property->getType().getNonReferenceType())) {
    Diag(property->getLocation(),
         diag::warn_accessor_property_type_mismatch)
      << property->getDeclName()
      << SetterMethod->getSelector();
    Diag(SetterMethod->getLocation(), diag::note_declared_at);
  }
}

// Synthesize getter/setter methods if none exist.
// Find the default getter and if one not found, add one.
// FIXME: The synthesized property we set here is misleading. We almost always
// synthesize these methods unless the user explicitly provided prototypes
// (which is odd, but allowed). Sema should be typechecking that the
// declarations jive in that situation (which it is not currently).
if (!GetterMethod) {
  // No instance/class method of same name as property getter name was found.
  // Declare a getter method and add it to the list of methods
  // for this class.
  SourceLocation Loc = property->getLocation();

  // The getter returns the declared property type with all qualifiers
  // removed.
  QualType resultTy = property->getType().getAtomicUnqualifiedType();

  // If the property is null_resettable, the getter returns nonnull.
  if (property->getPropertyAttributes() &
      ObjCPropertyAttribute::kind_null_resettable) {
    QualType modifiedTy = resultTy;
    if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)) {
      if (*nullability == NullabilityKind::Unspecified)
        resultTy = Context.getAttributedType(attr::TypeNonNull,
                                             modifiedTy, modifiedTy);
    }
  }

  GetterMethod = ObjCMethodDecl::Create(
      Context, Loc, Loc, property->getGetterName(), resultTy, nullptr, CD,
      !IsClassProperty, /*isVariadic=*/false,
      /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
      /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
      (property->getPropertyImplementation() == ObjCPropertyDecl::Optional)
          ? ObjCMethodDecl::Optional
          : ObjCMethodDecl::Required);
  CD->addDecl(GetterMethod);

  AddPropertyAttrs(*this, GetterMethod, property);

  if (property->isDirectProperty())
    GetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));

  if (property->hasAttr<NSReturnsNotRetainedAttr>())
    GetterMethod->addAttr(NSReturnsNotRetainedAttr::CreateImplicit(Context,
                                                                   Loc));

  if (property->hasAttr<ObjCReturnsInnerPointerAttr>())
    GetterMethod->addAttr(
      ObjCReturnsInnerPointerAttr::CreateImplicit(Context, Loc));

  if (const SectionAttr *SA = property->getAttr<SectionAttr>())
    GetterMethod->addAttr(SectionAttr::CreateImplicit(
        Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
        SectionAttr::GNU_section));

  if (getLangOpts().ObjCAutoRefCount)
    CheckARCMethodDecl(GetterMethod);
} else
  // A user declared getter will be synthesize when @synthesize of
  // the property with the same name is seen in the @implementation
  GetterMethod->setPropertyAccessor(true);

GetterMethod->createImplicitParams(Context,
                                   GetterMethod->getClassInterface());
property->setGetterMethodDecl(GetterMethod);

// Skip setter if property is read-only.
if (!property->isReadOnly()) {
  // Find the default setter and if one not found, add one.
  if (!SetterMethod) {
    // No instance/class method of same name as property setter name was
    // found.
    // Declare a setter method and add it to the list of methods
    // for this class.
    SourceLocation Loc = property->getLocation();

    SetterMethod =
      ObjCMethodDecl::Create(Context, Loc, Loc,
                             property->getSetterName(), Context.VoidTy,
                             nullptr, CD, !IsClassProperty,
                             /*isVariadic=*/false,
                             /*isPropertyAccessor=*/true,
                             /*isSynthesizedAccessorStub=*/false,
                             /*isImplicitlyDeclared=*/true,
                             /*isDefined=*/false,
                             (property->getPropertyImplementation() ==
                              ObjCPropertyDecl::Optional) ?
                              ObjCMethodDecl::Optional :
                              ObjCMethodDecl::Required);

    // Remove all qualifiers from the setter's parameter type.
    QualType paramTy =
        property->getType().getUnqualifiedType().getAtomicUnqualifiedType();

    // If the property is null_resettable, the setter accepts a
    // nullable value.
    if (property->getPropertyAttributes() &
        ObjCPropertyAttribute::kind_null_resettable) {
      QualType modifiedTy = paramTy;
      if (auto nullability = AttributedType::stripOuterNullability(modifiedTy)){
        if (*nullability == NullabilityKind::Unspecified)
          paramTy = Context.getAttributedType(attr::TypeNullable,
                                              modifiedTy, modifiedTy);
      }
    }

    // Invent the arguments for the setter. We don't bother making a
    // nice name for the argument.
    ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
                                                Loc, Loc,
                                                property->getIdentifier(),
                                                paramTy,
                                                /*TInfo=*/nullptr,
                                                SC_None,
                                                nullptr);
    SetterMethod->setMethodParams(Context, Argument, None);

    AddPropertyAttrs(*this, SetterMethod, property);

    if (property->isDirectProperty())
      SetterMethod->addAttr(ObjCDirectAttr::CreateImplicit(Context, Loc));

    CD->addDecl(SetterMethod);
    if (const SectionAttr *SA = property->getAttr<SectionAttr>())
      SetterMethod->addAttr(SectionAttr::CreateImplicit(
          Context, SA->getName(), Loc, AttributeCommonInfo::AS_GNU,
          SectionAttr::GNU_section));
    // It's possible for the user to have set a very odd custom
    // setter selector that causes it to have a method family.
    if (getLangOpts().ObjCAutoRefCount)
      CheckARCMethodDecl(SetterMethod);
  } else
    // A user declared setter will be synthesize when @synthesize of
    // the property with the same name is seen in the @implementation
    SetterMethod->setPropertyAccessor(true);

  SetterMethod->createImplicitParams(Context,
                                     SetterMethod->getClassInterface());
  property->setSetterMethodDecl(SetterMethod);
}
// Add any synthesized methods to the global pool. This allows us to
// handle the following, which is supported by GCC (and part of the design).
//
// @interface Foo
// @property double bar;
// @end
//
// void thisIsUnfortunate() {
//   id foo;
//   double bar = [foo bar];
// }
//
if (!IsClassProperty) {
  if (GetterMethod)
    AddInstanceMethodToGlobalPool(GetterMethod);
  if (SetterMethod)
    AddInstanceMethodToGlobalPool(SetterMethod);
} else {
  if (GetterMethod)
    AddFactoryMethodToGlobalPool(GetterMethod);
  if (SetterMethod)
    AddFactoryMethodToGlobalPool(SetterMethod);
}

ObjCInterfaceDecl *CurrentClass = dyn_cast<ObjCInterfaceDecl>(CD);
if (!CurrentClass) {
  if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CD))
    CurrentClass = Cat->getClassInterface();
  else if (ObjCImplDecl *Impl = dyn_cast<ObjCImplDecl>(CD))
    CurrentClass = Impl->getClassInterface();
}
if (GetterMethod)
  CheckObjCMethodOverrides(GetterMethod, CurrentClass, Sema::RTC_Unknown);
if (SetterMethod)
  CheckObjCMethodOverrides(SetterMethod, CurrentClass, Sema::RTC_Unknown);
2637}

2639void Sema::CheckObjCPropertyAttributes(Decl *PDecl,
                                     SourceLocation Loc,
                                     unsigned &Attributes,
                                     bool propertyInPrimaryClass) {
// FIXME: Improve the reported location.
if (!PDecl || PDecl->isInvalidDecl())
  return;

if ((Attributes & ObjCPropertyAttribute::kind_readonly) &&
    (Attributes & ObjCPropertyAttribute::kind_readwrite))
  Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
  << "readonly" << "readwrite";

ObjCPropertyDecl *PropertyDecl = cast<ObjCPropertyDecl>(PDecl);
QualType PropertyTy = PropertyDecl->getType();

// Check for copy or retain on non-object types.
if ((Attributes &
     (ObjCPropertyAttribute::kind_weak | ObjCPropertyAttribute::kind_copy |
      ObjCPropertyAttribute::kind_retain |
      ObjCPropertyAttribute::kind_strong)) &&
    !PropertyTy->isObjCRetainableType() &&
    !PropertyDecl->hasAttr<ObjCNSObjectAttr>()) {
  Diag(Loc, diag::err_objc_property_requires_object)
      << (Attributes & ObjCPropertyAttribute::kind_weak
              ? "weak"
              : Attributes & ObjCPropertyAttribute::kind_copy
                    ? "copy"
                    : "retain (or strong)");
  Attributes &=
      ~(ObjCPropertyAttribute::kind_weak | ObjCPropertyAttribute::kind_copy |
        ObjCPropertyAttribute::kind_retain |
        ObjCPropertyAttribute::kind_strong);
  PropertyDecl->setInvalidDecl();
}

// Check for assign on object types.
if ((Attributes & ObjCPropertyAttribute::kind_assign) &&
    !(Attributes & ObjCPropertyAttribute::kind_unsafe_unretained) &&
    PropertyTy->isObjCRetainableType() &&
    !PropertyTy->isObjCARCImplicitlyUnretainedType()) {
  Diag(Loc, diag::warn_objc_property_assign_on_object);
}

// Check for more than one of { assign, copy, retain }.
if (Attributes & ObjCPropertyAttribute::kind_assign) {
  if (Attributes & ObjCPropertyAttribute::kind_copy) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "assign" << "copy";
    Attributes &= ~ObjCPropertyAttribute::kind_copy;
  }
  if (Attributes & ObjCPropertyAttribute::kind_retain) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "assign" << "retain";
    Attributes &= ~ObjCPropertyAttribute::kind_retain;
  }
  if (Attributes & ObjCPropertyAttribute::kind_strong) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "assign" << "strong";
    Attributes &= ~ObjCPropertyAttribute::kind_strong;
  }
  if (getLangOpts().ObjCAutoRefCount &&
      (Attributes & ObjCPropertyAttribute::kind_weak)) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "assign" << "weak";
    Attributes &= ~ObjCPropertyAttribute::kind_weak;
  }
  if (PropertyDecl->hasAttr<IBOutletCollectionAttr>())
    Diag(Loc, diag::warn_iboutletcollection_property_assign);
} else if (Attributes & ObjCPropertyAttribute::kind_unsafe_unretained) {
  if (Attributes & ObjCPropertyAttribute::kind_copy) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "unsafe_unretained" << "copy";
    Attributes &= ~ObjCPropertyAttribute::kind_copy;
  }
  if (Attributes & ObjCPropertyAttribute::kind_retain) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "unsafe_unretained" << "retain";
    Attributes &= ~ObjCPropertyAttribute::kind_retain;
  }
  if (Attributes & ObjCPropertyAttribute::kind_strong) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "unsafe_unretained" << "strong";
    Attributes &= ~ObjCPropertyAttribute::kind_strong;
  }
  if (getLangOpts().ObjCAutoRefCount &&
      (Attributes & ObjCPropertyAttribute::kind_weak)) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "unsafe_unretained" << "weak";
    Attributes &= ~ObjCPropertyAttribute::kind_weak;
  }
} else if (Attributes & ObjCPropertyAttribute::kind_copy) {
  if (Attributes & ObjCPropertyAttribute::kind_retain) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "copy" << "retain";
    Attributes &= ~ObjCPropertyAttribute::kind_retain;
  }
  if (Attributes & ObjCPropertyAttribute::kind_strong) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "copy" << "strong";
    Attributes &= ~ObjCPropertyAttribute::kind_strong;
  }
  if (Attributes & ObjCPropertyAttribute::kind_weak) {
    Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
      << "copy" << "weak";
    Attributes &= ~ObjCPropertyAttribute::kind_weak;
  }
} else if ((Attributes & ObjCPropertyAttribute::kind_retain) &&
           (Attributes & ObjCPropertyAttribute::kind_weak)) {
  Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "retain"
                                                             << "weak";
  Attributes &= ~ObjCPropertyAttribute::kind_retain;
} else if ((Attributes & ObjCPropertyAttribute::kind_strong) &&
           (Attributes & ObjCPropertyAttribute::kind_weak)) {
  Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "strong"
                                                             << "weak";
  Attributes &= ~ObjCPropertyAttribute::kind_weak;
}

if (Attributes & ObjCPropertyAttribute::kind_weak) {
  // 'weak' and 'nonnull' are mutually exclusive.
  if (auto nullability = PropertyTy->getNullability(Context)) {
    if (*nullability == NullabilityKind::NonNull)
      Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
        << "nonnull" << "weak";
  }
}

if ((Attributes & ObjCPropertyAttribute::kind_atomic) &&
    (Attributes & ObjCPropertyAttribute::kind_nonatomic)) {
  Diag(Loc, diag::err_objc_property_attr_mutually_exclusive) << "atomic"
                                                             << "nonatomic";
  Attributes &= ~ObjCPropertyAttribute::kind_atomic;
}

// Warn if user supplied no assignment attribute, property is
// readwrite, and this is an object type.
if (!getOwnershipRule(Attributes) && PropertyTy->isObjCRetainableType()) {
  if (Attributes & ObjCPropertyAttribute::kind_readonly) {
    // do nothing
  } else if (getLangOpts().ObjCAutoRefCount) {
    // With arc, @property definitions should default to strong when
    // not specified.
    PropertyDecl->setPropertyAttributes(ObjCPropertyAttribute::kind_strong);
  } else if (PropertyTy->isObjCObjectPointerType()) {
    bool isAnyClassTy = (PropertyTy->isObjCClassType() ||
                         PropertyTy->isObjCQualifiedClassType());
    // In non-gc, non-arc mode, 'Class' is treated as a 'void *' no need to
    // issue any warning.
    if (isAnyClassTy && getLangOpts().getGC() == LangOptions::NonGC)
      ;
    else if (propertyInPrimaryClass) {
      // Don't issue warning on property with no life time in class
      // extension as it is inherited from property in primary class.
      // Skip this warning in gc-only mode.
      if (getLangOpts().getGC() != LangOptions::GCOnly)
        Diag(Loc, diag::warn_objc_property_no_assignment_attribute);

      // If non-gc code warn that this is likely inappropriate.
      if (getLangOpts().getGC() == LangOptions::NonGC)
        Diag(Loc, diag::warn_objc_property_default_assign_on_object);
    }
  }

  // FIXME: Implement warning dependent on NSCopying being
  // implemented. See also:
  // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
  // (please trim this list while you are at it).
}

if (!(Attributes & ObjCPropertyAttribute::kind_copy) &&
    !(Attributes & ObjCPropertyAttribute::kind_readonly) &&
    getLangOpts().getGC() == LangOptions::GCOnly &&
    PropertyTy->isBlockPointerType())
  Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
else if ((Attributes & ObjCPropertyAttribute::kind_retain) &&
         !(Attributes & ObjCPropertyAttribute::kind_readonly) &&
         !(Attributes & ObjCPropertyAttribute::kind_strong) &&
         PropertyTy->isBlockPointerType())
  Diag(Loc, diag::warn_objc_property_retain_of_block);

if ((Attributes & ObjCPropertyAttribute::kind_readonly) &&
    (Attributes & ObjCPropertyAttribute::kind_setter))
  Diag(Loc, diag::warn_objc_readonly_property_has_setter);
2823}