Check in LLVM r95781.
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
new file mode 100644
index 0000000..13eeb6c
--- /dev/null
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -0,0 +1,2559 @@
+//===--- SemaDeclObjC.cpp - Semantic Analysis for ObjC Declarations -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements semantic analysis for Objective C declarations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sema.h"
+#include "Lookup.h"
+#include "clang/Sema/ExternalSemaSource.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/Parse/DeclSpec.h"
+using namespace clang;
+
+bool Sema::DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *property,
+                                            ObjCMethodDecl *GetterMethod,
+                                            SourceLocation Loc) {
+  if (GetterMethod &&
+      GetterMethod->getResultType() != property->getType()) {
+    AssignConvertType result = Incompatible;
+    if (property->getType()->isObjCObjectPointerType())
+      result = CheckAssignmentConstraints(GetterMethod->getResultType(), property->getType());
+    if (result != Compatible) {
+      Diag(Loc, diag::warn_accessor_property_type_mismatch)
+        << property->getDeclName()
+        << GetterMethod->getSelector();
+      Diag(GetterMethod->getLocation(), diag::note_declared_at);
+      return true;
+    }
+  }
+  return false;
+}
+
+/// ActOnStartOfObjCMethodDef - This routine sets up parameters; invisible
+/// and user declared, in the method definition's AST.
+void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, DeclPtrTy D) {
+  assert(getCurMethodDecl() == 0 && "Method parsing confused");
+  ObjCMethodDecl *MDecl = dyn_cast_or_null<ObjCMethodDecl>(D.getAs<Decl>());
+
+  // If we don't have a valid method decl, simply return.
+  if (!MDecl)
+    return;
+
+  CurFunctionNeedsScopeChecking = false;
+
+  // Allow the rest of sema to find private method decl implementations.
+  if (MDecl->isInstanceMethod())
+    AddInstanceMethodToGlobalPool(MDecl);
+  else
+    AddFactoryMethodToGlobalPool(MDecl);
+
+  // Allow all of Sema to see that we are entering a method definition.
+  PushDeclContext(FnBodyScope, MDecl);
+
+  // Create Decl objects for each parameter, entrring them in the scope for
+  // binding to their use.
+
+  // Insert the invisible arguments, self and _cmd!
+  MDecl->createImplicitParams(Context, MDecl->getClassInterface());
+
+  PushOnScopeChains(MDecl->getSelfDecl(), FnBodyScope);
+  PushOnScopeChains(MDecl->getCmdDecl(), FnBodyScope);
+
+  // Introduce all of the other parameters into this scope.
+  for (ObjCMethodDecl::param_iterator PI = MDecl->param_begin(),
+       E = MDecl->param_end(); PI != E; ++PI)
+    if ((*PI)->getIdentifier())
+      PushOnScopeChains(*PI, FnBodyScope);
+}
+
+Sema::DeclPtrTy Sema::
+ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
+                         IdentifierInfo *ClassName, SourceLocation ClassLoc,
+                         IdentifierInfo *SuperName, SourceLocation SuperLoc,
+                         const DeclPtrTy *ProtoRefs, unsigned NumProtoRefs,
+                         const SourceLocation *ProtoLocs, 
+                         SourceLocation EndProtoLoc, AttributeList *AttrList) {
+  assert(ClassName && "Missing class identifier");
+
+  // Check for another declaration kind with the same name.
+  NamedDecl *PrevDecl = LookupSingleName(TUScope, ClassName, LookupOrdinaryName);
+  if (PrevDecl && PrevDecl->isTemplateParameter()) {
+    // Maybe we will complain about the shadowed template parameter.
+    DiagnoseTemplateParameterShadow(ClassLoc, PrevDecl);
+    // Just pretend that we didn't see the previous declaration.
+    PrevDecl = 0;
+  }
+
+  if (PrevDecl && !isa<ObjCInterfaceDecl>(PrevDecl)) {
+    Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
+    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+  }
+
+  ObjCInterfaceDecl* IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+  if (IDecl) {
+    // Class already seen. Is it a forward declaration?
+    if (!IDecl->isForwardDecl()) {
+      IDecl->setInvalidDecl();
+      Diag(AtInterfaceLoc, diag::err_duplicate_class_def)<<IDecl->getDeclName();
+      Diag(IDecl->getLocation(), diag::note_previous_definition);
+
+      // Return the previous class interface.
+      // FIXME: don't leak the objects passed in!
+      return DeclPtrTy::make(IDecl);
+    } else {
+      IDecl->setLocation(AtInterfaceLoc);
+      IDecl->setForwardDecl(false);
+      IDecl->setClassLoc(ClassLoc);
+      
+      // Since this ObjCInterfaceDecl was created by a forward declaration,
+      // we now add it to the DeclContext since it wasn't added before
+      // (see ActOnForwardClassDeclaration).
+      CurContext->addDecl(IDecl);
+      
+      if (AttrList)
+        ProcessDeclAttributeList(TUScope, IDecl, AttrList);
+    }
+  } else {
+    IDecl = ObjCInterfaceDecl::Create(Context, CurContext, AtInterfaceLoc,
+                                      ClassName, ClassLoc);
+    if (AttrList)
+      ProcessDeclAttributeList(TUScope, IDecl, AttrList);
+
+    PushOnScopeChains(IDecl, TUScope);
+  }
+
+  if (SuperName) {
+    // Check if a different kind of symbol declared in this scope.
+    PrevDecl = LookupSingleName(TUScope, SuperName, LookupOrdinaryName);
+
+    if (!PrevDecl) {
+      // Try to correct for a typo in the superclass name.
+      LookupResult R(*this, SuperName, SuperLoc, LookupOrdinaryName);
+      if (CorrectTypo(R, TUScope, 0) &&
+          (PrevDecl = R.getAsSingle<ObjCInterfaceDecl>())) {
+        Diag(SuperLoc, diag::err_undef_superclass_suggest)
+          << SuperName << ClassName << PrevDecl->getDeclName();
+        Diag(PrevDecl->getLocation(), diag::note_previous_decl)
+          << PrevDecl->getDeclName();
+      }
+    }
+
+    if (PrevDecl == IDecl) {
+      Diag(SuperLoc, diag::err_recursive_superclass)
+        << SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
+      IDecl->setLocEnd(ClassLoc);
+    } else {
+      ObjCInterfaceDecl *SuperClassDecl =
+                                dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+
+      // Diagnose classes that inherit from deprecated classes.
+      if (SuperClassDecl)
+        (void)DiagnoseUseOfDecl(SuperClassDecl, SuperLoc);
+
+      if (PrevDecl && SuperClassDecl == 0) {
+        // The previous declaration was not a class decl. Check if we have a
+        // typedef. If we do, get the underlying class type.
+        if (const TypedefDecl *TDecl = dyn_cast_or_null<TypedefDecl>(PrevDecl)) {
+          QualType T = TDecl->getUnderlyingType();
+          if (T->isObjCInterfaceType()) {
+            if (NamedDecl *IDecl = T->getAs<ObjCInterfaceType>()->getDecl())
+              SuperClassDecl = dyn_cast<ObjCInterfaceDecl>(IDecl);
+          }
+        }
+
+        // This handles the following case:
+        //
+        // typedef int SuperClass;
+        // @interface MyClass : SuperClass {} @end
+        //
+        if (!SuperClassDecl) {
+          Diag(SuperLoc, diag::err_redefinition_different_kind) << SuperName;
+          Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+        }
+      }
+
+      if (!dyn_cast_or_null<TypedefDecl>(PrevDecl)) {
+        if (!SuperClassDecl)
+          Diag(SuperLoc, diag::err_undef_superclass)
+            << SuperName << ClassName << SourceRange(AtInterfaceLoc, ClassLoc);
+        else if (SuperClassDecl->isForwardDecl())
+          Diag(SuperLoc, diag::err_undef_superclass)
+            << SuperClassDecl->getDeclName() << ClassName
+            << SourceRange(AtInterfaceLoc, ClassLoc);
+      }
+      IDecl->setSuperClass(SuperClassDecl);
+      IDecl->setSuperClassLoc(SuperLoc);
+      IDecl->setLocEnd(SuperLoc);
+    }
+  } else { // we have a root class.
+    IDecl->setLocEnd(ClassLoc);
+  }
+
+  /// Check then save referenced protocols.
+  if (NumProtoRefs) {
+    IDecl->setProtocolList((ObjCProtocolDecl**)ProtoRefs, NumProtoRefs,
+                           ProtoLocs, Context);
+    IDecl->setLocEnd(EndProtoLoc);
+  }
+
+  CheckObjCDeclScope(IDecl);
+  return DeclPtrTy::make(IDecl);
+}
+
+/// ActOnCompatiblityAlias - this action is called after complete parsing of
+/// @compatibility_alias declaration. It sets up the alias relationships.
+Sema::DeclPtrTy Sema::ActOnCompatiblityAlias(SourceLocation AtLoc,
+                                             IdentifierInfo *AliasName,
+                                             SourceLocation AliasLocation,
+                                             IdentifierInfo *ClassName,
+                                             SourceLocation ClassLocation) {
+  // Look for previous declaration of alias name
+  NamedDecl *ADecl = LookupSingleName(TUScope, AliasName, LookupOrdinaryName);
+  if (ADecl) {
+    if (isa<ObjCCompatibleAliasDecl>(ADecl))
+      Diag(AliasLocation, diag::warn_previous_alias_decl);
+    else
+      Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
+    Diag(ADecl->getLocation(), diag::note_previous_declaration);
+    return DeclPtrTy();
+  }
+  // Check for class declaration
+  NamedDecl *CDeclU = LookupSingleName(TUScope, ClassName, LookupOrdinaryName);
+  if (const TypedefDecl *TDecl = dyn_cast_or_null<TypedefDecl>(CDeclU)) {
+    QualType T = TDecl->getUnderlyingType();
+    if (T->isObjCInterfaceType()) {
+      if (NamedDecl *IDecl = T->getAs<ObjCInterfaceType>()->getDecl()) {
+        ClassName = IDecl->getIdentifier();
+        CDeclU = LookupSingleName(TUScope, ClassName, LookupOrdinaryName);
+      }
+    }
+  }
+  ObjCInterfaceDecl *CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(CDeclU);
+  if (CDecl == 0) {
+    Diag(ClassLocation, diag::warn_undef_interface) << ClassName;
+    if (CDeclU)
+      Diag(CDeclU->getLocation(), diag::note_previous_declaration);
+    return DeclPtrTy();
+  }
+
+  // Everything checked out, instantiate a new alias declaration AST.
+  ObjCCompatibleAliasDecl *AliasDecl =
+    ObjCCompatibleAliasDecl::Create(Context, CurContext, AtLoc, AliasName, CDecl);
+
+  if (!CheckObjCDeclScope(AliasDecl))
+    PushOnScopeChains(AliasDecl, TUScope);
+
+  return DeclPtrTy::make(AliasDecl);
+}
+
+void Sema::CheckForwardProtocolDeclarationForCircularDependency(
+  IdentifierInfo *PName,
+  SourceLocation &Ploc, SourceLocation PrevLoc,
+  const ObjCList<ObjCProtocolDecl> &PList) {
+  for (ObjCList<ObjCProtocolDecl>::iterator I = PList.begin(),
+       E = PList.end(); I != E; ++I) {
+
+    if (ObjCProtocolDecl *PDecl = LookupProtocol((*I)->getIdentifier())) {
+      if (PDecl->getIdentifier() == PName) {
+        Diag(Ploc, diag::err_protocol_has_circular_dependency);
+        Diag(PrevLoc, diag::note_previous_definition);
+      }
+      CheckForwardProtocolDeclarationForCircularDependency(PName, Ploc,
+        PDecl->getLocation(), PDecl->getReferencedProtocols());
+    }
+  }
+}
+
+Sema::DeclPtrTy
+Sema::ActOnStartProtocolInterface(SourceLocation AtProtoInterfaceLoc,
+                                  IdentifierInfo *ProtocolName,
+                                  SourceLocation ProtocolLoc,
+                                  const DeclPtrTy *ProtoRefs,
+                                  unsigned NumProtoRefs,
+                                  const SourceLocation *ProtoLocs,
+                                  SourceLocation EndProtoLoc,
+                                  AttributeList *AttrList) {
+  // FIXME: Deal with AttrList.
+  assert(ProtocolName && "Missing protocol identifier");
+  ObjCProtocolDecl *PDecl = LookupProtocol(ProtocolName);
+  if (PDecl) {
+    // Protocol already seen. Better be a forward protocol declaration
+    if (!PDecl->isForwardDecl()) {
+      Diag(ProtocolLoc, diag::warn_duplicate_protocol_def) << ProtocolName;
+      Diag(PDecl->getLocation(), diag::note_previous_definition);
+      // Just return the protocol we already had.
+      // FIXME: don't leak the objects passed in!
+      return DeclPtrTy::make(PDecl);
+    }
+    ObjCList<ObjCProtocolDecl> PList;
+    PList.set((ObjCProtocolDecl *const*)ProtoRefs, NumProtoRefs, Context);
+    CheckForwardProtocolDeclarationForCircularDependency(
+      ProtocolName, ProtocolLoc, PDecl->getLocation(), PList);
+    PList.Destroy(Context);
+
+    // Make sure the cached decl gets a valid start location.
+    PDecl->setLocation(AtProtoInterfaceLoc);
+    PDecl->setForwardDecl(false);
+  } else {
+    PDecl = ObjCProtocolDecl::Create(Context, CurContext,
+                                     AtProtoInterfaceLoc,ProtocolName);
+    PushOnScopeChains(PDecl, TUScope);
+    PDecl->setForwardDecl(false);
+  }
+  if (AttrList)
+    ProcessDeclAttributeList(TUScope, PDecl, AttrList);
+  if (NumProtoRefs) {
+    /// Check then save referenced protocols.
+    PDecl->setProtocolList((ObjCProtocolDecl**)ProtoRefs, NumProtoRefs,
+                           ProtoLocs, Context);
+    PDecl->setLocEnd(EndProtoLoc);
+  }
+
+  CheckObjCDeclScope(PDecl);
+  return DeclPtrTy::make(PDecl);
+}
+
+/// FindProtocolDeclaration - This routine looks up protocols and
+/// issues an error if they are not declared. It returns list of
+/// protocol declarations in its 'Protocols' argument.
+void
+Sema::FindProtocolDeclaration(bool WarnOnDeclarations,
+                              const IdentifierLocPair *ProtocolId,
+                              unsigned NumProtocols,
+                              llvm::SmallVectorImpl<DeclPtrTy> &Protocols) {
+  for (unsigned i = 0; i != NumProtocols; ++i) {
+    ObjCProtocolDecl *PDecl = LookupProtocol(ProtocolId[i].first);
+    if (!PDecl) {
+      LookupResult R(*this, ProtocolId[i].first, ProtocolId[i].second,
+                     LookupObjCProtocolName);
+      if (CorrectTypo(R, TUScope, 0) &&
+          (PDecl = R.getAsSingle<ObjCProtocolDecl>())) {
+        Diag(ProtocolId[i].second, diag::err_undeclared_protocol_suggest)
+          << ProtocolId[i].first << R.getLookupName();
+        Diag(PDecl->getLocation(), diag::note_previous_decl)
+          << PDecl->getDeclName();
+      }
+    }
+
+    if (!PDecl) {
+      Diag(ProtocolId[i].second, diag::err_undeclared_protocol)
+        << ProtocolId[i].first;
+      continue;
+    }
+
+    (void)DiagnoseUseOfDecl(PDecl, ProtocolId[i].second);
+
+    // If this is a forward declaration and we are supposed to warn in this
+    // case, do it.
+    if (WarnOnDeclarations && PDecl->isForwardDecl())
+      Diag(ProtocolId[i].second, diag::warn_undef_protocolref)
+        << ProtocolId[i].first;
+    Protocols.push_back(DeclPtrTy::make(PDecl));
+  }
+}
+
+/// DiagnosePropertyMismatch - Compares two properties for their
+/// attributes and types and warns on a variety of inconsistencies.
+///
+void
+Sema::DiagnosePropertyMismatch(ObjCPropertyDecl *Property,
+                               ObjCPropertyDecl *SuperProperty,
+                               const IdentifierInfo *inheritedName) {
+  ObjCPropertyDecl::PropertyAttributeKind CAttr =
+  Property->getPropertyAttributes();
+  ObjCPropertyDecl::PropertyAttributeKind SAttr =
+  SuperProperty->getPropertyAttributes();
+  if ((CAttr & ObjCPropertyDecl::OBJC_PR_readonly)
+      && (SAttr & ObjCPropertyDecl::OBJC_PR_readwrite))
+    Diag(Property->getLocation(), diag::warn_readonly_property)
+      << Property->getDeclName() << inheritedName;
+  if ((CAttr & ObjCPropertyDecl::OBJC_PR_copy)
+      != (SAttr & ObjCPropertyDecl::OBJC_PR_copy))
+    Diag(Property->getLocation(), diag::warn_property_attribute)
+      << Property->getDeclName() << "copy" << inheritedName;
+  else if ((CAttr & ObjCPropertyDecl::OBJC_PR_retain)
+           != (SAttr & ObjCPropertyDecl::OBJC_PR_retain))
+    Diag(Property->getLocation(), diag::warn_property_attribute)
+      << Property->getDeclName() << "retain" << inheritedName;
+
+  if ((CAttr & ObjCPropertyDecl::OBJC_PR_nonatomic)
+      != (SAttr & ObjCPropertyDecl::OBJC_PR_nonatomic))
+    Diag(Property->getLocation(), diag::warn_property_attribute)
+      << Property->getDeclName() << "atomic" << inheritedName;
+  if (Property->getSetterName() != SuperProperty->getSetterName())
+    Diag(Property->getLocation(), diag::warn_property_attribute)
+      << Property->getDeclName() << "setter" << inheritedName;
+  if (Property->getGetterName() != SuperProperty->getGetterName())
+    Diag(Property->getLocation(), diag::warn_property_attribute)
+      << Property->getDeclName() << "getter" << inheritedName;
+
+  QualType LHSType =
+    Context.getCanonicalType(SuperProperty->getType());
+  QualType RHSType =
+    Context.getCanonicalType(Property->getType());
+
+  if (!Context.typesAreCompatible(LHSType, RHSType)) {
+    // FIXME: Incorporate this test with typesAreCompatible.
+    if (LHSType->isObjCQualifiedIdType() && RHSType->isObjCQualifiedIdType())
+      if (Context.ObjCQualifiedIdTypesAreCompatible(LHSType, RHSType, false))
+        return;
+    Diag(Property->getLocation(), diag::warn_property_types_are_incompatible)
+      << Property->getType() << SuperProperty->getType() << inheritedName;
+  }
+}
+
+/// ComparePropertiesInBaseAndSuper - This routine compares property
+/// declarations in base and its super class, if any, and issues
+/// diagnostics in a variety of inconsistant situations.
+///
+void Sema::ComparePropertiesInBaseAndSuper(ObjCInterfaceDecl *IDecl) {
+  ObjCInterfaceDecl *SDecl = IDecl->getSuperClass();
+  if (!SDecl)
+    return;
+  // FIXME: O(N^2)
+  for (ObjCInterfaceDecl::prop_iterator S = SDecl->prop_begin(),
+       E = SDecl->prop_end(); S != E; ++S) {
+    ObjCPropertyDecl *SuperPDecl = (*S);
+    // Does property in super class has declaration in current class?
+    for (ObjCInterfaceDecl::prop_iterator I = IDecl->prop_begin(),
+         E = IDecl->prop_end(); I != E; ++I) {
+      ObjCPropertyDecl *PDecl = (*I);
+      if (SuperPDecl->getIdentifier() == PDecl->getIdentifier())
+          DiagnosePropertyMismatch(PDecl, SuperPDecl,
+                                   SDecl->getIdentifier());
+    }
+  }
+}
+
+/// MatchOneProtocolPropertiesInClass - This routine goes thru the list
+/// of properties declared in a protocol and compares their attribute against
+/// the same property declared in the class or category.
+void
+Sema::MatchOneProtocolPropertiesInClass(Decl *CDecl,
+                                          ObjCProtocolDecl *PDecl) {
+  ObjCInterfaceDecl *IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(CDecl);
+  if (!IDecl) {
+    // Category
+    ObjCCategoryDecl *CatDecl = static_cast<ObjCCategoryDecl*>(CDecl);
+    assert (CatDecl && "MatchOneProtocolPropertiesInClass");
+    for (ObjCProtocolDecl::prop_iterator P = PDecl->prop_begin(),
+         E = PDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Pr = (*P);
+      ObjCCategoryDecl::prop_iterator CP, CE;
+      // Is this property already in  category's list of properties?
+      for (CP = CatDecl->prop_begin(), CE = CatDecl->prop_end(); CP != CE; ++CP)
+        if ((*CP)->getIdentifier() == Pr->getIdentifier())
+          break;
+      if (CP != CE)
+        // Property protocol already exist in class. Diagnose any mismatch.
+        DiagnosePropertyMismatch((*CP), Pr, PDecl->getIdentifier());
+    }
+    return;
+  }
+  for (ObjCProtocolDecl::prop_iterator P = PDecl->prop_begin(),
+       E = PDecl->prop_end(); P != E; ++P) {
+    ObjCPropertyDecl *Pr = (*P);
+    ObjCInterfaceDecl::prop_iterator CP, CE;
+    // Is this property already in  class's list of properties?
+    for (CP = IDecl->prop_begin(), CE = IDecl->prop_end(); CP != CE; ++CP)
+      if ((*CP)->getIdentifier() == Pr->getIdentifier())
+        break;
+    if (CP != CE)
+      // Property protocol already exist in class. Diagnose any mismatch.
+      DiagnosePropertyMismatch((*CP), Pr, PDecl->getIdentifier());
+    }
+}
+
+/// CompareProperties - This routine compares properties
+/// declared in 'ClassOrProtocol' objects (which can be a class or an
+/// inherited protocol with the list of properties for class/category 'CDecl'
+///
+void Sema::CompareProperties(Decl *CDecl,
+                             DeclPtrTy ClassOrProtocol) {
+  Decl *ClassDecl = ClassOrProtocol.getAs<Decl>();
+  ObjCInterfaceDecl *IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(CDecl);
+
+  if (!IDecl) {
+    // Category
+    ObjCCategoryDecl *CatDecl = static_cast<ObjCCategoryDecl*>(CDecl);
+    assert (CatDecl && "CompareProperties");
+    if (ObjCCategoryDecl *MDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
+      for (ObjCCategoryDecl::protocol_iterator P = MDecl->protocol_begin(),
+           E = MDecl->protocol_end(); P != E; ++P)
+      // Match properties of category with those of protocol (*P)
+      MatchOneProtocolPropertiesInClass(CatDecl, *P);
+
+      // Go thru the list of protocols for this category and recursively match
+      // their properties with those in the category.
+      for (ObjCCategoryDecl::protocol_iterator P = CatDecl->protocol_begin(),
+           E = CatDecl->protocol_end(); P != E; ++P)
+        CompareProperties(CatDecl, DeclPtrTy::make(*P));
+    } else {
+      ObjCProtocolDecl *MD = cast<ObjCProtocolDecl>(ClassDecl);
+      for (ObjCProtocolDecl::protocol_iterator P = MD->protocol_begin(),
+           E = MD->protocol_end(); P != E; ++P)
+        MatchOneProtocolPropertiesInClass(CatDecl, *P);
+    }
+    return;
+  }
+
+  if (ObjCInterfaceDecl *MDecl = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
+    for (ObjCInterfaceDecl::protocol_iterator P = MDecl->protocol_begin(),
+         E = MDecl->protocol_end(); P != E; ++P)
+      // Match properties of class IDecl with those of protocol (*P).
+      MatchOneProtocolPropertiesInClass(IDecl, *P);
+
+    // Go thru the list of protocols for this class and recursively match
+    // their properties with those declared in the class.
+    for (ObjCInterfaceDecl::protocol_iterator P = IDecl->protocol_begin(),
+         E = IDecl->protocol_end(); P != E; ++P)
+      CompareProperties(IDecl, DeclPtrTy::make(*P));
+  } else {
+    ObjCProtocolDecl *MD = cast<ObjCProtocolDecl>(ClassDecl);
+    for (ObjCProtocolDecl::protocol_iterator P = MD->protocol_begin(),
+         E = MD->protocol_end(); P != E; ++P)
+      MatchOneProtocolPropertiesInClass(IDecl, *P);
+  }
+}
+
+/// DiagnoseClassExtensionDupMethods - Check for duplicate declaration of
+/// a class method in its extension.
+///
+void Sema::DiagnoseClassExtensionDupMethods(ObjCCategoryDecl *CAT,
+                                            ObjCInterfaceDecl *ID) {
+  if (!ID)
+    return;  // Possibly due to previous error
+
+  llvm::DenseMap<Selector, const ObjCMethodDecl*> MethodMap;
+  for (ObjCInterfaceDecl::method_iterator i = ID->meth_begin(),
+       e =  ID->meth_end(); i != e; ++i) {
+    ObjCMethodDecl *MD = *i;
+    MethodMap[MD->getSelector()] = MD;
+  }
+
+  if (MethodMap.empty())
+    return;
+  for (ObjCCategoryDecl::method_iterator i = CAT->meth_begin(),
+       e =  CAT->meth_end(); i != e; ++i) {
+    ObjCMethodDecl *Method = *i;
+    const ObjCMethodDecl *&PrevMethod = MethodMap[Method->getSelector()];
+    if (PrevMethod && !MatchTwoMethodDeclarations(Method, PrevMethod)) {
+      Diag(Method->getLocation(), diag::err_duplicate_method_decl)
+            << Method->getDeclName();
+      Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
+    }
+  }
+}
+
+/// ActOnForwardProtocolDeclaration - Handle @protocol foo;
+Action::DeclPtrTy
+Sema::ActOnForwardProtocolDeclaration(SourceLocation AtProtocolLoc,
+                                      const IdentifierLocPair *IdentList,
+                                      unsigned NumElts,
+                                      AttributeList *attrList) {
+  llvm::SmallVector<ObjCProtocolDecl*, 32> Protocols;
+  llvm::SmallVector<SourceLocation, 8> ProtoLocs;
+
+  for (unsigned i = 0; i != NumElts; ++i) {
+    IdentifierInfo *Ident = IdentList[i].first;
+    ObjCProtocolDecl *PDecl = LookupProtocol(Ident);
+    if (PDecl == 0) { // Not already seen?
+      PDecl = ObjCProtocolDecl::Create(Context, CurContext,
+                                       IdentList[i].second, Ident);
+      PushOnScopeChains(PDecl, TUScope);
+    }
+    if (attrList)
+      ProcessDeclAttributeList(TUScope, PDecl, attrList);
+    Protocols.push_back(PDecl);
+    ProtoLocs.push_back(IdentList[i].second);
+  }
+
+  ObjCForwardProtocolDecl *PDecl =
+    ObjCForwardProtocolDecl::Create(Context, CurContext, AtProtocolLoc,
+                                    Protocols.data(), Protocols.size(),
+                                    ProtoLocs.data());
+  CurContext->addDecl(PDecl);
+  CheckObjCDeclScope(PDecl);
+  return DeclPtrTy::make(PDecl);
+}
+
+Sema::DeclPtrTy Sema::
+ActOnStartCategoryInterface(SourceLocation AtInterfaceLoc,
+                            IdentifierInfo *ClassName, SourceLocation ClassLoc,
+                            IdentifierInfo *CategoryName,
+                            SourceLocation CategoryLoc,
+                            const DeclPtrTy *ProtoRefs,
+                            unsigned NumProtoRefs,
+                            const SourceLocation *ProtoLocs,
+                            SourceLocation EndProtoLoc) {
+  ObjCCategoryDecl *CDecl =
+    ObjCCategoryDecl::Create(Context, CurContext, AtInterfaceLoc, ClassLoc,
+                             CategoryLoc, CategoryName);
+  // FIXME: PushOnScopeChains?
+  CurContext->addDecl(CDecl);
+
+  ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(ClassName, ClassLoc);
+  /// Check that class of this category is already completely declared.
+  if (!IDecl || IDecl->isForwardDecl()) {
+    CDecl->setInvalidDecl();
+    Diag(ClassLoc, diag::err_undef_interface) << ClassName;
+    return DeclPtrTy::make(CDecl);
+  }
+
+  CDecl->setClassInterface(IDecl);
+
+  // If the interface is deprecated, warn about it.
+  (void)DiagnoseUseOfDecl(IDecl, ClassLoc);
+
+  /// Check for duplicate interface declaration for this category
+  ObjCCategoryDecl *CDeclChain;
+  for (CDeclChain = IDecl->getCategoryList(); CDeclChain;
+       CDeclChain = CDeclChain->getNextClassCategory()) {
+    if (CategoryName && CDeclChain->getIdentifier() == CategoryName) {
+      Diag(CategoryLoc, diag::warn_dup_category_def)
+      << ClassName << CategoryName;
+      Diag(CDeclChain->getLocation(), diag::note_previous_definition);
+      break;
+    }
+  }
+  if (!CDeclChain)
+    CDecl->insertNextClassCategory();
+
+  if (NumProtoRefs) {
+    CDecl->setProtocolList((ObjCProtocolDecl**)ProtoRefs, NumProtoRefs, 
+                           ProtoLocs, Context);
+    // Protocols in the class extension belong to the class.
+    if (!CDecl->getIdentifier())
+     IDecl->mergeClassExtensionProtocolList((ObjCProtocolDecl**)ProtoRefs, 
+                                            NumProtoRefs, ProtoLocs,
+                                            Context); 
+  }
+
+  CheckObjCDeclScope(CDecl);
+  return DeclPtrTy::make(CDecl);
+}
+
+/// ActOnStartCategoryImplementation - Perform semantic checks on the
+/// category implementation declaration and build an ObjCCategoryImplDecl
+/// object.
+Sema::DeclPtrTy Sema::ActOnStartCategoryImplementation(
+                      SourceLocation AtCatImplLoc,
+                      IdentifierInfo *ClassName, SourceLocation ClassLoc,
+                      IdentifierInfo *CatName, SourceLocation CatLoc) {
+  ObjCInterfaceDecl *IDecl = getObjCInterfaceDecl(ClassName, ClassLoc);
+  ObjCCategoryDecl *CatIDecl = 0;
+  if (IDecl) {
+    CatIDecl = IDecl->FindCategoryDeclaration(CatName);
+    if (!CatIDecl) {
+      // Category @implementation with no corresponding @interface.
+      // Create and install one.
+      CatIDecl = ObjCCategoryDecl::Create(Context, CurContext, SourceLocation(),
+                                          SourceLocation(), SourceLocation(),
+                                          CatName);
+      CatIDecl->setClassInterface(IDecl);
+      CatIDecl->insertNextClassCategory();
+    }
+  }
+
+  ObjCCategoryImplDecl *CDecl =
+    ObjCCategoryImplDecl::Create(Context, CurContext, AtCatImplLoc, CatName,
+                                 IDecl);
+  /// Check that class of this category is already completely declared.
+  if (!IDecl || IDecl->isForwardDecl())
+    Diag(ClassLoc, diag::err_undef_interface) << ClassName;
+
+  // FIXME: PushOnScopeChains?
+  CurContext->addDecl(CDecl);
+
+  /// Check that CatName, category name, is not used in another implementation.
+  if (CatIDecl) {
+    if (CatIDecl->getImplementation()) {
+      Diag(ClassLoc, diag::err_dup_implementation_category) << ClassName
+        << CatName;
+      Diag(CatIDecl->getImplementation()->getLocation(),
+           diag::note_previous_definition);
+    } else
+      CatIDecl->setImplementation(CDecl);
+  }
+
+  CheckObjCDeclScope(CDecl);
+  return DeclPtrTy::make(CDecl);
+}
+
+Sema::DeclPtrTy Sema::ActOnStartClassImplementation(
+                      SourceLocation AtClassImplLoc,
+                      IdentifierInfo *ClassName, SourceLocation ClassLoc,
+                      IdentifierInfo *SuperClassname,
+                      SourceLocation SuperClassLoc) {
+  ObjCInterfaceDecl* IDecl = 0;
+  // Check for another declaration kind with the same name.
+  NamedDecl *PrevDecl
+    = LookupSingleName(TUScope, ClassName, LookupOrdinaryName);
+  if (PrevDecl && !isa<ObjCInterfaceDecl>(PrevDecl)) {
+    Diag(ClassLoc, diag::err_redefinition_different_kind) << ClassName;
+    Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+  } else if ((IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl))) {
+    // If this is a forward declaration of an interface, warn.
+    if (IDecl->isForwardDecl()) {
+      Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
+      IDecl = 0;
+    }
+  } else {
+    // We did not find anything with the name ClassName; try to correct for 
+    // typos in the class name.
+    LookupResult R(*this, ClassName, ClassLoc, LookupOrdinaryName);
+    if (CorrectTypo(R, TUScope, 0) &&
+        (IDecl = R.getAsSingle<ObjCInterfaceDecl>())) {
+      // Suggest the (potentially) correct interface name. However, put the
+      // fix-it hint itself in a separate note, since changing the name in 
+      // the warning would make the fix-it change semantics.However, don't
+      // provide a code-modification hint or use the typo name for recovery,
+      // because this is just a warning. The program may actually be correct.
+      Diag(ClassLoc, diag::warn_undef_interface_suggest)
+        << ClassName << R.getLookupName();
+      Diag(IDecl->getLocation(), diag::note_previous_decl)
+        << R.getLookupName()
+        << CodeModificationHint::CreateReplacement(ClassLoc,
+                                               R.getLookupName().getAsString());
+      IDecl = 0;
+    } else {
+      Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
+    }
+  }
+
+  // Check that super class name is valid class name
+  ObjCInterfaceDecl* SDecl = 0;
+  if (SuperClassname) {
+    // Check if a different kind of symbol declared in this scope.
+    PrevDecl = LookupSingleName(TUScope, SuperClassname, LookupOrdinaryName);
+    if (PrevDecl && !isa<ObjCInterfaceDecl>(PrevDecl)) {
+      Diag(SuperClassLoc, diag::err_redefinition_different_kind)
+        << SuperClassname;
+      Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+    } else {
+      SDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+      if (!SDecl)
+        Diag(SuperClassLoc, diag::err_undef_superclass)
+          << SuperClassname << ClassName;
+      else if (IDecl && IDecl->getSuperClass() != SDecl) {
+        // This implementation and its interface do not have the same
+        // super class.
+        Diag(SuperClassLoc, diag::err_conflicting_super_class)
+          << SDecl->getDeclName();
+        Diag(SDecl->getLocation(), diag::note_previous_definition);
+      }
+    }
+  }
+
+  if (!IDecl) {
+    // Legacy case of @implementation with no corresponding @interface.
+    // Build, chain & install the interface decl into the identifier.
+
+    // FIXME: Do we support attributes on the @implementation? If so we should
+    // copy them over.
+    IDecl = ObjCInterfaceDecl::Create(Context, CurContext, AtClassImplLoc,
+                                      ClassName, ClassLoc, false, true);
+    IDecl->setSuperClass(SDecl);
+    IDecl->setLocEnd(ClassLoc);
+
+    PushOnScopeChains(IDecl, TUScope);
+  } else {
+    // Mark the interface as being completed, even if it was just as
+    //   @class ....;
+    // declaration; the user cannot reopen it.
+    IDecl->setForwardDecl(false);
+  }
+
+  ObjCImplementationDecl* IMPDecl =
+    ObjCImplementationDecl::Create(Context, CurContext, AtClassImplLoc,
+                                   IDecl, SDecl);
+
+  if (CheckObjCDeclScope(IMPDecl))
+    return DeclPtrTy::make(IMPDecl);
+
+  // Check that there is no duplicate implementation of this class.
+  if (IDecl->getImplementation()) {
+    // FIXME: Don't leak everything!
+    Diag(ClassLoc, diag::err_dup_implementation_class) << ClassName;
+    Diag(IDecl->getImplementation()->getLocation(),
+         diag::note_previous_definition);
+  } else { // add it to the list.
+    IDecl->setImplementation(IMPDecl);
+    PushOnScopeChains(IMPDecl, TUScope);
+  }
+  return DeclPtrTy::make(IMPDecl);
+}
+
+void Sema::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
+                                    ObjCIvarDecl **ivars, unsigned numIvars,
+                                    SourceLocation RBrace) {
+  assert(ImpDecl && "missing implementation decl");
+  ObjCInterfaceDecl* IDecl = ImpDecl->getClassInterface();
+  if (!IDecl)
+    return;
+  /// Check case of non-existing @interface decl.
+  /// (legacy objective-c @implementation decl without an @interface decl).
+  /// Add implementations's ivar to the synthesize class's ivar list.
+  if (IDecl->isImplicitInterfaceDecl()) {
+    IDecl->setIVarList(ivars, numIvars, Context);
+    IDecl->setLocEnd(RBrace);
+    return;
+  }
+  // If implementation has empty ivar list, just return.
+  if (numIvars == 0)
+    return;
+
+  assert(ivars && "missing @implementation ivars");
+
+  // Check interface's Ivar list against those in the implementation.
+  // names and types must match.
+  //
+  unsigned j = 0;
+  ObjCInterfaceDecl::ivar_iterator
+    IVI = IDecl->ivar_begin(), IVE = IDecl->ivar_end();
+  for (; numIvars > 0 && IVI != IVE; ++IVI) {
+    ObjCIvarDecl* ImplIvar = ivars[j++];
+    ObjCIvarDecl* ClsIvar = *IVI;
+    assert (ImplIvar && "missing implementation ivar");
+    assert (ClsIvar && "missing class ivar");
+
+    // First, make sure the types match.
+    if (Context.getCanonicalType(ImplIvar->getType()) !=
+        Context.getCanonicalType(ClsIvar->getType())) {
+      Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_type)
+        << ImplIvar->getIdentifier()
+        << ImplIvar->getType() << ClsIvar->getType();
+      Diag(ClsIvar->getLocation(), diag::note_previous_definition);
+    } else if (ImplIvar->isBitField() && ClsIvar->isBitField()) {
+      Expr *ImplBitWidth = ImplIvar->getBitWidth();
+      Expr *ClsBitWidth = ClsIvar->getBitWidth();
+      if (ImplBitWidth->EvaluateAsInt(Context).getZExtValue() !=
+          ClsBitWidth->EvaluateAsInt(Context).getZExtValue()) {
+        Diag(ImplBitWidth->getLocStart(), diag::err_conflicting_ivar_bitwidth)
+          << ImplIvar->getIdentifier();
+        Diag(ClsBitWidth->getLocStart(), diag::note_previous_definition);
+      }
+    }
+    // Make sure the names are identical.
+    if (ImplIvar->getIdentifier() != ClsIvar->getIdentifier()) {
+      Diag(ImplIvar->getLocation(), diag::err_conflicting_ivar_name)
+        << ImplIvar->getIdentifier() << ClsIvar->getIdentifier();
+      Diag(ClsIvar->getLocation(), diag::note_previous_definition);
+    }
+    --numIvars;
+  }
+
+  if (numIvars > 0)
+    Diag(ivars[j]->getLocation(), diag::err_inconsistant_ivar_count);
+  else if (IVI != IVE)
+    Diag((*IVI)->getLocation(), diag::err_inconsistant_ivar_count);
+}
+
+void Sema::WarnUndefinedMethod(SourceLocation ImpLoc, ObjCMethodDecl *method,
+                               bool &IncompleteImpl) {
+  if (!IncompleteImpl) {
+    Diag(ImpLoc, diag::warn_incomplete_impl);
+    IncompleteImpl = true;
+  }
+  Diag(ImpLoc, diag::warn_undef_method_impl) << method->getDeclName();
+}
+
+void Sema::WarnConflictingTypedMethods(ObjCMethodDecl *ImpMethodDecl,
+                                       ObjCMethodDecl *IntfMethodDecl) {
+  if (!Context.typesAreCompatible(IntfMethodDecl->getResultType(),
+                                  ImpMethodDecl->getResultType()) &&
+      !Context.QualifiedIdConformsQualifiedId(IntfMethodDecl->getResultType(),
+                                              ImpMethodDecl->getResultType())) {
+    Diag(ImpMethodDecl->getLocation(), diag::warn_conflicting_ret_types)
+      << ImpMethodDecl->getDeclName() << IntfMethodDecl->getResultType()
+      << ImpMethodDecl->getResultType();
+    Diag(IntfMethodDecl->getLocation(), diag::note_previous_definition);
+  }
+
+  for (ObjCMethodDecl::param_iterator IM = ImpMethodDecl->param_begin(),
+       IF = IntfMethodDecl->param_begin(), EM = ImpMethodDecl->param_end();
+       IM != EM; ++IM, ++IF) {
+    QualType ParmDeclTy = (*IF)->getType().getUnqualifiedType();
+    QualType ParmImpTy = (*IM)->getType().getUnqualifiedType();
+    if (Context.typesAreCompatible(ParmDeclTy, ParmImpTy) ||
+        Context.QualifiedIdConformsQualifiedId(ParmDeclTy, ParmImpTy))
+      continue;
+
+    Diag((*IM)->getLocation(), diag::warn_conflicting_param_types)
+      << ImpMethodDecl->getDeclName() << (*IF)->getType()
+      << (*IM)->getType();
+    Diag((*IF)->getLocation(), diag::note_previous_definition);
+  }
+}
+
+/// isPropertyReadonly - Return true if property is readonly, by searching
+/// for the property in the class and in its categories and implementations
+///
+bool Sema::isPropertyReadonly(ObjCPropertyDecl *PDecl,
+                              ObjCInterfaceDecl *IDecl) {
+  // by far the most common case.
+  if (!PDecl->isReadOnly())
+    return false;
+  // Even if property is ready only, if interface has a user defined setter,
+  // it is not considered read only.
+  if (IDecl->getInstanceMethod(PDecl->getSetterName()))
+    return false;
+
+  // Main class has the property as 'readonly'. Must search
+  // through the category list to see if the property's
+  // attribute has been over-ridden to 'readwrite'.
+  for (ObjCCategoryDecl *Category = IDecl->getCategoryList();
+       Category; Category = Category->getNextClassCategory()) {
+    // Even if property is ready only, if a category has a user defined setter,
+    // it is not considered read only.
+    if (Category->getInstanceMethod(PDecl->getSetterName()))
+      return false;
+    ObjCPropertyDecl *P =
+      Category->FindPropertyDeclaration(PDecl->getIdentifier());
+    if (P && !P->isReadOnly())
+      return false;
+  }
+
+  // Also, check for definition of a setter method in the implementation if
+  // all else failed.
+  if (ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(CurContext)) {
+    if (ObjCImplementationDecl *IMD =
+        dyn_cast<ObjCImplementationDecl>(OMD->getDeclContext())) {
+      if (IMD->getInstanceMethod(PDecl->getSetterName()))
+        return false;
+    } else if (ObjCCategoryImplDecl *CIMD =
+               dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext())) {
+      if (CIMD->getInstanceMethod(PDecl->getSetterName()))
+        return false;
+    }
+  }
+  // Lastly, look through the implementation (if one is in scope).
+  if (ObjCImplementationDecl *ImpDecl = IDecl->getImplementation())
+    if (ImpDecl->getInstanceMethod(PDecl->getSetterName()))
+      return false;
+  // If all fails, look at the super class.
+  if (ObjCInterfaceDecl *SIDecl = IDecl->getSuperClass())
+    return isPropertyReadonly(PDecl, SIDecl);
+  return true;
+}
+
+/// FIXME: Type hierarchies in Objective-C can be deep. We could most likely
+/// improve the efficiency of selector lookups and type checking by associating
+/// with each protocol / interface / category the flattened instance tables. If
+/// we used an immutable set to keep the table then it wouldn't add significant
+/// memory cost and it would be handy for lookups.
+
+/// CheckProtocolMethodDefs - This routine checks unimplemented methods
+/// Declared in protocol, and those referenced by it.
+void Sema::CheckProtocolMethodDefs(SourceLocation ImpLoc,
+                                   ObjCProtocolDecl *PDecl,
+                                   bool& IncompleteImpl,
+                                   const llvm::DenseSet<Selector> &InsMap,
+                                   const llvm::DenseSet<Selector> &ClsMap,
+                                   ObjCInterfaceDecl *IDecl) {
+  ObjCInterfaceDecl *Super = IDecl->getSuperClass();
+  ObjCInterfaceDecl *NSIDecl = 0;
+  if (getLangOptions().NeXTRuntime) {
+    // check to see if class implements forwardInvocation method and objects
+    // of this class are derived from 'NSProxy' so that to forward requests
+    // from one object to another.
+    // Under such conditions, which means that every method possible is
+    // implemented in the class, we should not issue "Method definition not
+    // found" warnings.
+    // FIXME: Use a general GetUnarySelector method for this.
+    IdentifierInfo* II = &Context.Idents.get("forwardInvocation");
+    Selector fISelector = Context.Selectors.getSelector(1, &II);
+    if (InsMap.count(fISelector))
+      // Is IDecl derived from 'NSProxy'? If so, no instance methods
+      // need be implemented in the implementation.
+      NSIDecl = IDecl->lookupInheritedClass(&Context.Idents.get("NSProxy"));
+  }
+
+  // If a method lookup fails locally we still need to look and see if
+  // the method was implemented by a base class or an inherited
+  // protocol. This lookup is slow, but occurs rarely in correct code
+  // and otherwise would terminate in a warning.
+
+  // check unimplemented instance methods.
+  if (!NSIDecl)
+    for (ObjCProtocolDecl::instmeth_iterator I = PDecl->instmeth_begin(),
+         E = PDecl->instmeth_end(); I != E; ++I) {
+      ObjCMethodDecl *method = *I;
+      if (method->getImplementationControl() != ObjCMethodDecl::Optional &&
+          !method->isSynthesized() && !InsMap.count(method->getSelector()) &&
+          (!Super ||
+           !Super->lookupInstanceMethod(method->getSelector()))) {
+            // Ugly, but necessary. Method declared in protcol might have
+            // have been synthesized due to a property declared in the class which
+            // uses the protocol.
+            ObjCMethodDecl *MethodInClass =
+            IDecl->lookupInstanceMethod(method->getSelector());
+            if (!MethodInClass || !MethodInClass->isSynthesized())
+              WarnUndefinedMethod(ImpLoc, method, IncompleteImpl);
+          }
+    }
+  // check unimplemented class methods
+  for (ObjCProtocolDecl::classmeth_iterator
+         I = PDecl->classmeth_begin(), E = PDecl->classmeth_end();
+       I != E; ++I) {
+    ObjCMethodDecl *method = *I;
+    if (method->getImplementationControl() != ObjCMethodDecl::Optional &&
+        !ClsMap.count(method->getSelector()) &&
+        (!Super || !Super->lookupClassMethod(method->getSelector())))
+      WarnUndefinedMethod(ImpLoc, method, IncompleteImpl);
+  }
+  // Check on this protocols's referenced protocols, recursively.
+  for (ObjCProtocolDecl::protocol_iterator PI = PDecl->protocol_begin(),
+       E = PDecl->protocol_end(); PI != E; ++PI)
+    CheckProtocolMethodDefs(ImpLoc, *PI, IncompleteImpl, InsMap, ClsMap, IDecl);
+}
+
+/// MatchAllMethodDeclarations - Check methods declaraed in interface or
+/// or protocol against those declared in their implementations.
+///
+void Sema::MatchAllMethodDeclarations(const llvm::DenseSet<Selector> &InsMap,
+                                      const llvm::DenseSet<Selector> &ClsMap,
+                                      llvm::DenseSet<Selector> &InsMapSeen,
+                                      llvm::DenseSet<Selector> &ClsMapSeen,
+                                      ObjCImplDecl* IMPDecl,
+                                      ObjCContainerDecl* CDecl,
+                                      bool &IncompleteImpl,
+                                      bool ImmediateClass) {
+  // Check and see if instance methods in class interface have been
+  // implemented in the implementation class. If so, their types match.
+  for (ObjCInterfaceDecl::instmeth_iterator I = CDecl->instmeth_begin(),
+       E = CDecl->instmeth_end(); I != E; ++I) {
+    if (InsMapSeen.count((*I)->getSelector()))
+        continue;
+    InsMapSeen.insert((*I)->getSelector());
+    if (!(*I)->isSynthesized() &&
+        !InsMap.count((*I)->getSelector())) {
+      if (ImmediateClass)
+        WarnUndefinedMethod(IMPDecl->getLocation(), *I, IncompleteImpl);
+      continue;
+    } else {
+      ObjCMethodDecl *ImpMethodDecl =
+      IMPDecl->getInstanceMethod((*I)->getSelector());
+      ObjCMethodDecl *IntfMethodDecl =
+      CDecl->getInstanceMethod((*I)->getSelector());
+      assert(IntfMethodDecl &&
+             "IntfMethodDecl is null in ImplMethodsVsClassMethods");
+      // ImpMethodDecl may be null as in a @dynamic property.
+      if (ImpMethodDecl)
+        WarnConflictingTypedMethods(ImpMethodDecl, IntfMethodDecl);
+    }
+  }
+
+  // Check and see if class methods in class interface have been
+  // implemented in the implementation class. If so, their types match.
+   for (ObjCInterfaceDecl::classmeth_iterator
+       I = CDecl->classmeth_begin(), E = CDecl->classmeth_end(); I != E; ++I) {
+     if (ClsMapSeen.count((*I)->getSelector()))
+       continue;
+     ClsMapSeen.insert((*I)->getSelector());
+    if (!ClsMap.count((*I)->getSelector())) {
+      if (ImmediateClass)
+        WarnUndefinedMethod(IMPDecl->getLocation(), *I, IncompleteImpl);
+    } else {
+      ObjCMethodDecl *ImpMethodDecl =
+        IMPDecl->getClassMethod((*I)->getSelector());
+      ObjCMethodDecl *IntfMethodDecl =
+        CDecl->getClassMethod((*I)->getSelector());
+      WarnConflictingTypedMethods(ImpMethodDecl, IntfMethodDecl);
+    }
+  }
+  if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (CDecl)) {
+    // Check for any implementation of a methods declared in protocol.
+    for (ObjCInterfaceDecl::protocol_iterator PI = I->protocol_begin(),
+         E = I->protocol_end(); PI != E; ++PI)
+      MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
+                                 IMPDecl,
+                                 (*PI), IncompleteImpl, false);
+    if (I->getSuperClass())
+      MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
+                                 IMPDecl,
+                                 I->getSuperClass(), IncompleteImpl, false);
+  }
+}
+
+/// CollectImmediateProperties - This routine collects all properties in
+/// the class and its conforming protocols; but not those it its super class.
+void Sema::CollectImmediateProperties(ObjCContainerDecl *CDecl,
+                llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*>& PropMap) {
+  if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
+    for (ObjCContainerDecl::prop_iterator P = IDecl->prop_begin(),
+         E = IDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Prop = (*P);
+      PropMap[Prop->getIdentifier()] = Prop;
+    }
+    // scan through class's protocols.
+    for (ObjCInterfaceDecl::protocol_iterator PI = IDecl->protocol_begin(),
+         E = IDecl->protocol_end(); PI != E; ++PI)
+      CollectImmediateProperties((*PI), PropMap);
+  }
+  if (ObjCCategoryDecl *CATDecl = dyn_cast<ObjCCategoryDecl>(CDecl)) {
+    for (ObjCContainerDecl::prop_iterator P = CATDecl->prop_begin(),
+         E = CATDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Prop = (*P);
+      PropMap[Prop->getIdentifier()] = Prop;
+    }
+    // scan through class's protocols.
+    for (ObjCInterfaceDecl::protocol_iterator PI = CATDecl->protocol_begin(),
+         E = CATDecl->protocol_end(); PI != E; ++PI)
+      CollectImmediateProperties((*PI), PropMap);
+  }  
+  else if (ObjCProtocolDecl *PDecl = dyn_cast<ObjCProtocolDecl>(CDecl)) {
+    for (ObjCProtocolDecl::prop_iterator P = PDecl->prop_begin(),
+         E = PDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Prop = (*P);
+      ObjCPropertyDecl *&PropEntry = PropMap[Prop->getIdentifier()];
+      if (!PropEntry)
+        PropEntry = Prop;
+    }
+    // scan through protocol's protocols.
+    for (ObjCProtocolDecl::protocol_iterator PI = PDecl->protocol_begin(),
+         E = PDecl->protocol_end(); PI != E; ++PI)
+      CollectImmediateProperties((*PI), PropMap);
+  }
+}
+
+/// LookupPropertyDecl - Looks up a property in the current class and all
+/// its protocols.
+ObjCPropertyDecl *Sema::LookupPropertyDecl(const ObjCContainerDecl *CDecl, 
+                                     IdentifierInfo *II) {
+  if (const ObjCInterfaceDecl *IDecl = 
+        dyn_cast<ObjCInterfaceDecl>(CDecl)) {
+    for (ObjCContainerDecl::prop_iterator P = IDecl->prop_begin(),
+         E = IDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Prop = (*P);
+      if (Prop->getIdentifier() == II)
+        return Prop;
+    }
+    // scan through class's protocols.
+    for (ObjCInterfaceDecl::protocol_iterator PI = IDecl->protocol_begin(),
+         E = IDecl->protocol_end(); PI != E; ++PI) {
+      ObjCPropertyDecl *Prop = LookupPropertyDecl((*PI), II);
+      if (Prop)
+        return Prop;
+    }
+  }
+  else if (const ObjCProtocolDecl *PDecl = 
+            dyn_cast<ObjCProtocolDecl>(CDecl)) {
+    for (ObjCProtocolDecl::prop_iterator P = PDecl->prop_begin(),
+         E = PDecl->prop_end(); P != E; ++P) {
+      ObjCPropertyDecl *Prop = (*P);
+      if (Prop->getIdentifier() == II)
+        return Prop;
+    }
+    // scan through protocol's protocols.
+    for (ObjCProtocolDecl::protocol_iterator PI = PDecl->protocol_begin(),
+         E = PDecl->protocol_end(); PI != E; ++PI) {
+      ObjCPropertyDecl *Prop = LookupPropertyDecl((*PI), II);
+      if (Prop)
+        return Prop;
+    }
+  }
+  return 0;
+}
+
+
+void Sema::DiagnoseUnimplementedProperties(ObjCImplDecl* IMPDecl,
+                                      ObjCContainerDecl *CDecl,
+                                      const llvm::DenseSet<Selector>& InsMap) {
+  llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*> PropMap;
+  CollectImmediateProperties(CDecl, PropMap);
+  if (PropMap.empty())
+    return;
+  
+  llvm::DenseSet<ObjCPropertyDecl *> PropImplMap;
+  for (ObjCImplDecl::propimpl_iterator
+       I = IMPDecl->propimpl_begin(),
+       EI = IMPDecl->propimpl_end(); I != EI; ++I)
+    PropImplMap.insert((*I)->getPropertyDecl());
+  
+  for (llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*>::iterator 
+       P = PropMap.begin(), E = PropMap.end(); P != E; ++P) {
+    ObjCPropertyDecl *Prop = P->second;
+    // Is there a matching propery synthesize/dynamic?
+    if (Prop->isInvalidDecl() ||
+        Prop->getPropertyImplementation() == ObjCPropertyDecl::Optional ||
+        PropImplMap.count(Prop))
+      continue;
+    if (LangOpts.ObjCNonFragileABI2) {
+      ActOnPropertyImplDecl(IMPDecl->getLocation(),
+                            SourceLocation(),
+                            true, DeclPtrTy::make(IMPDecl), 
+                            Prop->getIdentifier(),
+                            Prop->getIdentifier());
+      continue;
+    }
+    if (!InsMap.count(Prop->getGetterName())) {
+      Diag(Prop->getLocation(),
+           isa<ObjCCategoryDecl>(CDecl) ? 
+            diag::warn_setter_getter_impl_required_in_category : 
+            diag::warn_setter_getter_impl_required)
+      << Prop->getDeclName() << Prop->getGetterName();
+      Diag(IMPDecl->getLocation(),
+           diag::note_property_impl_required);
+    }
+    
+    if (!Prop->isReadOnly() && !InsMap.count(Prop->getSetterName())) {
+      Diag(Prop->getLocation(),
+           isa<ObjCCategoryDecl>(CDecl) ? 
+           diag::warn_setter_getter_impl_required_in_category :
+           diag::warn_setter_getter_impl_required)
+      << Prop->getDeclName() << Prop->getSetterName();
+      Diag(IMPDecl->getLocation(),
+           diag::note_property_impl_required);
+    }    
+  }
+}
+
+void Sema::ImplMethodsVsClassMethods(ObjCImplDecl* IMPDecl,
+                                     ObjCContainerDecl* CDecl,
+                                     bool IncompleteImpl) {
+  llvm::DenseSet<Selector> InsMap;
+  // Check and see if instance methods in class interface have been
+  // implemented in the implementation class.
+  for (ObjCImplementationDecl::instmeth_iterator
+         I = IMPDecl->instmeth_begin(), E = IMPDecl->instmeth_end(); I!=E; ++I)
+    InsMap.insert((*I)->getSelector());
+
+  // Check and see if properties declared in the interface have either 1)
+  // an implementation or 2) there is a @synthesize/@dynamic implementation
+  // of the property in the @implementation.
+  if (isa<ObjCInterfaceDecl>(CDecl))
+    DiagnoseUnimplementedProperties(IMPDecl, CDecl, InsMap);
+      
+  llvm::DenseSet<Selector> ClsMap;
+  for (ObjCImplementationDecl::classmeth_iterator
+       I = IMPDecl->classmeth_begin(),
+       E = IMPDecl->classmeth_end(); I != E; ++I)
+    ClsMap.insert((*I)->getSelector());
+
+  // Check for type conflict of methods declared in a class/protocol and
+  // its implementation; if any.
+  llvm::DenseSet<Selector> InsMapSeen, ClsMapSeen;
+  MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
+                             IMPDecl, CDecl,
+                             IncompleteImpl, true);
+
+  // Check the protocol list for unimplemented methods in the @implementation
+  // class.
+  // Check and see if class methods in class interface have been
+  // implemented in the implementation class.
+
+  if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (CDecl)) {
+    for (ObjCInterfaceDecl::protocol_iterator PI = I->protocol_begin(),
+         E = I->protocol_end(); PI != E; ++PI)
+      CheckProtocolMethodDefs(IMPDecl->getLocation(), *PI, IncompleteImpl,
+                              InsMap, ClsMap, I);
+    // Check class extensions (unnamed categories)
+    for (ObjCCategoryDecl *Categories = I->getCategoryList();
+         Categories; Categories = Categories->getNextClassCategory()) {
+      if (!Categories->getIdentifier()) {
+        ImplMethodsVsClassMethods(IMPDecl, Categories, IncompleteImpl);
+        break;
+      }
+    }
+  } else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(CDecl)) {
+    // For extended class, unimplemented methods in its protocols will
+    // be reported in the primary class.
+    if (C->getIdentifier()) {
+      for (ObjCCategoryDecl::protocol_iterator PI = C->protocol_begin(),
+           E = C->protocol_end(); PI != E; ++PI)
+        CheckProtocolMethodDefs(IMPDecl->getLocation(), *PI, IncompleteImpl,
+                                InsMap, ClsMap, C->getClassInterface());
+      // Report unimplemented properties in the category as well.
+      // When reporting on missing setter/getters, do not report when
+      // setter/getter is implemented in category's primary class 
+      // implementation.
+      if (ObjCInterfaceDecl *ID = C->getClassInterface())
+        if (ObjCImplDecl *IMP = ID->getImplementation()) {
+          for (ObjCImplementationDecl::instmeth_iterator
+               I = IMP->instmeth_begin(), E = IMP->instmeth_end(); I!=E; ++I)
+            InsMap.insert((*I)->getSelector());
+        }
+      DiagnoseUnimplementedProperties(IMPDecl, CDecl, InsMap);      
+    } 
+  } else
+    assert(false && "invalid ObjCContainerDecl type.");
+}
+
+void
+Sema::AtomicPropertySetterGetterRules (ObjCImplDecl* IMPDecl,
+                                       ObjCContainerDecl* IDecl) {
+  // Rules apply in non-GC mode only
+  if (getLangOptions().getGCMode() != LangOptions::NonGC)
+    return;
+  for (ObjCContainerDecl::prop_iterator I = IDecl->prop_begin(),
+       E = IDecl->prop_end();
+       I != E; ++I) {
+    ObjCPropertyDecl *Property = (*I);
+    unsigned Attributes = Property->getPropertyAttributes();
+    // We only care about readwrite atomic property.
+    if ((Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) ||
+        !(Attributes & ObjCPropertyDecl::OBJC_PR_readwrite))
+      continue;
+    if (const ObjCPropertyImplDecl *PIDecl
+         = IMPDecl->FindPropertyImplDecl(Property->getIdentifier())) {
+      if (PIDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+        continue;
+      ObjCMethodDecl *GetterMethod =
+        IMPDecl->getInstanceMethod(Property->getGetterName());
+      ObjCMethodDecl *SetterMethod = 
+        IMPDecl->getInstanceMethod(Property->getSetterName());
+      if ((GetterMethod && !SetterMethod) || (!GetterMethod && SetterMethod)) {
+        SourceLocation MethodLoc = 
+          (GetterMethod ? GetterMethod->getLocation() 
+                        : SetterMethod->getLocation());
+        Diag(MethodLoc, diag::warn_atomic_property_rule)
+          << Property->getIdentifier();
+        Diag(Property->getLocation(), diag::note_property_declare);
+      }
+    }
+  }
+}
+
+/// ActOnForwardClassDeclaration -
+Action::DeclPtrTy
+Sema::ActOnForwardClassDeclaration(SourceLocation AtClassLoc,
+                                   IdentifierInfo **IdentList,
+                                   SourceLocation *IdentLocs,
+                                   unsigned NumElts) {
+  llvm::SmallVector<ObjCInterfaceDecl*, 32> Interfaces;
+
+  for (unsigned i = 0; i != NumElts; ++i) {
+    // Check for another declaration kind with the same name.
+    NamedDecl *PrevDecl
+      = LookupSingleName(TUScope, IdentList[i], LookupOrdinaryName);
+    if (PrevDecl && PrevDecl->isTemplateParameter()) {
+      // Maybe we will complain about the shadowed template parameter.
+      DiagnoseTemplateParameterShadow(AtClassLoc, PrevDecl);
+      // Just pretend that we didn't see the previous declaration.
+      PrevDecl = 0;
+    }
+
+    if (PrevDecl && !isa<ObjCInterfaceDecl>(PrevDecl)) {
+      // GCC apparently allows the following idiom:
+      //
+      // typedef NSObject < XCElementTogglerP > XCElementToggler;
+      // @class XCElementToggler;
+      //
+      // FIXME: Make an extension?
+      TypedefDecl *TDD = dyn_cast<TypedefDecl>(PrevDecl);
+      if (!TDD || !isa<ObjCInterfaceType>(TDD->getUnderlyingType())) {
+        Diag(AtClassLoc, diag::err_redefinition_different_kind) << IdentList[i];
+        Diag(PrevDecl->getLocation(), diag::note_previous_definition);
+      } else if (TDD) {
+        // a forward class declaration matching a typedef name of a class refers
+        // to the underlying class.
+        if (ObjCInterfaceType * OI =
+              dyn_cast<ObjCInterfaceType>(TDD->getUnderlyingType()))
+          PrevDecl = OI->getDecl();
+      }
+    }
+    ObjCInterfaceDecl *IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+    if (!IDecl) {  // Not already seen?  Make a forward decl.
+      IDecl = ObjCInterfaceDecl::Create(Context, CurContext, AtClassLoc,
+                                        IdentList[i], IdentLocs[i], true);
+      
+      // Push the ObjCInterfaceDecl on the scope chain but do *not* add it to
+      // the current DeclContext.  This prevents clients that walk DeclContext
+      // from seeing the imaginary ObjCInterfaceDecl until it is actually
+      // declared later (if at all).  We also take care to explicitly make
+      // sure this declaration is visible for name lookup.
+      PushOnScopeChains(IDecl, TUScope, false);
+      CurContext->makeDeclVisibleInContext(IDecl, true);
+    }
+
+    Interfaces.push_back(IDecl);
+  }
+
+  assert(Interfaces.size() == NumElts);
+  ObjCClassDecl *CDecl = ObjCClassDecl::Create(Context, CurContext, AtClassLoc,
+                                               Interfaces.data(), IdentLocs,
+                                               Interfaces.size());
+  CurContext->addDecl(CDecl);
+  CheckObjCDeclScope(CDecl);
+  return DeclPtrTy::make(CDecl);
+}
+
+
+/// MatchTwoMethodDeclarations - Checks that two methods have matching type and
+/// returns true, or false, accordingly.
+/// TODO: Handle protocol list; such as id<p1,p2> in type comparisons
+bool Sema::MatchTwoMethodDeclarations(const ObjCMethodDecl *Method,
+                                      const ObjCMethodDecl *PrevMethod,
+                                      bool matchBasedOnSizeAndAlignment) {
+  QualType T1 = Context.getCanonicalType(Method->getResultType());
+  QualType T2 = Context.getCanonicalType(PrevMethod->getResultType());
+
+  if (T1 != T2) {
+    // The result types are different.
+    if (!matchBasedOnSizeAndAlignment)
+      return false;
+    // Incomplete types don't have a size and alignment.
+    if (T1->isIncompleteType() || T2->isIncompleteType())
+      return false;
+    // Check is based on size and alignment.
+    if (Context.getTypeInfo(T1) != Context.getTypeInfo(T2))
+      return false;
+  }
+
+  ObjCMethodDecl::param_iterator ParamI = Method->param_begin(),
+       E = Method->param_end();
+  ObjCMethodDecl::param_iterator PrevI = PrevMethod->param_begin();
+
+  for (; ParamI != E; ++ParamI, ++PrevI) {
+    assert(PrevI != PrevMethod->param_end() && "Param mismatch");
+    T1 = Context.getCanonicalType((*ParamI)->getType());
+    T2 = Context.getCanonicalType((*PrevI)->getType());
+    if (T1 != T2) {
+      // The result types are different.
+      if (!matchBasedOnSizeAndAlignment)
+        return false;
+      // Incomplete types don't have a size and alignment.
+      if (T1->isIncompleteType() || T2->isIncompleteType())
+        return false;
+      // Check is based on size and alignment.
+      if (Context.getTypeInfo(T1) != Context.getTypeInfo(T2))
+        return false;
+    }
+  }
+  return true;
+}
+
+/// \brief Read the contents of the instance and factory method pools
+/// for a given selector from external storage.
+///
+/// This routine should only be called once, when neither the instance
+/// nor the factory method pool has an entry for this selector.
+Sema::MethodPool::iterator Sema::ReadMethodPool(Selector Sel,
+                                                bool isInstance) {
+  assert(ExternalSource && "We need an external AST source");
+  assert(InstanceMethodPool.find(Sel) == InstanceMethodPool.end() &&
+         "Selector data already loaded into the instance method pool");
+  assert(FactoryMethodPool.find(Sel) == FactoryMethodPool.end() &&
+         "Selector data already loaded into the factory method pool");
+
+  // Read the method list from the external source.
+  std::pair<ObjCMethodList, ObjCMethodList> Methods
+    = ExternalSource->ReadMethodPool(Sel);
+
+  if (isInstance) {
+    if (Methods.second.Method)
+      FactoryMethodPool[Sel] = Methods.second;
+    return InstanceMethodPool.insert(std::make_pair(Sel, Methods.first)).first;
+  }
+
+  if (Methods.first.Method)
+    InstanceMethodPool[Sel] = Methods.first;
+
+  return FactoryMethodPool.insert(std::make_pair(Sel, Methods.second)).first;
+}
+
+void Sema::AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method) {
+  llvm::DenseMap<Selector, ObjCMethodList>::iterator Pos
+    = InstanceMethodPool.find(Method->getSelector());
+  if (Pos == InstanceMethodPool.end()) {
+    if (ExternalSource && !FactoryMethodPool.count(Method->getSelector()))
+      Pos = ReadMethodPool(Method->getSelector(), /*isInstance=*/true);
+    else
+      Pos = InstanceMethodPool.insert(std::make_pair(Method->getSelector(),
+                                                     ObjCMethodList())).first;
+  }
+
+  ObjCMethodList &Entry = Pos->second;
+  if (Entry.Method == 0) {
+    // Haven't seen a method with this selector name yet - add it.
+    Entry.Method = Method;
+    Entry.Next = 0;
+    return;
+  }
+
+  // We've seen a method with this name, see if we have already seen this type
+  // signature.
+  for (ObjCMethodList *List = &Entry; List; List = List->Next)
+    if (MatchTwoMethodDeclarations(Method, List->Method))
+      return;
+
+  // We have a new signature for an existing method - add it.
+  // This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
+  Entry.Next = new ObjCMethodList(Method, Entry.Next);
+}
+
+// FIXME: Finish implementing -Wno-strict-selector-match.
+ObjCMethodDecl *Sema::LookupInstanceMethodInGlobalPool(Selector Sel,
+                                                       SourceRange R,
+                                                       bool warn) {
+  llvm::DenseMap<Selector, ObjCMethodList>::iterator Pos
+    = InstanceMethodPool.find(Sel);
+  if (Pos == InstanceMethodPool.end()) {
+    if (ExternalSource && !FactoryMethodPool.count(Sel))
+      Pos = ReadMethodPool(Sel, /*isInstance=*/true);
+    else
+      return 0;
+  }
+
+  ObjCMethodList &MethList = Pos->second;
+  bool issueWarning = false;
+
+  if (MethList.Method && MethList.Next) {
+    for (ObjCMethodList *Next = MethList.Next; Next; Next = Next->Next)
+      // This checks if the methods differ by size & alignment.
+      if (!MatchTwoMethodDeclarations(MethList.Method, Next->Method, true))
+        issueWarning = warn;
+  }
+  if (issueWarning && (MethList.Method && MethList.Next)) {
+    Diag(R.getBegin(), diag::warn_multiple_method_decl) << Sel << R;
+    Diag(MethList.Method->getLocStart(), diag::note_using)
+      << MethList.Method->getSourceRange();
+    for (ObjCMethodList *Next = MethList.Next; Next; Next = Next->Next)
+      Diag(Next->Method->getLocStart(), diag::note_also_found)
+        << Next->Method->getSourceRange();
+  }
+  return MethList.Method;
+}
+
+void Sema::AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method) {
+  llvm::DenseMap<Selector, ObjCMethodList>::iterator Pos
+    = FactoryMethodPool.find(Method->getSelector());
+  if (Pos == FactoryMethodPool.end()) {
+    if (ExternalSource && !InstanceMethodPool.count(Method->getSelector()))
+      Pos = ReadMethodPool(Method->getSelector(), /*isInstance=*/false);
+    else
+      Pos = FactoryMethodPool.insert(std::make_pair(Method->getSelector(),
+                                                    ObjCMethodList())).first;
+  }
+
+  ObjCMethodList &FirstMethod = Pos->second;
+  if (!FirstMethod.Method) {
+    // Haven't seen a method with this selector name yet - add it.
+    FirstMethod.Method = Method;
+    FirstMethod.Next = 0;
+  } else {
+    // We've seen a method with this name, now check the type signature(s).
+    bool match = MatchTwoMethodDeclarations(Method, FirstMethod.Method);
+
+    for (ObjCMethodList *Next = FirstMethod.Next; !match && Next;
+         Next = Next->Next)
+      match = MatchTwoMethodDeclarations(Method, Next->Method);
+
+    if (!match) {
+      // We have a new signature for an existing method - add it.
+      // This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
+      struct ObjCMethodList *OMI = new ObjCMethodList(Method, FirstMethod.Next);
+      FirstMethod.Next = OMI;
+    }
+  }
+}
+
+ObjCMethodDecl *Sema::LookupFactoryMethodInGlobalPool(Selector Sel,
+                                                      SourceRange R) {
+  llvm::DenseMap<Selector, ObjCMethodList>::iterator Pos
+    = FactoryMethodPool.find(Sel);
+  if (Pos == FactoryMethodPool.end()) {
+    if (ExternalSource && !InstanceMethodPool.count(Sel))
+      Pos = ReadMethodPool(Sel, /*isInstance=*/false);
+    else
+      return 0;
+  }
+
+  ObjCMethodList &MethList = Pos->second;
+  bool issueWarning = false;
+
+  if (MethList.Method && MethList.Next) {
+    for (ObjCMethodList *Next = MethList.Next; Next; Next = Next->Next)
+      // This checks if the methods differ by size & alignment.
+      if (!MatchTwoMethodDeclarations(MethList.Method, Next->Method, true))
+        issueWarning = true;
+  }
+  if (issueWarning && (MethList.Method && MethList.Next)) {
+    Diag(R.getBegin(), diag::warn_multiple_method_decl) << Sel << R;
+    Diag(MethList.Method->getLocStart(), diag::note_using)
+      << MethList.Method->getSourceRange();
+    for (ObjCMethodList *Next = MethList.Next; Next; Next = Next->Next)
+      Diag(Next->Method->getLocStart(), diag::note_also_found)
+        << Next->Method->getSourceRange();
+  }
+  return MethList.Method;
+}
+
+/// ProcessPropertyDecl - Make sure that any user-defined setter/getter methods
+/// have the property type and issue diagnostics if they don't.
+/// Also synthesize a getter/setter method if none exist (and update the
+/// appropriate lookup tables. FIXME: Should reconsider if adding synthesized
+/// methods is the "right" thing to do.
+void Sema::ProcessPropertyDecl(ObjCPropertyDecl *property,
+                               ObjCContainerDecl *CD) {
+  ObjCMethodDecl *GetterMethod, *SetterMethod;
+
+  GetterMethod = CD->getInstanceMethod(property->getGetterName());
+  SetterMethod = CD->getInstanceMethod(property->getSetterName());
+  DiagnosePropertyAccessorMismatch(property, GetterMethod,
+                                   property->getLocation());
+
+  if (SetterMethod) {
+    ObjCPropertyDecl::PropertyAttributeKind CAttr = 
+      property->getPropertyAttributes();
+    if ((!(CAttr & ObjCPropertyDecl::OBJC_PR_readonly)) &&
+        Context.getCanonicalType(SetterMethod->getResultType()) != 
+          Context.VoidTy)
+      Diag(SetterMethod->getLocation(), diag::err_setter_type_void);
+    if (SetterMethod->param_size() != 1 ||
+        ((*SetterMethod->param_begin())->getType() != property->getType())) {
+      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 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.
+    GetterMethod = ObjCMethodDecl::Create(Context, property->getLocation(),
+                             property->getLocation(), property->getGetterName(),
+                             property->getType(), CD, true, false, true,
+                             (property->getPropertyImplementation() ==
+                              ObjCPropertyDecl::Optional) ?
+                             ObjCMethodDecl::Optional :
+                             ObjCMethodDecl::Required);
+    CD->addDecl(GetterMethod);
+  } else
+    // A user declared getter will be synthesize when @synthesize of
+    // the property with the same name is seen in the @implementation
+    GetterMethod->setSynthesized(true);
+  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 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.
+      SetterMethod = ObjCMethodDecl::Create(Context, property->getLocation(),
+                               property->getLocation(),
+                               property->getSetterName(),
+                               Context.VoidTy, CD, true, false, true,
+                               (property->getPropertyImplementation() ==
+                                ObjCPropertyDecl::Optional) ?
+                               ObjCMethodDecl::Optional :
+                               ObjCMethodDecl::Required);
+      // Invent the arguments for the setter. We don't bother making a
+      // nice name for the argument.
+      ParmVarDecl *Argument = ParmVarDecl::Create(Context, SetterMethod,
+                                                  property->getLocation(),
+                                                  property->getIdentifier(),
+                                                  property->getType(),
+                                                  /*TInfo=*/0,
+                                                  VarDecl::None,
+                                                  0);
+      SetterMethod->setMethodParams(Context, &Argument, 1);
+      CD->addDecl(SetterMethod);
+    } else
+      // A user declared setter will be synthesize when @synthesize of
+      // the property with the same name is seen in the @implementation
+      SetterMethod->setSynthesized(true);
+    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 (GetterMethod)
+    AddInstanceMethodToGlobalPool(GetterMethod);
+  if (SetterMethod)
+    AddInstanceMethodToGlobalPool(SetterMethod);
+}
+
+/// CompareMethodParamsInBaseAndSuper - This routine compares methods with
+/// identical selector names in current and its super classes and issues
+/// a warning if any of their argument types are incompatible.
+void Sema::CompareMethodParamsInBaseAndSuper(Decl *ClassDecl,
+                                             ObjCMethodDecl *Method,
+                                             bool IsInstance)  {
+  ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(ClassDecl);
+  if (ID == 0) return;
+
+  while (ObjCInterfaceDecl *SD = ID->getSuperClass()) {
+    ObjCMethodDecl *SuperMethodDecl =
+        SD->lookupMethod(Method->getSelector(), IsInstance);
+    if (SuperMethodDecl == 0) {
+      ID = SD;
+      continue;
+    }
+    ObjCMethodDecl::param_iterator ParamI = Method->param_begin(),
+      E = Method->param_end();
+    ObjCMethodDecl::param_iterator PrevI = SuperMethodDecl->param_begin();
+    for (; ParamI != E; ++ParamI, ++PrevI) {
+      // Number of parameters are the same and is guaranteed by selector match.
+      assert(PrevI != SuperMethodDecl->param_end() && "Param mismatch");
+      QualType T1 = Context.getCanonicalType((*ParamI)->getType());
+      QualType T2 = Context.getCanonicalType((*PrevI)->getType());
+      // If type of arguement of method in this class does not match its
+      // respective argument type in the super class method, issue warning;
+      if (!Context.typesAreCompatible(T1, T2)) {
+        Diag((*ParamI)->getLocation(), diag::ext_typecheck_base_super)
+          << T1 << T2;
+        Diag(SuperMethodDecl->getLocation(), diag::note_previous_declaration);
+        return;
+      }
+    }
+    ID = SD;
+  }
+}
+
+// Note: For class/category implemenations, allMethods/allProperties is
+// always null.
+void Sema::ActOnAtEnd(SourceRange AtEnd,
+                      DeclPtrTy classDecl,
+                      DeclPtrTy *allMethods, unsigned allNum,
+                      DeclPtrTy *allProperties, unsigned pNum,
+                      DeclGroupPtrTy *allTUVars, unsigned tuvNum) {
+  Decl *ClassDecl = classDecl.getAs<Decl>();
+
+  // FIXME: If we don't have a ClassDecl, we have an error. We should consider
+  // always passing in a decl. If the decl has an error, isInvalidDecl()
+  // should be true.
+  if (!ClassDecl)
+    return;
+  
+  bool isInterfaceDeclKind =
+        isa<ObjCInterfaceDecl>(ClassDecl) || isa<ObjCCategoryDecl>(ClassDecl)
+         || isa<ObjCProtocolDecl>(ClassDecl);
+  bool checkIdenticalMethods = isa<ObjCImplementationDecl>(ClassDecl);
+
+  if (!isInterfaceDeclKind && AtEnd.isInvalid()) {
+    // FIXME: This is wrong.  We shouldn't be pretending that there is
+    //  an '@end' in the declaration.
+    SourceLocation L = ClassDecl->getLocation();
+    AtEnd.setBegin(L);
+    AtEnd.setEnd(L);
+    Diag(L, diag::warn_missing_atend);
+  }
+  
+  DeclContext *DC = dyn_cast<DeclContext>(ClassDecl);
+
+  // FIXME: Remove these and use the ObjCContainerDecl/DeclContext.
+  llvm::DenseMap<Selector, const ObjCMethodDecl*> InsMap;
+  llvm::DenseMap<Selector, const ObjCMethodDecl*> ClsMap;
+
+  for (unsigned i = 0; i < allNum; i++ ) {
+    ObjCMethodDecl *Method =
+      cast_or_null<ObjCMethodDecl>(allMethods[i].getAs<Decl>());
+
+    if (!Method) continue;  // Already issued a diagnostic.
+    if (Method->isInstanceMethod()) {
+      /// Check for instance method of the same name with incompatible types
+      const ObjCMethodDecl *&PrevMethod = InsMap[Method->getSelector()];
+      bool match = PrevMethod ? MatchTwoMethodDeclarations(Method, PrevMethod)
+                              : false;
+      if ((isInterfaceDeclKind && PrevMethod && !match)
+          || (checkIdenticalMethods && match)) {
+          Diag(Method->getLocation(), diag::err_duplicate_method_decl)
+            << Method->getDeclName();
+          Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
+      } else {
+        DC->addDecl(Method);
+        InsMap[Method->getSelector()] = Method;
+        /// The following allows us to typecheck messages to "id".
+        AddInstanceMethodToGlobalPool(Method);
+        // verify that the instance method conforms to the same definition of
+        // parent methods if it shadows one.
+        CompareMethodParamsInBaseAndSuper(ClassDecl, Method, true);
+      }
+    } else {
+      /// Check for class method of the same name with incompatible types
+      const ObjCMethodDecl *&PrevMethod = ClsMap[Method->getSelector()];
+      bool match = PrevMethod ? MatchTwoMethodDeclarations(Method, PrevMethod)
+                              : false;
+      if ((isInterfaceDeclKind && PrevMethod && !match)
+          || (checkIdenticalMethods && match)) {
+        Diag(Method->getLocation(), diag::err_duplicate_method_decl)
+          << Method->getDeclName();
+        Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
+      } else {
+        DC->addDecl(Method);
+        ClsMap[Method->getSelector()] = Method;
+        /// The following allows us to typecheck messages to "Class".
+        AddFactoryMethodToGlobalPool(Method);
+        // verify that the class method conforms to the same definition of
+        // parent methods if it shadows one.
+        CompareMethodParamsInBaseAndSuper(ClassDecl, Method, false);
+      }
+    }
+  }
+  if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
+    // Compares properties declared in this class to those of its
+    // super class.
+    ComparePropertiesInBaseAndSuper(I);
+    CompareProperties(I, DeclPtrTy::make(I));
+  } else if (ObjCCategoryDecl *C = dyn_cast<ObjCCategoryDecl>(ClassDecl)) {
+    // Categories are used to extend the class by declaring new methods.
+    // By the same token, they are also used to add new properties. No
+    // need to compare the added property to those in the class.
+
+    // Compare protocol properties with those in category
+    CompareProperties(C, DeclPtrTy::make(C));
+    if (C->getIdentifier() == 0)
+      DiagnoseClassExtensionDupMethods(C, C->getClassInterface());
+  }
+  if (ObjCContainerDecl *CDecl = dyn_cast<ObjCContainerDecl>(ClassDecl)) {
+    // ProcessPropertyDecl is responsible for diagnosing conflicts with any
+    // user-defined setter/getter. It also synthesizes setter/getter methods
+    // and adds them to the DeclContext and global method pools.
+    for (ObjCContainerDecl::prop_iterator I = CDecl->prop_begin(),
+                                          E = CDecl->prop_end();
+         I != E; ++I)
+      ProcessPropertyDecl(*I, CDecl);
+    CDecl->setAtEndRange(AtEnd);
+  }
+  if (ObjCImplementationDecl *IC=dyn_cast<ObjCImplementationDecl>(ClassDecl)) {
+    IC->setAtEndRange(AtEnd);
+    if (ObjCInterfaceDecl* IDecl = IC->getClassInterface()) {
+      ImplMethodsVsClassMethods(IC, IDecl);
+      AtomicPropertySetterGetterRules(IC, IDecl);
+    }
+  } else if (ObjCCategoryImplDecl* CatImplClass =
+                                   dyn_cast<ObjCCategoryImplDecl>(ClassDecl)) {
+    CatImplClass->setAtEndRange(AtEnd);
+
+    // Find category interface decl and then check that all methods declared
+    // in this interface are implemented in the category @implementation.
+    if (ObjCInterfaceDecl* IDecl = CatImplClass->getClassInterface()) {
+      for (ObjCCategoryDecl *Categories = IDecl->getCategoryList();
+           Categories; Categories = Categories->getNextClassCategory()) {
+        if (Categories->getIdentifier() == CatImplClass->getIdentifier()) {
+          ImplMethodsVsClassMethods(CatImplClass, Categories);
+          break;
+        }
+      }
+    }
+  }
+  if (isInterfaceDeclKind) {
+    // Reject invalid vardecls.
+    for (unsigned i = 0; i != tuvNum; i++) {
+      DeclGroupRef DG = allTUVars[i].getAsVal<DeclGroupRef>();
+      for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
+        if (VarDecl *VDecl = dyn_cast<VarDecl>(*I)) {
+          if (!VDecl->hasExternalStorage())
+            Diag(VDecl->getLocation(), diag::err_objc_var_decl_inclass);
+        }
+    }
+  }
+}
+
+
+/// CvtQTToAstBitMask - utility routine to produce an AST bitmask for
+/// objective-c's type qualifier from the parser version of the same info.
+static Decl::ObjCDeclQualifier
+CvtQTToAstBitMask(ObjCDeclSpec::ObjCDeclQualifier PQTVal) {
+  Decl::ObjCDeclQualifier ret = Decl::OBJC_TQ_None;
+  if (PQTVal & ObjCDeclSpec::DQ_In)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_In);
+  if (PQTVal & ObjCDeclSpec::DQ_Inout)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_Inout);
+  if (PQTVal & ObjCDeclSpec::DQ_Out)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_Out);
+  if (PQTVal & ObjCDeclSpec::DQ_Bycopy)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_Bycopy);
+  if (PQTVal & ObjCDeclSpec::DQ_Byref)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_Byref);
+  if (PQTVal & ObjCDeclSpec::DQ_Oneway)
+    ret = (Decl::ObjCDeclQualifier)(ret | Decl::OBJC_TQ_Oneway);
+
+  return ret;
+}
+
+Sema::DeclPtrTy Sema::ActOnMethodDeclaration(
+    SourceLocation MethodLoc, SourceLocation EndLoc,
+    tok::TokenKind MethodType, DeclPtrTy classDecl,
+    ObjCDeclSpec &ReturnQT, TypeTy *ReturnType,
+    Selector Sel,
+    // optional arguments. The number of types/arguments is obtained
+    // from the Sel.getNumArgs().
+    ObjCArgInfo *ArgInfo,
+    llvm::SmallVectorImpl<Declarator> &Cdecls,
+    AttributeList *AttrList, tok::ObjCKeywordKind MethodDeclKind,
+    bool isVariadic) {
+  Decl *ClassDecl = classDecl.getAs<Decl>();
+
+  // Make sure we can establish a context for the method.
+  if (!ClassDecl) {
+    Diag(MethodLoc, diag::error_missing_method_context);
+    FunctionLabelMap.clear();
+    return DeclPtrTy();
+  }
+  QualType resultDeclType;
+
+  if (ReturnType) {
+    resultDeclType = GetTypeFromParser(ReturnType);
+
+    // Methods cannot return interface types. All ObjC objects are
+    // passed by reference.
+    if (resultDeclType->isObjCInterfaceType()) {
+      Diag(MethodLoc, diag::err_object_cannot_be_passed_returned_by_value)
+        << 0 << resultDeclType;
+      return DeclPtrTy();
+    }
+  } else // get the type for "id".
+    resultDeclType = Context.getObjCIdType();
+
+  ObjCMethodDecl* ObjCMethod =
+    ObjCMethodDecl::Create(Context, MethodLoc, EndLoc, Sel, resultDeclType,
+                           cast<DeclContext>(ClassDecl),
+                           MethodType == tok::minus, isVariadic,
+                           false,
+                           MethodDeclKind == tok::objc_optional ?
+                           ObjCMethodDecl::Optional :
+                           ObjCMethodDecl::Required);
+
+  llvm::SmallVector<ParmVarDecl*, 16> Params;
+
+  for (unsigned i = 0, e = Sel.getNumArgs(); i != e; ++i) {
+    QualType ArgType;
+    TypeSourceInfo *DI;
+
+    if (ArgInfo[i].Type == 0) {
+      ArgType = Context.getObjCIdType();
+      DI = 0;
+    } else {
+      ArgType = GetTypeFromParser(ArgInfo[i].Type, &DI);
+      // Perform the default array/function conversions (C99 6.7.5.3p[7,8]).
+      ArgType = adjustParameterType(ArgType);
+    }
+
+    ParmVarDecl* Param
+      = ParmVarDecl::Create(Context, ObjCMethod, ArgInfo[i].NameLoc,
+                            ArgInfo[i].Name, ArgType, DI,
+                            VarDecl::None, 0);
+
+    if (ArgType->isObjCInterfaceType()) {
+      Diag(ArgInfo[i].NameLoc,
+           diag::err_object_cannot_be_passed_returned_by_value)
+        << 1 << ArgType;
+      Param->setInvalidDecl();
+    }
+
+    Param->setObjCDeclQualifier(
+      CvtQTToAstBitMask(ArgInfo[i].DeclSpec.getObjCDeclQualifier()));
+
+    // Apply the attributes to the parameter.
+    ProcessDeclAttributeList(TUScope, Param, ArgInfo[i].ArgAttrs);
+
+    Params.push_back(Param);
+  }
+
+  ObjCMethod->setMethodParams(Context, Params.data(), Sel.getNumArgs());
+  ObjCMethod->setObjCDeclQualifier(
+    CvtQTToAstBitMask(ReturnQT.getObjCDeclQualifier()));
+  const ObjCMethodDecl *PrevMethod = 0;
+
+  if (AttrList)
+    ProcessDeclAttributeList(TUScope, ObjCMethod, AttrList);
+
+  const ObjCMethodDecl *InterfaceMD = 0;
+
+  // For implementations (which can be very "coarse grain"), we add the
+  // method now. This allows the AST to implement lookup methods that work
+  // incrementally (without waiting until we parse the @end). It also allows
+  // us to flag multiple declaration errors as they occur.
+  if (ObjCImplementationDecl *ImpDecl =
+        dyn_cast<ObjCImplementationDecl>(ClassDecl)) {
+    if (MethodType == tok::minus) {
+      PrevMethod = ImpDecl->getInstanceMethod(Sel);
+      ImpDecl->addInstanceMethod(ObjCMethod);
+    } else {
+      PrevMethod = ImpDecl->getClassMethod(Sel);
+      ImpDecl->addClassMethod(ObjCMethod);
+    }
+    InterfaceMD = ImpDecl->getClassInterface()->getMethod(Sel,
+                                                   MethodType == tok::minus);
+    if (AttrList)
+      Diag(EndLoc, diag::warn_attribute_method_def);
+  } else if (ObjCCategoryImplDecl *CatImpDecl =
+             dyn_cast<ObjCCategoryImplDecl>(ClassDecl)) {
+    if (MethodType == tok::minus) {
+      PrevMethod = CatImpDecl->getInstanceMethod(Sel);
+      CatImpDecl->addInstanceMethod(ObjCMethod);
+    } else {
+      PrevMethod = CatImpDecl->getClassMethod(Sel);
+      CatImpDecl->addClassMethod(ObjCMethod);
+    }
+    if (AttrList)
+      Diag(EndLoc, diag::warn_attribute_method_def);
+  }
+  if (PrevMethod) {
+    // You can never have two method definitions with the same name.
+    Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
+      << ObjCMethod->getDeclName();
+    Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
+  }
+
+  // If the interface declared this method, and it was deprecated there,
+  // mark it deprecated here.
+  if (InterfaceMD && InterfaceMD->hasAttr<DeprecatedAttr>())
+    ObjCMethod->addAttr(::new (Context) DeprecatedAttr());
+
+  return DeclPtrTy::make(ObjCMethod);
+}
+
+void Sema::CheckObjCPropertyAttributes(QualType PropertyTy,
+                                       SourceLocation Loc,
+                                       unsigned &Attributes) {
+  // FIXME: Improve the reported location.
+
+  // readonly and readwrite/assign/retain/copy conflict.
+  if ((Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
+      (Attributes & (ObjCDeclSpec::DQ_PR_readwrite |
+                     ObjCDeclSpec::DQ_PR_assign |
+                     ObjCDeclSpec::DQ_PR_copy |
+                     ObjCDeclSpec::DQ_PR_retain))) {
+    const char * which = (Attributes & ObjCDeclSpec::DQ_PR_readwrite) ?
+                          "readwrite" :
+                         (Attributes & ObjCDeclSpec::DQ_PR_assign) ?
+                          "assign" :
+                         (Attributes & ObjCDeclSpec::DQ_PR_copy) ?
+                          "copy" : "retain";
+
+    Diag(Loc, (Attributes & (ObjCDeclSpec::DQ_PR_readwrite)) ?
+                 diag::err_objc_property_attr_mutually_exclusive :
+                 diag::warn_objc_property_attr_mutually_exclusive)
+      << "readonly" << which;
+  }
+
+  // Check for copy or retain on non-object types.
+  if ((Attributes & (ObjCDeclSpec::DQ_PR_copy | ObjCDeclSpec::DQ_PR_retain)) &&
+      !PropertyTy->isObjCObjectPointerType() &&
+      !PropertyTy->isBlockPointerType() &&
+      !Context.isObjCNSObjectType(PropertyTy)) {
+    Diag(Loc, diag::err_objc_property_requires_object)
+      << (Attributes & ObjCDeclSpec::DQ_PR_copy ? "copy" : "retain");
+    Attributes &= ~(ObjCDeclSpec::DQ_PR_copy | ObjCDeclSpec::DQ_PR_retain);
+  }
+
+  // Check for more than one of { assign, copy, retain }.
+  if (Attributes & ObjCDeclSpec::DQ_PR_assign) {
+    if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
+      Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
+        << "assign" << "copy";
+      Attributes &= ~ObjCDeclSpec::DQ_PR_copy;
+    }
+    if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
+      Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
+        << "assign" << "retain";
+      Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
+    }
+  } else if (Attributes & ObjCDeclSpec::DQ_PR_copy) {
+    if (Attributes & ObjCDeclSpec::DQ_PR_retain) {
+      Diag(Loc, diag::err_objc_property_attr_mutually_exclusive)
+        << "copy" << "retain";
+      Attributes &= ~ObjCDeclSpec::DQ_PR_retain;
+    }
+  }
+
+  // Warn if user supplied no assignment attribute, property is
+  // readwrite, and this is an object type.
+  if (!(Attributes & (ObjCDeclSpec::DQ_PR_assign | ObjCDeclSpec::DQ_PR_copy |
+                      ObjCDeclSpec::DQ_PR_retain)) &&
+      !(Attributes & ObjCDeclSpec::DQ_PR_readonly) &&
+      PropertyTy->isObjCObjectPointerType()) {
+    // Skip this warning in gc-only mode.
+    if (getLangOptions().getGCMode() != LangOptions::GCOnly)
+      Diag(Loc, diag::warn_objc_property_no_assignment_attribute);
+
+    // If non-gc code warn that this is likely inappropriate.
+    if (getLangOptions().getGCMode() == 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 & ObjCDeclSpec::DQ_PR_copy)
+      && getLangOptions().getGCMode() == LangOptions::GCOnly
+      && PropertyTy->isBlockPointerType())
+    Diag(Loc, diag::warn_objc_property_copy_missing_on_block);
+}
+
+Sema::DeclPtrTy Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
+                                    FieldDeclarator &FD,
+                                    ObjCDeclSpec &ODS,
+                                    Selector GetterSel,
+                                    Selector SetterSel,
+                                    DeclPtrTy ClassCategory,
+                                    bool *isOverridingProperty,
+                                    tok::ObjCKeywordKind MethodImplKind) {
+  unsigned Attributes = ODS.getPropertyAttributes();
+  bool isReadWrite = ((Attributes & ObjCDeclSpec::DQ_PR_readwrite) ||
+                      // default is readwrite!
+                      !(Attributes & ObjCDeclSpec::DQ_PR_readonly));
+  // property is defaulted to 'assign' if it is readwrite and is
+  // not retain or copy
+  bool isAssign = ((Attributes & ObjCDeclSpec::DQ_PR_assign) ||
+                   (isReadWrite &&
+                    !(Attributes & ObjCDeclSpec::DQ_PR_retain) &&
+                    !(Attributes & ObjCDeclSpec::DQ_PR_copy)));
+  QualType T = GetTypeForDeclarator(FD.D, S);
+  if (T->isReferenceType()) {
+    Diag(AtLoc, diag::error_reference_property);
+    return DeclPtrTy();
+  }
+  Decl *ClassDecl = ClassCategory.getAs<Decl>();
+  ObjCInterfaceDecl *CCPrimary = 0; // continuation class's primary class
+  // May modify Attributes.
+  CheckObjCPropertyAttributes(T, AtLoc, Attributes);
+  if (ObjCCategoryDecl *CDecl = dyn_cast<ObjCCategoryDecl>(ClassDecl))
+    if (!CDecl->getIdentifier()) {
+      // This is a continuation class. property requires special
+      // handling.
+      if ((CCPrimary = CDecl->getClassInterface())) {
+        // Find the property in continuation class's primary class only.
+        IdentifierInfo *PropertyId = FD.D.getIdentifier();
+        if (ObjCPropertyDecl *PIDecl = 
+              CCPrimary->FindPropertyVisibleInPrimaryClass(PropertyId)) {
+          // property 'PIDecl's readonly attribute will be over-ridden
+          // with continuation class's readwrite property attribute!
+          unsigned PIkind = PIDecl->getPropertyAttributes();
+          if (isReadWrite && (PIkind & ObjCPropertyDecl::OBJC_PR_readonly)) {
+            unsigned retainCopyNonatomic = 
+              (ObjCPropertyDecl::OBJC_PR_retain |
+               ObjCPropertyDecl::OBJC_PR_copy |
+               ObjCPropertyDecl::OBJC_PR_nonatomic);
+            if ((Attributes & retainCopyNonatomic) !=
+                (PIkind & retainCopyNonatomic)) {
+              Diag(AtLoc, diag::warn_property_attr_mismatch);
+              Diag(PIDecl->getLocation(), diag::note_property_declare);
+            }
+            DeclContext *DC = dyn_cast<DeclContext>(CCPrimary);
+            assert(DC && "ClassDecl is not a DeclContext");
+            DeclContext::lookup_result Found = 
+              DC->lookup(PIDecl->getDeclName());
+            bool PropertyInPrimaryClass = false;
+            for (; Found.first != Found.second; ++Found.first)
+              if (isa<ObjCPropertyDecl>(*Found.first)) {
+                PropertyInPrimaryClass = true;
+                break;
+              }
+            if (!PropertyInPrimaryClass) {
+              // Protocol is not in the primary class. Must build one for it.
+              ObjCDeclSpec ProtocolPropertyODS;
+              // FIXME. Assuming that ObjCDeclSpec::ObjCPropertyAttributeKind and
+              // ObjCPropertyDecl::PropertyAttributeKind have identical values.
+              // Should consolidate both into one enum type.
+              ProtocolPropertyODS.setPropertyAttributes(
+                (ObjCDeclSpec::ObjCPropertyAttributeKind)PIkind);
+              DeclPtrTy ProtocolPtrTy = 
+                ActOnProperty(S, AtLoc, FD, ProtocolPropertyODS, 
+                              PIDecl->getGetterName(), 
+                              PIDecl->getSetterName(), 
+                              DeclPtrTy::make(CCPrimary), isOverridingProperty, 
+                              MethodImplKind);
+              PIDecl = ProtocolPtrTy.getAs<ObjCPropertyDecl>();
+            }
+            PIDecl->makeitReadWriteAttribute();
+            if (Attributes & ObjCDeclSpec::DQ_PR_retain)
+              PIDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
+            if (Attributes & ObjCDeclSpec::DQ_PR_copy)
+              PIDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
+            PIDecl->setSetterName(SetterSel);
+          } else {
+            Diag(AtLoc, diag::err_use_continuation_class)
+              << CCPrimary->getDeclName();
+            Diag(PIDecl->getLocation(), diag::note_property_declare);
+          }
+          *isOverridingProperty = true;
+          // Make sure setter decl is synthesized, and added to primary
+          // class's list.
+          ProcessPropertyDecl(PIDecl, CCPrimary);
+          return DeclPtrTy();
+        }
+        // No matching property found in the primary class. Just fall thru
+        // and add property to continuation class's primary class.
+        ClassDecl = CCPrimary;
+      } else {
+        Diag(CDecl->getLocation(), diag::err_continuation_class);
+        *isOverridingProperty = true;
+        return DeclPtrTy();
+      }
+    }
+
+  // Issue a warning if property is 'assign' as default and its object, which is
+  // gc'able conforms to NSCopying protocol
+  if (getLangOptions().getGCMode() != LangOptions::NonGC &&
+      isAssign && !(Attributes & ObjCDeclSpec::DQ_PR_assign))
+      if (T->isObjCObjectPointerType()) {
+        QualType InterfaceTy = T->getPointeeType();
+        if (const ObjCInterfaceType *OIT =
+              InterfaceTy->getAs<ObjCInterfaceType>()) {
+        ObjCInterfaceDecl *IDecl = OIT->getDecl();
+        if (IDecl)
+          if (ObjCProtocolDecl* PNSCopying =
+                LookupProtocol(&Context.Idents.get("NSCopying")))
+            if (IDecl->ClassImplementsProtocol(PNSCopying, true))
+              Diag(AtLoc, diag::warn_implements_nscopying)
+                << FD.D.getIdentifier();
+        }
+      }
+  if (T->isObjCInterfaceType())
+    Diag(FD.D.getIdentifierLoc(), diag::err_statically_allocated_object);
+
+  DeclContext *DC = dyn_cast<DeclContext>(ClassDecl);
+  assert(DC && "ClassDecl is not a DeclContext");
+  ObjCPropertyDecl *PDecl = ObjCPropertyDecl::Create(Context, DC,
+                                                     FD.D.getIdentifierLoc(),
+                                                     FD.D.getIdentifier(), 
+                                                     AtLoc, T);
+  DeclContext::lookup_result Found = DC->lookup(PDecl->getDeclName());
+  if (Found.first != Found.second && isa<ObjCPropertyDecl>(*Found.first)) {
+    Diag(PDecl->getLocation(), diag::err_duplicate_property);
+    Diag((*Found.first)->getLocation(), diag::note_property_declare);
+    PDecl->setInvalidDecl();
+  }
+  else
+    DC->addDecl(PDecl);
+
+  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);
+  PDecl->setSetterName(SetterSel);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_readonly)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readonly);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_getter)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_getter);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_setter)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_setter);
+
+  if (isReadWrite)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_readwrite);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_retain)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_retain);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_copy)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_copy);
+
+  if (isAssign)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_assign);
+
+  if (Attributes & ObjCDeclSpec::DQ_PR_nonatomic)
+    PDecl->setPropertyAttributes(ObjCPropertyDecl::OBJC_PR_nonatomic);
+
+  if (MethodImplKind == tok::objc_required)
+    PDecl->setPropertyImplementation(ObjCPropertyDecl::Required);
+  else if (MethodImplKind == tok::objc_optional)
+    PDecl->setPropertyImplementation(ObjCPropertyDecl::Optional);
+  // A case of continuation class adding a new property in the class. This
+  // is not what it was meant for. However, gcc supports it and so should we.
+  // Make sure setter/getters are declared here.
+  if (CCPrimary)
+    ProcessPropertyDecl(PDecl, CCPrimary);
+
+  return DeclPtrTy::make(PDecl);
+}
+
+ObjCIvarDecl* 
+Sema::SynthesizeNewPropertyIvar(ObjCInterfaceDecl *IDecl,
+                                IdentifierInfo *NameII) {
+  ObjCIvarDecl *Ivar = 0;
+  ObjCPropertyDecl *Prop = LookupPropertyDecl(IDecl, NameII);
+  if (Prop && !Prop->isInvalidDecl()) {
+    DeclContext *EnclosingContext = cast_or_null<DeclContext>(IDecl);
+    QualType PropType = Context.getCanonicalType(Prop->getType());
+    assert(EnclosingContext &&
+           "null DeclContext for synthesized ivar - SynthesizeNewPropertyIvar");
+    Ivar = ObjCIvarDecl::Create(Context, EnclosingContext, 
+                                              Prop->getLocation(),
+                                              NameII, PropType, /*Dinfo=*/0,
+                                              ObjCIvarDecl::Public,
+                                              (Expr *)0);
+    Ivar->setLexicalDeclContext(IDecl);
+    IDecl->addDecl(Ivar);
+    Prop->setPropertyIvarDecl(Ivar);
+  }
+  return Ivar;
+}
+
+/// ActOnPropertyImplDecl - This routine performs semantic checks and
+/// builds the AST node for a property implementation declaration; declared
+/// as @synthesize or @dynamic.
+///
+Sema::DeclPtrTy Sema::ActOnPropertyImplDecl(SourceLocation AtLoc,
+                                            SourceLocation PropertyLoc,
+                                            bool Synthesize,
+                                            DeclPtrTy ClassCatImpDecl,
+                                            IdentifierInfo *PropertyId,
+                                            IdentifierInfo *PropertyIvar) {
+  Decl *ClassImpDecl = ClassCatImpDecl.getAs<Decl>();
+  // Make sure we have a context for the property implementation declaration.
+  if (!ClassImpDecl) {
+    Diag(AtLoc, diag::error_missing_property_context);
+    return DeclPtrTy();
+  }
+  ObjCPropertyDecl *property = 0;
+  ObjCInterfaceDecl* IDecl = 0;
+  // Find the class or category class where this property must have
+  // a declaration.
+  ObjCImplementationDecl *IC = 0;
+  ObjCCategoryImplDecl* CatImplClass = 0;
+  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 &&
+           "ActOnPropertyImplDecl - @implementation without @interface");
+
+    // Look for this property declaration in the @implementation's @interface
+    property = IDecl->FindPropertyDeclaration(PropertyId);
+    if (!property) {
+      Diag(PropertyLoc, diag::error_bad_property_decl) << IDecl->getDeclName();
+      return DeclPtrTy();
+    }
+    if (const ObjCCategoryDecl *CD = 
+        dyn_cast<ObjCCategoryDecl>(property->getDeclContext())) {
+      if (CD->getIdentifier()) {
+        Diag(PropertyLoc, diag::error_category_property) << CD->getDeclName();
+        Diag(property->getLocation(), diag::note_property_declare);
+        return DeclPtrTy();
+      }
+    }
+  } else if ((CatImplClass = dyn_cast<ObjCCategoryImplDecl>(ClassImpDecl))) {
+    if (Synthesize) {
+      Diag(AtLoc, diag::error_synthesize_category_decl);
+      return DeclPtrTy();
+    }
+    IDecl = CatImplClass->getClassInterface();
+    if (!IDecl) {
+      Diag(AtLoc, diag::error_missing_property_interface);
+      return DeclPtrTy();
+    }
+    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 DeclPtrTy();
+    // Look for this property declaration in @implementation's category
+    property = Category->FindPropertyDeclaration(PropertyId);
+    if (!property) {
+      Diag(PropertyLoc, diag::error_bad_category_property_decl)
+        << Category->getDeclName();
+      return DeclPtrTy();
+    }
+  } else {
+    Diag(AtLoc, diag::error_bad_property_context);
+    return DeclPtrTy();
+  }
+  ObjCIvarDecl *Ivar = 0;
+  // Check that we have a valid, previously declared ivar for @synthesize
+  if (Synthesize) {
+    // @synthesize
+    if (!PropertyIvar)
+      PropertyIvar = PropertyId;
+    QualType PropType = Context.getCanonicalType(property->getType());
+    // Check that this is a previously declared 'ivar' in 'IDecl' interface
+    ObjCInterfaceDecl *ClassDeclared;
+    Ivar = IDecl->lookupInstanceVariable(PropertyIvar, ClassDeclared);
+    if (!Ivar) {
+      DeclContext *EnclosingContext = cast_or_null<DeclContext>(IDecl);
+      assert(EnclosingContext &&
+             "null DeclContext for synthesized ivar - ActOnPropertyImplDecl");
+      Ivar = ObjCIvarDecl::Create(Context, EnclosingContext, PropertyLoc,
+                                  PropertyIvar, PropType, /*Dinfo=*/0,
+                                  ObjCIvarDecl::Public,
+                                  (Expr *)0);
+      Ivar->setLexicalDeclContext(IDecl);
+      IDecl->addDecl(Ivar);
+      property->setPropertyIvarDecl(Ivar);
+      if (!getLangOptions().ObjCNonFragileABI)
+        Diag(PropertyLoc, diag::error_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 (getLangOptions().ObjCNonFragileABI &&
+               ClassDeclared != IDecl) {
+      Diag(PropertyLoc, diag::error_ivar_in_superclass_use)
+        << property->getDeclName() << Ivar->getDeclName()
+        << ClassDeclared->getDeclName();
+      Diag(Ivar->getLocation(), diag::note_previous_access_declaration)
+        << Ivar << Ivar->getNameAsCString();
+      // Note! I deliberately want it to fall thru so more errors are caught.
+    }
+    QualType IvarType = Context.getCanonicalType(Ivar->getType());
+
+    // Check that type of property and its ivar are type compatible.
+    if (PropType != IvarType) {
+      if (CheckAssignmentConstraints(PropType, IvarType) != Compatible) {
+        Diag(PropertyLoc, diag::error_property_ivar_type)
+          << property->getDeclName() << Ivar->getDeclName();
+        // Note! I deliberately want it to fall thru so, we have a
+        // a property implementation and to avoid future warnings.
+      }
+
+      // 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(PropType).getUnqualifiedType();
+      QualType rhsType =Context.getCanonicalType(IvarType).getUnqualifiedType();
+      if (lhsType != rhsType &&
+          lhsType->isArithmeticType()) {
+        Diag(PropertyLoc, diag::error_property_ivar_type)
+        << property->getDeclName() << Ivar->getDeclName();
+        // Fall thru - see previous comment
+      }
+      // __weak is explicit. So it works on Canonical type.
+      if (PropType.isObjCGCWeak() && !IvarType.isObjCGCWeak() &&
+          getLangOptions().getGCMode() != LangOptions::NonGC) {
+        Diag(PropertyLoc, diag::error_weak_property)
+        << property->getDeclName() << Ivar->getDeclName();
+        // Fall thru - see previous comment
+      }
+      if ((property->getType()->isObjCObjectPointerType() ||
+           PropType.isObjCGCStrong()) && IvarType.isObjCGCWeak() &&
+           getLangOptions().getGCMode() != LangOptions::NonGC) {
+        Diag(PropertyLoc, diag::error_strong_property)
+        << property->getDeclName() << Ivar->getDeclName();
+        // Fall thru - see previous comment
+      }
+    }
+  } else if (PropertyIvar)
+      // @dynamic
+      Diag(PropertyLoc, diag::error_dynamic_property_ivar_decl);
+  assert (property && "ActOnPropertyImplDecl - property declaration missing");
+  ObjCPropertyImplDecl *PIDecl =
+    ObjCPropertyImplDecl::Create(Context, CurContext, AtLoc, PropertyLoc,
+                                 property,
+                                 (Synthesize ?
+                                  ObjCPropertyImplDecl::Synthesize
+                                  : ObjCPropertyImplDecl::Dynamic),
+                                 Ivar);
+  if (IC) {
+    if (Synthesize)
+      if (ObjCPropertyImplDecl *PPIDecl =
+          IC->FindPropertyImplIvarDecl(PropertyIvar)) {
+        Diag(PropertyLoc, diag::error_duplicate_ivar_use)
+          << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
+          << PropertyIvar;
+        Diag(PPIDecl->getLocation(), diag::note_previous_use);
+      }
+
+    if (ObjCPropertyImplDecl *PPIDecl
+          = IC->FindPropertyImplDecl(PropertyId)) {
+      Diag(PropertyLoc, diag::error_property_implemented) << PropertyId;
+      Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
+      return DeclPtrTy();
+    }
+    IC->addPropertyImplementation(PIDecl);
+  } else {
+    if (Synthesize)
+      if (ObjCPropertyImplDecl *PPIDecl =
+          CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
+        Diag(PropertyLoc, diag::error_duplicate_ivar_use)
+          << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier()
+          << PropertyIvar;
+        Diag(PPIDecl->getLocation(), diag::note_previous_use);
+      }
+
+    if (ObjCPropertyImplDecl *PPIDecl =
+          CatImplClass->FindPropertyImplDecl(PropertyId)) {
+      Diag(PropertyLoc, diag::error_property_implemented) << PropertyId;
+      Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
+      return DeclPtrTy();
+    }
+    CatImplClass->addPropertyImplementation(PIDecl);
+  }
+
+  return DeclPtrTy::make(PIDecl);
+}
+
+bool Sema::CheckObjCDeclScope(Decl *D) {
+  if (isa<TranslationUnitDecl>(CurContext->getLookupContext()))
+    return false;
+
+  Diag(D->getLocation(), diag::err_objc_decls_may_only_appear_in_global_scope);
+  D->setInvalidDecl();
+
+  return true;
+}
+
+/// Called whenever @defs(ClassName) is encountered in the source.  Inserts the
+/// instance variables of ClassName into Decls.
+void Sema::ActOnDefs(Scope *S, DeclPtrTy TagD, SourceLocation DeclStart,
+                     IdentifierInfo *ClassName,
+                     llvm::SmallVectorImpl<DeclPtrTy> &Decls) {
+  // Check that ClassName is a valid class
+  ObjCInterfaceDecl *Class = getObjCInterfaceDecl(ClassName);
+  if (!Class) {
+    Diag(DeclStart, diag::err_undef_interface) << ClassName;
+    return;
+  }
+  if (LangOpts.ObjCNonFragileABI) {
+    Diag(DeclStart, diag::err_atdef_nonfragile_interface);
+    return;
+  }
+
+  // Collect the instance variables
+  llvm::SmallVector<FieldDecl*, 32> RecFields;
+  Context.CollectObjCIvars(Class, RecFields);
+  // For each ivar, create a fresh ObjCAtDefsFieldDecl.
+  for (unsigned i = 0; i < RecFields.size(); i++) {
+    FieldDecl* ID = RecFields[i];
+    RecordDecl *Record = dyn_cast<RecordDecl>(TagD.getAs<Decl>());
+    Decl *FD = ObjCAtDefsFieldDecl::Create(Context, Record, ID->getLocation(),
+                                           ID->getIdentifier(), ID->getType(),
+                                           ID->getBitWidth());
+    Decls.push_back(Sema::DeclPtrTy::make(FD));
+  }
+
+  // Introduce all of these fields into the appropriate scope.
+  for (llvm::SmallVectorImpl<DeclPtrTy>::iterator D = Decls.begin();
+       D != Decls.end(); ++D) {
+    FieldDecl *FD = cast<FieldDecl>(D->getAs<Decl>());
+    if (getLangOptions().CPlusPlus)
+      PushOnScopeChains(cast<FieldDecl>(FD), S);
+    else if (RecordDecl *Record = dyn_cast<RecordDecl>(TagD.getAs<Decl>()))
+      Record->addDecl(FD);
+  }
+}
+