MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 321 insertions, 87 deletions

diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaDeclObjC.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaDeclObjC.cpp
index f33e7bc..f44fb32 100644
--- a/contrib/llvm/tools/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/SemaDeclObjC.cpp
@@ -324,15 +324,15 @@ void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
   PushOnScopeChains(MDecl->getSelfDecl(), FnBodyScope);
   PushOnScopeChains(MDecl->getCmdDecl(), FnBodyScope);
 
+  // The ObjC parser requires parameter names so there's no need to check.
+  CheckParmsForFunctionDef(MDecl->param_begin(), MDecl->param_end(),
+                           /*CheckParameterNames=*/false);
+
   // Introduce all of the other parameters into this scope.
   for (ObjCMethodDecl::param_iterator PI = MDecl->param_begin(),
        E = MDecl->param_end(); PI != E; ++PI) {
     ParmVarDecl *Param = (*PI);
     if (!Param->isInvalidDecl() &&
-        RequireCompleteType(Param->getLocation(), Param->getType(),
-                            diag::err_typecheck_decl_incomplete_type))
-          Param->setInvalidDecl();
-    if (!Param->isInvalidDecl() &&
         getLangOpts().ObjCAutoRefCount &&
         !HasExplicitOwnershipAttr(*this, Param))
       Diag(Param->getLocation(), diag::warn_arc_strong_pointer_objc_pointer) <<
@@ -350,7 +350,7 @@ void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
     case OMF_release:
     case OMF_autorelease:
       Diag(MDecl->getLocation(), diag::err_arc_illegal_method_def)
-        << MDecl->getSelector();
+        << 0 << MDecl->getSelector();
       break;
 
     case OMF_None:
@@ -459,6 +459,23 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
 
   // Create a declaration to describe this @interface.
   ObjCInterfaceDecl* PrevIDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+
+  if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
+    // A previous decl with a different name is because of
+    // @compatibility_alias, for example:
+    // \code
+    //   @class NewImage;
+    //   @compatibility_alias OldImage NewImage;
+    // \endcode
+    // A lookup for 'OldImage' will return the 'NewImage' decl.
+    //
+    // In such a case use the real declaration name, instead of the alias one,
+    // otherwise we will break IdentifierResolver and redecls-chain invariants.
+    // FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
+    // has been aliased.
+    ClassName = PrevIDecl->getIdentifier();
+  }
+
   ObjCInterfaceDecl *IDecl
     = ObjCInterfaceDecl::Create(Context, CurContext, AtInterfaceLoc, ClassName,
                                 PrevIDecl, ClassLoc);
@@ -494,11 +511,9 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
       if (TypoCorrection Corrected = CorrectTypo(
           DeclarationNameInfo(SuperName, SuperLoc), LookupOrdinaryName, TUScope,
           NULL, Validator)) {
+        diagnoseTypo(Corrected, PDiag(diag::err_undef_superclass_suggest)
+                                    << SuperName << ClassName);
         PrevDecl = Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>();
-        Diag(SuperLoc, diag::err_undef_superclass_suggest)
-          << SuperName << ClassName << PrevDecl->getDeclName();
-        Diag(PrevDecl->getLocation(), diag::note_previous_decl)
-          << PrevDecl->getDeclName();
       }
     }
 
@@ -575,6 +590,29 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
   return ActOnObjCContainerStartDefinition(IDecl);
 }
 
+/// ActOnTypedefedProtocols - this action finds protocol list as part of the
+/// typedef'ed use for a qualified super class and adds them to the list
+/// of the protocols.
+void Sema::ActOnTypedefedProtocols(SmallVectorImpl<Decl *> &ProtocolRefs,
+                                   IdentifierInfo *SuperName,
+                                   SourceLocation SuperLoc) {
+  if (!SuperName)
+    return;
+  NamedDecl* IDecl = LookupSingleName(TUScope, SuperName, SuperLoc,
+                                      LookupOrdinaryName);
+  if (!IDecl)
+    return;
+  
+  if (const TypedefNameDecl *TDecl = dyn_cast_or_null<TypedefNameDecl>(IDecl)) {
+    QualType T = TDecl->getUnderlyingType();
+    if (T->isObjCObjectType())
+      if (const ObjCObjectType *OPT = T->getAs<ObjCObjectType>())
+        for (ObjCObjectType::qual_iterator I = OPT->qual_begin(),
+             E = OPT->qual_end(); I != E; ++I)
+          ProtocolRefs.push_back(*I);
+  }
+}
+
 /// ActOnCompatibilityAlias - this action is called after complete parsing of
 /// a \@compatibility_alias declaration. It sets up the alias relationships.
 Decl *Sema::ActOnCompatibilityAlias(SourceLocation AtLoc,
@@ -586,10 +624,7 @@ Decl *Sema::ActOnCompatibilityAlias(SourceLocation AtLoc,
   NamedDecl *ADecl = LookupSingleName(TUScope, AliasName, AliasLocation,
                                       LookupOrdinaryName, ForRedeclaration);
   if (ADecl) {
-    if (isa<ObjCCompatibleAliasDecl>(ADecl))
-      Diag(AliasLocation, diag::warn_previous_alias_decl);
-    else
-      Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
+    Diag(AliasLocation, diag::err_conflicting_aliasing_type) << AliasName;
     Diag(ADecl->getLocation(), diag::note_previous_declaration);
     return 0;
   }
@@ -732,12 +767,9 @@ Sema::FindProtocolDeclaration(bool WarnOnDeclarations,
       TypoCorrection Corrected = CorrectTypo(
           DeclarationNameInfo(ProtocolId[i].first, ProtocolId[i].second),
           LookupObjCProtocolName, TUScope, NULL, Validator);
-      if ((PDecl = Corrected.getCorrectionDeclAs<ObjCProtocolDecl>())) {
-        Diag(ProtocolId[i].second, diag::err_undeclared_protocol_suggest)
-          << ProtocolId[i].first << Corrected.getCorrection();
-        Diag(PDecl->getLocation(), diag::note_previous_decl)
-          << PDecl->getDeclName();
-      }
+      if ((PDecl = Corrected.getCorrectionDeclAs<ObjCProtocolDecl>()))
+        diagnoseTypo(Corrected, PDiag(diag::err_undeclared_protocol_suggest)
+                                    << ProtocolId[i].first);
     }
 
     if (!PDecl) {
@@ -819,7 +851,7 @@ Sema::ActOnForwardProtocolDeclaration(SourceLocation AtProtocolLoc,
     DeclsInGroup.push_back(PDecl);
   }
 
-  return BuildDeclaratorGroup(DeclsInGroup.data(), DeclsInGroup.size(), false);
+  return BuildDeclaratorGroup(DeclsInGroup, false);
 }
 
 Decl *Sema::
@@ -935,6 +967,7 @@ Decl *Sema::ActOnStartCategoryImplementation(
         << CatName;
       Diag(CatIDecl->getImplementation()->getLocation(),
            diag::note_previous_definition);
+      CDecl->setInvalidDecl();
     } else {
       CatIDecl->setImplementation(CDecl);
       // Warn on implementating category of deprecated class under 
@@ -954,7 +987,7 @@ Decl *Sema::ActOnStartClassImplementation(
                       IdentifierInfo *ClassName, SourceLocation ClassLoc,
                       IdentifierInfo *SuperClassname,
                       SourceLocation SuperClassLoc) {
-  ObjCInterfaceDecl* IDecl = 0;
+  ObjCInterfaceDecl *IDecl = 0;
   // Check for another declaration kind with the same name.
   NamedDecl *PrevDecl
     = LookupSingleName(TUScope, ClassName, ClassLoc, LookupOrdinaryName,
@@ -966,24 +999,19 @@ Decl *Sema::ActOnStartClassImplementation(
     RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
                         diag::warn_undef_interface);
   } else {
-    // We did not find anything with the name ClassName; try to correct for 
+    // We did not find anything with the name ClassName; try to correct for
     // typos in the class name.
     ObjCInterfaceValidatorCCC Validator;
-    if (TypoCorrection Corrected = CorrectTypo(
-        DeclarationNameInfo(ClassName, ClassLoc), LookupOrdinaryName, TUScope,
-        NULL, Validator)) {
-      // 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.
-      IDecl = Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>();
-      DeclarationName CorrectedName = Corrected.getCorrection();
-      Diag(ClassLoc, diag::warn_undef_interface_suggest)
-        << ClassName << CorrectedName;
-      Diag(IDecl->getLocation(), diag::note_previous_decl) << CorrectedName
-        << FixItHint::CreateReplacement(ClassLoc, CorrectedName.getAsString());
-      IDecl = 0;
+    TypoCorrection Corrected =
+            CorrectTypo(DeclarationNameInfo(ClassName, ClassLoc),
+                        LookupOrdinaryName, TUScope, NULL, Validator);
+    if (Corrected.getCorrectionDeclAs<ObjCInterfaceDecl>()) {
+      // Suggest the (potentially) correct interface name. 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.
+      diagnoseTypo(Corrected,
+                   PDiag(diag::warn_undef_interface_suggest) << ClassName,
+                   /*ErrorRecovery*/false);
     } else {
       Diag(ClassLoc, diag::warn_undef_interface) << ClassName;
     }
@@ -1056,6 +1084,7 @@ Decl *Sema::ActOnStartClassImplementation(
     Diag(ClassLoc, diag::err_dup_implementation_class) << ClassName;
     Diag(IDecl->getImplementation()->getLocation(),
          diag::note_previous_definition);
+    IMPDecl->setInvalidDecl();
   } else { // add it to the list.
     IDecl->setImplementation(IMPDecl);
     PushOnScopeChains(IMPDecl, TUScope);
@@ -1084,7 +1113,7 @@ Sema::ActOnFinishObjCImplementation(Decl *ObjCImpDecl, ArrayRef<Decl *> Decls) {
 
   DeclsInGroup.push_back(ObjCImpDecl);
 
-  return BuildDeclaratorGroup(DeclsInGroup.data(), DeclsInGroup.size(), false);
+  return BuildDeclaratorGroup(DeclsInGroup, false);
 }
 
 void Sema::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
@@ -1124,6 +1153,19 @@ void Sema::CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
         Diag(ClsIvar->getLocation(), diag::note_previous_definition);
         continue;
       }
+      // Check class extensions (unnamed categories) for duplicate ivars.
+      for (ObjCInterfaceDecl::visible_extensions_iterator
+           Ext = IDecl->visible_extensions_begin(),
+           ExtEnd = IDecl->visible_extensions_end();
+         Ext != ExtEnd; ++Ext) {
+        ObjCCategoryDecl *CDecl = *Ext;
+        if (const ObjCIvarDecl *ClsExtIvar = 
+            CDecl->getIvarDecl(ImplIvar->getIdentifier())) {
+          Diag(ImplIvar->getLocation(), diag::err_duplicate_ivar_declaration); 
+          Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
+          continue;
+        }
+      }
       // Instance ivar to Implementation's DeclContext.
       ImplIvar->setLexicalDeclContext(ImpDecl);
       IDecl->makeDeclVisibleInContext(ImplIvar);
@@ -1469,8 +1511,8 @@ static bool checkMethodFamilyMismatch(Sema &S, ObjCMethodDecl *impl,
     reasonSelector = R_NonObjectReturn;
   }
 
-  S.Diag(impl->getLocation(), errorID) << familySelector << reasonSelector;
-  S.Diag(decl->getLocation(), noteID) << familySelector << reasonSelector;
+  S.Diag(impl->getLocation(), errorID) << int(familySelector) << int(reasonSelector);
+  S.Diag(decl->getLocation(), noteID) << int(familySelector) << int(reasonSelector);
 
   return true;
 }
@@ -1689,9 +1731,8 @@ void Sema::MatchAllMethodDeclarations(const SelectorSet &InsMap,
   // 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 (!InsMapSeen.insert((*I)->getSelector()))
+      continue;
     if (!(*I)->isPropertyAccessor() &&
         !InsMap.count((*I)->getSelector())) {
       if (ImmediateClass)
@@ -1718,11 +1759,11 @@ void Sema::MatchAllMethodDeclarations(const SelectorSet &InsMap,
 
   // 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());
+  for (ObjCInterfaceDecl::classmeth_iterator I = CDecl->classmeth_begin(),
+                                             E = CDecl->classmeth_end();
+       I != E; ++I) {
+    if (!ClsMapSeen.insert((*I)->getSelector()))
+      continue;
     if (!ClsMap.count((*I)->getSelector())) {
       if (ImmediateClass)
         WarnUndefinedMethod(IMPDecl->getLocation(), *I, IncompleteImpl,
@@ -1742,6 +1783,16 @@ void Sema::MatchAllMethodDeclarations(const SelectorSet &InsMap,
     }
   }
   
+  if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl> (CDecl)) {
+    // Also, check for methods declared in protocols inherited by
+    // this protocol.
+    for (ObjCProtocolDecl::protocol_iterator
+          PI = PD->protocol_begin(), E = PD->protocol_end(); PI != E; ++PI)
+      MatchAllMethodDeclarations(InsMap, ClsMap, InsMapSeen, ClsMapSeen,
+                                 IMPDecl, (*PI), IncompleteImpl, false,
+                                 WarnCategoryMethodImpl);
+  }
+  
   if (ObjCInterfaceDecl *I = dyn_cast<ObjCInterfaceDecl> (CDecl)) {
     // when checking that methods in implementation match their declaration,
     // i.e. when WarnCategoryMethodImpl is false, check declarations in class
@@ -1901,13 +1952,6 @@ Sema::ActOnForwardClassDeclaration(SourceLocation AtClassLoc,
     NamedDecl *PrevDecl
       = LookupSingleName(TUScope, IdentList[i], IdentLocs[i], 
                          LookupOrdinaryName, ForRedeclaration);
-    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:
       //
@@ -1936,17 +1980,35 @@ Sema::ActOnForwardClassDeclaration(SourceLocation AtClassLoc,
     // Create a declaration to describe this forward declaration.
     ObjCInterfaceDecl *PrevIDecl
       = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
+
+    IdentifierInfo *ClassName = IdentList[i];
+    if (PrevIDecl && PrevIDecl->getIdentifier() != ClassName) {
+      // A previous decl with a different name is because of
+      // @compatibility_alias, for example:
+      // \code
+      //   @class NewImage;
+      //   @compatibility_alias OldImage NewImage;
+      // \endcode
+      // A lookup for 'OldImage' will return the 'NewImage' decl.
+      //
+      // In such a case use the real declaration name, instead of the alias one,
+      // otherwise we will break IdentifierResolver and redecls-chain invariants.
+      // FIXME: If necessary, add a bit to indicate that this ObjCInterfaceDecl
+      // has been aliased.
+      ClassName = PrevIDecl->getIdentifier();
+    }
+
     ObjCInterfaceDecl *IDecl
       = ObjCInterfaceDecl::Create(Context, CurContext, AtClassLoc,
-                                  IdentList[i], PrevIDecl, IdentLocs[i]);
+                                  ClassName, PrevIDecl, IdentLocs[i]);
     IDecl->setAtEndRange(IdentLocs[i]);
     
     PushOnScopeChains(IDecl, TUScope);
     CheckObjCDeclScope(IDecl);
     DeclsInGroup.push_back(IDecl);
   }
-  
-  return BuildDeclaratorGroup(DeclsInGroup.data(), DeclsInGroup.size(), false);
+
+  return BuildDeclaratorGroup(DeclsInGroup, false);
 }
 
 static bool tryMatchRecordTypes(ASTContext &Context,
@@ -2093,6 +2155,10 @@ void Sema::addMethodToGlobalList(ObjCMethodList *List, ObjCMethodDecl *Method) {
   // signature.
   ObjCMethodList *Previous = List;
   for (; List; Previous = List, List = List->getNext()) {
+    // If we are building a module, keep all of the methods.
+    if (getLangOpts().Modules && !getLangOpts().CurrentModule.empty())
+      continue;
+
     if (!MatchTwoMethodDeclarations(Method, List->Method))
       continue;
     
@@ -2182,7 +2248,7 @@ ObjCMethodDecl *Sema::LookupMethodInGlobalPool(Selector Sel, SourceRange R,
 
   // Gather the non-hidden methods.
   ObjCMethodList &MethList = instance ? Pos->second.first : Pos->second.second;
-  llvm::SmallVector<ObjCMethodDecl *, 4> Methods;
+  SmallVector<ObjCMethodDecl *, 4> Methods;
   for (ObjCMethodList *M = &MethList; M; M = M->getNext()) {
     if (M->Method && !M->Method->isHidden()) {
       // If we're not supposed to warn about mismatches, we're done.
@@ -2269,7 +2335,140 @@ ObjCMethodDecl *Sema::LookupImplementedMethodInGlobalPool(Selector Sel) {
   return 0;
 }
 
-/// DiagnoseDuplicateIvars - 
+static void
+HelperSelectorsForTypoCorrection(
+                      SmallVectorImpl<const ObjCMethodDecl *> &BestMethod,
+                      StringRef Typo, const ObjCMethodDecl * Method) {
+  const unsigned MaxEditDistance = 1;
+  unsigned BestEditDistance = MaxEditDistance + 1;
+  std::string MethodName = Method->getSelector().getAsString();
+  
+  unsigned MinPossibleEditDistance = abs((int)MethodName.size() - (int)Typo.size());
+  if (MinPossibleEditDistance > 0 &&
+      Typo.size() / MinPossibleEditDistance < 1)
+    return;
+  unsigned EditDistance = Typo.edit_distance(MethodName, true, MaxEditDistance);
+  if (EditDistance > MaxEditDistance)
+    return;
+  if (EditDistance == BestEditDistance)
+    BestMethod.push_back(Method);
+  else if (EditDistance < BestEditDistance) {
+    BestMethod.clear();
+    BestMethod.push_back(Method);
+  }
+}
+
+static bool HelperIsMethodInObjCType(Sema &S, Selector Sel,
+                                     QualType ObjectType) {
+  if (ObjectType.isNull())
+    return true;
+  if (S.LookupMethodInObjectType(Sel, ObjectType, true/*Instance method*/))
+    return true;
+  return S.LookupMethodInObjectType(Sel, ObjectType, false/*Class method*/) != 0;
+}
+
+const ObjCMethodDecl *
+Sema::SelectorsForTypoCorrection(Selector Sel,
+                                 QualType ObjectType) {
+  unsigned NumArgs = Sel.getNumArgs();
+  SmallVector<const ObjCMethodDecl *, 8> Methods;
+  bool ObjectIsId = true, ObjectIsClass = true;
+  if (ObjectType.isNull())
+    ObjectIsId = ObjectIsClass = false;
+  else if (!ObjectType->isObjCObjectPointerType())
+    return 0;
+  else if (const ObjCObjectPointerType *ObjCPtr =
+           ObjectType->getAsObjCInterfacePointerType()) {
+    ObjectType = QualType(ObjCPtr->getInterfaceType(), 0);
+    ObjectIsId = ObjectIsClass = false;
+  }
+  else if (ObjectType->isObjCIdType() || ObjectType->isObjCQualifiedIdType())
+    ObjectIsClass = false;
+  else if (ObjectType->isObjCClassType() || ObjectType->isObjCQualifiedClassType())
+    ObjectIsId = false;
+  else
+    return 0;
+  
+  for (GlobalMethodPool::iterator b = MethodPool.begin(),
+       e = MethodPool.end(); b != e; b++) {
+    // instance methods
+    for (ObjCMethodList *M = &b->second.first; M; M=M->getNext())
+      if (M->Method &&
+          (M->Method->getSelector().getNumArgs() == NumArgs) &&
+          (M->Method->getSelector() != Sel)) {
+        if (ObjectIsId)
+          Methods.push_back(M->Method);
+        else if (!ObjectIsClass &&
+                 HelperIsMethodInObjCType(*this, M->Method->getSelector(), ObjectType))
+          Methods.push_back(M->Method);
+      }
+    // class methods
+    for (ObjCMethodList *M = &b->second.second; M; M=M->getNext())
+      if (M->Method &&
+          (M->Method->getSelector().getNumArgs() == NumArgs) &&
+          (M->Method->getSelector() != Sel)) {
+        if (ObjectIsClass)
+          Methods.push_back(M->Method);
+        else if (!ObjectIsId &&
+                 HelperIsMethodInObjCType(*this, M->Method->getSelector(), ObjectType))
+          Methods.push_back(M->Method);
+      }
+  }
+  
+  SmallVector<const ObjCMethodDecl *, 8> SelectedMethods;
+  for (unsigned i = 0, e = Methods.size(); i < e; i++) {
+    HelperSelectorsForTypoCorrection(SelectedMethods,
+                                     Sel.getAsString(), Methods[i]);
+  }
+  return (SelectedMethods.size() == 1) ? SelectedMethods[0] : NULL;
+}
+
+static void
+HelperToDiagnoseMismatchedMethodsInGlobalPool(Sema &S,
+                                              ObjCMethodList &MethList) {
+  ObjCMethodList *M = &MethList;
+  ObjCMethodDecl *TargetMethod = M->Method;
+  while (TargetMethod &&
+         isa<ObjCImplDecl>(TargetMethod->getDeclContext())) {
+    M = M->getNext();
+    TargetMethod = M ? M->Method : 0;
+  }
+  if (!TargetMethod)
+    return;
+  bool FirstTime = true;
+  for (M = M->getNext(); M; M=M->getNext()) {
+    ObjCMethodDecl *MatchingMethodDecl = M->Method;
+    if (isa<ObjCImplDecl>(MatchingMethodDecl->getDeclContext()))
+      continue;
+    if (!S.MatchTwoMethodDeclarations(TargetMethod,
+                                      MatchingMethodDecl, Sema::MMS_loose)) {
+      if (FirstTime) {
+        FirstTime = false;
+        S.Diag(TargetMethod->getLocation(), diag::warning_multiple_selectors)
+        << TargetMethod->getSelector();
+      }
+      S.Diag(MatchingMethodDecl->getLocation(), diag::note_also_found);
+    }
+  }
+}
+
+void Sema::DiagnoseMismatchedMethodsInGlobalPool() {
+  unsigned DIAG = diag::warning_multiple_selectors;
+  if (Diags.getDiagnosticLevel(DIAG, SourceLocation())
+      == DiagnosticsEngine::Ignored)
+    return;
+  for (GlobalMethodPool::iterator b = MethodPool.begin(),
+       e = MethodPool.end(); b != e; b++) {
+    // first, instance methods
+    ObjCMethodList &InstMethList = b->second.first;
+    HelperToDiagnoseMismatchedMethodsInGlobalPool(*this, InstMethList);
+    // second, class methods
+    ObjCMethodList &ClsMethList = b->second.second;
+    HelperToDiagnoseMismatchedMethodsInGlobalPool(*this, ClsMethList);
+  }
+}
+
+/// DiagnoseDuplicateIvars -
 /// Check for duplicate ivars in the entire class at the start of 
 /// \@implementation. This becomes necesssary because class extension can
 /// add ivars to a class in random order which will not be known until
@@ -2313,13 +2512,9 @@ Sema::ObjCContainerKind Sema::getObjCContainerKind() const {
   }
 }
 
-// Note: For class/category implemenations, allMethods/allProperties is
-// always null.
-Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd,
-                       Decl **allMethods, unsigned allNum,
-                       Decl **allProperties, unsigned pNum,
-                       DeclGroupPtrTy *allTUVars, unsigned tuvNum) {
-
+// Note: For class/category implementations, allMethods is always null.
+Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd, ArrayRef<Decl *> allMethods,
+                       ArrayRef<DeclGroupPtrTy> allTUVars) {
   if (getObjCContainerKind() == Sema::OCK_None)
     return 0;
 
@@ -2337,7 +2532,7 @@ Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd,
   llvm::DenseMap<Selector, const ObjCMethodDecl*> InsMap;
   llvm::DenseMap<Selector, const ObjCMethodDecl*> ClsMap;
 
-  for (unsigned i = 0; i < allNum; i++ ) {
+  for (unsigned i = 0, e = allMethods.size(); i != e; i++ ) {
     ObjCMethodDecl *Method =
       cast_or_null<ObjCMethodDecl>(allMethods[i]);
 
@@ -2504,8 +2699,8 @@ Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd,
   }
   if (isInterfaceDeclKind) {
     // Reject invalid vardecls.
-    for (unsigned i = 0; i != tuvNum; i++) {
-      DeclGroupRef DG = allTUVars[i].getAsVal<DeclGroupRef>();
+    for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
+      DeclGroupRef DG = allTUVars[i].get();
       for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
         if (VarDecl *VDecl = dyn_cast<VarDecl>(*I)) {
           if (!VDecl->hasExternalStorage())
@@ -2515,8 +2710,8 @@ Decl *Sema::ActOnAtEnd(Scope *S, SourceRange AtEnd,
   }
   ActOnObjCContainerFinishDefinition();
 
-  for (unsigned i = 0; i != tuvNum; i++) {
-    DeclGroupRef DG = allTUVars[i].getAsVal<DeclGroupRef>();
+  for (unsigned i = 0, e = allTUVars.size(); i != e; i++) {
+    DeclGroupRef DG = allTUVars[i].get();
     for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
       (*I)->setTopLevelDeclInObjCContainer();
     Consumer.HandleTopLevelDeclInObjCContainer(DG);
@@ -2911,14 +3106,9 @@ Decl *Sema::ActOnMethodDeclaration(
   if (ReturnType) {
     resultDeclType = GetTypeFromParser(ReturnType, &ResultTInfo);
 
-    // Methods cannot return interface types. All ObjC objects are
-    // passed by reference.
-    if (resultDeclType->isObjCObjectType()) {
-      Diag(MethodLoc, diag::err_object_cannot_be_passed_returned_by_value)
-        << 0 << resultDeclType;
+    if (CheckFunctionReturnType(resultDeclType, MethodLoc))
       return 0;
-    }    
-    
+
     HasRelatedResultType = (resultDeclType == Context.getObjCInstanceType());
   } else { // get the type for "id".
     resultDeclType = Context.getObjCIdType();
@@ -2945,7 +3135,7 @@ Decl *Sema::ActOnMethodDeclaration(
     QualType ArgType;
     TypeSourceInfo *DI;
 
-    if (ArgInfo[i].Type == 0) {
+    if (!ArgInfo[i].Type) {
       ArgType = Context.getObjCIdType();
       DI = 0;
     } else {
@@ -3001,14 +3191,8 @@ Decl *Sema::ActOnMethodDeclaration(
     else
       // Perform the default array/function conversions (C99 6.7.5.3p[7,8]).
       ArgType = Context.getAdjustedParameterType(ArgType);
-    if (ArgType->isObjCObjectType()) {
-      Diag(Param->getLocation(),
-           diag::err_object_cannot_be_passed_returned_by_value)
-      << 1 << ArgType;
-      Param->setInvalidDecl();
-    }
+
     Param->setDeclContext(ObjCMethod);
-    
     Params.push_back(Param);
   }
   
@@ -3034,6 +3218,12 @@ Decl *Sema::ActOnMethodDeclaration(
     if (ObjCInterfaceDecl *IDecl = ImpDecl->getClassInterface())
       IMD = IDecl->lookupMethod(ObjCMethod->getSelector(), 
                                 ObjCMethod->isInstanceMethod());
+    if (IMD && IMD->hasAttr<ObjCRequiresSuperAttr>() &&
+        !ObjCMethod->hasAttr<ObjCRequiresSuperAttr>()) {
+      // merge the attribute into implementation.
+      ObjCMethod->addAttr(
+        new (Context) ObjCRequiresSuperAttr(ObjCMethod->getLocation(), Context));
+    }
     if (ObjCMethod->hasAttrs() &&
         containsInvalidMethodImplAttribute(IMD, ObjCMethod->getAttrs())) {
       SourceLocation MethodLoc = IMD->getLocation();
@@ -3052,6 +3242,8 @@ Decl *Sema::ActOnMethodDeclaration(
     Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
       << ObjCMethod->getDeclName();
     Diag(PrevMethod->getLocation(), diag::note_previous_declaration);
+    ObjCMethod->setInvalidDecl();
+    return ObjCMethod;
   }
 
   // If this Objective-C method does not have a related result type, but we
@@ -3290,6 +3482,8 @@ void Sema::DiagnoseUseOfUnimplementedSelectors() {
       ReferencedSelectors[Sels[I].first] = Sels[I].second;
   }
   
+  DiagnoseMismatchedMethodsInGlobalPool();
+  
   // Warning will be issued only when selector table is
   // generated (which means there is at lease one implementation
   // in the TU). This is to match gcc's behavior.
@@ -3305,3 +3499,43 @@ void Sema::DiagnoseUseOfUnimplementedSelectors() {
   }
   return;
 }
+
+ObjCIvarDecl *
+Sema::GetIvarBackingPropertyAccessor(const ObjCMethodDecl *Method,
+                                     const ObjCPropertyDecl *&PDecl) const {
+  
+  const ObjCInterfaceDecl *IDecl = Method->getClassInterface();
+  if (!IDecl)
+    return 0;
+  Method = IDecl->lookupMethod(Method->getSelector(), true);
+  if (!Method || !Method->isPropertyAccessor())
+    return 0;
+  if ((PDecl = Method->findPropertyDecl())) {
+    if (!PDecl->getDeclContext())
+      return 0;
+    // Make sure property belongs to accessor's class and not to
+    // one of its super classes.
+    if (const ObjCInterfaceDecl *CID =
+        dyn_cast<ObjCInterfaceDecl>(PDecl->getDeclContext()))
+      if (CID != IDecl)
+        return 0;
+    return PDecl->getPropertyIvarDecl();
+  }
+  return 0;
+}
+
+void Sema::DiagnoseUnusedBackingIvarInAccessor(Scope *S) {
+  if (S->hasUnrecoverableErrorOccurred() || !S->isInObjcMethodScope())
+    return;
+  
+  const ObjCMethodDecl *CurMethod = getCurMethodDecl();
+  if (!CurMethod)
+    return;
+  const ObjCPropertyDecl *PDecl;
+  const ObjCIvarDecl *IV = GetIvarBackingPropertyAccessor(CurMethod, PDecl);
+  if (IV && !IV->getBackingIvarReferencedInAccessor()) {
+    Diag(getCurMethodDecl()->getLocation(), diag::warn_unused_property_backing_ivar)
+    << IV->getDeclName();
+    Diag(PDecl->getLocation(), diag::note_property_declare);
+  }
+}