2 files changed, 28 insertions, 2 deletions
diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index 4ac172d1cb..e0762846dc 100644
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -613,7 +613,16 @@ PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
     // which translates to objc_storeStrong.  This isn't required, but
     // it's slightly nicer.
     } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
-      Kind = Expression;
+      // Using standard expression emission for the setter is only
+      // acceptable if the ivar is __strong, which won't be true if
+      // the property is annotated with __attribute__((NSObject)).
+      // TODO: falling all the way back to objc_setProperty here is
+      // just laziness, though;  we could still use objc_storeStrong
+      // if we hacked it right.
+      if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
+        Kind = Expression;
+      else
+        Kind = SetPropertyAndExpressionGet;
       return;
 
     // Otherwise, we need to at least use setProperty.  However, if
diff --git a/lib/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 27deab226f..8a8927d362 100644
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -43,7 +43,7 @@ static Qualifiers::ObjCLifetime getImpliedARCOwnership(
   if (attrs & (ObjCPropertyDecl::OBJC_PR_retain |
                ObjCPropertyDecl::OBJC_PR_strong |
                ObjCPropertyDecl::OBJC_PR_copy)) {
-    return type->getObjCARCImplicitLifetime();
+    return Qualifiers::OCL_Strong;
   } else if (attrs & ObjCPropertyDecl::OBJC_PR_weak) {
     return Qualifiers::OCL_Weak;
   } else if (attrs & ObjCPropertyDecl::OBJC_PR_unsafe_unretained) {
@@ -543,6 +543,23 @@ static void checkARCPropertyImpl(Sema &S, SourceLocation propertyImplLoc,
       ivarLifetime == Qualifiers::OCL_Autoreleasing)
     return;
 
+  // If the ivar is private, and it's implicitly __unsafe_unretained
+  // becaues of its type, then pretend it was actually implicitly
+  // __strong.  This is only sound because we're processing the
+  // property implementation before parsing any method bodies.
+  if (ivarLifetime == Qualifiers::OCL_ExplicitNone &&
+      propertyLifetime == Qualifiers::OCL_Strong &&
+      ivar->getAccessControl() == ObjCIvarDecl::Private) {
+    SplitQualType split = ivarType.split();
+    if (split.Quals.hasObjCLifetime()) {
+      assert(ivarType->isObjCARCImplicitlyUnretainedType());
+      split.Quals.setObjCLifetime(Qualifiers::OCL_Strong);
+      ivarType = S.Context.getQualifiedType(split);
+      ivar->setType(ivarType);
+      return;
+    }
+  }
+
   switch (propertyLifetime) {
   case Qualifiers::OCL_Strong:
     S.Diag(propertyImplLoc, diag::err_arc_strong_property_ownership)