diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index d39679c..d90bd92 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -812,7 +812,7 @@
   Res.push_back("-fobjc-runtime=" + Opts.ObjCRuntime.getAsString());
   if (Opts.ObjCAutoRefCount)
     Res.push_back("-fobjc-arc");
-  if (Opts.ObjCRuntimeHasWeak)
+  if (Opts.ObjCARCWeak)
     Res.push_back("-fobjc-runtime-has-weak");
   if (!Opts.ObjCInferRelatedResultType)
     Res.push_back("-fno-objc-infer-related-result-type");
@@ -1941,13 +1941,15 @@
       Opts.setGC(LangOptions::HybridGC);
     else if (Args.hasArg(OPT_fobjc_arc)) {
       Opts.ObjCAutoRefCount = 1;
-      if (!Opts.ObjCRuntime.isNonFragile())
-        Diags.Report(diag::err_arc_nonfragile_abi);
-    }
+      if (!Opts.ObjCRuntime.allowsARC())
+        Diags.Report(diag::err_arc_unsupported_on_runtime);
 
-    Opts.ObjCRuntimeHasWeak = Opts.ObjCRuntime.hasWeak();
-    if (Args.hasArg(OPT_fobjc_runtime_has_weak))
-      Opts.ObjCRuntimeHasWeak = 1;
+      // Only set ObjCARCWeak if ARC is enabled.
+      if (Args.hasArg(OPT_fobjc_runtime_has_weak))
+        Opts.ObjCARCWeak = 1;
+      else
+        Opts.ObjCARCWeak = Opts.ObjCRuntime.allowsWeak();
+    }
 
     if (Args.hasArg(OPT_fno_objc_infer_related_result_type))
       Opts.ObjCInferRelatedResultType = 0;