diff --git a/js/src/builtin/Object.cpp b/js/src/builtin/Object.cpp
index 5e8e4e246e0..fe1f61ea7ca 100644
--- a/js/src/builtin/Object.cpp
+++ b/js/src/builtin/Object.cpp
@@ -736,13 +736,14 @@ obj_create(JSContext *cx, unsigned argc, Value *vp)
 static JSBool
 obj_getOwnPropertyDescriptor(JSContext *cx, unsigned argc, Value *vp)
 {
+    CallArgs args = CallArgsFromVp(argc, vp);
     RootedObject obj(cx);
     if (!GetFirstArgumentAsObject(cx, argc, vp, "Object.getOwnPropertyDescriptor", &obj))
         return JS_FALSE;
     RootedId id(cx);
-    if (!ValueToId(cx, argc >= 2 ? vp[3] : UndefinedValue(), &id))
+    if (!ValueToId(cx, args.length() > 1 ? args[1] : UndefinedValue(), &id))
         return JS_FALSE;
-    return GetOwnPropertyDescriptor(cx, obj, id, vp);
+    return GetOwnPropertyDescriptor(cx, obj, id, args.rval());
 }
 
 static JSBool
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 046818235c0..e47d1dab7f1 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -4162,7 +4162,11 @@ JS_GetOwnPropertyDescriptor(JSContext *cx, JSObject *objArg, jsid idArg, jsval *
     AssertHeapIsIdle(cx);
     CHECK_REQUEST(cx);
 
-    return GetOwnPropertyDescriptor(cx, obj, id, vp);
+    RootedValue value(cx);
+    if (!GetOwnPropertyDescriptor(cx, obj, id, &value))
+        return false;
+    *vp = value;
+    return true;
 }
 
 static JSBool
diff --git a/js/src/jsobj.cpp b/js/src/jsobj.cpp
index a3894f895f4..9da60b38dcb 100644
--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -293,11 +293,11 @@ js::GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id,
 }
 
 bool
-js::GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id, Value *vp)
+js::GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp)
 {
     AutoPropertyDescriptorRooter desc(cx);
     return GetOwnPropertyDescriptor(cx, obj, id, &desc) &&
-           NewPropertyDescriptorObject(cx, &desc, vp);
+           NewPropertyDescriptorObject(cx, &desc, vp.address());
 }
 
 bool
diff --git a/js/src/jsobj.h b/js/src/jsobj.h
index bce2fbe60e7..9920d949cea 100644
--- a/js/src/jsobj.h
+++ b/js/src/jsobj.h
@@ -1312,7 +1312,7 @@ bool
 GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id, PropertyDescriptor *desc);
 
 bool
-GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id, Value *vp);
+GetOwnPropertyDescriptor(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp);
 
 bool
 NewPropertyDescriptorObject(JSContext *cx, const PropertyDescriptor *desc, Value *vp);