--- old/src/hotspot/share/oops/oop.inline.hpp	2019-08-20 10:52:35.900905175 +0200
+++ new/src/hotspot/share/oops/oop.inline.hpp	2019-08-20 10:52:35.676901720 +0200
@@ -82,11 +82,11 @@
 }
 
 void oopDesc::init_mark() {
-  set_mark(markWord::prototype_for_object(this));
+  set_mark(markWord::prototype_for_klass(klass()));
 }
 
 void oopDesc::init_mark_raw() {
-  set_mark_raw(markWord::prototype_for_object(this));
+  set_mark_raw(markWord::prototype_for_klass(klass()));
 }
 
 Klass* oopDesc::klass() const {
@@ -483,4 +483,34 @@
   mark_raw().set_displaced_mark_helper(m);
 }
 
+// Supports deferred calling of obj->klass().
+class DeferredObjectToKlass {
+  const oopDesc* _obj;
+
+public:
+  DeferredObjectToKlass(const oopDesc* obj) : _obj(obj) {}
+
+  // Implicitly convertible to const Klass*.
+  operator const Klass*() const {
+    return _obj->klass();
+  }
+};
+
+bool oopDesc::mark_must_be_preserved() const {
+  return mark_must_be_preserved(mark_raw());
+}
+
+bool oopDesc::mark_must_be_preserved(markWord m) const {
+  // There's a circular dependency between oop.inline.hpp and
+  // markWord.inline.hpp because markWord::must_be_preserved wants to call
+  // oopDesc::klass(). This could be solved by calling klass() here. However,
+  // not all paths inside must_be_preserved calls klass(). Defer the call until
+  // the klass is actually needed.
+  return m.must_be_preserved(DeferredObjectToKlass(this));
+}
+
+bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
+  return m.must_be_preserved_for_promotion_failure(DeferredObjectToKlass(this));
+}
+
 #endif // SHARE_OOPS_OOP_INLINE_HPP