8305898: Alternative self-forwarding mechanism

src/hotspot/share/oops/oop.inline.hpp

@@ -268,14 +268,14 @@ bool oopDesc::is_forwarded() const {
 // Used by scavengers
 void oopDesc::forward_to(oop p) {
   markWord m = markWord::encode_pointer_as_mark(p);
-  assert(forwardee(m) == p, "encoding must be reversable");
+  assert(forwardee(m) == p, "encoding must be reversible");
   set_mark(m);
 }
 
 void oopDesc::forward_to_self() {
   if (UseAltGCForwarding) {
     markWord m = mark();
-    // If mark is displaced, we need to preserve real header during GC.
+    // If mark is displaced, we need to preserve the real header during GC.
     // It will be restored to the displaced header after GC.
     assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
     if (m.has_displaced_mark_helper()) {
@@ -303,7 +303,7 @@ oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order orde
 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
   if (UseAltGCForwarding) {
     markWord m = compare;
-    // If mark is displaced, we need to preserve real header during GC.
+    // If mark is displaced, we need to preserve the real header during GC.
     // It will be restored to the displaced header after GC.
     assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
     if (m.has_displaced_mark_helper()) {
@@ -319,7 +319,7 @@ oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order)
       return forwardee(old_mark);
     }
   } else {
-    return forward_to_atomic(oop(this), compare, order);
+    return forward_to_atomic(cast_to_oop(this), compare, order);
   }
 }