[GR-21996] [GR-22875] Add guarantee about neutral header.

PullRequest: labsjdk-ce-11/98

src/hotspot/share/runtime/synchronizer.cpp

@@ -1493,7 +1493,7 @@ ObjectMonitor* ObjectSynchronizer::inflate(Thread * Self,
       // object is in the mark.  Furthermore the owner can't complete
       // an unlock on the object, either.
       markOop dmw = mark->displaced_mark_helper();
-      assert(dmw->is_neutral(), "invariant");
+      guarantee(dmw->is_neutral(), "displaced mark in " INTPTR_FORMAT "is not neutral " INTPTR_FORMAT, p2i(object), p2i(dmw));
 
       // Setup monitor fields to proper values -- prepare the monitor
       m->set_header(dmw);
@@ -1540,7 +1540,7 @@ ObjectMonitor* ObjectSynchronizer::inflate(Thread * Self,
     // An inflateTry() method that we could call from fast_enter() and slow_enter()
     // would be useful.
 
-    assert(mark->is_neutral(), "invariant");
+    guarantee(mark->is_neutral(), "mark in " INTPTR_FORMAT "is not neutral " INTPTR_FORMAT, p2i(object), p2i(mark));
     ObjectMonitor * m = omAlloc(Self);
     // prepare m for installation - set monitor to initial state
     m->Recycle();