RFR (S) 8249938: Move mirror oops from Universe into OopStorage

[Ioi Lam]

On 7/23/20 10:05 AM, coleen.phillimore at oracle.com wrote:
> Summary: Save and restore mirror oops to temporary array for CDS, and 
> move them to OopStorage once restored.
>
> This is a subtask of moving oops out of Universe.  I ran performance 
> tested of this and there is no performance change. Some slight 
> decrease in number of instructions (improvement!) in Perfstartup-Noop 
> that were flagged as significant - 0.10%
>
> Tested with mach5 tier1-3.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/2020/8249938.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8249938
>
> Thanks,
> Coleen

Hi Coleen,

The changes looks good. I think Universe::serialize() can be simplified 
as (not tested):

void Universe::serialize(SerializeClosure* f) {

#if INCLUDE_CDS_JAVA_HEAP
   {
     oop mirror_oop;
     for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
       if (f->is_reading()) {
         f->do_oop(&mirror_oop); // read from archive
         _mirrors[i] = OopHandle(vm_global(), mirror_oop);
       } else {
         mirror_oop = _mirrors[i].resolve();
         f->do_oop(&mirror_oop); // write to archive
       }
       if (mirror_oop != NULL) { // may be null if archived heap is disabled
java_lang_Class::update_archived_primitive_mirror_native_pointers(mirror_oop);
       }
     }
   }
#endif

Thanks
- Ioi