[lworld] RFR: 8343554: [lworld] VM crashes when running runtime/valhalla/inlinetypes/InlineOops.java with ZGC in interpreted mode

[Axel Boldt-Christmas]

On Wed, 4 Dec 2024 16:52:33 GMT, David Simms <dsimms at openjdk.org> wrote:

> Don't use HeapAccess for frame roots

src/hotspot/share/prims/whitebox.cpp line 1988:

> 1986: 
> 1987:   void do_oop(oop* o) { add_oop(*o); }
> 1988:   void do_oop(narrowOop* v) { add_oop(CompressedOops::decode(*v)); }

I think we rarely do this directly but let RawAccess handle the load and decode. 
Suggestion:

  void do_oop(oop* o) { add_oop(RawAccess<>::oop_load(o)); }
  void do_oop(narrowOop* v) { add_oop(RawAccess<>::oop_load(v)); }


and the most common way to write oop closures which are used in both oop and narrowOop contexts:
```c++
  template <class T>
  void do_oop_work(T* p) {
    oop o =  RawAccess<>::oop_load(p); 
    // Do the work
  }
  void do_oop(oop* o) { do_oop_work(o); }
  void do_oop(narrowOop* v) { do_oop_work(v); }

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1313#discussion_r1870726909