State of x86_32 port of JEP 425: Virtual Threads (Preview)

[dean.long at oracle.com]

On 6/15/22 9:54 AM, Aleksey Shipilev wrote:
> (I *suspect* that somewhere we stash the "current" thread onto stack, 
> and then remount to another thread, which makes "current" thread 
> obsolete. Assuming current thread does not change is quite pervasive, 
> and saving "current thread" on architectures without dedicated thread 
> register is rather common.)

That does sound like a problem.  I noticed that 
SharedRuntime::generate_native_wrapper() does this:

1554    // We use rdi as a thread pointer because it is callee save and
1555    // if we load it once it is usable thru the entire wrapper
1556    const Register thread = rdi;

This comment seems wrong for loom.

dl