C2 support for reference fields in value types

[Tobias Hartmann]

Hi,

I updated the webrev to include tests for array fields in value types and fixed some minor issues:
http://cr.openjdk.java.net/~thartmann/valhalla/vt_prototype/webrev.15/

Thanks,
Tobias

On 04.05.2017 13:56, Tobias Hartmann wrote:
> Hi Roland,
> 
> I refactored the changes in nmethod.cpp and fixed some other issues. JPRT now passes:
> http://cr.openjdk.java.net/~thartmann/valhalla/vt_prototype/webrev.15/
> 
> I still need to disable the assert in ConstantPool::klass_at_impl(). In the long term, we need to find a better solution to get to the extended signature without (re-)resolving the call site in nmethod::preserve_callee_argument_oops(). I would like to push this version and then work on fixing the remaining issues.
> 
> On 27.04.2017 17:57, Roland Westrelin wrote:
>> Instead of indirecting through the adapter to get the extended
>> signature, could you instead:
>>
>> - in gen_c2i_adapter() rather than build an OopMap with all registers,
>> construct one that only contains live oops
>>
>> - then make the gc code use that oop map, maybe by not going through
>> nmethod::preserve_callee_argument_oops() at all?
> 
> I think that's not sufficient as we may not have an adapter frame on the stack but block while resolving the call in SharedRuntime::resolve_virtual_call_C().
> 
> Thanks,
> Tobias
>