[lworld] RFR: 8242210: [lworld] TestCallingConvention::test36 spuriously fails

[Tobias Hartmann]

On Tue, 7 Apr 2020 17:11:50 GMT, Frederic Parain <fparain at openjdk.org> wrote:

>> Problems:
>> - G1 pre- and post-barriers used when (un-)packing arguments for the calling convention can call into the runtime which
>>   screws up argument registers. Save all registers until JDK-8232094 is fixed in mainline (it's the slow path anyway).
>> - SignatureStream::as_value_klass triggers a SystemDictionary lookup which acquires the ProtectionDomainSet_lock. When
>>   used from fieldDescriptor::print_on_for when some debug printing flags are enabled, this conflicts with the tty_lock.
>>   We should simply use get_value_field_klass instead. Also, we should handle null as a vale for non-flattened fields.
>>   TraceDeoptimization needs to handle re-allocation of the inline type return value.
>> 
>> I've also added a new StressCC option to the ValueTypeTest suite to randomly restrict some compilation to C1 and
>> thereby stress test the calling convention.
>
> Looks good to me, however, I haven't reviewed the tests.

Thanks, Frederic!

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PR: https://git.openjdk.java.net/valhalla/pull/13