[9] RFR (S): 8148994: Replacing MH::invokeBasic with a direct call breaks LF customization

[Vladimir Ivanov]

Good catch, Chris. Removed:
   http://cr.openjdk.java.net/~vlivanov/8148994/webrev.01/

Best regards,
Vladimir Ivanov

On 2/4/16 8:25 PM, Christian Thalinger wrote:
> While you are in there can you remove this line a few lines above:
>
>   828         guarantee(!target->is_method_handle_intrinsic(), "should not happen");  // XXX remove
>
> I think it’s proven that it doesn’t trigger (I’ve added that guarantee a looooong time ago).
>
>> On Feb 4, 2016, at 7:51 AM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
>>
>> http://cr.openjdk.java.net/~vlivanov/8148994/webrev.00
>> https://bugs.openjdk.java.net/browse/JDK-8148994
>>
>> JDK-8072008 [1] introduced an optimization to bypass linker calls in generated code when target method can't be inlined.
>>
>> Unfortunately, it doesn't work well with MH::invokeBasic(), because it clashes with LambdaForm customization: if a call is not inlined, it is important for performance to update (customize) corresponding LambdaForm on-the-fly. MH::invokeBasic() linker does MH -> LF -> Method* -> _from_compiled_entry traversal on every invocation, while direct call points right to the _from_compiled_entry. So, any LambdaForm updates aren't visible until recompilation.
>>
>> The fix is to keep MH::invokeBasic linker, so up-to-date LambdaForm instance is used on every invocation.
>>
>> Also, cleaned up relevant tests a bit.
>>
>> Testing: octane, JPRT.
>>
>> Best regards,
>> Vladimir Ivanov
>>
>> [1] https://bugs.openjdk.java.net/browse/JDK-8072008
>>     "Emit direct call instead of linkTo* for recursive indy/MH.invoke* calls"
>