RFR(L): 8143211: provide bytecode intrinsics for loop and try/finally executors

[Vladimir Ivanov]

> InvokerBytecodeGenerator/IntrinsicMethodHandle: stringly typed
> localStateDesc seems like a wart to me. Since this is all package
> private, couldn't IntrinsicMethodHandle contain a @Stable Class<?>[]
> localStateTypes, then convert directly from List<MethodHandle> init to
> the class array in MethodHandleImpl::makeLoop etc:

Good point, Claes. But BasicType[] looks like a better fit.
Unfortunately, it can't be used as a key into the cache, so some 
flattening is needed.

Best regards,
Vladimir Ivanov

>
>         Class<?>[] localVarTypes = new Class<?>[init.size()];
>         for (int i = 0; i < localVarTypes.length; i++) {
>             Class<?> initRtype = init.get(i).type().returnType();
>             localVarTypes[i] =
> BasicType.basicType(initRtype).basicTypeClass();
>         }
>         LambdaForm form = makeLoopForm(type.basicType(), localVarTypes);
>
> The consuming code in InvokerBytecodeGenerator could then be simplified
> a bit on top of that: use arrays instead of List should be safe since
> it's private data that never escapes, the array from
> IntrinsicMethodHandle can be used directly when available etc.
>
> /Claes
>
> On 2016-06-20 08:49, Michael Haupt wrote:
>> ... gentle reminder ... :-)
>>
>>> Am 16.06.2016 um 15:17 schrieb Michael Haupt <michael.haupt at oracle.com>:
>>>
>>> Dear all,
>>>
>>> please review this change.
>>> RFE: https://bugs.openjdk.java.net/browse/JDK-8143211
>>> Webrev: http://cr.openjdk.java.net/~mhaupt/8143211/webrev.00/
>>>
>>> The change puts the tryFinally and loop method handle combinator
>>> implementations, which were introduced as part of the JEP 274 effort,
>>> on a LambdaForm basis, which executes in bytecode generating
>>> (default) and LambdaForm interpretation
>>> (-Djava.lang.invoke.MethodHandle.COMPILE_THRESHOLD=-1) modes. It also
>>> changes the output formatting of LambdaForms, introducing a
>>> (hopefully) more readable format.
>>>
>>> Thanks,
>>>
>>> Michael
>>
>