RFR(S) 8173054: [AOT] Avoid zero-shift for compressed oops

[Vladimir Kozlov]

Thank you, Igor

I am concern with object alignment value. I think it should be 
recalculated based on shift values in AOTGraalHotSpotVMConfig().

Vladimir

On 1/19/17 6:42 AM, Igor Veresov wrote:
> AOT captures VM settings during compilation. For compressed oops it presents a problem for the case when VM selects a zero-shift mode (that depends on being able to map the heap into the lower 4G). Compiling AOT binary with zero-shift limits it's usability. The AOT compiler should be able to avoid zero-shift.
>
> Webrev: http://cr.openjdk.java.net/~iveresov/8173054/webrev.00/
>
> Thanks,
> igor
>