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

[Igor Veresov]

Yes, you’re right. In fact there is a better way of doing it all. I’ll just capture the alignment value, which would be the shift value in the non-zero shift case.

Updated webrev: http://cr.openjdk.java.net/~iveresov/8173054/webrev.01/ <http://cr.openjdk.java.net/~iveresov/8173054/webrev.01/>

igor

> On Jan 19, 2017, at 10:50 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> 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
>> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20170120/e291b7b9/attachment.html>