RFR (M): (x86) Fix up and refactor store checks

[Roman Kennke]

Am 25.04.2017 um 22:02 schrieb Aleksey Shipilev:
> On 04/25/2017 08:31 PM, Aleksey Shipilev wrote:
>> Hi,
>>
>> With Verify{Reads|Writes} purged, the only way for us to verify store invariants
>> is compiler-assisted checks. Which means we would like make them work better
>> than they are now.
>>
>> This is the update:
>>   http://cr.openjdk.java.net/~shade/shenandoah/store-check-refactor/webrev.01/
> 
> Roman had remembered (offline) that there is a reason for a combined check: we
> should only do val_checks for targets in heap, because we accept from-refs
> stores to roots, as they would be fixed up later.
> 
> Accepted this by doing a light-weight in_heap_check in val_check:
>   http://cr.openjdk.java.net/~shade/shenandoah/store-check-refactor/webrev.02/
> 
> Thanks,
> -Aleksey
> 

Ok