RFR (M) CR 8050147: StoreLoad barrier interferes with stack usages
john.r.rose at oracle.com
Fri Aug 8 19:38:00 UTC 2014
On Aug 8, 2014, at 5:01 AM, Aleksey Shipilev <aleksey.shipilev at oracle.com> wrote:
> On 08/08/2014 02:57 AM, John Rose wrote:
>>> Vladimir pointed where to look for frame structure , but I
>>> still haven't parsed it to make an educated guess about how much to
>>> step back. Any ideas?
>> Callee saves will get spilled in the general spill area, IIRC. That
>> will be near the callee SP, which is unpredictable.
>> I don't see any area in the generic frame layout which is reliably
>> better than SP - CLSize. Maybe SP - MaxTinyImmediateOffset, or the
>> min of the two.
> Okay, let's go with this one then:
Why 8+CLSize (40/72/136) instead of just CLSize (32/64/128)?
Is there usually something hovering at sp(-8), like a frequently pushed temp?
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