[16] RFR 8248227: Shenandoah: Refactor Shenandoah::heap() to match other GCs

[Aleksey Shipilev]

On 6/29/20 3:29 PM, Zhengyu Gu wrote:
> Hi Aleksey,
> 
> On 6/29/20 3:04 AM, Aleksey Shipilev wrote:
>> On 6/24/20 2:18 PM, Zhengyu Gu wrote:
>>> Please review this small patch that refactors Shenandoah::heap() to
>>> match other GCs.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8248227
>>> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8248227/webev.00/index.html
>>
>> Wait. We do the same thing as ZHeap::heap(). This patch clashes with the intent of JDK-8241743. At
>> very least we have to prove it compiles down to the same.
>>
> 
> Based on comments of JDK-8247740, it intends to make the call inline-able.
> 
> ZGC is different story, it is not derived from CollectedHeap.
> 
> I checked a few places, it does seem to inline ShenandoahHeap::heap() 
> calls, e.g.
> 
>     0x00007ffff780c29c <+28>:	push   %rbx
>     0x00007ffff780c29d <+29>:	sub    $0x48,%rsp
>     0x00007ffff780c2a1 <+33>:	lea    0x54e8c8(%rip),%rax        # 
> 0x7ffff7d5ab70 <_ZN14ShenandoahHeap5_heapE>
>     0x00007ffff780c2a8 <+40>:	mov    (%rax),%rbx

OK then! Looks good.

-- 
Thanks,
-Aleksey