RFR(S) 8231756: [JVMCI] need support for deoptimizing virtual byte arrays encoding non-byte primitives

[Tom Rodriguez]

Vladimir Kozlov wrote on 4/3/20 5:41 PM:
> I think new code in deoptimize.cpp should be JVMCI specific.
> 
> I filed 8242150 for serviceability tests failures in testing. It seems 
> caused by recent changes.
> 
> It is weird to see SPARC_32 checks in deoptimization.cpp which we should 
> not have in new code:
> 
> #ifdef _LP64
>          jlong res = (jlong) *((jlong *) &val);
> #else
> #ifdef SPARC
>        // For SPARC we have to swap high and low words.
> 
> We don't support such configuration for eons.

Currently there are 3 places in deoptimization.cpp that handle sparc 32 
bit, like 
http://hg.openjdk.java.net/jdk/jdk/file/tip/src/hotspot/share/runtime/deoptimization.cpp#l1084. 
  Should remove those and the logic in my new code?  output.cpp appears 
to have a case as well.

> 
> I don't see  where _support_large_access_byte_array_virtualization  is 
> checked. If it is only in Graal then it should be guarded by #if.

I'll add the requested ifdefs.

tom

> 
> Thanks,
> Vladimir
> 
> On 4/3/20 12:37 PM, Tom Rodriguez wrote:
>>
>>
>> Vladimir Kozlov wrote on 4/3/20 10:31 AM:
>>> Hi Tom,
>>>
>>> I looked on testing results and one test fails consistently:
>>>
>>> compiler/jvmci/jdk.vm.ci.hotspot.test/src/jdk/vm/ci/hotspot/test/VirtualObjectLayoutTest.java 
>>
>>
>> Sorry that was an old mach5 run and I forgot to update with the new 
>> one.  There are some failures but they seem unrelated to me.
>>
>> tom
>>
>>>
>>>
>>> Vladimir K
>>>
>>> On 4/2/20 12:12 PM, Tom Rodriguez wrote:
>>>> http://cr.openjdk.java.net/~never/8231756/webrev
>>>> https://bugs.openjdk.java.net/browse/JDK-8231756
>>>>
>>>> This adds support for deoptimizing with non-byte primitive values 
>>>> stored on top of a byte array, similarly to the way that a double or 
>>>> long can be stored on top of 2 int fields.  More detail is provided 
>>>> in the bug report and new unit tests exercise the deoptimization.  
>>>> mach5 testing is in progress.
>>>>
>>>> tom