RFR: 8222825: ARM32 SIGILL issue on single core CPU (not supported PLDW instruction)

[David Holmes]

Hi Boris,

On 16/05/2019 10:37 pm, Boris Ulasevich wrote:
> Hi David, Dean,
> 
> Yes. Thanks for waiting. I think two arm.ad rules are definitely better 
> than one with incorrect print. Now arm.ad looks very similar to the 
> state before removing obsolete AssumeMP option:
> 
> http://cr.openjdk.java.net/~bulasevich/8222825/webrev.04.jdk-jdk

ad files are not really my area but this seems okay.

One query in src/hotspot/cpu/arm/assembler_arm_32.hpp:

!     assert(!VM_Version::is_initialized() ||

I'm surprised this can be called before VM_Version is initialized. I 
presume you encountered an assertion failure without this - what was the 
call sequence that led here?

Thanks,
David

> thanks,
> Boris
> 
> On 16.05.2019 12:00, David Holmes wrote:
>> Hi Boris,
>>
>> Waiting to see if you have any response to Dean's suggestion before I 
>> push this for you.
>>
>> David
>>
>> On 14/05/2019 4:28 pm, dean.long at oracle.com wrote:
>>> This looks good.  In arm.ad, you could use two rules and a predicate, 
>>> so that the PrintOptoAssembly output is correct.
>>>
>>> dl
>>>
>>> On 5/13/19 11:04 PM, Boris Ulasevich wrote:
>>>> Hi David,
>>>>
>>>>   It took a time to test the change :)
>>>>   Yes, please. Thank you!
>>>>
>>>> Boris
>>>>
>>>> 14.05.2019 8:00, David Holmes пишет:
>>>>> Hi Boris,
>>>>>
>>>>> I was wondering what had happened to this one :)
>>>>>
>>>>> Looks good! I can sponsor for you.
>>>>>
>>>>> Thanks,
>>>>> David
>>>>>
>>>>> On 14/05/2019 2:45 pm, Boris Ulasevich wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> Please review the fix for SIGILL that happens on ARM32 CPU without 
>>>>>> Multiprocessing Extensions support (this applies to single-core 
>>>>>> arm32 processors, which are not very common this days). With the 
>>>>>> fix we check PLDW instruction availability on JVM start-up to 
>>>>>> correct further instructions generation.
>>>>>>
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8222825
>>>>>> http://cr.openjdk.java.net/~bulasevich/8222825/webrev.03.jdk-jdk
>>>>>>
>>>>>> thanks,
>>>>>> Boris
>>>>
>>>>
>>>