Howto replicate failure of 8254790?

[Viswanathan, Sandhya]

Hi Jason,

I think I found the problem looking at the error log from Vladimir Kozlov. In stringL_indexof_char() function, the following snippet is the cause of problem:

2807   bind(FOUND_CHAR);
2808   if (UseAVX >= 2) {
2809     vpmovmskb(tmp, vec3);
2810   } else {
2811     pmovmskb(tmp, vec3);
2812   }
2813   bsfl(ch, tmp);
2814   addl(result, ch);                         <====   The problem is here
2815
2816   bind(FOUND_SEQ_CHAR);
2817   subptr(result, str1);

The line addl(result, ch) should have been addptr(result, ch).

The same problem exists in the Unicode string index of char intrinsic as well and need to be fixed.

Hope this helps.

Best Regards,
Sandhya

-----Original Message-----
From: hotspot-compiler-dev <hotspot-compiler-dev-retn at openjdk.java.net> On Behalf Of Vladimir Kozlov
Sent: Thursday, October 15, 2020 3:59 PM
To: Tatton, Jason <jptatton at amazon.com>; David Holmes <david.holmes at oracle.com>; hotspot-compiler-dev at openjdk.java.net; core-libs-dev at openjdk.java.net
Subject: Re: Howto replicate failure of 8254790?

Hi Jason,

I added surrounding instructions dump from hs_err file we have so you can reconstruct x86 assembler from it.

If you look on si_addr: 0x00000000e41d2718 which case memory map failure, it looks like R8 =0x00000007e41d2700 is an
oop: [B with upper 32-bits zeroed. It seems uppers 32-bits of address were cut.

But I don't see it can happens in stringL_indexof_char() sub. You correctly used movptr() and addptr() instructions.

Vladimir K

On 10/15/20 2:10 PM, Tatton, Jason wrote:
> Thanks Vladimir and David, I have access to a new macbook with an Intel i7-9750H (supports AVX2) so I will try on that.
> 
> -----Original Message-----
> From: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> Sent: 15 October 2020 20:25
> To: David Holmes <david.holmes at oracle.com>; Tatton, Jason 
> <jptatton at amazon.com>; hotspot-compiler-dev at openjdk.java.net; 
> core-libs-dev at openjdk.java.net
> Subject: RE: [EXTERNAL] Howto replicate failure of 8254790?
> 
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
> 
> 
> 
> Note, we have old Mac machines in our testing env:
> cx8, cmov, fxsr, ht, mmx, 3dnowpref, sse, sse2, sse3, ssse3, sse4.1, 
> sse4.2, popcnt, lzcnt, tsc, tscinvbit, avx, avx2, aes, erms, clmul, 
> bmi1, bmi2, rtm, adx, fma, vzeroupper, clflush, clflushopt
> 
> Use -XX:UseAVX=2
> 
> But I was not able reproduce failure on my Skylake Linux machine even with -XX:UseAVX=2. Maybe there are other factors on MacOS.
> 
> Regards,
> Vladimir K
> 
> On 10/14/20 5:48 PM, David Holmes wrote:
>> Hi Jason,
>>
>> On 15/10/2020 10:42 am, Tatton, Jason wrote:
>>> Hi all,
>>>
>>>
>>>
>>> I am trying to replicate the failure of the tier2 test mentioned in 
>>> 8254790<https://bugs.openjdk.java.net/browse/JDK-8254790> but I am 
>>> only seeing it pass under an x86 linux machine. Are there any specific architectural constraints under which this test should be run in order to make it fail?
>>
>> It failed on a Mac, not Linux.
>>
>> Cheers,
>> David
>>
>>>
>>>
>>> I am running the test via: make test TEST="test/jdk/javax/xml/crypto/dsig/GenerationTests.java"
>>>
>>>
>>>
>>> Note that I am running the test against master without the commit:
>>> "8254792: Disable intrinsic StringLatin1.indexOf until 8254790 is fixed" which disables the intrinsic that is causing the test to fail.
>>>
>>>
>>>
>>> Thanks
>>> --
>>> Jason
>>>