[PATCH] linux-sparc build fixes

[Erik Helin]

On 06/14/2017 02:21 PM, Severin Gehwolf wrote:
> Hi Eric,
> 
> On Wed, 2017-06-14 at 13:50 +0200, Erik Helin wrote:
>> For the fourth patch, fix-zero-build-on-sparc.diff, I'm not so sure. For 
>> example, the following is a bit surprising to me (mostly because I'm not 
>> familiar with zero):
>>
>> --- a/hotspot/src/share/vm/gc/shared/memset_with_concurrent_readers.hpp
>> +++ b/hotspot/src/share/vm/gc/shared/memset_with_concurrent_readers.hpp
>> @@ -37,7 +37,7 @@
>>   // understanding that there may be concurrent readers of that memory.
>>   void memset_with_concurrent_readers(void* to, int value, size_t size);
>>
>> -#ifdef SPARC
>> +#if defined(SPARC) && !defined(ZERO)
>>
>> When this code was written, the intent was clearly to have a specialized 
>> version of this function for SPARC. When writing such code, do we always 
>> have to take into account the zero case with !defined(ZERO)?
> 
> As of now, yes I think so. The thing is that Zero is supposed to be
> architecture agnostic for the most part. That is, you can build Zero on
> x86_64, SPARC, aarch64, etc.

Ok. But if Zero is architecture agnostic, why do we have the directory
hotspot/src/cpu/zero? Sorry, I don't know much about Zero...

>> That 
>> doesn't seem like the right (or a scalable) approach to me.
> 
> Agreed. That's how it is at the moment, though.
> 
>> Severin and/or Roman, do you guys know more about Zero and how this 
>> should work? If I want to write a function that I want to specialize for 
>> e.g. x86-64 or arm, do I always have to take Zero into account? Or 
>> should some other define be used, like #ifdef TARGET_ARCH_sparc?
> 
> So the ZERO define can happen regardless of arch. I don't really know
> any define which does what you want except #if defined(<ARCH>) &&
> !defined(ZERO) perhaps.

Hmm, ok, but for the above code snippet, if we are running with Zero on
Sparc, can't we use the Sparc optimized version of
memset_with_concurrent_readers? Or can't we use Sparc assembly in the
runtime when running with Zero?

Thanks,
Erik

> Thanks,
> Severin
> 
>> Thanks,
>> Erik
>>
>> On 06/09/2017 12:20 PM, John Paul Adrian Glaubitz wrote:
>>> Hi!
>>>
>>> I am currently working on fixing OpenJDK-9 on all non-mainstream
>>> targets available in Debian. For Debian/sparc64, the attached four
>>> patches were necessary to make the build succeed [1].
>>>
>>> I know the patches cannot be merged right now, but I'm posting them
>>> anyway in case someone else is interested in using them.
>>>
>>> All patches are:
>>>
>>>     Signed-off-by: John Paul Adrian Glaubitz <glaubitz at physik.fu-berlin.de>
>>>
>>> I also signed the OCA.
>>>
>>> I'm now looking into fixing the builds on alpha (DEC Alpha), armel
>>> (ARMv4T), m68k (680x0), powerpc (PPC32) and sh4 (SuperH/J-Core).
>>>
>>> Cheers,
>>> Adrian
>>>
>>>> [1] https://buildd.debian.org/status/fetch.php?pkg=openjdk-9&arch=sparc64&ver=9%7Eb170-2&stamp=1496931563&raw=0
>