[PATCH] linux-sparc build fixes

[Severin Gehwolf]

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.

> 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.

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