RFR: 8171853: Remove Shark compiler

Roman Kennke rkennke at redhat.com
Sun Oct 15 20:52:43 UTC 2017

Am 15.10.2017 um 22:44 schrieb John Paul Adrian Glaubitz:
> On 10/15/2017 10:34 PM, Roman Kennke wrote:
>>> It's a pity that this value is not seen within the OpenJDK project.
>> Yes, I agree with you. However, at this point, fixing Shark amounts 
>> to almost
>> complete rewrite of it. It would nowadays be based on jvmci. It would 
>> use the
>> new and presumably much better JIT interface of LLVM. It would not 
>> use a shadow
>> stack and a sane interface between LLVM and the GC (which hasn't 
>> existed back then).
> Ok, that gives me some consolation, although I'm still sad about this 
> decision.
>> It's a project I'd personally like to do just for the fun of it, but 
>> I simply don't
>> have enough time and the nerve to pull it off alone. In any case, as 
>> I said, it
>> would probably make sense to start it from scratch.
> FWIW, there are actually quite a number of users for Zero who would be 
> happy to
> have a JIT-version of it. One major user for Zero is MIPS (big-, 
> little-endian,
> 32 and 64 bit) which still doesn't have a native code generator in 
> Hotspot.
> But we're also using Zero on architectures like m68k (yes, that still 
> exists
> as people are upgrading their Amigas and Ataris with fast FPGA 
> accelerators)
> and SuperH and it works fine.
And here is another complication: the last time I checked, the LLVM JIT 
only support very few platforms. I don't remember from the top off my 
head, but I'm pretty sure it's a subset of those supported natively by 
hotspot now (x86, arm and probably ppc). I doubt that MIPS and m68k are 
on the list of LLVM JIT supported platforms. A quick search yields no 
current information about this though.

> I have also contributed several patches already to get Zero into a better
> shape which allows it to build within Debian without additional patches,
> I would definitely be interested in helping with a new Shark JVM although
> I understand that would be a bigger project :).
Ok cool! If/when I ever get to do it (or somebody else) this will be 
very welcome :-)

Cheers, Roman

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