RFR: 8171853: Remove Shark compiler

[Andrew Haley]

On 15/10/17 21:26, John Paul Adrian Glaubitz wrote:

> On 10/15/2017 12:41 AM, Roman Kennke wrote:
>> The JEP to remove the Shark compiler has received exclusively positive
>> feedback (JDK-8189173) on zero-dev. So here comes the big patch to remove it.
> 
> I have now read through the JEP and I have to say, I'm sad to see
> Shark go.
> 
> In my opinion, Shark should be a supported version of the JVM as
> LLVM is gaining code generation support for more and more
> architectures. I have always liked the idea to split out the code
> generation of compilers into a separate project and, in fact, the
> compilers for many other languages like Rust and Julia rely on LLVM.

There's no reason that something like Shark couldn't be written again,
but the problem at the time was that LLVM was a work in flux, and its
interface to the JIT continually mutated.  In addition, each LLVM
version had bugs which broke HotSpot; these bugs would be fixed in the
next version, but the next version had more bugs which broke HotSpot.
It was impossible to keep it working.

> It's a pity that this value is not seen within the OpenJDK project.

It's seen, for sure.  Otherwise I wouldn't have wanted us to do it.

There's no reason something like Shark couldn't be done again, but you
wouldn't start from here.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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