RFC: JEP JDK-8208089: Implement C++14 Language Features

Volker Simonis volker.simonis at gmail.com
Mon Nov 19 08:21:08 UTC 2018


On Mon, Nov 19, 2018 at 9:00 AM Kim Barrett <kim.barrett at oracle.com> wrote:
>
> > On Nov 19, 2018, at 2:04 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
> >
> >> On Nov 19, 2018, at 1:31 AM, David Holmes <david.holmes at oracle.com> wrote:
> >> I think it is important that all the port owners buy into this.
> >
> > At least one port (aix_ppc) presently seems to have no way to support this change, because
> > the compiler being used is seriously deficient and appears to be languishing.  (It doesn’t even
> > support C++11, let alone C++14.)  I think the community could (and in my opinion, should)
> > chose to move ahead despite that.  If a new and adequate compiler is expected “soon” then
> > the community might choose to wait, or might proceed and let that port languish until the new
> > compiler is available.  I think that’s all part of the discussion that should happen around the
> > targeting of this JEP.  I hope this inadequate compiler on a relatively niche platform won’t be
> > an indefinite blocker in this area.
>
> Here’s what Volker said on the build-dev list, 2017-07-19, subject “C++11/C++14 support in XLC ?”
>
> <begin quote>
> - SAP is currently maintaining the AIX port in the OpenJDK and we're
> willing to do that in the future. But we're not IBM and we can not
> decide about the XLC feature list. If Oracle and the OpenJDK community
> finally decide to use C++11/14 features which are not available in XLC
> we have to live with that. We can either escalate the XLC deficiencies
> to IBM and suspend the port until the compiler gets fixed. Or we can
> switch the port to use the GCC tool chain with all the pros (bigger
> compatibility with Linux platforms) and cons (porting effort, testing,
> compatibility with other AIX software compiled with XLC, compiler
> support). While the GCC alternative sounds very appealing at a first
> glance it really isn't that perfect in reality, especially not for our
> commercial SAP JVM version of OpenJDK. One problem is the fact that
> there's no official support for GCC on AIX, the other is
> compatibility. Just think you had to replace Solaris Studio by GCC on
> Solaris :)
> <end quote>
>
> He had more to say on the general topic at the time.  I don’t know if anything
> has changed in the intervening nearly 1 1/2 years.
>

Not really. IBM is working on a new compiler which is in Beta now. But
neither have I tested it nor do I know exactly if it will have full
C++11/14 support.

As I wrote before, this is a chicken/egg problem which I can not solve
and I agree that it shouldn't be a blocker for OpenJDK. Therefore,
please go ahead and use whichever feature the OpenJDK community agrees
upon.

Regards,
Volker


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