[External] : Re: Rename jdk.internal.vm.compiler to jdk.compiler.graal

[Foivos Zakkak]

Hi Doug,

Thanks for the additional information.

Given there are indeed no other JVMCI consumers other than Graal (at least
known to us) I see how it might not be worth maintaining as a generic API
and making it Graal-specific would make things easier.

Foivos

On Fri, Oct 20, 2023 at 3:02 PM Douglas Simon <doug.simon at oracle.com> wrote:

> Hi Foivos,
>
> JVMCI is not a general API but has always been somewhat Graal specific.
> Project Galahad is demonstrating this strong coupling and taking the next
> logical step which is to move Graal into the JDK. At that point, we will
> strongly consider positioning JVMCI as JDK internal only.
>
> Note that projects such as Tornado VM rely on Graal, not just JVMCI.
> Without this proposed change, these projects would no longer work with
> OpenJDK. I would recommend that any project wanting to develop a Java based
> compiler for OpenJDK, follow the pattern of Tornado VM and build on Graal
> instead of JVMCI.
>
> -Doug
>
> > On 20 Oct 2023, at 10:59, Foivos Zakkak <fzakkak at redhat.com> wrote:
> >
> > Hi Doug,
> >
> > On Thu, Oct 19, 2023 at 5:45 PM Douglas Simon <doug.simon at oracle.com>
> wrote:
> > Adding galahad-dev at openjdk.org <mailto:galahad-dev at openjdk.org> to the
> thread.
> >
> > > On 19 Oct 2023, at 16:38, Douglas Simon <doug.simon at oracle.com> wrote:
> > >
> > > Within the last year or so, the Graal team have been making large
> structural changes to the Graal code base to prepare for merging it into
> OpenJDK under Project Galahad. It’s important to make these structural
> changes prior to merging the sources into OpenJDK as they typically involve
> changes to a large number of files. For example, all code in the
> jdk.internal.vm.compiler module was consolidated into a single source
> directory using the standard OpenJDK layout[1]. The commit for this change
> alone had 3,481 changed files, 317 additions and 1,759 deletions.
> > >
> > > The above change could be made without any JDK changes. The next large
> change being undertaken is to rename the jdk.internal.vm.compiler module to
> jdk.compiler.graal[4]. Due to the way Java modules work, this does require
> a JDK change. The details are in
> https://bugs.openjdk.org/browse/JDK-8318027 but the core of the issue is
> that the service[2] by which HotSpot can request a Graal compilation is
> defined in JVMCI and implemented by Graal. Since this service is in the
> boot layer, it can only be implemented by a provider in the boot layer.
> This export currently targets jdk.internal.vm.compiler[3] and so the
> binding will fail once the Graal module is renamed. That is, an export to
> jdk.compiler.graal is required.
> > >
> >
> > My concern is that this change means that moving forward any
> implementation of a compiler through JVMCI will have to provide the module
> jdk.compiler.graal instead of jdk.internal.vm.compiler. I am afraid this
> move is making JVMCI look Graal-specific which to my understanding was
> never the goal [1] despite its implementation being mostly Graal-driven in
> practice.
> >
> > Has this been considered?
> >
> > Thanks,
> >
> > [1] https://openjdk.org/jeps/243
> > > The plan here is to replace the export to jdk.internal.vm.compiler
> with jdk.compiler.graal. This will allow OpenJDK binaries to keep working
> with the Graal code base post renaming. That is, it will allow the tip of
> Graal to continue working with the tip of OpenJDK, something that is
> important on the path to merging these 2 projects.
> > >
> > > Please leave feedback by replying to this email or with comments on
> https://github.com/openjdk/jdk/pull/16189
> > >
> > > -Doug
> > >
> > > [1]
> https://github.com/oracle/graal/commit/8be56121aa31e7448b4adb0224ab2ac44095ed9b
> > > [2]
> https://github.com/openjdk/jdk/blob/56aa1e8dc8047cbc29d554889c64beb6eca0b8eb/src/jdk.internal.vm.ci/share/classes/module-info.java#L37
> > > [3]
> https://github.com/openjdk/jdk/blob/56aa1e8dc8047cbc29d554889c64beb6eca0b8eb/src/jdk.internal.vm.export
> to jdk.compiler.graalexport to
> jdk.compiler.graalci/share/classes/module-info.java#L28
> > > [4] https://github.com/oracle/graal/pull/7621
> >
> >
> >
> >
> > --
> > Foivos Zakkak
> > Senior Software Engineer, R&D Product Middleware
> > Red Hat
> > 7B4069D929BAAE91C0B3220A0846BFD103F04EA1
>
>

-- 
Foivos Zakkak
Senior Software Engineer, R&D Product Middleware
Red Hat
7B4069D929BAAE91C0B3220A0846BFD103F04EA1
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