iOS OpenJDK-11 Hotspot Arm64 & Intro

[Johan Vos]

Hi Sven,

Sorry about the delay, glad you started looking yourself already :)

As for the hotspot build: that is possible in theory (and indeed requires
some additions in os_cpu/... similar to the JDK 9 diffs), but the Apple
restrictions won't allow a JIT running on the devices.
That is why we use GraalVM native-image and the SubstrateVM as the
underlying VM, which is compiled into the final executable.

Therefore, we "only" need to have the OpenJDK core classes and native libs
being ported to iOS.

- Johan


On Mon, Jul 15, 2019 at 6:13 AM Sven Gothel <sgothel at jausoft.com> wrote:

> I have worked myself through the OpenJDK9 to
> OpenJDK9-mobile differences and also compared both with
> the OpenJDK11 source tree.
>
> Hence I answer myself for now ..
>
> On 7/9/19 6:15 AM, Sven Gothel wrote:
> >
> > I have observed Johan's work over the last months, i.e. working
> > on the openjdk-9-mobile port to openjdk-11.
> > Johan, I would love to learn about the status/result of your work
> > here - i.e. is it now possible to produce an iOS Hotspot-Arm64 build?
> > What's left to do to produce a
> >    "iOS OpenJDK-11+ Hotspot Arm64 Build"?
>
> To have a working Hotspot-Arm64 or better Hotspot-Aarch64
> build, I have added the os_cpu/bsd_aarch64 code path also
> to be used for iOS.
>
> When I successfully have brought up this build on iOS,
> I will publish these changes of course, using git.
>
> The next step might be the migration to OpenJDK11
> and maybe testing the AOT OpenJDK work later on (depending on GraalVM).
>
> ~Sven
>