iOS OpenJDK-11 Hotspot Arm64 & Intro

[Sven Gothel]

Hi Johan,

thank you for your reply, mine inline ..

On 7/15/19 11:53 AM, Johan Vos wrote:
> 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), 
Yes, thank you.

> 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.
I replied on this issue in a separate email on this mailinglist,
as it seemingly be the case that Apple is no more hindering a
self contained VM technology on the Apple store,
so we may debate this in that thread to keep the legal debate separate.

However, AOT has also technical benefits of course and IMHO
the use case may decide which path favors the application more.

In this sense, yes, the AOT 'hook' for GraalVM and SubstraatVM would be
a next thing for me to look at.

For now, I go step by step to produce a Hotspot-Aarch64 for iOS,
which may also be used for BSD in general (FreeBSD, OpenBSD?).

> 
> Therefore, we "only" need to have the OpenJDK core classes and native libs
> being ported to iOS.
Knowing your priorities, this is very sensible.

Thank you Johan.

~Sven

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