Making (useful subsets of) bytecode portable between targets

[Manuel M T Chakravarty]

Ok, I am not saying that it is technical impossible. I am saying that it is *impractical*. 

Imagine Travis CI needing to run stuff on my phone that is attached to my Mac (if we are lucky), which is behind NAT somewhere in Australia. 

Running stuff in the simulator during a build would be pretty awkward, but running it on the device is not practical.

Manuel

PS: BTW, shipping binary code to the device means it has to be code signed using a distribution profile of a registered developer. That is one thing if Xcode does all the magic behind the scenes, but do you really want to make that part of the GHC build process?

> Edward Z. Yang <ezyang at MIT.EDU>:
> 
> At least for Travis, you can generate a private key that only Travis
> has access to, and use this to authenticate access to the runner.
> See https://docs.travis-ci.com/user/encryption-keys/
> 
> Edward
> 
> Excerpts from Manuel M T Chakravarty's message of 2016-11-24 16:38:34 +1100:
>> If you use Travis CI or such, do you really want to have a runner accessible from an arbitrary host on the Internet?
>> 
>>> Moritz Angermann <moritz at lichtzwerge.de>:
>>> 
>>> It's certainly far from ideal, but for CI, what obstacles are there besides needing a runner accessible from cross compiling machine?
>>> 
>>> E.g. Start the runner app on an iPhone plugged in into a USB power source and leave it there?
>>> 
>>> Sent from my iPhone
>>> 
>>>> On 24 Nov 2016, at 12:42 PM, Manuel M T Chakravarty <chak at justtesting.org> wrote:
>>>> 
>>>> Sorry, but I don’t think running on the device is practical. How do you want to do CI, for example?
>>>> 
>>>> Manuel
>>>> 
>>>>> Moritz Angermann <moritz at lichtzwerge.de>:
>>>>> 
>>>>> 
>>>>>> On Nov 23, 2016, at 7:50 PM, Simon Marlow <marlowsd at gmail.com> wrote:
>>>>>> 
>>>>>> […]
>>>>>> 
>>>>>> My question would be: are you *sure* you can't run target code at compile time?  Not even with an iphone simulator?
>>>>> 
>>>>> This should be possible. However for proper development one would need to run on the
>>>>> device (iPhone, iPad, …) for armv7 or arm64, as the Simulator is i386 or x86_64.
>>>>> 
>>>>> There is a bit of additional engineering required here to get the shipping of
>>>>> code from ghc to the runner on the target required (e.g. via network).  As executing
>>>>> and controlling applications on the actual hardware is limited, I guess a custom
>>>>> ghc-runner application would have to be manually started on the device, which could
>>>>> trivially be discovered using bonjour/zeroconf (or just giving ghc the host:port information).
>>>>> 
>>>>> In general though, the runner does not have to obey all the restrictions apple puts
>>>>> onto app-store distributed apps, as I expect that everyone could build and install
>>>>> the runner themselves when intending to do iOS development with ghc.
>>>>> 
>>>>> cheers,
>>>>> moritz
>>>>> _______________________________________________
>>>>> ghc-devs mailing list
>>>>> ghc-devs at haskell.org
>>>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
>>>> 
>>> 
>> 
> _______________________________________________
> ghc-devs mailing list
> ghc-devs at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs