[Buildroot] [PATCH v2 1/5] support/scripts/gen-bootlin-toolchains: add new script to support Bootlin toolchains

[Romain Naour <romain.naour@gmail.com>]

Hello,

Le 13/08/2020 ? 23:41, Thomas Petazzoni a ?crit?:
> On Thu, 13 Aug 2020 23:21:12 +0200
> "Yann E. MORIN" <yann.morin.1998@free.fr> wrote:
> 
>>> We create a single external toolchain package, with a Kconfig "choice"
>>> as a sub-option to select the toolchain variant to be used. The script
>>> contains a Python dict that provides the mapping between the
>>> toolchains provided by toolchains.bootlin.com, and the architecture
>>> options/variants they are applicable to.  
>>
>> I think it would be much better if that metadata were to be available on
>> and served by toolchains.bootlin.com, possibly as a json blob (which
>> maps very well to, and looks very much like, the python dict). Maybe one
>> small json blurb for each toolchain.
> 
> What metadata exactly should be provided ? The only metadata that is
> not provided by toolchains.bootlin.com today is which toolchain is
> applicable to which Buildroot architecture variants.
> 
> But that is really Buildroot's business. I don't see why
> toolchains.bootlin.com should maintain that sort of metadata. What if
> then OpenEmbedded, PTXdist and OpenWrt also want to have their "custom
> metadata" stored on toolchains.bootlin.com ?

[off-topic]
Openembedded/Yocto would require a meta-bootlin-toolchain to use pre-built
Bootlin toolchains instead of internal toolchain, like for meta-arm-toolchain to
use ARM arm/aarch64 toolchains.

> 
>> That way, when you add or remove toolchains, you are also responsible
>> for updating that metadata on your side, and then the script is more
>> generic.
>>
>> Otherwise, that script will get out of sync when / if you change the
>> configuration of a toolchain (e.g. if the x86-i686 toolchain bumps to at
>> least i486 instead of i386).
> 
> Yes, I agree the script needs to be maintained, but what you're asking
> is to push the "Buildroot integration complexity" to a project that is
> in essence not related to Buildroot (beyond the fact that the
> toolchains are generated by Buildroot of course).

Toolchain-builder generate new batch of toolchain once a year (but without
promise), so the script will be occasionally used. Indeed, there is a risk to be
out of sync but Toolchain-builder is used/maintained by Buildroot users (Thomas,
Matt Weber and me) as a side project. The script will likely be updated if a
toolchain configuration is updated.

Best regards,
Romain

> 
> Best regards,
> 
> Thomas
>