[yocto] External toolchains

[Khem Raj]

On Tue, Jul 7, 2015 at 10:35 AM, Luke (Lucas) Starrett
<lstarret at broadcom.com> wrote:
> Hi,
>
>
>
> For various reasons, we have a need to work with pre-compiled external
> toolchains, in this case, the 2014-09 Linaro aarch64 release.  A key
> difference between this specific toolchain vs. the Fido/1.8 out of the box
> toolchain (4.9.2 + patches?), is that the Linaro version is built with
> --enable-multiarch.  We end up with applications built with search paths
> such as /lib/aarch64, /usr/lib/aarch64, etc,  but libraries installed in the
> normal /lib, /usr/lib paths.  Obviously if we use the built-in toolchain
> recipes in 1.8, life is good, search paths match install paths.
>
>
>
> I wanted to understand a couple points.
>
>
>
> 1)      What are the long term goals/roadmap are in this area specific to
> Yocto/OE?

OE provides provisions to hook in external toolchain thats where it
ends. Its a moving target since the specifics of internal toolchain
and metadata
change all the time, so external toolchain recipe has to constantly modify.

>
> 2)      Where is the “right” place to deal with this?

external toolchain providers they need to keep it in sync

>
> a.       Configure (based on detected toolchain capability)



>
> b.      Install (override library destination?)
>
> c.       Other?
>
> 3)      Any other examples that can be used as a reference?
>
>
> I’ve seen a few emails in the archives that seem to touch on this, but none
> that really seemed to come to any conclusion.


there is external-sourcery-toolchain recipe that you can use as
template, but since people generate toolchains
with different infrastructures and options its simply not a
supportable model, it never ends and cant be defined.