[yocto] examples / docs on utilizing an external toolchain

[Chris Larson]

On Thu, Aug 4, 2011 at 8:06 AM, Khem Raj <raj.khem at gmail.com> wrote:
> On Thursday, August 04, 2011 08:58:59 AM Gary Thomas wrote:
>> On 2011-08-04 08:49, Richard Purdie wrote:
>> > On Wed, 2011-08-03 at 23:59 -0500, Kumar Gala wrote:
>> >> On Aug 3, 2011, at 10:12 AM, Richard Purdie wrote:
>> >>> On Wed, 2011-08-03 at 09:50 -0500, Kumar Gala wrote:
>> >>>> On Aug 3, 2011, at 9:22 AM, Richard Purdie wrote:
>> >>>>> On Wed, 2011-08-03 at 09:04 -0500, Kumar Gala wrote:
>> >>>>>> Bug submitted:
>> >>>>>>
>> >>>>>> http://bugzilla.pokylinux.org/show_bug.cgi?id=1323
>> >>>>>>
>> >>>>>> My question still stands even w/o it being in formal docs.
>> >>>>>
>> >>>>> FWIW, POKYMODE was replaced by TCMODE as part of the OE-Core
>> >>>>> changes.
>> >>>>> I'd be interested to know where we've missed the references to
>> >>>>> it and
>> >>>>> get to get those references fixed.
>> >>>>
>> >>>> Ok, but how does one use TCMODE?  :)
>> >>>>
>> >>>> is there an example around anywhere?
>> >>>
>> >>> I'll explain on the condition that someone actually documents this
>> >>> ;-).
>> >>>
>> >>> TCMODE determines which of the files in
>> >>> meta/conf/distro/include/tcmode-* is used. It defaults to "default"
>> >>> and
>> >>> our default toolchain definition is in tcmode-default.inc.
>> >>>
>> >>> There is another example there which is "external-csl2008q3". As you
>> >>> can see from the tcmode-external-csl2008q3 file, it sets up the
>> >>> system to use an external toolchain instead.
>> >>>
>> >>> So you can define one of these files in your layer and then the
>> >>> system
>> >>> can select alternative toolchain configurations.
>> >>>
>> >>> Does that help? :)
>> >>>
>> >>> There is a similar TCLIBC variable which controls which libc is used
>> >>> (eglibc or uclibc).
>> >>
>> >> Yes that helps.  So it looks as if today there is not a means to point
>> >> to SDK prebuilt toolchain via this means.
>> >
>> > We have supported this in the past but it got messy and I'd really
>> > prefer people to use sstate for this.
>>
>> That would be great, if only it worked for this purpose.  Sadly, I've not
>> had much luck with sharing toolchains like this.
>>
>> Here's my problem - I have a number of different target platforms (MACHINE),
>> all of which are really the same ARM SoC (OMAP/3530==armv7a).  When I try
>> to share the sstate between them, the toolchain always rebuilds from
>> scratch.
>
> can you post bitbake -e of say gcc-cross gcc-runtime and eglibc
> for both machines ? We somehow need to figure what changes the signatures


No need to use bitbake -e, just use bitbake-diffsigs.
-- 
Christopher Larson
clarson at kergoth dot com
Founder - BitBake, OpenEmbedded, OpenZaurus
Maintainer - Tslib
Senior Software Engineer, Mentor Graphics