[yocto] examples / docs on utilizing an external toolchain

[Gary Thomas]

On 2011-08-04 09:29, Chris Larson wrote:
> 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.

How do I use this?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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