[yocto] examples / docs on utilizing an external toolchain

[Khem Raj]

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

> A lot of other packages do seem to share state properly, e.g.
> busybox built for these platforms uses sstate well, but not so with
> toolchains.
> 
> Is there any way for this to work?  I'd love to be able to hand my customers
> a set of sstate files for the things they don't really need to rebuild and
> the toolchains are a giant part of it.  If this should work and the current
> failures a bug, I'll report it as such.
> 
> Thanks
-- 
Khem Raj