Re: Moving toolchain to other host

[Rod Nussbaumer <bomr at triumf dot ca>]

Martin Guy wrote:
> On 1/22/10, Rod Nussbaumer <bomr@triumf.ca> wrote:
> >  Because I have had no end of problems getting ct-ng to build toolchains on
> > my normally designated development host (RHEL 4.X clone), I have created a
> > Debian 5.02 host for the sole purpose of running ct-ng.
>
> Well, a separate question is, what were those problems and can you
> hack ct-ng to work round them? If you can do that in a portable way it
> would save other people's time in future. However, you may not have
> the time to do that.

It isn't really so much a matter of time, as the ability to bring all of 
the support tools up time version levels required to install and run 
ct-ng. I posted a message some time ago, querying whether the stated 
versions were required, and Yann replied that indeed they are.
As I become more acquainted with ct-ng and its inner workings, I feel 
certain that I will indeed kick back some hacks.


> >  Now, the question is, can I move those toolchains over to my RHEL 4.X &/or
> > RHEL 5.X host(s), in order to compile code to run on embedded targets? The
> > Redhat boxes are presently running kernels version 2.6.9 & version 2.68.18.
>
> Like Joachim says, the kernel version in crosstool refers to the
> version of the kernel running on the target ARM host, not the one the
> crosstool-builder runs on, and is most likely to affect the building
> of the C library for the target.

Thanks. That makes sense. Can you confirm that the directory structure 
that was created by ct-ng on the original build host must be (or need 
not be) maintained on the new build host (there should be a name for 
that; how about 'refugee host'?).

And speaking of directory structures, I am still struggling with the 
nature of such directories. In the documentation, 'overview.txt', I see 
the command:
export PATH="${PATH}:/your/toolchain/path/bin"
My toolchain is in the default ${HOME}/x-tools/....
Within that tree, I can find no less than four 'bin' directories:

${HOME}/x-tools/i686-nptl-linux-gnu/bin
${HOME}/x-tools/i686-nptl-linux-gnu/i686-nptl-linux-gnu/bin
${HOME}/x-tools/i686-nptl-linux-gnu/i686-nptl-linux-gnu/sys-root/usr/bin
${HOME}/x-tools/i686-nptl-linux-gnu/i686-nptl-linux-gnu/debug-root/usr/bin

It would be nice if the doc's were a bit more explicit about which of 
these bin directories is considered to be '/your/toolchain/path/bin'. 
For the record, I've been trying to use 
'${HOME}/x-tools/i686-nptl-linux-gnu/i686-nptl-linux-gnu/bin', but I am 
unsure whether this is actually correct, and have no idea what pupose is 
served by the others. I can guess a little about the sys-root one, but 
the rest is a mystery to me.

> > Are there general rules
> > about what object code is runnable on other OS versions?
>
> As long as they use the same ABI and have the same major version of
> the same C library (almost certainly glibc) you will usually be OK.
> The kernel is usually careful to keep ABI compatability. If you do
> have a mismatch it should become evident pretty soon, like the
> binaries refusing to run at all.

Thanks for the helpful replies Martin and Joachim.

   ---   rod.


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