Building a static toolchain ?

[Yann E. MORIN]

Trevor, Dimitry, All,

On Wednesday 31 March 2010 22:50:24 Dimitry Andric wrote:
> On 2010-03-31 22:37, Trevor Woerner wrote:
> > Just out of curiosity... I keep thinking about this question off and
> > on and I just can't figure out what the advantage would be to having a
> > toolchain that doesn't use the build host's language libraries. So it
> > can be copied to and run from another machine (one which may be using
> > a different version of, say, glibc)?
> - glibc is always compiled with a 'minimum supported kernel version',
> so even if you link your application statically with it, that does not
> guarantee that the application runs on any lower kernel version.
> 
> - newer glibc versions are always compatible with older glibc versions
> (on the same architecture, of course), but not the other way around.

That, plus:

- glibc has issues with NSS (Name Service Switch) when compiled statically.
  Although I don't see why a toolchain would need to resolve host or user
  names... Nice to keep in mind whenever building statically with glibc.

> So linking all toolchain executables completely static is really a tiny
> bit overkill. :)  It is mostly enough to:

I would tend to agree with you, Dimitry. But, think about this hypotetical
situation (which I do *not* condone):

- responsible for build tools, you build updated toolchains for you team,
  and make those available to all your developpers;

- you have a fast, very recent multi-core machine, so you can easily
  experiment with new toolchains, and build them *fast*; most probably,
  being a recent machine, you installed the latest (stable?) version of
  your favourite distro (Debian/Udbuntu/Fedora/...)

- OTOH, your developpers have lower-end machines, that date a few years
  back, if not more (I know some situations where this is the case, up
  to 6 year-old machines), that have not been updated, out of lazyness,
  or just because "It Works (TM)";

- so if you give them your shared-linked toolchain, Kaboom! it breaks on
  their machines...

> - build your toolchain on an "oldish" Linux distro (at least, one with
> an oldish version of glibc), such as Debian Stable or Red Hat 5, or even
> 4, if you really want to go for lowest common denominator.

Or you can do that, of course! :-) Anyone has an yggdrasil handy?

> - make sure any extra dependencies, usually libgmp and/or libmpfr,
> *are* statically linked into the toolchain executables, since not
> everybody will have those as .so files on their system, or may have
> different, incompatible versions.

Yes, and those *I* was not able to properly build statically (yet!)... :-(

Regards,
Yann E. MORIN.

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