Re: [HEADS UP] ar(1) front-end committed. (notes for cross compile)

On Fri, Feb 22, 2008 at 01:32:34AM -0800, David O'Brien wrote:
> On Fri, Feb 22, 2008 at 12:16:42PM +0300, Ruslan Ermilov wrote:
> > Here's the promised patch.  What it does:
> > - Switch again to using BSD ar(1) by default, but provide a knob
> >   to use GNU ar(1) as the system ar(1).  (Option WITH_BSDAR is
> >   replaced with option WITH_GNUAR.)
> > 
> > - Install BSD ar(1) as bsdar(1) with the necessary links:
> >   bsdranlib(1), ar(1), and ranlib(1) (the latter two unless we
> >   build WITH_GNUAR).
> ..
> > - ar.1 moved to bsdar.1 along with some bugfixing.
> 
> I don't quite follow what you want the end state to be.  If it is to
> quickly convert to the new BSDLed ar & ranlib, then I don't care for the
> "creatation" of a bsdar binary and manpage (below you delete
> src/usr.bin/ar/ar.1 and create bsdar.1).  The FreeBSD 8 official 'ar'
> should have its man page named "ar.1" - I don't see what is gained
> otherwise.  bsdtar could be mentioned as an example where we went this
> path - but I think bsdtar (and associated libarchive) has a large life
> outside of FreeBSD.  I really see that for 'ar'.
> 
I don't mind reverting this.

> > - Handle upgrades nicely: use GNU ar(1) during the build on older
> >   systems, and use BSD ar(1) on newer systems.
> 
> If we need GNU ar for the upgrade path - then lets just install it (and
> its manage) as gnu-ar and let that be that.
> 
I don't get you, GNU ar(1) is always installed.  Only the name is
changes.  But let me explain more about the upgrades.

Currently, we always build binutils as part of cross-tools, including
GNU ar(1) and ranlib(1).  These binaries are then used during the build.
The BSD ar(1) doesn't need to be a cross-tool -- it doesn't depend on
TARGET_ARCH/TARGET and is platform-neutral.  (I hope I'm right about it,
otherwise it all doesn't make sense and cross-builds are broken.)
We could just use /usr/bin/ar and don't bother bootstrapping it if we
knew it's a BSD ar(1) without known bugs (determined by __FreeBSD_version).
If it has compatibility issues or bugs, we can bootstrap it.
Unfortunalely, since we provide the WITH_GNUAR option, we don't know if
/usr/bin/ar and /usr/bin/ranlib are GNU or BSD versions, so we should
always bootstrap BSD ar(1).

The short version is as simple as this:

You have            You specified           ar(1) used for builds
=================== ======================= =====================

OS before bsdar     WITH_GNUAR              GNU ar
OS before bsdar     -                       GNU ar

OS after bsdar      WITH_GNUAR              GNU ar
OS after bsdar      -                       BSD ar (*)

(*) We need to bootstrap BSD ar(1) because we don't know if
/usr/bin/ar is GNU ar(1) or BSD ar(1), and GNU ar(1) for one
arch cannot be used to cross-build to a different arch.


Cheers,
-- 
Ruslan Ermilov
ru_at_FreeBSD.org
FreeBSD committer