-B${prefix} during bootstrap

-B${prefix} during bootstrap

[Phil Edwards]

Something that's bothered me for years that I'm just now asking...

Why is -B$prefix passed to the stage1 compiler when building the stage2
compiler?  If $prefix isn't there yet (normal when bootstrapping, I would
think), then what's the point?

When bootstrapping with a previous gcc installed in the same $prefix, I
once ended up with a permanently buggy toolchain.  Some back-end binary
was being picked up because of this, and propogating its bugs into the
newly-bootstrapped compiler.  Installing the new compiler over the old
one didn't fix the bug (the goal of the exercise).  Lather, rinse, repeat.
(Thank goodness for prebuilt binaries.)

It was long enough ago that I don't remember details, and I didn't understand
the nature of the bug.  Once the problem with -B was pointed out to me
(some kind soul on a mailing list), I started using different $prefix'es
for every build, but always wondered what the rationale for this was.


Phil

-- 
pedwards at disaster dot jaj dot com  |  pme at sources dot redhat dot com
devphil at several other less interesting addresses in various dot domains
The gods do not protect fools.  Fools are protected by more capable fools.

Re: -B${prefix} during bootstrap

[Alexandre Oliva]

On Sep 21, 2000, Phil Edwards <pedwards@disaster.jaj.com> wrote:

> Why is -B$prefix passed to the stage1 compiler when building the stage2
> compiler?  If $prefix isn't there yet (normal when bootstrapping, I would
> think), then what's the point?

The point is that sometimes it is there, and you actually need that to
get pre-installed headers.  This is essential for a GCC+glibc
bootstrap.

> When bootstrapping with a previous gcc installed in the same $prefix, I
> once ended up with a permanently buggy toolchain.

This is no longer the case.  The -B flags are now given in the right
order.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me

Re: -B${prefix} during bootstrap

[Phil Edwards]

On Fri, Sep 22, 2000 at 03:40:11PM -0300, Alexandre Oliva wrote:
> 
> This is essential for a GCC+glibc
> bootstrap.

Ah.  That's good to know.  Thanks!

Phil

-- 
pedwards at disaster dot jaj dot com  |  pme at sources dot redhat dot com
devphil at several other less interesting addresses in various dot domains
The gods do not protect fools.  Fools are protected by more capable fools.

Re: -B${prefix} during bootstrap

[Jeffrey A Law]

  In message < 20000921150050.A11167@disaster.jaj.com >you write:
  > Something that's bothered me for years that I'm just now asking...
  > 
  > Why is -B$prefix passed to the stage1 compiler when building the stage2
  > compiler?  If $prefix isn't there yet (normal when bootstrapping, I would
  > think), then what's the point?
Sometimes $prefix is there and sometimes it has programs we want to use
during the bootstrapping process.

jeff