RE: configure-build ?

[Jay <jay dot krell at cornell dot edu>]

sorry, forgot to do plain text again..so this and Paulo's response out of order..
(since it bounced to the list but not to him..) 


________________________________

From: jay.krell@cornell.edu
To: bonzini@gnu.org
CC: gcc@gcc.gnu.org
Subject: RE: configure-build ?
Date: Mon, 15 Sep 2008 11:24:44 +0000




--disable-libiconv, really?
There is configuration stuff related to libiconv, but it isn't so simple/clear.
Building on a system without libiconv appears to just work (except maybe libjava),
but what I want to do is build on a system with libiconv but without that dependency.
I have it working, by patching up the Makefile's after configuration.

> But, do not distribute/install that, it would be too slow for *users*.

Understood.
(all my systems are single-user, so I'll install.)

Actually I might be distributing this too a small number of folks already.
I can fix that if it's really not popular here. (users didn't notice)

> (--disable-bootstrap)

Yep, I've been doing that.
That helps /a lot/.
I'm also looking to eliminating rebuilding some stuff, when building
multiple configurations e.g. if host is the same and target varies,
don't need to keep building liberty, and maybe speeding up Cygwin fork a lot.
More "advanced", would be nice if -enable-all-targets worked, at least for binutils.
It does somewhat, but not quite. It does work for libbfd, at least with
patching out some broken targets (tic), but not ld and gas.
Gas just seems to need to be told what format to output, which could probably
be a simple command line option. ld I didn't look at.

Anyone thinking seriously of the likes of:
 gcc -c 1.c 2.c 3.c

writing out three .o files directly, without creating any processes, not going through gas,
and either linking cc1 into gcc, or using .so files?

I realize most Makefiles are not setup to take full advantage of that but still...

I realize .so files might be "scary" and that linking it all together breaks extensibility
that is in there, separatly installing other compilers.

> BOOT_CFLAGS=-g

I think that misses a lot, but I'm not certain.
e.g.:
  LIBGCC2_CFLAGS
  CRTSTUFF_CFLAGS
  building ada/s-assert.o (though I'm not building Ada lately)
  GNATLIBCFLAGS (ditto)
  FCFLAGS (analogous ditto)

Granted, the first two probably apply to very little code.

Anyway, I can imagine the real point of even allowing turning it off for "bootstrap" is
because the bootstrap compiler could be relatively buggy and avoiding its optimizer
is probably a good way to avoid most of the bugs.

But still, in case I have to debug anything...
Actually there is something I need to debug.
And I can understand, narrow down which source/.o files you want to debug and
rebuild just them without -O2.

Thanks,
- Jay