[Clfs-dev] Improvement suggestion for Embedded CLFS (for mips)

[Andrew Bradford]

2011/4/27 Aleksander Wabik <alex.wabik at gmail.com>:
>>2011/4/23 Aleksander Wabik <alex.wabik at gmail.com>:
>>> 2) Binutils-2.21 build fails:
>>> ....
> Reproduced with the clean env:
>
> ar: can't set BFD
> default target to `x86_64-unknown-linux-gnu': Invalid bfd target
> make[4]: *** [libbfd.la] Error 1 make[4]: Leaving directory
> `/media/krypta/clfs-mips/rootfs/sources/binutils-build/bfd' make[3]:
> *** [all-recursive] Error 1 make[3]: Leaving directory
> `/media/krypta/clfs-mips/rootfs/sources/binutils-build/bfd' make[2]:
> *** [all] Error 2 make[2]: Leaving directory
> `/media/krypta/clfs-mips/rootfs/sources/binutils-build/bfd' make[1]:
> *** [all-bfd] Error 2 make[1]: Leaving directory
> `/media/krypta/clfs-mips/rootfs/sources/binutils-build' make: *** [all]
> Error 2
> Environment:
>
> $ env
> CLFS_HOST=x86_64-cross-linux-gnu
> TERM=xterm
> CLFS_TARGET=mips-unknown-linux-uclibc
> OLDPWD=/media/krypta/clfs-mips/rootfs/sources/binutils-2.21
> LC_ALL=POSIX
> CLFS=/media/krypta/clfs-mips/rootfs
> PATH=/media/krypta/clfs-mips/rootfs/cross-tools/bin:/bin:/usr/bin:/usr/local/bin
> PWD=/media/krypta/clfs-mips/rootfs/sources/binutils-build
> CLFS_ARCH=mips
> PS1=\u:\w\$
> SHLVL=1
> HOME=/home/clfs
> CLFS_MIPS_LEVEL=32

CLFS_MIPS_LEVEL shouldn't be anything other than "1" or "3".  This
isn't the problem for binutils, but thought I'd mention it.  It could
affect GCC compilation.

> CLFS_ABI=32
> CLFS_ENDIAN=big
> CLFS_FLOAT=hard
> _=/usr/bin/env
>
> Please notice, that my CLFS_HOST is x86_64-cross-linux-gnu, and my
> whole system is x86_64-unknown-linux-gnu - that's the one that can't be
> set as BFD target.

Noted.  The reason I'm confused is because my binutils configures for
x86_64-unknown-linux-gnu as well, and I don't have any issues building
binutils (just built cleanly again while writing this email).  My
CLFS_HOST is x86_64-cross-linux-gnu.  This should be the same to
yours.

What host distribution are you running?  What version of GCC?
I'm running Debian 6 x86_64 and GCC 4.4.5 on my host.  If you're
running Debian or Ubuntu, I have chroots on my host for most recent
versions of those and I can test this out to see if it can be
reproduced.

>>> 3) Building kernel with gcc 4.6.0 fails in mips-specific code. The problem is caused by new warnings in gcc 4.6.0:
> I attached the config file. It still fails when I have clean
> environment - or in fact, the following environment:

I've not had time yet to build this kernel but I will do this and let
you know my findings.

>>> 6) A word about CFLAGS:
> Yes, but the point here is that I want to use platform-specific flags
> for host and for target. While I can export CFLAGS="-march=core2 ..."
> before building mpfr, and CFLAGS="-march=24kc ..." before building
> uClibc, I can't do this before building gcc final, because this is the
> build both for target (libgcc, libstdc++) and for host (gcc
> executables). That's why I proposed to use CFLAGS_FOR_HOST,
> CFLAGS_FOR_TARGET... before building gcc final.

Ah, OK.  I think I understand now.  Yeah, that could be a deficiency.
>From looking through GCC's config.log (from the final build
configure), it looks like the variables you'd want to set might be
CFLAGS, CFLAGS_FOR_BUILD, and CFLAGS_FOR_TARGET.  I'm not sure how
CLFAGS is different than the other two, the build scripts should hold
the secret.  If you have some insight here, it'd be appreciated.

I can see now what you're getting at.  It would be cool if there was a
way to set these different CFLAGS.  If you have any proposals, let me
know or send a patch to the book.

-Andrew