[oe] gcc disable-libunwind-exceptions, VFP, iWMMXt, crunch - nokia800, mx31ads, etc

[Hasjim Williams]

On Tue, 01 Apr 2008 16:10:42 +1000, "Hasjim Williams"
<openembedded-devel at lists.futaris.org> said:
> Hi All,
> 
> I was recently looking in gcc-cross-4.2.2.bb and 4.3.0.bb and noticed
> that in our EXTRA_OECONF we have:
> 
> --disable-libunwind-exceptions

Sorry all, this is due to my misunderstanding of what this does. 
gcc-cross can be compiled with libunwind extensions:

http://www.nongnu.org/libunwind/

Obviously we don't have anything in the oe tree that uses this (to
determine the call-chain of a program), and there is no libunwind.bb. 
Would it be possible to build gcc with libunwind support?  AFAIK, only
the git development tree has support for ARM.

I guess it would mean another stage after or that replaces gcc-cross,
and a different glibc?  Or could we have some sort of
TARGET_UNWIND_SUPPORT variable or something similar?

Incidentally, someone wanted to put a patch to disable some other libs
in gcc:
http://projects.linuxtogo.org/pipermail/openembedded-commits/2007-November/010465.html

It would be good if we could figure out a nice way to enable/disable
certain libraries, much like the way TARGET_FPU affects certain
packages.

> Also, I couldn't build glibc-intermediate (with system-wide iwmmxt) with
> the tag enabled, when building with binutils-2.18, gcc-4.3.0 and
> glibc-2.6.1 ...

NB, this is also why yesterday I couldn't build glibc as I hadn't
installed libunwind, i.e. created a libunwind bb.