Re: arm/iwmmxt VFP errors during linking

[Dimitry Andric <dimitry at andric dot com>]

On 2005-04-12 at 15:27:09 Nick Nuziale wrote:

>>With which options did you compile blahblah?  Can you show us the
>>(full) output of arm-iwmmxt-linux-gnu-gcc -v when you compile it?
> [NN] - The problem occurs when linking several libraries together.  See
> below output containing -v.

Your output shows only the linking stage, so I can only guess how you
actually compiled your .o files.  The linking problems are:

1) The libappbase-xscale-r.so file is built with gcc 3.3.x, so it
   links against an older libstdc++ than you have.
2) Your own .o files are most probably hard FPA format, while the
   libappbase-xscale-r.so file is VFP format.


>>> I have not applied the patch in Scott Merritt's posting yet,
>>> perhaps this will fix the VFP problems??
>>Maybe, depending on your compile options.
> [NN] - what are the correct options to use?

If you apply my vfp patch, you simply use NO floating point options,
so neither -msoft-float, nor -mhard-float, and that should result in
.o files in soft VFP format.

You can verify the format of your .o (and .so) files with:

  arm-linux-objdump -p foo.o


> However this means I would now need build my cross compiler with gcc
> 3.3.3 and apply any necessary patches to get VFP working.

I would advise you to just ask the supplier of libappbase-xscale-r.so
for the toolchain they've used, and use that to build your app.  This
is the best way to make sure you don't run into any incompatibilities.


> I noticed that crosstool has the glibc patch needed
> (glibc-fp-byteorder.patch in glibc 2.3.2/3), however I guess I would I need
> a gcc-3.3.3-arm-softvfp.patch (I noticed you created the 
> gcc-3.4.3-arm-softvfp.patch.bz2 and attached it in the mailing list).
> Dimitri, can you create this patch?

Try:
http://www.andric.com/cross/patches/gcc-3.3.2-arm-softfloat.patch.bz2


> This patch would need to be applied after all the other gcc crosstool
> patches, correct?

Yes.  I'm not sure it'll apply cleanly with the latest crosstool
patches, though...

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