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

[Hasjim Williams]

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

Won't this cause a problem for a VFP system (when an exception occurs),
i.e. mx31ads, nokia800?  
e.g. libunwind.S in gcc/config/arm has some specific functions to
save/restore VFP and iWMMXt registers...

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 ...

How does the TARGET_FPU_arm = "hard" overcome this on nokia800, mx31ads,
etc?  Are we only building with-float in certain packages, and using
softfp float-abi otherwise?

Does this mean for a MaverickCrunch system (with system-wide FPU
enabled), we should be setting TARGET_FPU_arm = "hard" too?

What about for a PXA27x system with a iWMMXt coprocessor (and
system-wide iwmmxt) ???  It should be using soft-float, but it should
have libunwind-exceptions enabled (I think) because of the code in
libunwind.S...