[PATCH] Add libgcc support for cache clearing on ARM VxWorks

[Olivier Hainque]

Hi Richard,

I discussed with the original author, have looked into the ARM cache matters
in greater detail and certainly agree with your general concerns.

There are pieces related to the insn cache clearing in the code, but I can
see how architecture specific everything is here, indeed not appropriate as
a single non-specialized entry point in libgcc.

Thanks again for your arm-expert input on the topic.

Still working on this. 

In the meantime, opinion on the two patches below ?

  https://gcc.gnu.org/ml/gcc-patches/2017-08/msg00278.html
  (Handle DWARF2_UNWIND_INFO in arm_except_unwind_info)

  https://gcc.gnu.org/ml/gcc-patches/2017-08/msg00271.html
  (Fix .cfi inconsistency out of builtin_eh_return)

Maybe the dwarf2 unwind support could go away when support for the old ABI
gets removed. From the VxWorks perspective, dwarf2 is only needed by versions
of VxWorks which rely on the old ABI.

Thanks in advance for your feedback,

With Kind Regards,

Olivier