Xtensa port

[Jim Blandy]

Maxim Grigoriev <maxim@tensilica.com> writes:
>    Basic Xtensa port. It doesn't include any targets. The next step will be
> a submission of "xtensa*-*-linux" target. It will include gdbserver port and
> everything else necessary to debug Xtensa code on this target.

Thanks for the contribution!

I haven't looked at the code closely, but I have a few questions.

- Where does xtensa-config.h come from?

- Does xtensa-config.c need to be listed in ALLDEPFILES as well?

- I don't see anything that actually plugs in xtensa-linux-tdep.o.
  Should that be kept out until the linux target is ready?

- In your DejaGnu config files, there is a way to tell GDB not to run
  tests that depend on the inferior being able to do I/O; this is used
  to run the tests against embedded systems that don't implement the
  semi-hosting protocol packets, like yours.  Look for uses of
  'gdb_skip_stdio_test'.

- Can you explain more about the differences between the
  Xtensa-generated DWARF and what GDB expects?  Ideally, GDB should
  accept DWARF from any compiler, but because DWARF is so flexible
  it's easy for inappropriate expectations to creep in.