aarch64-tdep.c:aarch64_skip_prologue oddity, what's going on???

[Doug Evans]

Yao Qi writes:
 > Doug Evans <dje@google.com> writes:
 > 
 > > So, second question: Can we remove both the above call to
 > > find_pc_partial_function, and the second call to skip_prologue_using_sal?
 > > Or, under what circumstances will the second call to
 > > skip_prologue_using_sal return a non-zero value?
 > 
 > Is it https://www.sourceware.org/ml/gdb/2008-09/msg00111.html the case?
 > The fix is about ARM, but looks the problem is arch independent.

Thanks!

I looked at this and I'm still confused why the code is the way it is,
it seems unnecessarily complex (not massively so of course, just that
some useful simplification is possible (I think!).

I've got a patch to post.
Hopefully it will help someone clear things up.