> Andrew Cagney wrote:
> 
> 
>>>> > Hello,
>>>> > 
>>>> > this patch fixes the gdb.base/gdb1476.exp test case (backtrace from NULL
>>>> > function pointer call).
>>>> > 
>>>> > When calling via an invalid function pointer, what we should do is simply
>>>> > unwind the PC from the return address register and continue.  This is
>>>> > exactly what is done to unwind from a PLT stub as well, so the patch 
>>>> > simply uses the PLT frame unwinder to handle this case as well.
>>
>>> 
>>> While that might be true, I don't know that its the job of something 
>>> called "PLTSTUB".  
> 
> 
> Yes, the name's a bit unfortunate.  What this unwinder does is basically
> unwind from any situation where we don't have a proper function prolog.
> It could in theory handle all kinds of stubs, trampolines etc.
> 
> 
>>> I can think of either:
>>> - renaming pltstub to something that matches its new purpose (just "stub"?)
> 
> 
> This would be my preferred solution.

Try the attached.

Andrew

>>> - using the default unwinder
> 
> 
> The default unwinder as it is now would handle the situation incorrectly.
> I could build the stub detection logic into the default unwinder, but that
> would make it even more complex than it already is; I would think with the
> new frame logic it is preferable to have multiple unwinders rather than a
> single one that handles everything.
> 
> Bye,
> Ulrich