[rfc/rfa v2] Use ARM exception tables as GDB unwinder

[Daniel Jacobowitz]

On Wed, Dec 01, 2010 at 05:07:37PM +0100, Ulrich Weigand wrote:
> - We now only trust ARM unwind info at call sites, not at arbitrary
>   PC locations.  (Note that we consider system calls to be call sites
>   as well for this purpose, see the comment in the code.)

That's a clever compromise; I like it.  We lose a bit with
asynchronous signals, but it's a very small bit since you consider
system calls as call sites too.

> @@ -1899,6 +1909,744 @@ struct frame_unwind arm_prologue_unwind 
>    default_frame_sniffer
>  };
>  
> +/* Maintain a list of ARM exception table entries per objfile, similar to the
> +   list of mapping symbols.  We only cache entries for standard ARM-defined
> +   personality routines; the cache will contains only the frame unwinding
> +   instructions associated with the entry (not the descriptors).  */

"will contain" or "contains".

Otherwise, looks good to me.

-- 
Daniel Jacobowitz
CodeSourcery