Re: RFA: ia64 portion of libunwind patch

[Andrew Cagney <ac131313 at redhat dot com>]

> On Fri, 31 Oct 2003 13:35:51 -0800, Marcel Moolenaar <marcel@xcllnt.net> said:
>
>
>   Marcel> Since libunwind already does its own caching, we may be
>   Marcel> better off not caching in gdb.
>
> That's true.  However, note that by default, caching is not enabled
> for remote unwinding (which is what gdb does).  To enable caching, gdb
> would have to make a call of the form:
>
> 	unw_set_caching_policy(ADDR_SPACE, UNW_CACHE_GLOBAL);
>
> Also, whenever something changes in the target that could invalidate
> cached unwind info, gdb would have to call:
>
> 	unw_flush_cache(ADDR_SPACE, LO, HI);

> where LO and HI is the address range that was affected (or LO=0, HI=0
> to flush the entire cache).

Just FYI, for GDB, it will be better to let the target stack to do the 
cache management.  That way the user can set/override the policy.  For 
instance, in the case in question, the user would be inane to specify 
anything other than:


	(gdb) set trust-readonly-sections 1

(which causes all read-only reads to be handled locally) this is also 
why the issue isn't really that much of a problem.

Andrew