Re: [RFC] Detecting and printing 128-bit long double values for PPC

[Luis Machado <luisgpm@linux.vnet.ibm.com>]

Isn't GDB currently able to detect the type length in runtime in order
to correctly print those values?

With this modification i've noticed that GDB cuts the extra precision
bytes for a binary built with -mlong-double-64, while printing the value
with the total avaiable precision when it's built with
-mlong-double-128.

Regards,
Luis

On Sat, 2007-04-28 at 12:27 -0400, Daniel Jacobowitz wrote:
> On Sat, Apr 28, 2007 at 06:24:14PM +0200, Ulrich Weigand wrote:
> > We have the same situation on s390, where we switched from 64-bit to
> > 128-bit long double a while ago.  Like PowerPC, there is currently no
> > way to recognize how a binary was built ...
> > 
> > While an ABI marker might be a good idea in the future, we're stuck
> > with the situation right now that many unmarked 128-bit long double
> > binaries are already out there (e.g. all of SLES 10 and RHEL 5),
> > and we really should be able to debug those properly.
> > 
> > Thus I'm wondering whether we shouldn't have a reasonable default
> > for unmarked binaries, presumably based on the system compiler
> > defaults detected at configure time for native builds, and then
> > provide a command allowing the user to override that default?
> 
> Well, that's pretty much what I did for our customer who reported the
> equivalent problem with PowerPC -msoft-float; except instead of
> detecting it at configure time I added a manual configure option
> (since this was for a cross-debugger).
> 
> But it doesn't really scale... I'm open to better ideas...
>