Re: [rfa/mips] Stop backtraces when we've lost the PC

Daniel Jacobowitz
2004-03-11T20:57:52Z

On Thu, Mar 11, 2004 at 03:51:11PM -0500, Andrew Cagney wrote:
> >I hypothesize that if two consecutive frames, regardless of their type,
> >claim to save the PC register at the same location, then unwinding is
> >hosed.
>
> It would need to do a deep analysis of the location (think about a
> register window architecture), hence I don't know that there's that much
> cost benefit. Something simpler such as a list of functions known to
> terminate the stack might be more useful.

Er, no. frame_unwind_register tells us where, relative to the current
machine state, the register is saved. If it returns lval_register and
real_regnum == O7_REGNUM, then that means it leaves in
read_register(O7_REGNUM) at this moment, not that it did at some point
in the past. Isn't that the point of the recursive unwinder?