Re: `chain-frame'

[Daniel Jacobowitz <drow@mvista.com>]

On Wed, Jan 08, 2003 at 10:06:12PM -0500, Andrew Cagney wrote:
> >I'm trying, but I still don't quite see how you're laying this out. 
> >All help welcomed!  Maybe I should look over your WIP again; has it
> >changed since you last posted it?
> 
> It's changed.  I'm going to cut a branch.
> 
> >regcache-frame (regs-frame?):
> >>A frame that maps directly onto the register cache.
> >
> >
> >Doesn't unwind, since we're at the top.
> 
> Nope!  At the bottom, and it does unwind.
> 
> This unwinds to the ``inner most frame''.  Instead of calling 
> create_new_frame(), get_current_frame() creates this frame and then 
> unwinds it.

Oh, er.  Right, I should have understood that by now.  Thank you.

> Another name for this one is:
> 
> 	sentinal-frame
> 
> since it acts as the sentinal one beyond the inner most frame.

Great.  (Sentinel btw).

> >fake-frame (?):
> >>Recently discussed, would also use dwarf2cfi but with fake debug 
> >>information.
> >
> >
> >Unwinds using the CFI reader and fake DWARF-2 CFI information.  Someday
> >maybe have a more generalized "unwind language"; that's my hope,
> >anyway.  So we don't have to encode and decode the CFI gunk.
> 
> Yes, and Yes.  The later can just plug in.
> 
> >And the other group of frames just use the current frame chain code,
> >and poke at the stack to find the saved registers; maybe
> >"stack-chain-frame"?
> 
> Oops, yes.  Just:
> 
> 	chain-frame:
> 
> though I think.

This'll require playing around with my vocabulary a little to get used
to it, but I can buy it.  The general action is "unwinding"; looking
for the "chain" is one mechanism.  I like it.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer