Re: [rfc] Add per frame frame_saved_pc()

[Kevin Buettner <kevinb@redhat.com>]

On Sep 19, 11:30pm, Andrew Cagney wrote:

> Back to (trumpet noises) CFI and more fall-out from the MIPS and generic 
> dummy frames.
> 
> - The CFI doco describes a ``return_address_register'' which ``[...] 
> might not correspond to a machine register''.  This means a CFI specific 
> frame saved PC method.

I'm not certain that this should (necessarily) drive our decisions.

> - Given a generic dummy frame, it knows exactly where the callers frame 
> PC is.  No need to ask the target code.
> 
> With this in mind, I'd like to propose making frame_saved_pc() a 
> per-frame method.

I'd be willing to look at a patch.  In particular, what I'm curious
about it to see the places where the frame_saved_pc field is
initialized in the frame.  I can picture how the generic dummy
frame code would look, but what I'm less clear about is what it'd
look like for normal frames.  It seems to me that you have two choices,
1) have a generic method which falls back on the current machinery, or
2) have architecture specific methods.  I'm more interested in how (2)
will be accomplished.

Kevin