Re: [PATCH] Remove zero PC check from blockframe.c:inside_main_func()

Andrew Cagney
2003-12-31T19:58:27Z

> Date: Sat, 13 Dec 2003 19:22:47 -0500
> From: Andrew Cagney <cagney@gnu.org>
>
> > RCS file: /cvs/src/src/gdb/frame.c,v
> > retrieving revision 1.153
> > diff -u -p -r1.153 frame.c
> > --- frame.c 10 Dec 2003 17:40:42 -0000 1.153
> > +++ frame.c 13 Dec 2003 21:47:43 -0000
> > @@ -1732,6 +1732,7 @@ struct frame_info *
> > get_prev_frame (struct frame_info *this_frame)
> > {
> > struct frame_info *prev_frame;
> > + CORE_ADDR pc;
> >
> > if (frame_debug)
> > {
> > @@ -1961,7 +1962,8 @@ get_prev_frame (struct frame_info *this_
> > because (well ignoring the PPC) a dummy frame can be located
> > using THIS_FRAME's frame ID. */
> >
> > - if (frame_pc_unwind (this_frame) == 0)
> > + pc = frame_pc_unwind (this_frame);
> > + if (this_frame->level >= 0 && pc == 0)
> > {
> > /* The allocated PREV_FRAME will be reclaimed when the frame
> > obstack is next purged.
>
> Can it be deleted?
>
> I think so. I tested i386-unknown-freebsd4.7, i386-pc-solaris2.9,
> x86_64-unknown-freebsd5.2 and alpha-unknown-freenbsd5.2, and things
> didn't change.
>
> This would likely affect the initial call sequence made to the unwinder
> - frame_pc_unwind may not be called first (?). But I also think that
> the reason for insisting on an explicit pc unwind may have also been
> removed - the new code is written more robustly anyway.
>
> I think I agree. So shall I remove the code?

Yes, just watch for comments claiming that the pc is unwound first
though though. I believe it's now really entirely determined by the
per-architecture frame sniffers.

Andrew