Re: [patch, rfc, 6?] Enable identical frame sanity check

[Andrew Cagney <ac131313@redhat.com>]

> On Wed, Jul 02, 2003 at 02:27:39PM -0400, Andrew Cagney wrote:
> 
> Hello,
> 
> This patch enables the `is the prev frame identical to this frame' check in get_prev_frame().  I forgot to enable it when I switched the frame ID code from using the frame's PC to using the frame's function.  Noticed this when reviewing Daniel's Arm frame update.
> 
> It should probably go straight into the mainline (tested on i386 and d10v).
> 
> 
> d10v, AVR, and soon ARM all include this check as a silent stop
> condition rather than an error... perhaps that has some significance.
> 
> Ulgh! `prior art' :-)
> 
> I know it's hit at least on ARM.
> 
> It hit the d10v as well, I'd have not otherwize added the test.

>> I'd have to dumb down the prologue
>> analyzer if I wanted it not to be, or else figure out where an
>> inside_entry_func check has gone completely missing in the new frame
>> code.  Just putting it unwind_this_id didn't work (don't remember why
>> not).

> 
> Sounds like it should be treated like the stack bottom?
> 
> The other choice is to treat it as undefined and accept the warning.

Hmm, I think this is all really a GDB (or testsuite?) bug in asm-source. 
  The backtrace should have stopped at main but instead (at least for 
the d10v) it kept going.

If someone tells GDB to backtrace past main then well, I think, all bets 
should be off.

Andrew