Re: gdb stack trace problems (Addendum)

[Christopher Faylor <me@cgf.cx>]

On Sun, May 08, 2005 at 03:30:20PM +0200, Mark Kettenis wrote:
>   Date: Mon, 02 May 2005 09:03:08 +0200
>   From: Roland Schwingel <roland.schwingel@onevision.de>
>
>   Hi Mark...
>
>   Have you already had some time to look into my results with your patch to
>   the i386 stack unwinder? At basically it could work but obviously it
>   is not advancing to the next stack frame... Attached you will find my 
>   results
>
>This isn't very encouraging.  My approach obviously isn't working very
>well.  My suggestion is to go for a Windows-specific solution, where
>one would use a special unwinder for the sort of undebuggable code
>that's found in the Windows system DLLs.  But I'm afraid I can't
>really do much since I don't have a Windows system.  Chris, is there
>any change you can hack something like this into i386-cygwin-tdep.c?

What kind of windows-specific solution do you have in mind?  How would
you know what to unwind?  You could potentially figure out that you're
stuck in a system function but that doesn't mean that you know the
state of the stack.

If a function doesn't set up a frame pointer and there is no debugging
information available, how would one derive a stack frame?  I could
imagine a really complicated "search the stack" technique but I can't
see how it would ever be foolproof.

cgf