[sheepdog] [PATCH] Fix hardcode AMD64 assembly code (RSP)

[Liu Yuan]

On Tue, Jul 30, 2013 at 08:35:23AM +0900, MORITA Kazutaka wrote:
> At Mon, 29 Jul 2013 14:41:35 +0800,
> Liu Yuan wrote:
> > 
> > diff --git a/lib/logger.c b/lib/logger.c
> > index 253163d..da1221b 100644
> > --- a/lib/logger.c
> > +++ b/lib/logger.c
> > @@ -697,11 +697,15 @@ static bool check_gdb(void)
> >  	return system("which gdb > /dev/null") == 0;
> >  }
> >  
> > +#define STACK_POINTER	\
> > +	((char *)__builtin_frame_address(0) + __SIZEOF_POINTER__ * 2)
> > +
> 
> I think we should add some explanation why this would work.
> 
>  - IIUC, we have to add (__SIZEOF_POINTER__ * 2) since the old ebp and
>    eip are saved in the stack.

I thought of it too, but I have some questions with this assumption.
 - Your old asm("esp") means the end of the caller's frame or begin of the
   callee's frame?
 - so GDB expect the address of end of the frame or the begin of the frame?

Thanks
Yuan