Re: Variable identification (Was: [RFA] Don't reset watchpoint block on solib load.)

[Michael Snyder <msnyder at specifix dot com>]

On Thu, 2007-11-29 at 22:02 +0300, Vladimir Prus wrote:
> Jim Blandy wrote:
> 
> >> This is probably good behaviour, indeed. Or maybe we should not
> >> disable watchpoint, but mark it as pending, in the same sense of
> >> "user wanted it to be enabled, but it won't trigger until a shared
> >> lib is loaded" that is used for ordinary watchpoints.
> > 
> > I think so, too.  I guess the key observation is that, while it's not
> > meaningful to talk about a particular local variable "coming back
> > alive", since each function call creates a distinct set of local
> > variables, and you can have recursion, etc., it is meaningful to talk
> > about a shared library being reloaded, and it's intuitive to identify
> > the 'X' from the first loading with the 'X' in the second loading,
> > even if they're at different addresses.
> 
> Yes. I now recall this is more general problem with identification of
> variables in GDB. Say, you're in function, and you have local variable
> 'foo'. In GUI, you do something with 'foo' -- set display format to
> hex, expand it, and so on. It's highly desirable to keep this
> information for the next run of program, or even next run of the GUI --
> even if variable is local, it's not likely that the display properties
> user wants depend on frame.
> 
> Unfortunately, there's no way to do that.

I haven't followed the discussion closely, but
shouldn't it be up to the GUI to keep such persistant
info?  It's nothing to do with gdb, really.  It's the
GUI's state.