Re: Macro code crasher on re-run

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Nov 03, 2003 at 04:33:44PM -0500, Jim Blandy wrote:
> 
> Daniel Jacobowitz <drow@mvista.com> writes:
> > On Mon, Nov 03, 2003 at 03:59:41PM -0500, Jim Blandy wrote:
> > > 
> > > Daniel Jacobowitz <drow@mvista.com> writes:
> > > > > I don't follow.  All default_macro_scope's callers check for null
> > > > > return; it's documented to return zero at times.  So you must be
> > > > > talking about that code in sal_macro_scope itself.  Line 39 refers to
> > > > > sal.symtab, initialized by line 115, so you must be talking about line
> > > > > 40.  But sal.symtab must be non-zero, or else we wouldn't reach the
> > > > > right operand of the ||.
> > > > > 
> > > > > Or should I sleep and try again?
> > > > > 
> > > > 
> > > > Right.  sal.symtab is nonzero.  sal.symtab->macro_table, however, is
> > > > uninitialized.  The short-circuit if on line 40 does not trigger, but
> > > > the remainder of sal_macro_scope assumes that sal.symtab->macro_table
> > > > is valid.
> > > > 
> > > > In my case it happens to be 0xB.
> > > 
> > > Every symtab's macro_table field should be initialized, at least to
> > > zero.  Which symtab is it?  Who creates it?
> > 
> > If you thought I wasn't making sense, you were right.  I really needed
> > some sleep when I wrote that.
> > 
> > My best guess is that the returned symtab belongs to the old (already
> > unloaded) binary.  Which would put the bug somewhere else.
> 
> I haven't debugged it (only Daniel J. has seen the problem, as far as
> I know), but I kind of suspect this change:
> 
> 2003-10-22  Andrew Cagney  <cagney@redhat.com>
> 
> 	* target.c (target_close): New function.
> 	(debug_to_close): Use "target_close".
> 	(push_target): Use "target_close".
> 	(unpush_target): Use "target_close".
> 	(pop_target): Use "target_close".
> 	* target.h (struct target_ops): Add "to_xclose".
> 	(target_open): Delete macro.  Move comment to "to_open".
> 	(target_close): Replace macro with function that takes a target.
> 	* top.c (quit_target): Pass "current_target" to "target_close".
> 
> The to_close method of the "exec" target calls free_objfile, which
> assumes that its callers call clear_symtab_users at some appropriate
> time.  This change seems to have introduced several new callers to
> target_close, so it may have broken that assumption.
> 
> Having free_objfile require its callers to take care of things this
> way is not very nice.

I was using the 6.0 branch when I found the problem, so that's not it. 
It may be a related problem in a caller of free_objfile, though.  Or
reread_objfile?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer