Re: [RFA]: Fix do_cleanups if oldchain is NULL

["J. Johnston" <jjohnstn at redhat dot com>]

Daniel Jacobowitz wrote:
> On Mon, Jan 05, 2004 at 01:59:53PM -0500, J. Johnston wrote:
>
> > Andrew Cagney wrote:
> >
> > > > I recently solved a bug on the ia64 concerning cleanups.  What was 
> > > > happening was that a cleanup list was being re-initialized to NULL 
> > > > inside a loop and later do_cleanups() was called.  This caused the 
> > > > entire cleanup list to be run because the design is to run the list 
> > > > until the passed in cleanup is reached.  This caused other errors when 
> > > > the stream being used was deleted, etc...
> > > >
> > > > This patch adds a check to do_my_cleanups() so no cleanups will be 
> > > > performed if the passed in chain is NULL.
> > > >
> > > > Ok to commit?
> > >
> > >
> > > (hmm, no one thought to review this while I was on hols :-()
> > > I think the bug is in the calling code, and not utils.c.  That patch 
> > > unfortunatly makes a fundamental change to the core of the cleanup code 
> > > and there's no easy way of demonstrating that other callers aren't 
> > > assuming that NULL implies do all cleanups.
> > >
> > > Andrew
> >
> > Perhaps, but there is no way to properly initialize a cleanup to avoid 
> > compiler warnings.
>
>
> Sure there is:
>   struct cleanup *old_chain = make_cleanup (null_cleanup, 0);

Ok, that suits me fine.

> > If you set it to NULL which is the obvious choice, this 
> > currently means run all cleanups.  IMHO, this is the wrong choice for the 
> > default.  I found no cases where NULL was passed in directly.  Do you see a 
> > case where a gdb routine has the right to run all previous cleanups except 
> > in an exit scenario?
>
>
> This function is not just used for do_cleanups, but also for
> do_run_cleanups et cetera.

I just saw the note regarding do_run_cleanup (NULL).  My fault for not looking 
ahead in my mass of e-mails :(.  I didn't check for that scenario.  I no longer 
have any issue.

-- Jeff J.