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

["J. Johnston" <jjohnstn@redhat.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.