Re: GNU Objective-C runtime support for @synchronized()

[IainS <developer at sandoe-acoustics dot co dot uk>]

Hi Nicola,

welcome back, ObjC can use all the help it can get :-)

I haven't tried the patch yet (having read a subsequent mail).

Looks like a great clean-up.

On 4 Sep 2010, at 21:44, Nicola Pero wrote:

> The only real problem is that I am not particularly convinced by
> Apple's decision to have @synchronized(nil) do nothing.  I think an
> exception would have made more sense.  At a moment, if @synchronized
> is passed a nil object due to a bug, it would do no synchronization at
> all and this problem could remain invisible until it causes a
> hard-to-reproduce bug in a production system.  Maybe in the GNU
> runtime we could have a static lock associated with nil and have
> @synchronized(nil) lock that global lock.  That would still be
> somewhat compatible with Apple's runtime (no exception raised if you  
> do
> @synchronized(nil)), but would prevent a bug triggering
> a @synchronized(nil) from causing a lack of synchronization. ;-)

(IMO) this would be a good plan --  and I  don't see why we shouldn't  
have a diagnostic too (and, perhaps, raise a radar).

> Else, we'll just leave as it is, which is fully compatible with the  
> Apple's
> runtime behaviour. :-)

I'm getting tempted to add an -mcompat=apple for *-*-darwin* (I know  
Mike hates extra flags, but we're diverging)

Either way, it would be good to keep at least superficial compatibility.

----

on the subject of exceptions ......
.... any thoughts on http://gcc.gnu.org/bugzilla/show_bug.cgi? 
id=23616 ? ;-)

cheers,
Iain