indy and tailc

[Rémi Forax]

Le 27/01/2010 10:16, John Rose a écrit :
> On Jan 27, 2010, at 1:03 AM, Patrick Wright wrote:
>
>    
>> On Wed, Jan 27, 2010 at 9:45 AM, John Rose<John.Rose at sun.com>  wrote:
>>      
>>> On Jan 27, 2010, at 12:30 AM, Patrick Wright wrote:
>>>
>>>        
>>>> Is the EG considering Anonymous classes for JSR 292?
>>>>          
>>> No, sorry.  Should we be... what's the use case?  -- John
>>>        
>> From
>> what I read on this mailing list, Charles Nutter for example was quite
>> excited to have them.
>>
>> I may have misunderstood the point of ACs, however.
>>      
> They also provide a way to do something like bytecode-level templating, since CP elements can be varied while the rest of the code is held fixed.  I hope somebody experiments with loop customization at some point, using anonymous classes or a higher-level bytecode weaver.  But that's in the future.
>    

The problem with the bytecode templating provided by anonymous class is that
you can't change the bytecode operations.
The bytecode ops are typed (areturn, ireturn, freturn, etc)
therefore you can't really patch class unless you only relies on Objects.

> The uses you and Charlie point out are less important that they seemed at first for two reasons:
>
> 1. Method handles provide a better replacement for the swarm of tiny classes.
>
> 2. Hotspot is in the process of weaning itself off of perm gen.  One of the main features of perm-gen is that its objects never move except during full GC, and the code cache relied on this invariant until just last year, with the 'ScavengeRootsInCode' changes.
>
> -- John
>    

Rémi