Re: Empty base optimization, sharing vptrs
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Empty base optimization, sharing vptrs
- To: "Matt Austern" <austern@xxxxxxxxxxxxxxxxxxx>
- Subject: Re: Empty base optimization, sharing vptrs
- From: Christophe de Dinechin <ddd@xxxxxxxxxx>
- Date: Wed, 16 Jun 1999 16:57:40 -0700
From: "Matt Austern" <austern@xxxxxxxxxxxxxxxxxxx>
> NONPOLYMORPHIC BASES
>
> We may allocate any number of empty base subobjects at the same
location
> (the beginning of the complete object) except when, because of repeated
> inheritance, we'd have multiple subobjects of the same type
allocated in
> the same place.
You probably have noticed that I currently don't read the standard
that way. But I also acknowledge that this is quite a reasonable way
of implementing things. Jason was supposed to send a message to
c++core regarding this issue. I did not receive this message, but
this might be a problem with our mail setup. Was the message sent?
> (Oh, another point. I don't have a proof, but my guess is that
> finding an optimal space-minimizing solution to the class layout
> problem is equivalent to the travelling salesman problem. I'm not
> going to try.
Ah ah, but that's the kind of optimization that could be useful to
make people buy IA64-class machines :-)
Christophe