llvm dev - Apr 2005 - [LLVMdev] isa and friends as an alternative to dynamic cast?

On Thu, 2005-21-04 at 19:43 -0700, Reid Spencer wrote:
> In case it wasn't obvious from Misha's answer, the main reason for
> doing this is speed. RTTI is not very quick.
Right. This is why I was somewhat suprized to see the "isa" facilities
included in LLVM without also disabling rtti. It will reduce the memory
footprint a fair bit if you do disable it, at least based on my
experience with other C++ projects.

Evan Jones

That's a good point.

Evan Jones wrote:
>On Thu, 2005-21-04 at 19:43 -0700, Reid Spencer wrote:
>  
>
>>In case it wasn't obvious from Misha's answer, the main reason
for
>>doing this is speed. RTTI is not very quick.
>>    
>>
>
>Right. This is why I was somewhat suprized to see the "isa"
facilities
>included in LLVM without also disabling rtti. It will reduce the memory
>footprint a fair bit if you do disable it, at least based on my
>experience with other C++ projects.
>
>Evan Jones
>
>
>_______________________________________________
>LLVM Developers mailing list
>LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>  
>

Yeah, I petitioned Chris on this a long time ago but he had a good
reason for not disabling it. I think LLVM uses some minimal RTTI
features, but I can't remember what now.

Reid.

On Thu, 2005-04-21 at 22:47 -0400, Evan Jones wrote:
> On Thu, 2005-21-04 at 19:43 -0700, Reid Spencer wrote:
> > In case it wasn't obvious from Misha's answer, the main reason
for
> > doing this is speed. RTTI is not very quick.
> 
> Right. This is why I was somewhat suprized to see the "isa"
facilities
> included in LLVM without also disabling rtti. It will reduce the memory
> footprint a fair bit if you do disable it, at least based on my
> experience with other C++ projects.
> 
> Evan Jones
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev


_______________________
Reid Spencer
President & CTO
eXtensible Systems, Inc.
rspencer at x10sys.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20050421/123af5a4/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20050421/123af5a4/attachment.sig>

On Thu, 21 Apr 2005, Jeff Cohen wrote:
> That's a good point.
I think there are some issues with doing this (e.g. EH doesn't work, so 
the very few places we use it would have to be modified), but other than 
that I fully support the idea.

-Chris
> Evan Jones wrote:
>
>> On Thu, 2005-21-04 at 19:43 -0700, Reid Spencer wrote:
>> 
>>> In case it wasn't obvious from Misha's answer, the main
reason for
>>> doing this is speed. RTTI is not very quick.
>>> 
>> 
>> Right. This is why I was somewhat suprized to see the "isa"
facilities
>> included in LLVM without also disabling rtti. It will reduce the memory
>> footprint a fair bit if you do disable it, at least based on my
>> experience with other C++ projects.
>> 
>> Evan Jones
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
>> 
>> 
>> 
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
>
-Chris

-- 
http://nondot.org/sabre/
http://llvm.cs.uiuc.edu/