[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Objective-C++
From: |
Marcel Weiher |
Subject: |
Re: Objective-C++ |
Date: |
Wed, 27 Apr 2005 17:48:17 +0100 |
On 27 Apr 2005, at 02:23, Greg Parker wrote:
* fast dispatching
The compiler assumes that a copy of objc_msgSend() is at a fixed
memory address, and jumps directly to it. This is most useful in
the context of PowerPC and Mac OS X's dynamic linker: the dynamic
linker overhead for cross-library calls is significant, and the
fast objc_msgSend() can be placed in a memory range that is
reachable by single absolute branch instruction. I don't know how
interesting this change is for GNUstep, given GNUstep's portability
goals.
Great!! (Note: almost half the cost of a message send on OS X was
going through the cross-library call, so this is fantastic). Would
it be possible to have it go through a pointer instead, and have that
pointer then take part in normal compiler optimizations?
* GC
Apple is working on a garbage collection system for Objective-C. It
is still under development, but does not use the Boehm GC available
in GNUstep. These compiler changes mostly add a write barrier when
assigning Objective-C instance pointers to ivars and a few other
places. The write barrier is a runtime function, and is similar to
the fast dispatching above. This is likely to evolve further, and
probably isn't interesting for GNUstep yet.
Interesting, especially the idea of a more indirect variable access
mechanism.
Great news, overall.
Cheers,
Marcel
- Objective-C++, Mike Stump, 2005/04/26
- Re: Objective-C++, Lars Sonchocky-Helldorf, 2005/04/26
- Re: Objective-C++, Mike Stump, 2005/04/26
- CoreData, OmniBase, OmniFoundation?, Lloyd Dupont, 2005/04/28
- Re: CoreData, OmniBase, OmniFoundation?, Chris Vetter, 2005/04/28
- Make std variable?, Lloyd Dupont, 2005/04/28
- Re: CoreData, OmniBase, OmniFoundation?, Alex Perez, 2005/04/28
- Re: CoreData, OmniBase, OmniFoundation?, Lloyd Dupont, 2005/04/29
- Re: Objective-C++, Greg Parker, 2005/04/26
- Re: Objective-C++,
Marcel Weiher <=
- Re: Objective-C++, Adrian Robert, 2005/04/26
- Re: Objective-C++, Nicolas Roard, 2005/04/27
- Re: Objective-C++, Frederic Stark, 2005/04/29