[cfe-dev] Weak pointer support on 32-bit platforms

[David Majnemer]

Filing a bug with a reduced test-case would be helpful to get this fixed.


On Fri, May 9, 2014 at 2:25 AM, Hovik Melikyan <hovik.melikyan at gmail.com>wrote:

> Hi David,
>
> (I should have made it clear that I do understand there's GNUstep
> (whose GUI is so horrible and 1990-ish that makes me want to switch to
> an entirely different industry altogether :) and I do understand I
> can't use Apple's code unless it's covered by a more or less
> permissive license. Libobjc is APSL so we're fine with that. As for
> the rest, Foundation & Cocoa, there is at least one open source
> implementation named Cocotron that's pretty good but is a bit behind
> in terms of the runtime and language features. One possibility, for
> example, would be to adapt Cocotron to the latest libobjc, that's all.
> But let's forget about higher layers for now.)
>
> My point is, theoretically there's nothing that stops clang from
> making Apple's libobjc compile and work on Windows, less exceptions.
> We can wait until clang brings exceptions to Windows, that's fine,
> because exceptions are kind of not critical to F/Cocoa.
>
> But weak pointers, I think what I found is a bug. You declare a __weak
> pointer and the compiler treats it as __strong for a particular
> target. The consequences of this bug for an app can be catastrophic.
>
> Let's say my setup is a bit unusual, but if there is one little thing
> that possibly needs a little fix, why not? I was hoping to hear some
> ideas as to what I can do: file a bug? suggest a patch? use some
> compiler flag that I didn't know of?
>
> --
> H.M.
>
>
> On Fri, May 9, 2014 at 9:29 AM, David Chisnall
> <David.Chisnall at cl.cam.ac.uk> wrote:
> > Hi,
> >
> >
> > On 8 May 2014, at 23:17, Hovik Melikyan <hovik.melikyan at gmail.com>
> wrote:
> >
> >> And finally, the GNU compiler is not an option for me because it lags
> >> in some crucial aspects of the ObjC language. I really, really want to
> >> get clang to compile libobjc and then the entire Foundation/Cocoa
> >> emulation layers. Ideally, clang should be able cross-compile this
> >> stuff on OSX.
> >
> > You seem to be conflating many parts of the stack.  For all of the stuff
> that you want, you need:
> >
> > - A compiler
> > - An Objective-C runtime
> > - A Foundation / AppKit implementation
> >
> > Clang is the compiler, and supports several Objective-C runtimes.  The
> only supported configurations on Windows, however, are the GNU family of
> runtimes (the Apple runtime works on Windows, but requires code that Apple
> has not open sourced to actually be useful).  The GCC and GNUstep runtimes
> both work on Windows and the GNUstep runtime has supported ARC for several
> years and is used by a number of commercial products on Windows, Android,
> and so on.
> >
> > Once you have the compiler and runtime, you need a Foundation
> implementation that supports the runtime.  Again, GNUstep provides this for
> the GCC and GNUstep runtimes.
> >
> > I'm not sure what you mean by 'the entire Foundation/Cocoa emulation
> layers'.  Foundation and Cocoa are just libraries.  You can not use Apple's
> implementation on Windows[1], because Apple doesn't license their library
> implementations for third parties.
> >
> > David
> >
> > [1] Unless you can find a copy of Yellow Box for Windows, in which case
> you can but you'll have a *really* old version.
>
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