[haiku-development] Re: GCC2 and GCC4 on same System
- From: "Ithamar R. Adema" <ithamar@xxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Mon, 03 Sep 2007 09:25:45 +0200
Hi Brecht,
Brecht Machiels wrote:
> Hello,
>
> This is great news. However, I'm a bit concerned about the fact that
> you only talk about GCC2 and GCC4. What if the GCC boys decide to
> change name mangling again in, say 2 years from now? Will you add yet
> another directory with copies of the libraries? The same applies for
> other compilers. I have no problem with GCC, but I don't think it's a
> good idea to limit developers to one compiler.
It would indeed add another set of libraries, using this technique.
> Perhaps we can come up with a more general solution to this problem?
> It might take a larger effort, but it can probably save us a lot of
> trouble in the future.
Well, the point being that backwards compatibility is currently assumed
to be a short-lived thing (e.g. GCC2 support), and as there's plenty to
do to get to R1, I'm assuming everybody is more worried about getting
the OS complete enough for that.....
> I'm anything but an expert on compilers or OS design, but here's my
> view. I suppose GCC uses a function to mangle C++ names. Is it
> possible to have Haiku to do a 'translation' of mangled names between
> compiler naming schemes (is as much information in a GCC2 executable
> as there is in a GCC4 executable?)? An executable could include an
> indication of which name mangling scheme is used. The loader can then
> use this to translate the names.
If the name mangling was the only problem, this would have been a neat
idea. However, there's more changes then just the name mangling between
GCC2/GCC4, which makes things (esp. C++ related) a lot more difficult :(
> Now I'm sure there are plenty of holes in this reasoning which I'm not
> aware of. But please do look at the larger picture.
See the above, IIRC, there were changes in the runtime structures
related to C++ (exceptions, RTTI, etc) as well, making this all pretty
complex.
> PS. I bumped into the following a couple of days ago:
> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/binary-formats.html.
> I thought this might be useful.
This is a really cool thing in BSD, agreed. We might even consider doing
something simular in the future (would sure help stuff like ndiswrapper,
I guess). I'm sure we'd accept patches already, if anybody feels
inclined to do something similar ;)
HTH,
Ithamar.
PS: Please note that this is all IMHO, not any kind of official statement.
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