gdc-4.5 testing

[Iain Buclaw]

== Quote from Iain Buclaw (ibuclaw at ubuntu.com)'s article
> == Quote from Neal Becker (ndbecker2 at gmail.com)'s article
> > Anders F Björklund wrote:
> > > Neal Becker wrote:
> > >> Does this support building shared libs now (on x86_64)?
> > >>
> > > ...
> > >>> I uploaded the packages to SourceForge, if anyone else
> > >>> wants to try them... It's made for Fedora 14 (x86_64):
> > >>>
> > >>> http://sourceforge.net/projects/gdcgnu/files/gdc/8ac6cb4f40aa/
> > >
> > > You mean in general, or specifics ? (like throwing exceptions
> > > or allocating memory or whatever...) Was it a problem before ?
> > >
> > > Basic creation seems to work:
> > >
> > > $ gdc -fPIC -o foo.o -c foo.d
> > > $ gcc -shared -o libfoo.so foo.o
> > > $ file libfoo.so
> > > libfoo.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV),
> > > dynamically linked, not stripped
> > >
> > > AFAIK both shared libraries and x86_64 code have been working
> > > for years with GDC, even though that is not the case with DMD.
> > >
> > > Phobos is still static, though.
> > >
> > > --anders
> > But you can't link shared obj to static lib (Phobos), except on i386 - so
> > you really can't use shared obj on x86_64 (if you need phobos).
> As far as I'm aware, the #1 reason why (for GDC, at least) Phobos can't be
> compiled as shared is because of inline asm clobbering the PIC register (EBX on
> i386). Because we're not smart enough (LDC likely suffers from this also), in
> some instances EBX can be wrongly marked as being clobbered too.
> So things you can do to address this is:
> 1) Improve the inline asm. :~)
> 2) Hide all problematic places with version(D_PIC) in Phobos.
> 3) Turn off D_InlineAsm when flag_pic is turned on.

Reason #2, IMO, extern(C) main should **not** be in a shared library. :~)