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Re: 64bit: C++ templates


Hi Yaakov,

On May 20 11:26, Corinna Vinschen wrote:
> On May 20 01:59, Yaakov (Cygwin/X) wrote:
> > On 2013-05-16 03:25, Corinna Vinschen wrote:
> > >Yesterday it turned out that the visibility stuff is not the real
> > >problem.  Mingw gcc 4.8 also produces the same set of symbols, but it
> > >doesn't fail when linking.
> > 
> > Is that surprising, given that PE-COFF medium/large code models were
> > only added to trunk (AFAIK) post-4.8?
> 
> well, this is not exactly related to the medium/large code model
> introduction but rather a feature of gcc 4.8.  The same problematic
> symbols are generated in the small code model in 4.8, but not with gcc
> 4.7.2.
> 
> > >Some more testing now showed clearly that this problem is related to the
> > >high address used as base addresses in the Cygwin toolchain.  If you
> > >build the harfbuzz DLL not with
> > >
> > >   -Wl,--enable-auto-image-base
> > >
> > >but instead with a fixed address in the lower 31 bit address area,
> > >for instance
> > >
> > >   -Wl,--image-base -Wl,0x7ff00000
> > >
> > >the problem disappears and you can successfully build the DLL.
> > 
> > This seems to fix harfbuzz wrt gtk2; gtk3 still isn't working, but
> > I'm not sure it's related yet.
> 
> Dunno, but more info on that might help my collegues to fix the issue.

Any more info here?

> > >Alternatively, you can also workaround this issue by building harfbuzz
> > >with the -mcmodel=large option, which doesn't suffer this problem due to
> > >the way symbols are only indirectly addressed.
> > 
> > With this, the link succeeded but I got SEGVs in one of the same
> > symbols that failed to link previously.

Assuming the build worked, how can one reproduce this SEGV?


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat


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