[Numpy-discussion] Moving to gcc 4.* for win32 installers ?

[Ralf Gommers]

On Mon, Feb 6, 2012 at 10:54 PM, David Cournapeau <cournape at gmail.com>wrote:

> On Sat, Feb 4, 2012 at 3:55 PM, Ralf Gommers
> <ralf.gommers at googlemail.com> wrote:
> >
> >
> > On Wed, Dec 14, 2011 at 6:50 PM, Ralf Gommers <
> ralf.gommers at googlemail.com>
> > wrote:
> >>
> >>
> >>
> >> On Wed, Dec 14, 2011 at 3:04 PM, David Cournapeau <cournape at gmail.com>
> >> wrote:
> >>>
> >>> On Tue, Dec 13, 2011 at 3:43 PM, Ralf Gommers
> >>> <ralf.gommers at googlemail.com> wrote:
> >>> > On Sun, Oct 30, 2011 at 12:18 PM, David Cournapeau <
> cournape at gmail.com>
> >>> > wrote:
> >>> >>
> >>> >> On Thu, Oct 27, 2011 at 5:19 PM, Ralf Gommers
> >>> >> <ralf.gommers at googlemail.com> wrote:
> >>> >> > Hi David,
> >>> >> >
> >>> >> > On Thu, Oct 27, 2011 at 3:02 PM, David Cournapeau
> >>> >> > <cournape at gmail.com>
> >>> >> > wrote:
> >>> >> >>
> >>> >> >> Hi,
> >>> >> >>
> >>> >> >> I was wondering if we could finally move to a more recent version
> >>> >> >> of
> >>> >> >> compilers for official win32 installers. This would of course
> >>> >> >> concern
> >>> >> >> the next release cycle, not the ones where beta/rc are already in
> >>> >> >> progress.
> >>> >> >>
> >>> >> >> Basically, the pros:
> >>> >> >>  - we will have to move at some point
> >>> >> >>  - gcc 4.* seem less buggy, especially C++ and fortran.
> >>> >> >>  - no need to maintain msvcr90 vodoo
> >>> >> >> The cons:
> >>> >> >>  - it will most likely break the ABI
> >>> >> >>  - we need to recompile atlas (but I can take care of it)
> >>> >> >>  - the biggest: it is difficult to combine gfortran with visual
> >>> >> >> studio (more exactly you cannot link gfortran runtime to a visual
> >>> >> >> studio executable). The only solution I could think of would be
> to
> >>> >> >> recompile the gfortran runtime with Visual Studio, which for some
> >>> >> >> reason does not sound very appealing :)
> >>> >> >
> >>> >> > To get the datetime changes to work with MinGW, we already
> concluded
> >>> >> > that
> >>> >> > building with 4.x is more or less required (without recognizing
> some
> >>> >> > of
> >>> >> > the
> >>> >> > points you list above). Changes to mingw32ccompiler to fix
> >>> >> > compilation
> >>> >> > with
> >>> >> > 4.x went in in https://github.com/numpy/numpy/pull/156. It would
> be
> >>> >> > good
> >>> >> > if
> >>> >> > you could check those.
> >>> >>
> >>> >> I will look into it more carefully, but overall, it seems that
> >>> >> building atlas 3.8.4, numpy and scipy with gcc 4.x works quite well.
> >>> >> The main issue is that gcc 4.* adds some dependencies on mingw dlls.
> >>> >> There are two options:
> >>> >>  - adding the dlls in the installers
> >>> >>  - statically linking those, which seems to be a bad idea
> >>> >> (generalizing the dll boundaries problem to exception and things we
> >>> >> would rather not care about:
> >>> >> http://cygwin.com/ml/cygwin/2007-06/msg00332.html).
> >>> >>
> >>> >> > It probably makes sense make this move for numpy 1.7. If this
> breaks
> >>> >> > the
> >>> >> > ABI
> >>> >> > then it would be easiest to make numpy 1.7 the minimum required
> >>> >> > version
> >>> >> > for
> >>> >> > scipy 0.11.
> >>> >>
> >>> >> My thinking as well.
> >>> >>
> >>> >
> >>> > Hi David, what is the current status of this issue? I kind of forgot
> >>> > this is
> >>> > a prerequisite for the next release when starting the 1.7.0 release
> >>> > thread.
> >>>
> >>> The only issue at this point is the distribution of mingw dlls. I have
> >>> not found a way to do it nicely (where nicely means something that is
> >>> distributed within numpy package). Given that those dlls are actually
> >>> versioned and seem to have a strong versioning policy, maybe we can
> >>> just install them inside the python installation ?
> >>>
> >> Although not ideal, I don't have a problem with that in principle.
> >> However, wouldn't it break installing without admin rights if Python is
> >> installed by the admin?
> >
> >
> > David, do you have any more thoughts on this? Is there a final solution
> in
> > sight? Anything I or anyone else can do to help?
>
> I have not found a way to do it without installing the dll alongside
> python libraries. That brings the problem of how to install libraries
> there from bdist_wininst/bdist_msi installers, which I had not the
> time to look at.
>

Could you push your changes to github? The 3.4.5 installers are becoming
very hard to even locate, so I'd like to try them out. Han reported at
https://github.com/numpy/numpy/pull/214 that current master crashes with
MinGW 4.x.

Thanks,
Ralf
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