[Rd] New version of Rtools for Windows

[Jeroen Ooms]

On Wed, Jan 7, 2015 at 8:00 AM, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
>
> This version includes only minor updates to the tools.  I indicated last summer that I was hoping to update GCC from the current version 4.6.3 before the R 3.2.0 release, but this now looks unlikely, unless someone else with experience building it can help.

I have been looking into this a bit over the past few months, also
with mixed success. Nevertheless, below some experiences that might be
worth sharing.

The guys from mingw-w64 recommended (quite strongly) to move away from
multilib. They explained that the standard approach is to create two
separate toolchains; one that targets win32 and the other one that
targets win64 (both tool chains can compiled for win32). Hence the
only difference for R would be that instead of passing "-m64" and
"-m32", it would need to set the path to the proper compiler.

There are several initiatives that provide very complete suites of
precompiled mingw-w64 tools. I think the ideal scenario would be if we
could take advantage of an existing tool chain as we do on other
platforms, although perhaps I do not fully understand the R-specific
requirements on the windows compiler.

One project that looks very promising is msys2 [1,2]. It has a package
manager (port of pacman from arch linux) and comes with a pretty
complete set of msys [3] and other [4] packages that seems quite well
maintained.

The only issue I ran into with msys2 is that it uses a different c++
exception model (seh/dwarf) than the current Rtools (which uses sjlj).
See also [5]. Therefore, if a library uses exceptions, we cannot use
the current Rtools to link a static library that was created with
msys2  [6]. I am not sure if it also be a problem the other way
around, and if this is still the case for recent versions of
gcc/mingw.

Finally, Ruby has build very similar to Rtools called DevKit-mingw64
[7] that we might be able to borrow from.


[1] https://msys2.github.io/
[2] http://stackoverflow.com/questions/25019057/how-are-msys-msys2-and-msysgit-related-to-each-other
[3] https://github.com/Alexpux/MSYS2-packages
[4] https://github.com/Alexpux/MINGW-packages
[5] http://stackoverflow.com/questions/15670169/what-is-difference-between-sjlj-vs-dwarf-vs-seh
[6] http://stackoverflow.com/questions/7751640/undefined-reference-to-gxx-personality-sj0
[7] http://rubyinstaller.org/downloads/