Hi Florian, there are two different points to consider here.
The first one is to make the OpenJDK compile on Windows with the MinGW toolchain (instead of Cygwin). This currently doesn't work out of the box but is relatively easy to achieve (see for example "8022177: Windows/MSYS builds broken" https://bugs.openjdk.java.net/browse/JDK-8022177). Magnus and I are working on this (and actually I have an internal build which works with MinGW). Hopefully we can fix this in the OpenJDK soon. The second one is to cross compile the whole OpenJDK on Linux using gcc and MingGW. If I understood you right that's what you actually wanted. I personally think that would be nice to have but at the same time I also think it would be quite hard to get there and probably not worth doing it because even if you'd succeed nobody will probably maintain it and it would break quite soon (see for example the GCC/Solaris build or the Clang/Linux build). If you want to try it nevertheless, some of the problems you will face will be at least the following ones: - convert the HotSpot nmake makefiles to GNU syntax (notice that this project is currently underway under the umbrella of the new build system anyway, so you'd probably want to wait to avoid doing double work) - convert Visual Studio intrinsics, inline assembler and compiler idiosyncrasies to GCC syntax - you'll probably also need to cross compile dependencies like libfreetype with GCC/MinGW - I'm actually not an expert, but the OpenJDK is linked against some native Window libraries like DirectX and runtime libraries from the Microsoft SDKs. I'm not an expert here and I don't know how that would work for a cross-compile. I personally think we should rather focus on further improving the current Windows build. It's already a huge improvement compared to the old JDK7 Windows build. From what I see, the main remaining problems are to somehow make it possible to get a stable, defined and free version of the Microsoft development tools which are "known to work". But of course this is a problem which may need cooperation from Microsoft. Another improvement would be to make the build more agnostic against various Cygwin/MingGW version and to improve the build speed. Again, this issue partially depends on improving Cygwin/MingGW themselves (which would be at least theoretically possible). Regards, Volker On Wed, Apr 30, 2014 at 4:36 PM, Florian Weimer <fwei...@redhat.com> wrote: > I noticed that cross-building Windows binaries is currently not supported. > It seems that Hotspot in particular assumes that the host and target > operating systems are the same (for examples, Linux-to-Linux cross builds > are support). Assuming I can get it to work within the current build > system, would you be interested in integrating patches and carry them > forward? > > Cross-build support would make it easier for GNU/Linux developers to work on > features that should have parity on Windows, but lack shared native sources > (e.g. networking-related features). > > -- > Florian Weimer / Red Hat Product Security Team
