> It's not possible to cross compile all platforms from any single OS, so > you can't provide native toolchains for separate builds on the same host. > > Depending on how close to correct you need the java class files to be > produced, it could be possible to hack around in the build system to > achieve something that is perhaps close enough, but as I said already, > it won't be trivial. I doubt we would want to incorporate any such > change into the build permanently without some very strong motivation. > > /Erik
Thanks a lot for your and David Holmes' quick and extensive responses. I was a bit naive assuming that it would just work. I tried David's approach of including the `classes` directories for all supported platforms, but that fails already because for example the class `sun.nio.ch.PipeImpl` has a Unix and Windows specific implementation. It is a bit unfortunate that it is therefore not possible to build a CodeQL database which contains all the Java code of the JDK, but at least you can build databases containing the Java code for one specific platform. Most likely a database containing the Java code for all platforms would also not provide proper dataflow paths. I agree that the work required to have the JDK build system support this special use case is probably not worth it. Kind regards
