This has come up already when we discussed the jdk.vm.ci module but back then I though if we can't have more module separation (for every project) we could as well just have one.

It turns out that this is a problem in JDK 9. Having only one module makes it possible to use HotSpot-specific classes in VM-independent compiler code.

In order to avoid this and for code cleanliness we should have a separate jdk.vm.ci.hotspot module which contains all HotSpot-related classes.