Transition to JVMCI JDK8 (removing jvmci suite dependency)

[Doug Simon]

We will soon be removing the jvmci suite dependency from graal-core. Instead, you will use a JVMCI enabled JDK to develop/run Graal. I will send a more detailed message about the transition once we’ve made it, including where you can download JVMCI enabled JDKs. Unfortunately, I updated the jvmci import dependency in graal-core to fix a build issue[1] without realizing it also included another change to the way VMs are built and run[2] that was in preparation for the aforementioned transition. As such, I’m documenting the command line changes here. The usage changes reflect that fact that a single VM binary can be used for both hosted and non-hosted execution.

New usage without mx:

  "-XX:-UseJVMCICompiler" selects hosted mode (the default)
  "-XX:+UseJVMCICompiler" selects jvmci as system compiler
  "-XX:+/-EnableJVMCI" does nothing, it exists just for jdk9 compatibility (+ is the default, - prints a warning that it doesn't actually do anything)

New usage with mx:

  "--vm server" or "DEFAULT_VM=server" is now the default (no need to specify DEFAULT_VM anymore)
  "-Mhosted" selects hosted mode (the default)
  "-Mjit" selects jvmci as system compiler
  "--vm jvmci" still exists for backwards compatibility, it's rewritten by mx to "--vm server -Mjit" (and will print a deprecation warning)

Note that the mx usage above will change once the jvmci suite dependency is removed. The details will be in the message announcing the transition.

-Doug

[1] https://lafo.ssw.uni-linz.ac.at/hg/graal-jvmci-8/rev/b2ca0db14546
[2] https://lafo.ssw.uni-linz.ac.at/hg/graal-jvmci-8/rev/3ef45d0a6d77