[9] RFR(S): 8086068: VM crashes with "-Xint -XX:+UseCompiler" options

[Tobias Hartmann]

Hi,

please review the following patch:

https://bugs.openjdk.java.net/browse/JDK-8086068
http://cr.openjdk.java.net/~thartmann/8086068/webrev.00/

The VM crashes in product or fails with an assert in debug if -Xint and -XX:+UseCompiler is set. This is because CodeCache::heap_available() relies on the fact that if Arguments::mode() == _int, no compilation will be triggered. Although UseCompiler is first disabled by -Xint, the flag may be re-enabled if set via command line.

The solution is to catch such an inconsistent flag combination, issue a warning and reset the flag.

Tested with regression test and RBT (running).

Thanks,
Tobias