RFR(S): : 8211332: Space for stub routines (code_size2) is too small on new Skylake CPUs

[Schmelter, Ralf]

Please review this change which increases the space available for stub routines on Windows x86.



bug: https://bugs.openjdk.java.net/browse/JDK-8211332<https://bugs.openjdk.java.net/browse/JDK-8211350>

webrev: http://cr.openjdk.java.net/~clanger/webrevs/8211332.0/



My Windows x86 slowdebug build crashed in StubRoutines::initialize1(), since the estimated code size (code_size2 defined in stub_routines_x86.hpp) for the initial stubs was too low. I've increase code_size2 by 500 bytes per step, until the assertions vanished.



This seems to be 'caused' the new -XX:UseBASE64Intrinsics flag, which is only turned on if the machine supports the AVX-512VL and AVX-512BW extensions, which is the case for Skylake-SP and Skylake X and later/better CPUs.



Best regards,

Ralf Schmelter