Conditional compilation of ZGC

[Per Liden]

On 05/09/2018 03:15 PM, Stefan Karlsson wrote:
> Hi all,
> 
> This is the first version of the patch to allow the compilation of ZGC 
> to be turned on and off. This patch passes tier1, tier2, and hs-tier3 
> (except for the test in gcbarriers that need to be updated). This mostly 
> shows that we can build ZGC on Linux x86_64 and Solaris Sparc, and that 
> the other platforms still build without ZGC. It also shows that we don't 
> break the other GCs.
> 
> http://cr.openjdk.java.net/~stefank/zgc/zIncludeZGC/webrev.01/

Looks good! The stuff mentioned below can be done as a follow up.

/Per

> 
> There are a few changes that we want to do for next version:
> 
> 1) .ad file replace the fatal("ZGC specific code") with 
> ShouldNotReachHere(), and maybe assert that we are running with ZGC.
> 
> 2) Remove the INCLUDE_ZGC from gcCause and gcName, or add INCLUDE_<GC> 
> guards for the other GCs.
> 
> 3) c2_globals.hpp further cleanup. Probably move these flags into a 
> gc/z/c2 directory.
> 
> Cheers,
> StefanK