RFR [XS]: 8237374: configuring with --with-jvm-variants=minimal,server makes cds disappear in server

[Erik Joelsson]

Hello Matthias,

Using BUILDING_MULTIPLE_JVM_VARIANTS as condition is clever and happens 
to coincide with the set of variants that also support CDS, but I would 
say this correlation is incidental. I would still prefer an explicit 
test for if any of the variants that do support CDS is in the set of 
variants being built. This will make it much easier to read and 
understand the logic. Simply:

if ! HOTSPOT_CHECK_JVM_VARIANT(server) && ! 
HOTSPOT_CHECK_JVM_VARIANT(client); then
   ENABLE_CDS="false"
   ...

/Erik

On 2020-01-17 00:07, Baesken, Matthias wrote:
> Hello, please review  this small patch .
>
> When building 2 VM variants   minimal and server  in one build and using
>
>    --with-jvm-variants=minimal,server
>
> to configure this setup  , the build works nicely. But I notice that in the server VM, cds is removed.
> Instead of
>
> checking if cds should be enabled... yes
>
> I get (with some tracing added ) :
>
> configure: WARNING: ENABLE_CDS set to false because we found a minimal, core or zero JVM.
> checking if cds should be enabled... no
>
> The checks in hotspot.m4 disables cds by error for the server v,  because it matches to minimal  in the string  "minimal,server"  .
>
> The configure option  --with-jvm-variants=minimal,server   enables  a  multi-JVM variants build  (variable BUILDING_MULTIPLE_JVM_VARIANTS in hotspot.m4) .
> This   special build is only  supported  for   VALID_MULTIPLE_JVM_VARIANTS="server client minimal" .
> So  we  better do not  disable  cds  in  a  BUILDING_MULTIPLE_JVM_VARIANTS - build   (means minimal + server/client ) ;   minimal has cds disabled by default anyway.
>
>
> Bug/webrev :
>
> https://bugs.openjdk.java.net/browse/JDK-8237374
>
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8237374.0/
>
>
> Thanks, Matthias