RFR: JDK-8240224 Allow building hotspot without the serial gc

[David Holmes]

Hi Magnus,

On 9/03/2020 6:30 pm, Magnus Ihse Bursie wrote:
> When reworking the JVM feature handling, I wanted to try to compile 
> Hotspot with various features enabled/disabled. I quickly found out that 
> it's not really possible to build hotspot without the serial gc. While 
> this is not a terribly important use case, I think it's good to be able 
> to select serial freely, just as with the other collectors.

Really not sure this is a worthwhile exercise.

> With this patch it is possible to build a truly minimal JVM using 
> 'configure --with-jvm-variants=custom --with-jvm-features=g1gc'.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8240224
> WebRev: 
> http://cr.openjdk.java.net/~ihse/JDK-8240224-building-without-serial-gc/webrev.01 

make/ModuleTools.gmk

! TOOL_ADD_PACKAGES_ATTRIBUTE := $(BUILD_JAVA) 
$(JAVA_FLAGS_SMALL_BUILDJDK) \

that should be BUILDJDK_JAVA_FLAGS_SMALL.


make/RunTestsPrebuiltSpec.gmk
make/autoconf/boot-jdk.m4

! BUILDJDK_JAVA_FLAGS_SMALL := -Xms32M -Xmx512M -XX:TieredStopAtLevel=1

Depending on the default GC those -Xms and -Xmx settings may not be 
valid/possible.

Other changes seem okay but I'll leave it for GC folk to comment on that.

Cheers,
David


> 
> /Magnus