When trying a fastdebug Zero variant build of hotspot an assertion gets triggered:

Optimizing the exploded image
/home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/build/linux-x86_64-normal-zero-fastdebug/jdk/bin/java -Xms64M -Xmx1600M -XX:ThreadStackSize=1536 -XX:+UseSerialGC -Xms32M -Xmx512M -XX:TieredStopAtLevel=1 -cp /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/build/linux-x86_64-normal-zero-fastdebug/buildtools/tools_jigsaw_classes --add-exports java.base/jdk.internal.module=ALL-UNNAMED build.tools.jigsaw.AddPackagesAttribute /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/build/linux-x86_64-normal-zero-fastdebug/jdk
(cd /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/build/linux-x86_64-normal-zero-fastdebug/support/src/jaxws/src/jdk.xml.ws/share/classes/ && /usr/bin/zip -qru /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/build/linux-x86_64-normal-zero-fastdebug/support/src.zip . -i "*.java" -x \*_the.\* || test "$?" = "12" )
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/method.cpp:1052
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/hotspot/src/share/vm/oops/method.cpp:1052), pid=7225, tid=7228
# assert(entry != __null) failed: interpreter entry must be non-null
#
# JRE version: (9.0) (fastdebug build )
# Java VM: OpenJDK 64-Bit Zero VM (fastdebug 9-internal+0-2016-12-05-213618.sgehwolf.openjdk9-hs, interpreted mode, serial gc, linux-amd64)
# Core dump will be written. Default location: Core dumps may be processed with "/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I" (or dumping to /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/make/core.7225)
#
# An error report file with more information is saved as:
# /home/sgehwolf/Documents/openjdk/upstream-sources/openjdk9-hs/make/hs_err_pid7225.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#
Current thread is 7228