CDS Shared flags need constraint function which will guarantee that sum of the Shared flags is not greater than certain value.

JVM hit assertion when run with max values for SharedMiscCodeSize, SharedMiscDataSize, SharedReadOnlySize or SharedReadWriteSize flags and other flags have default value. E.g.:
java -XX:SharedReadWriteSize=2137932543 -Xshare:dump
Allocated shared space: 2159030272 bytes at 0x0000000800000000
Loading classes to share ...
Preload Warning: Cannot find java/awt/AWTKeyStroke$1
...
Updating ConstMethods ... done.
Removing unshareable information ... done.
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/compactHashtable.cpp:140
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/scratch/jprt/T/P1/013053.cphillim/s/hotspot/src/share/vm/classfile/compactHashtable.cpp:140), pid=6981, tid=6990
# assert(max_delta <= (0x7FFFFFFF)) failed: range check
#
# JRE version: (9.0) (build )
# Java VM: Java HotSpot(TM) 64-Bit Server VM (1.9.0-internal-fastdebug-20151120013053.cphillim.jdk9-sponsor2-b00, interpreted mode, tiered, compressed oops, g1 gc, linux-amd64)
...

I think that constrain should be applied after ergo phase.