RFR(8u): 8038636, 8055008, 8156137: SIGSEGV in ReceiverTypeData::clean_weak_klass_links ...and 8057570.

[Kevin Walls]

Hi,

I'd like to get approval for the 8u backport of these changes: we 
primarily want JDK-8156137 back into 8u, but it has some dependencies.

https://bugs.openjdk.java.net/browse/JDK-8156137

8u webrev: webrev: 
http://cr.openjdk.java.net/~kevinw/8055008.8156137/webrev.00/

8u backport approval on runtime-dev: 
http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2017-November/025354.html

..that's a long email that shows the chain of changes in order, with 
their jdk9 changesets and comments where they differ for 8u.


I will follow up on 8040237 separately: it's a short code change with 
further protection against tripping up on redefined classes, which was 
observed in a test.  The change in the webrev has now had some good 
real-world testing with no problems uncovered.

Many thanks,
Kevin