Heads up: XmlValidation fails with Shenandoah JDK 9, possible compiler bug

[Aleksey Shipilev]

Hi,

I think we got ourselves a regression. This is the first time I see it, probably
because of tiered compilation turned off, which puts more stress on C2.

$
~/trunks/shenandoah-jdk9/build/linux-x86_64-normal-server-release/images/jdk/bin/java
-jar target/benchmarks.jar XmlValidation -f 1 -t 8 --jvmArgs "-Xmx8g -Xms8g
-XX:+UseShenandoahGC -XX:-TieredCompilation -Xlog:gc
-XX:ShenandoahGCHeuristics=adaptive" -i 100

...

org.w3c.dom.DOMException: WRONG_DOCUMENT_ERR: A node is used in a different
document than the one that created it.
	at
java.xml/com.sun.org.apache.xerces.internal.dom.AttributeMap.setNamedItem(AttributeMap.java:85)
	at
java.xml/com.sun.org.apache.xerces.internal.dom.DeferredElementNSImpl.synchronizeData(DeferredElementNSImpl.java:138)
	at
java.xml/com.sun.org.apache.xerces.internal.dom.ElementNSImpl.getPrefix(ElementNSImpl.java:268)
	at
java.xml/com.sun.org.apache.xerces.internal.jaxp.validation.DOMValidatorHelper.fillQName(DOMValidatorHelper.java:400)
	at
java.xml/com.sun.org.apache.xerces.internal.jaxp.validation.DOMValidatorHelper.beginNode(DOMValidatorHelper.java:274)

Bisect points at mammoth change:

changeset:   13043:b1d87ff3b89a
user:        roland
date:        Mon Feb 27 13:57:51 2017 +0100
summary:     remove useless call to recompute_dom_depth + move loop opts to
shenandoah barrier classes + rework post expansion loop opts


Thanks,
-Aleksey