Hi Paul,
I took a look at the jdk changes. They look good to me.
One section of code gave me pause, which is the throw of ClassCastException at
339 of CallSite.java, and the throw of the exception returned from
wrongTargetType() at 344 of CallSite.java. This appears odd given the "rethrow
any Error and wrap anything else in BSME" rule. But these throws are caught by
the catch of Throwable below, which does the wrap and throw of BSME.
This arrangement was already present in the code.
Usually I wrinkle my nose at a throw that's caught by a catch clause later on,
but in this case it's not obvious what would be better. Maybe a comment is
warranted?
I didn't look too closely at the hotspot changes; somebody else should review
them.
s'marks
On 10/14/16 3:08 PM, Paul Sandoz wrote:
Hi,
Please review:
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8166974-indy-errors-not-wrapped-jdk/webrev/
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8166974-indy-errors-not-wrapped-hotspot/webrev/
The JMV spec was recently updated to state the following in the Linkage
Exceptions section of the invokedynamic instruction:
https://bugs.openjdk.java.net/browse/JDK-8164693
"If resolution of the symbolic reference to the call site specifier throws an
exception E, the invokedynamic instruction
<add>throws E if the type of E is Error or a subclass, else it</add>
throws a BootstrapMethodError that wraps E."
"Otherwise, during the continuing resolution of the call site specifier, if
invocation of the bootstrap method completes abruptly (§2.6.5) because of a throw of
exception E, the invokedynamic instruction
<add>throws E if the type of E is Error or a subclass, else it</add>
throws a BootstrapMethodError that wraps E.”
Namely if linkage fails due to the throwing of an Error or subclass then that
Error is re-thrown by the indy. All other types of exception that may be thrown
are wrapped in BootstrapMethodError that is then thrown. This means that errors
such as ThreadDeath or OutOfMemoryError will pass through unwrapped.
This is a behavioural change but we anticipate one that should have minimal
impact.
This change was motivated by updates to some classes using VarHandle for which
VarHandle method linkage unduly wrapped some errors (like ThreadDeath) in
LinkageError. (Note the same will apply for MethodHandle invoke linkage, or
MethodHandle/MethodType resolution in the constant pool, or for string
concatenation which now leverages indy). VarHandle/MethodHandle linkage error
behaviour is tracked by another issue,
https://bugs.openjdk.java.net/browse/JDK-8163553, which should not require any
specification change.
Thanks,
Paul.
