This review is being spread across four groups: langtools, core-libs,
hotspot and serviceability. This is the specific review thread for
serviceability - webrev:
http://cr.openjdk.java.net/~dholmes/8010319-JEP181/webrev.serviceability.v1/
See below for full details - including annotated full webrev guiding the
review.
The intent is to have JEP-181 targeted and integrated by the end of this
month.
Thanks,
David
-----
The nestmates project (JEP-181) introduces new classfile attributes to
identify classes and interfaces in the same nest, so that the VM can
perform access control based on those attributes and so allow direct
private access between nestmates without requiring javac to generate
synthetic accessor methods. These access control changes also extend to
core reflection and the MethodHandle.Lookup contexts.
Direct private calls between nestmates requires a more general calling
context than is permitted by invokespecial, and so the JVMS is updated
to allow, and javac updated to use, invokevirtual and invokeinterface
for private class and interface method calls respectively. These changed
semantics also extend to MethodHandle findXXX operations.
At this time we are only concerned with static nest definitions, which
map to a top-level class/interface as the nest-host and all its nested
types as nest-members.
Please see the JEP for further details.
JEP: https://bugs.openjdk.java.net/browse/JDK-8046171
Bug: https://bugs.openjdk.java.net/browse/JDK-8010319
CSR: https://bugs.openjdk.java.net/browse/JDK-8197445
All of the specification changes have been previously been worked out by
the Valhalla Project Expert Group, and the implementation reviewed by
the various contributors and discussed on the valhalla-dev mailing list.
Acknowledgments and contributions: Alex Buckley, Maurizio Cimadamore,
Mandy Chung, Tobias Hartmann, Vladimir Ivanov, Karen Kinnear, Vladimir
Kozlov, John Rose, Dan Smith, Serguei Spitsyn, Kumar Srinivasan
Master webrev of all changes:
http://cr.openjdk.java.net/~dholmes/8010319-JEP181/webrev.full.v1/
Annotated master webrev index:
http://cr.openjdk.java.net/~dholmes/8010319-JEP181/jep181-webrev.html
Performance: this is expected to be performance neutral in a general
sense. Benchmarking and performance runs are about to start.
Testing Discussion:
------------------
The testing for nestmates can be broken into four main groups:
- New tests specifically related to nestmates and currently in the
runtime/Nestmates directory
- New tests to complement existing tests by adding in testcases not
previously expressible.
- For example java/lang/invoke/SpecialInterfaceCall.java tests use
of invokespecial for private interface methods and performing receiver
typechecks, so we add java/lang/invoke/PrivateInterfaceCall.java to do
similar tests for invokeinterface.
- New JVM TI tests to verify the spec changes related to nest attributes.
- Existing tests significantly affected by the nestmates changes,
primarily:
- runtime/SelectionResolution
In most cases the nestmate changes makes certain invocations that
were illegal, legal (e.g. not requiring invokespecial to invoke private
interface methods; allowing access to private members via
reflection/Methodhandles that were previously not allowed).
- Existing tests incidentally affected by the nestmate changes
This includes tests of things utilising class
redefinition/retransformation to alter nested types but which
unintentionally alter nest relationships (which is not permitted).
There are still a number of tests problem-listed with issues filed
against them to have them adapted to work with nestmates. Some of these
are intended to be addressed in the short-term, while some (such as the
runtime/SelectionResolution test changes) may not eventuate.
- https://bugs.openjdk.java.net/browse/JDK-8203033
- https://bugs.openjdk.java.net/browse/JDK-8199450
- https://bugs.openjdk.java.net/browse/JDK-8196855
- https://bugs.openjdk.java.net/browse/JDK-8194857
- https://bugs.openjdk.java.net/browse/JDK-8187655
There is also further test work still to be completed (the JNI and JDI
invocation tests):
- https://bugs.openjdk.java.net/browse/JDK-8191117
which will continue in parallel with the main RFR.
Pre-integration Testing:
- General:
- Mach5: hs/jdk tier1,2
- Mach5: hs-nightly (tiers 1 -3)
- Targetted
- nashorn (for asm changes)
- hotspot: runtime/*
serviceability/*
compiler/*
vmTestbase/*
- jdk: java/lang/invoke/*
java/lang/reflect/*
java/lang/instrument/*
java/lang/Class/*
java/lang/management/*
- langtools: tools/javac
tools/javap
