[langtools] RFR (L): 8010319: Implementation of JEP 181: Nest-Based Access Control

[Jan Lahoda]

The javac/jshell changes look OK to me.

Jan

On 15.5.2018 02:52, David Holmes wrote:
> This review is being spread across four groups: langtools, core-libs,
> hotspot and serviceability. This is the specific review thread for
> langtools - webrev:
>
> http://cr.openjdk.java.net/~dholmes/8010319-JEP181/webrev.langtools.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
>