[svc] RFR (L): 8010319: Implementation of JEP 181: Nest-Based Access Control
David Holmes
david.holmes at oracle.com
Mon May 21 22:35:55 UTC 2018
Thanks Serguei, I'll update the code.
David
On 22/05/2018 8:15 AM, serguei.spitsyn at oracle.com wrote:
> Hi Coleen and David,
>
>
> On 5/21/18 14:19, David Holmes wrote:
>> Hi Coleen,
>>
>> I've moved your JVM TI comments here to the serviceability RFR thread.
>>
>> On 19/05/2018 8:36 AM, coleen.phillimore at oracle.com wrote:
>> >
>> >
>> http://cr.openjdk.java.net/~dholmes/8010319-JEP181/webrev.full.v1/src/hotspot/share/prims/jvmtiRedefineClasses.cpp.udiff.html
>>
>> >
>> >
>> > There is commented out code at line 806 in
>> > compare_and_normalize_class_versions.
>>
>> Oops - well spotted. A leftover from when the sorting code was
>> introduced. I'll remove it.
>
> Nice catch.
>
>> > Could you make the added code a separate function defined above so
>> > this isn't the longest function in the jvm?
>>
>> I'll try refactoring it. (Though it will likely still be one of the
>> longest functions :) )
>>
>> > 739 JvmtiThreadState *state =
>> > JvmtiThreadState::state_for((JavaThread*)thread);
>> > 740 RedefineVerifyMark rvm(the_class, scratch_class, state);
>> >
>> > Why does this need RedefineVerifyMark? It doesn't call the verifier.
>>
>> I'll defer to Serguei on that. But I think you're right that it is not
>> needed.
>
> Nice catch - the RedefineVerifyMark is not needed now.
> The RedefineVerifyMark was used to workaround an issue in the
> InstanceKlass::has_nest_member()
> that was called from the InstanceKlass::nest_host(). David convinced me
> that it is not right
> to call the nest_host() and that the nest_host_index() has to be used
> instead.
>
> Thanks,
> Serguei
>>
>>
>> Thanks,
>> David
>>
>> On 15/05/2018 10:52 AM, David Holmes wrote:
>>> 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
>>>
>
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