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

[David Holmes]

Thanks Maurizio!

David

On 15/05/2018 5:59 PM, Maurizio Cimadamore wrote:
> Hi David,
> the webrev looks good.
> 
> You did an excellent job in staying on top of all these different areas 
> - kudos!
> 
> The only thing I can't decide is whether we will need an escape hatch 
> flag for when you compile using -target 11 and, for some weird reason 
> you need to disable nestmates (e.g. you want javac to emit accessors). 
> But with all the testing you did, I'm confident that what we have is 
> good - we can always add such a flag at a later stage - it's so trivial.
> 
> Cheers
> Maurizio
> 
> 
> On 15/05/18 01:52, 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
>>
>