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

[David Holmes]

Hi Boris,

Many thanks for looking at this and working through the ARM code.

I will study your patch in detail but am concerned by the "passes most 
of runtime/Nestmates tests Ok."! What tests are not passing?

David

On 17/05/2018 1:05 AM, Boris Ulasevich wrote:
> Hi David,
> 
> Let us look to the change in templateTable_arm.cpp. I have several notes.
> 
> 1. We have compilation error because check_klass_subtype call needs one 
> more temporary register parameter. I think correct change is:
> check_klass_subtype(Rklass, Rinterf, R1_tmp, R0_tmp, subtype);
> ->
> check_klass_subtype(Rklass, Rinterf, R1_tmp, R0_tmp, noreg, subtype);
> 
> 2. R0_tmp holds mdp used for profilation several lines below, so we 
> can't spoil it. I think correct change is:
> check_klass_subtype(Rklass, Rinterf, R1_tmp, R0_tmp, noreg, subtype);
> ->
> check_klass_subtype(Rklass, Rinterf, R1_tmp, R2_tmp, noreg, subtype);
> 
> 3. We can't jump to Rindex. I believe it was supposed to jump to Rmethod:
> jump_from_interpreted(Rindex);
> ->
> jump_from_interpreted(Rmethod);
> 
> 4. Please note than Rklass and Rflags reuses same register. Before the 
> change their life ranges had no intersection. I would propose to use R2 
> for Rklass (same with Rrecv) and move load_klass call after 
> invokevirtual_helper call to avoid life range intersecton.
> 
> See my patch against original templateTable_arm.cpp version in attach - 
> with this change ARM build compiles and passes most of runtime/Nestmates 
> tests Ok.
> 
> regards,
> Boris
> 
> On 15.05.2018 03:52, David Holmes wrote:
>> This review is being spread across four groups: langtools, core-libs, 
>> hotspot and serviceability. This is the specific review thread for 
>> hotspot - webrev:
>>
>> http://cr.openjdk.java.net/~dholmes/8010319-JEP181/webrev.hotspot.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
>>