RFR 8129547 (S): Excess entries in BootstrapMethods with the same (bsm, bsmKind, bsmStaticArgs), but different dynamicArgs

[Aleksey Shipilev]

I agree. Please sponsor?

Not sure what pre-commit checks are needed to be run. I have only tested
with that regression test, plus some other related ones for indy string
concat.

-Aleksey

On 08/21/2015 06:42 PM, Maurizio Cimadamore wrote:
> Cool - many thanks!
> 
> I'd say we can go ahead with this.
> 
> Maurizio
> 
> On 21/08/15 16:10, Aleksey Shipilev wrote:
>> Hey Maurizio,
>>
>> I have tried to slim down TestInvokeDynamic to make a regression test.
>> It fails on current javac, and passes on a patched one:
>>    http://cr.openjdk.java.net/~shade/8129547/webrev.02/
>>
>> Thanks,
>> -Aleksey
>>
>> On 08/18/2015 12:23 AM, Maurizio Cimadamore wrote:
>>> Whoops - that's what I meant to write, sorry; I'm glad you like the
>>> overall scheme. I will cook up a test tomorrow - we do have one test
>>> which attaches fake dynamic symbols to AST nodes, (using an annotation
>>> processor) then invokes code generation and checks the resulting
>>> bytecode [1]. I think one such test might be useful here.
>>>
>>> [1] -
>>> http://hg.openjdk.java.net/jdk9/jdk9/langtools/file/tip/test/tools/javac/lambda/TestInvokeDynamic.java
>>>
>>>
>>>
>>> Maurizio
>>>
>>> On 17/08/15 20:24, Aleksey Shipilev wrote:
>>>> Hi Maurizio,
>>>>
>>>> Thanks for an idea! It almost works, but not quite: super.equals() from
>>>> Method checks the type, so we need to guard super.*, as you did in
>>>> hashCode(). We also need a proper subclass check for the keys alone,
>>>> which means we might move equals() there, and make key a proper
>>>> subclass
>>>> to gain access to "other".
>>>>
>>>> In short, this version works:
>>>>    http://cr.openjdk.java.net/~shade/8129547/webrev.01/
>>>>
>>>> Thanks,
>>>> -Aleksey
>>>>
>>>> On 17.08.2015 17:15, Maurizio Cimadamore wrote:
>>>>> Ok, I think I know what you meant now; DynamicMethod is used for two
>>>>> different purposes:
>>>>>
>>>>> * for the NameAndType CP entry associated with an invokedynamic
>>>>> instruction (pointed by the CONSTANT_InvokeDynamic entry); this bit
>>>>> _requires_ dynamic info to be taken into account - as different
>>>>> invoked
>>>>> types need to map to different entries - even if their underlying BSM
>>>>> entry is the same.
>>>>>
>>>>> * as keys in the BootstrapMethod attribute; in this case you want the
>>>>> dynamic info to be gone, as all it's going to be stored in the
>>>>> table is
>>>>> a bsmKind + static args list.
>>>>>
>>>>> How about something like this:
>>>>>
>>>>> http://cr.openjdk.java.net/~mcimadamore/8129547/
>>>>>
>>>>> Maurizio
>>>>>
>>>>>
>>>>>
>>>>> On 17/08/15 14:48, Maurizio Cimadamore wrote:
>>>>>> Hi Alex,
>>>>>> the only dfference I see between your patch and the current code is
>>>>>> that the current code is comparing the invokedType, while yours is
>>>>>> not
>>>>>> - am I reading your patch correctly?
>>>>>>
>>>>>> If that's the case, wouldn't dropping the call to super.equals from
>>>>>> Pool.DynamicMethod also resolve the issue?
>>>>>>
>>>>>> I'm, saying this because, from a design perspective, javac symbols
>>>>>> usually don't care about uniqueness etc. - that's an extra value
>>>>>> added
>>>>>> when storing them into a constant pool.
>>>>>>
>>>>>> Maurizio
>>>>>>
>>>>>> On 17/08/15 13:33, Aleksey Shipilev wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> This issue gets into way with my current work:
>>>>>>>      https://bugs.openjdk.java.net/browse/JDK-8129547
>>>>>>>
>>>>>>> There is a proof-of-concept patch:
>>>>>>>      http://cr.openjdk.java.net/~shade/8129547/webrev.00/
>>>>>>>
>>>>>>> The crux of an issue seems to be the Method.equals() call in
>>>>>>> DynamicMethod.equals(), that compares the type. The type of
>>>>>>> DynamicMethod includes the DynamicMethodSymbol.type, that includes
>>>>>>> dynamic args. It seems DynamicMethodSymbol is a better fit for
>>>>>>> BootstrapMethod table key, since it includes BSM symbol and static
>>>>>>> arguments only.
>>>>>>>
>>>>>>> I would be grateful if somebody from compiler team can help me out
>>>>>>> with
>>>>>>> this. Is this the fix above valid? Can you do it better?
>>>>>>>
>>>>>>> How would one write a regression test for it? My cursory grep
>>>>>>> through
>>>>>>> langtools tests does not yield a clear way to emit a special-shaped
>>>>>>> indy
>>>>>>> for such a test.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> -Aleksey
>>>>>>>
>>
> 


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