[9] RFR (S): 8036117: MethodHandles.catchException doesn't handle VarargsCollector right (8034120 failed)

[Vladimir Ivanov]

John, Chris, thanks!

Best regards,
Vladimir Ivanov

On 3/11/14 3:08 AM, Christian Thalinger wrote:
> Even better.
>
> On Mar 10, 2014, at 3:21 PM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
>
>> Chris, thanks for the review.
>>
>> John suggested an elegant way to fix the problem - use asFixedArity.
>>
>> Updated fix:
>> http://cr.openjdk.java.net/~vlivanov/8036117/webrev.01/
>>
>> Best regards,
>> Vladimir Ivanov
>>
>> On 3/8/14 4:51 AM, Christian Thalinger wrote:
>>> Seems good to me.  I’d like to have another name for this method:
>>>
>>> +     private static Object invokeCustom(MethodHandle target, Object... args) throws Throwable {
>>>
>>> On Mar 4, 2014, at 12:00 PM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
>>>
>>>> http://cr.openjdk.java.net/~vlivanov/8036117/webrev.00/
>>>> https://bugs.openjdk.java.net/browse/JDK-8036117
>>>> 84 lines changed: 74 ins; 3 del; 7 mod
>>>>
>>>> I have to revert a cleanup I did for 8027827.
>>>> MethodHandle.invokeWithArguments (and generic invocation) has unpleasant
>>>> peculiarity in behavior when used with VarargsCollector. So,
>>>> unfortunately, invokeWithArguments is not an option there.
>>>>
>>>> Looking at the API (excerpts from javadoc [1] [2]), the following
>>>> condition doesn't hold in that case:
>>>>    "trailing parameter type of the caller is a reference type identical
>>>> to or assignable to the trailing parameter type of the adapter".
>>>>
>>>> Example:
>>>>    target.invokeWithArguments((Object[])args)
>>>>    =>
>>>>    target.invoke((Object)o1,(Object)o2,(Object)o3)
>>>>    =/>
>>>>    target.invokeExact((Object)o1, (Object)o2, (Object[])o3)
>>>>
>>>> because Object !<: Object[].
>>>>
>>>> The fix is to skip unnecessary conversion when invoking a method handle
>>>> and just do a pairwise type conversion.
>>>>
>>>> Testing: failing test case, nashorn w/ experimental features (octane)
>>>>
>>>> Thanks!
>>>>
>>>> Best regards,
>>>> Vladimir Ivanov
>>>>
>>>> [1] MethodHandle.invokeWithArguments
>>>> "Performs a variable arity invocation, ..., as if via an inexact invoke
>>>> from a call site which mentions only the type Object, and whose arity is
>>>> the length of the argument array."
>>>>
>>>> [2] MethodHandle.asVarargsCollector
>>>> "When called with plain, inexact invoke, if the caller type is the same
>>>> as the adapter, the adapter invokes the target as with invokeExact.
>>>> (This is the normal behavior for invoke when types match.)
>>>>
>>>> Otherwise, if the caller and adapter arity are the same, and the
>>>> trailing parameter type of the caller is a reference type identical to
>>>> or assignable to the trailing parameter type of the adapter, the
>>>> arguments and return values are converted pairwise, as if by asType on a
>>>> fixed arity method handle.
>>>>
>>>> Otherwise, the arities differ, or the adapter's trailing parameter type
>>>> is not assignable from the corresponding caller type. In this case, the
>>>> adapter replaces all trailing arguments from the original trailing
>>>> argument position onward, by a new array of type arrayType, whose
>>>> elements comprise (in order) the replaced arguments."
>>>> _______________________________________________
>>>> mlvm-dev mailing list
>>>> mlvm-dev at openjdk.java.net
>>>> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
>>>
>>> _______________________________________________
>>> mlvm-dev mailing list
>>> mlvm-dev at openjdk.java.net
>>> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
>>>
>> _______________________________________________
>> mlvm-dev mailing list
>> mlvm-dev at openjdk.java.net
>> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
>
> _______________________________________________
> mlvm-dev mailing list
> mlvm-dev at openjdk.java.net
> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
>