RFR (S) 8150465: Unsafe methods to produce uninitialized arrays

[Vladimir Kozlov]

Okay. Looks good.

Thanks,
Vladimir

On 2/25/16 12:10 AM, Aleksey Shipilev wrote:
> On 02/25/2016 03:20 AM, Vladimir Kozlov wrote:
>> On 2/24/16 3:51 PM, Aleksey Shipilev wrote:
>>> On 02/25/2016 02:21 AM, Vladimir Kozlov wrote:
>>>> What is your story for GC? When an array become visible and GC happens,
>>>> it will expect only initialized arrays.
>>>
>>> New method allows primitive arrays only, and its headers should be
>>> intact. This is corroborated by the new jtreg test (and benchmarks!)
>>> that allocate lots of uninitialized arrays, and obviously they get GCed.
>>
>> Yes, primitive arrays are fine if the header is correct. In this case
>> changes are fine but you may need to add a check in
>> inline_unsafe_newArray() that it is only primitive types.
>
> Alas, the class argument may not be constant, and so we would need a
> runtime check there, which would duplicate the check we already have in
> Unsafe.java. I'd prefer to follow the upcoming pattern in Mikael's
> Unsafe cleanup with making as much checks on Java side.
>
>> testIAE() should throw exception if IllegalArgumentException is not thrown.
>
> D'uh, of course!
>
> See updates:
>    http://cr.openjdk.java.net/~shade/8150465/webrev.jdk.01/
>    http://cr.openjdk.java.net/~shade/8150465/webrev.hs.02/
>
> Cheers,
> -Aleksey
>