[1] RFR (S) 8179019: Correct range checks for command-line options ArraycopySrcPrefetchDistance and ArraycopyDstPrefetchDistance

[Zoltán Majó]

Thank you, Vladimir.

Best regards,


Zoltan

On 04/25/2017 09:34 AM, Vladimir Kozlov wrote:
> Good.
>
> Thanks,
> vladimir
>
> On 4/24/17 8:20 AM, Zoltán Majó wrote:
>> Hi,
>>
>>
>> please review the following fix for 8179019.
>> https://bugs.openjdk.java.net/browse/JDK-8179019
>> http://cr.openjdk.java.net/~zmajo/8179019/webrev.00/
>>
>> Currently, the HotSpot allows Arraycopy{Src|Dst}PrefetchDistance only
>> one value. Before JDK-8078554, values in the interval [0, 4096] were
>> allowed (without explicit checking, though).
>>
>> This change extends the set of values allowed to the interval [0, 4031].
>> We need the high bound 4032 (instead of 4096) because of [1]: the
>> largest value of offset is 64, so 4031 + 64 = 4095 is the maximum that
>> fits into the signed range of 13 bits. The change also includes
>> suggestions by Vladimir K [2] to avoid using too large immediate values.
>>
>> I tested the change manually with some values from both ends of the
>> range and also with JPRT (incl. the currently disabled
>> TestOptionsWithRanges.java test).
>>
>> Thank you!
>>
>> Best regards,
>>
>>
>> Zoltan
>>
>> [1]
>> http://hg.openjdk.java.net/jdk10/hs/hotspot/file/1617b39a1ae4/src/cpu/sparc/vm/stubGenerator_sparc.cpp#l2128 
>>
>>
>> [2]
>> https://bugs.openjdk.java.net/browse/JDK-8179019?focusedCommentId=14071776&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14071776 
>>
>>
>>