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

[Vladimir Kozlov]

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
>
>