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

[Vladimir Kozlov]

On 4/26/17 5:15 AM, Zoltán Majó wrote:
> Hi Vladimir,
>
>
> testing on all JPRT platforms (previously I tested only on SPARC)
> revealed a small problem.
>
> The flags we're checking are *unsigned* ints, therefore in
> commandLineFlagConstraintsCompiler.cpp it is sufficient to check
>
> if (value >= 4032) {

okay

>
> instead of
>
> if (value < 0 || value >= 4032) {
>
> The change is necessary to make gcc happy on linux_arm. (The '< 0' part
> of the check is anyway performed when the value is read -- I verified).
>
> Here's the updated webrev, please take a look:
> http://cr.openjdk.java.net/~zmajo/8179019/webrev.01/

Good.

Thanks,
Vladimir

>
> I re-tested with JPRT and did also some manual testing.
>
> Thank you!
>
> 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
>>>
>>>
>>>
>