RFR: 8358735: GenShen: block_start() may be incorrect after class unloading [v2]

[Kelvin Nilsen]

On Fri, 3 Oct 2025 20:15:16 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix idiosyncratic formatting
>
> src/hotspot/share/gc/shenandoah/shenandoahMarkBitMap.hpp line 180:
> 
>> 178:                                  const HeapWord* limit) const;
>> 179: 
>> 180:   // Return the last marked address in the range [limit, addr], or addr+1 if none found.
> 
> Symmetry would have preferred `(limit, addr]` as the range with `limit` if none found.
> However, may be usage of this method prefers the present shape?

Yeah.  The reason for the asymmetry is that forward-looking limit may not be a legitimate address (may be end of heap), whereas backward looking limit is a legitimate address.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27353#discussion_r2512294911