RFR: 8329331: Intrinsify Unsafe::setMemory [v22]

[Scott Gibbons]

On Fri, 19 Apr 2024 18:25:17 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Scott Gibbons has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Address review comments; update copyright years
>
> General comment/suggestion before I dive into review.
> Can we do renaming `UnsafeCopyMemory*` -> `UnsafeMemory*` in follow up RFE. This change hides the real change.

@vnkozlov I un-did the name change and will submit a separate request for re-naming.  Thanks.

> src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 8336:
> 
>> 8334:     // Initialize table for copy memory (arraycopy) check.
>> 8335:     if (UnsafeMemoryAccess::_table == nullptr) {
>> 8336:       UnsafeMemoryAccess::create_table(18);
> 
> Needs comment explaining 18 number

Hmmm...  There was no comment explaining the 8 number :-).  I added 10 to the table size because I knew I was going to add 7 places where a mark was required.  I left 3 for safety.

The algorithm has since changed, so I changed this to:

`UnsafeCopyMemory::create_table(8 + 4); // 8 for copyMemory; 4 for setMemory`

I did a similar change to all other table creation numbers.

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PR Comment: https://git.openjdk.org/jdk/pull/18555#issuecomment-2067197605
PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1572840222