RFR: 8358680: AOT cache creation fails: no strings should have been added [v4]

[Coleen Phillimore]

On Wed, 2 Jul 2025 16:02:33 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Background: when writing the string table in the AOT cache, we do this:
>> 
>> 1. Find out the number of strings in the interned string table
>> 2. Allocate Java object arrays that are large enough to store these strings. These arrays are used by `StringTable::lookup_shared()` in the production run.
>> 3. Enter safepoint
>> 4. Copy the strings into the arrays
>> 
>> This bug happened because:
>> 
>> - Step 1 is not thread safe, so it may be reading a stale version of `_items_count`
>> - JIT compiler threads may create more interned strings after step 1
>> 
>> This PR attempts to fix both issues.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   @coleep comments

Marked as reviewed by coleenp (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/25816#pullrequestreview-2980082840