RFR: 8358680: AOT cache creation fails: no strings should have been added [v2]

[Aleksey Shipilev]

On Fri, 27 Jun 2025 16:01:19 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 with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Merge branch 'master' into 8358680-aot-cache-creation-fails-with-no-strings-should-have-been-added
>  - @coleenp comment: change items_count() to items_count_acquire()
>  - 8358680: AOT cache creation fails: no strings should have been added

Yes, as we discussed offline, there seem to be no better solution for JDK 25 than this. Awkward as it is.

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PR Review: https://git.openjdk.org/jdk/pull/25816#pullrequestreview-2976418730