8369506: Bytecode rewriting causes Java heap corruption on AArch64

[jcking]

Unclean backport to JDK 21. The area in question was changed for JDK 25. Same approximate fix except adds a missing LoadLoad barrier to TemplateTable::fast_xaccess.

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Progress

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Issue

• JDK-8369506: Bytecode rewriting causes Java heap corruption on AArch64 (Bug - P2)

Reviewing

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[bridgekeeper]

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[jcking]

@shipilev Correct repo this time. PTAL to help verify barriers/fences for JDK 21.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

@jcking Please do not rebase or force-push to an active PR as it invalidates existing review comments. Note for future reference, the bots always squash all changes into a single commit automatically as part of the integration. See OpenJDK Developers’ Guide for more information.

[mlbridge]

Webrevs

• 01: Full - Incremental (f6e2040b)
• 00: Full (e548ef2a)

[theRealAph]

I spent a little while looking at the other uses of get_cache_and_index_at_bcp and I couldn't find anything obviously wrong, but that might not mean we're OK.

[jcking]

Ran this change with our reproducer, and no observable failures. I also made verify_field_offset be present in the optimized build to be sure. So I think we are good. This is as approximate of a fix we can get I think.