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ZJIT: Emit run-time check for write barrier #894
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Right now if we don't know statically that an object being written to the frame/an object is an immediate, we always emit a write barrier. Instead, we should emit a run-time check testing if it is false or an immediate and only conditionally fire the write barrier.
A reasonable first PR would guard if VM_ENV_FLAG_WB_REQUIRED is set before a setlocal and side-exit if so (thereby completely omitting the write barrier in the majority of cases)
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tekknolagi commentedon Dec 9, 2025
Linked PR crashes and I'm not sure why. We should be able to skip function calls in LIR that don't return anything (no need for block params).
tekknolagi commentedon Dec 9, 2025
It would also be good to know when VM_ENV_FLAG_WB_REQUIRED is set and if we can somehow skip explicitly checking that.
jacob-shops commentedon Jan 28, 2026
Working on this issue here