* jitexpr
* Added possible necessary conditions to jitexpr.
A function makes it possible to infer a necessary query from an expression to match.
We can then accelerate queries involving a calculated field by not even evaluating the expression
on docs that trivially do not match.
* CR comment
* CR comment
* Fixing unit tests
---------
Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>
Add MIT license metadata to the jitexpr crate manifest, matching
tantivy and the other workspace subcrates, and include a copy of
the MIT license text.
Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>
JITModule never releases its executable allocation on drop; the only
way to reclaim it is the consuming, unsafe JITModule::free_memory.
CompiledFn previously stored the module in a plain field, so every
compiled expression's executable memory leaked for the remainder of
the process once the CompiledFn was dropped.
Wrap the module in ManuallyDrop and add an explicit Drop impl for
CompiledFn that calls free_memory. This is safe because CompiledFn is
only ever constructed behind an Arc and never exposes its entry point
or other raw pointers into the module outside &self-bounded calls, so
drop only runs once no call into the module can be in flight or happen
afterward.
Verified empirically: 200k compile+drop cycles peaked at ~3.3 GB RSS
before this fix and ~6 MB after.
Paul MasurelandPaul Masurel