# BitFunnel/NativeJIT

A C++ expression -> x64 JIT

Repository: https://github.com/BitFunnel/NativeJIT
Canonical: https://ross.abutalabs.com/products/nativejit
Homepage: http://bitfunnel.org/
Language: C++
License: MIT
License Family: permissive
Topics: compiler, jit
Last push: 2020-08-21T07:00:42+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3798, "days_push": 2203, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1261, forks 88 (observed 2026-08-28T04:04:10.232186+00:00)

## What it is
NativeJIT is a cross-platform C++ library for just-in-time compilation of expressions involving C data structures into optimized x64 machine code. It was developed by the Bing team for fast runtime evaluation of query-specific scoring expressions and has no dependencies beyond the standard C++ runtime.

## Use cases
- compile expressions built at runtime into fast x64 code
- evaluate scoring expressions over large document sets with low latency
- generate optimized machine code with good register allocation from C++
- avoid interpreter overhead for repeatedly evaluated expressions
- embed a lightweight JIT in a C++ application without external dependencies

## When to choose
- you need to JIT-compile expressions that are only known at runtime
- compilation cost must be low and amortized over many evaluations
- you want a dependency-free, cross-platform C++ JIT library
- you need tight control over generated x64 code quality

## When to avoid
- you need a general-purpose compiler or full language runtime rather than expression compilation
- your expressions are evaluated only once, so JIT overhead is not amortized
- you need non-x64 targets or GPU code generation
- you need actively developed software with recent releases and extensive documentation

## Facets
- artifact type: library
- maturity: maintenance
- function: compiler, interpreter
- domain: compilers, performance, developer-tools
- platform: windows, cpp, cross-platform
- tags: jit, x64, code-generation, expression-evaluation, search-engine, linux, macos

## Member repositories
- BitFunnel/NativeJIT (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:10.232186+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T05:04:16.061940+00:00, confidence not recorded.
  - readme: https://github.com/BitFunnel/NativeJIT (fetched 2026-08-28T04:04:10.232186+00:00, sha c58ac3ce56ad)
  - homepage: http://bitfunnel.org/ (fetched 2026-08-29T12:16:28.705663+00:00, sha 219587d36b28)
- Data as of 2026-08-30T08:39:29.467469+00:00.