# Mir JIT compiler library

6 Hacker News commenters recommended Mir JIT compiler library and 10 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months.

**Verdict:** Fast code generation and a complete toolkit for building custom JIT compilers, but Canonical retired its display server, and critics call it a costly, limited detour.

## Why people recommend it

- Tools for building custom JIT compilers (2 comments): "There are JIT frameworks out there with much faster code-generation than LLVM: Cranelift, GNU Lightning, Mir." ([source](https://news.ycombinator.com/item?id=49407068)) "It has all the tools for custom JIT including a nice C compiler." ([source](https://news.ycombinator.com/item?id=47941351))

## What people warn about

- Abandoned by Canonical after years (3 comments): "Mir and Unity were perfectly fine technologies but they retired it because they didn't want to see things through" ([source](https://news.ycombinator.com/item?id=46047497)) "attempted to uproot for no purpose other than Canonical wanted more control" ([source](https://news.ycombinator.com/item?id=47724208)) "they figured out it was a really bad idea in time" ([source](https://news.ycombinator.com/item?id=46142318))
- Costly distraction for Ubuntu (2 comments): "Nobody picked Ubuntu because of Mir, or Compiz, or Upstart" ([source](https://news.ycombinator.com/item?id=47464948)) "the financial burden of Ubuntu Mobile, Unity 8, and Mir" ([source](https://news.ycombinator.com/item?id=50033481))
- Many limitations, hard to use (2 comments): "I see you ran into many of the same MIR issues and limitations I did." ([source](https://news.ycombinator.com/item?id=49176265)) "Neither of MIR or IR are friendly/easy though." ([source](https://news.ycombinator.com/item?id=48377932))
- Ubuntu-specific design, not standard (2 comments): "it also insists on doing a lot of its own thing like using Mir instead of X and click packages." ([source](https://news.ycombinator.com/item?id=46753080)) "Or when they created Mir to replace X." ([source](https://news.ycombinator.com/item?id=47521050))

## Alternatives hackers recommend

- [Numba](https://hackerapproved.com/p/numba.md): 30 recommend
- [CPython experimental JIT](https://hackerapproved.com/p/cpython-experimental-jit.md): 13 recommend
- [YJIT](https://hackerapproved.com/p/yjit.md): 10 recommend
- [HotSpot JVM](https://hackerapproved.com/p/hotspot.md): 8 recommend
- [ZJIT](https://hackerapproved.com/p/zjit.md): 7 recommend

## Cite as

Hacker Approved, "Mir JIT compiler library", https://hackerapproved.com/p/mir/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).