> For the complete documentation index, see [llms.txt](https://isubasinghe.gitbook.io/isithas-wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://isubasinghe.gitbook.io/isithas-wiki/software_engineering/frameworks/llvm.md).

# llvm

## Basic idea

Modular compiler infrastructure (formerly "Low Level Virtual Machine") used as a back-end by Clang, Rust, Swift, Julia, and many others. The defining abstraction is a typed, SSA-based intermediate representation.

## Key facts

* IR: typed, SSA form, three-address.
* Pass pipeline: front-end → IR → passes (analysis + transform) → back-end → target machine code.
* Clang, MLIR, Cranelift, llgo all build on LLVM.