LLVM Basics

Basic idea

A toolkit of reusable compiler passes over a typed SSA IR. Front-ends emit LLVM IR; opt runs analysis/transform passes; llc lowers it to a target ISA. Decouples language design from back-end engineering.

Key facts

• IR is SSA-form, statically typed, three-address.
• Pass kinds: analysis (read-only) and transform.
• Key tools: clang, opt, llc, lld, lli.
• Phi nodes select values at CFG join points.

Siblings

• SSA form