Systems & CLI · Pro
Optimizing Compiler to Native Code
A compiler for a small typed language that parses to an SSA IR, runs real optimization passes, and emits native machine code via LLVM
You build a complete ahead-of-time compiler for a small statically-typed language: a hand-written lexer and recursive-descent parser, a type checker, translation to SSA (Static Single Assignment) intermediate representation, a set of optimization passes (constant folding, dead code elimination, inlining), and finally native x86-64 or ARM code generation through LLVM via the inkwell crate or the LLVM C API. The project is worth building because it walks you through every layer that production compilers like Clang and Rustc traverse, giving you direct experience with each transformation rather than treating the compiler as a black box. By the end you can feed a source file in and get a runnable native binary out, with measurable speedups from your own optimization passes.
What you build
- Lexer and recursive-descent parser that produces a typed AST for a small C-like language with functions, loops, and structs
- Type checker with Hindley-Milner-style inference for local variables and explicit annotations on function signatures
- Lowering from AST to SSA IR including phi-node insertion via the standard dominance-frontier algorithm
- Optimization passes on SSA IR: constant folding, copy propagation, dead code elimination, and function inlining for small callees
- LLVM IR emission via inkwell (Rust) or the LLVM C API (C++), targeting the host triple so the output links natively
- Native binary generation and linking through LLVM's built-in target machine, producing an ELF or Mach-O executable
- A simple benchmark suite that measures the effect of each optimization pass on compile time and runtime performance
What it teaches
- SSA construction including dominance frontiers, phi-node placement, and the renaming algorithm
- How LLVM's IR, pass manager, and target machine pipeline fit together at the API level
- Classic dataflow optimization passes and why they must be applied in a specific order to reach a fixed point
- Type inference and type checking as a tree traversal that builds and solves constraints
- Register allocation concepts: live ranges, interference graphs, and why spilling to the stack occurs
- How native object files are structured and how a linker resolves symbols to produce an executable
How it works
- 1
Lexer + Parser
- Tokenize source
- Build typed AST
- Report syntax errors
- 2
Type Checker
- Infer + annotate types
- Reject mismatches
- 3
SSA IR
- Lower AST to CFG
- Insert phi nodes
- Compute dominance
- 4
Optimization Passes
- Constant folding
- Dead code elim
- Inlining
- 5
LLVM Codegen
- Emit LLVM IR
- Target machine
- Link native binary
Sign in to open the build guide
Free account. Get the step-by-step build and every resource link.
Take it further
- Implement a simple register allocator using linear scan so you can also emit x86-64 assembly directly without going through LLVM, giving you a direct comparison of code quality.
- Add a generics system (monomorphization strategy) so parameterized functions and structs are specialized at compile time, similar to how Rust and C++ templates work.
- Build a bytecode interpreter for your SSA IR so you can run programs for debugging without LLVM, then diff the interpreter and native outputs as a correctness oracle.
