Cwerg

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To try out Cwerg, please follow quick_start_user.md

The best C-like language that can be implemented in 10kLOC

Cwerg aims to be a complete, compact and fast "from-scratch" compiler for a C-like language. It has no dependencies and consists of the following components:

• Frontend (FE): Overview, Additional Docs, Code

  A low-level C-like language with a Python inspired concrete syntax. Still under active development

• Intermediate Representation (IR): Overview, Code

  Defines an IR that serves as the interface between frontend and backend.

• Backend (BE): Overview, Additional Docs, Code

  Muti-target (currently: X86-64, Aarch64, Arm32).

  Also suitable for other compilers and as a JIT.

To get started hacking on Cwerg please read quick_start_developer.md.

Philosophy

Most components are implemented twice (see rationale):

1. spec/reference implementation: Python 3.10
2. high performance implementation: C++20 (with limited STL usage)

Re-implementations in other languages are explicitly encouraged. A lot of code is table driven to facilitate that.

Cwerg de-emphasizes quality of the generated code (the hope is to come within 50% of state of the art compilers) in favor of a small code base that can be understood by a single developer and very fast translation times.

Explicit line number targets are in place to prevent feature creep:

• frontend: 10kLOC (current counts)
• backend 10kLOC (target independent code) + 5kLOC(per target (current counts) (We cheat a little bit and do not include various tables in these numbers.)

The translation speed target is 1000k LOC per sec using at most 4 cores on a 2020 era midrange desktop or high end laptop.

Inspirations

• LLVM
• QBE (QBE vs LLVM)
• Mir (blog post)
• Wirth: A Plea for Lean Software, Oberon (compiler implementation)
• Delphi's compilation speed
• gcc code size