compli

My compiler for PLI, the "programming language implementations" course.

Overview

compli is a functional-style programming language based on the language we implemented in the first six homeworks.

On a high level, the compiler pipeline consists of:

• Parsing (source code to AST)
• Type checking (provide type information in AST)
• Lowering (typed AST to compli's IR)
• Code generation (compli's IR to LLVM IR)

The main differences compared to the language we developed in the course are:

• My custom language design (with major additions, see next paragraph)
• Implementation specifics (used programming language & libraries)
• Much higher-level intermediate representation (thanks to the inkwell builder)

Language & compiler features

The highlights of my compiler project are:

• Capable front-end
  • Inspectable AST and IR (with pretty tree view)
  • Powerful type checker (allows for type-dependent lowering)
  • Nice error reports
• Floating-point numbers
• Records (product types)
• Runtime with useful builtins

Language tour & example programs

In the language-tour.compli all language features are shown.

There are also some more examples.

Building/Installation

You need to have installed:

• Rust toolchain (1.74.1 or newer)
• LLVM 18 (see llvm-sys documentation for more information)
• Additional libraries for linking
  • I needed to install: libz, libzstd, libffi

This project is Linux-only.

Example setup: Debian 12 (Bookworm)

apt install build-essential libzstd-dev zlib1g-dev libffi-dev

wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key > /etc/apt/trusted.gpg.d/llvm.asc
echo 'deb http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-18 main' > /etc/apt/sources.list.d/llvm-18.list
apt update
apt install llvm-18-dev libpolly-18-dev

cargo build

• For other Debian/Ubuntu versions: see https://apt.llvm.org/
• For Arch Linux: pacman -S llvm18

Usage

The compiler has multiple execution modes:

• compli build main.compli will compile the source code and automatically calls to the system C compiler to link the module with the runtime. This produces a main ELF executable.
• compli generate main.compli will only generate the compiled object (or assembly) file but won't link anything. This produces a main.o object file.
• compli inspect-ast main.compli will print the program's AST. With the --typed flag, it includes type information.
• compli inspect-ir main.compli will print the intermediate representation of the program.

See compli --help for all options.

Example usage

compli build main.compli
./main

# with manual linking
compli generate main.compli
gcc runtime.c main.o -o main
./main

Editor support (syntax highlighting)

Vim

There are syntax and filetype detection files for Vim provided (which can be copied/symlinked to the $VIMHOME/syntax/ and $VIMHOME/ftdetect/ directories).

Emacs

Also, there is a very basic Emacs major mode. To use it, open compli-mode.el, M-x eval-buffer, open a compli file and then M-x compli-mode.

Used crates

I used some awesome libraries for this compiler. The most interesting ones are:

• inkwell, a LLVM wrapper and building library
• chumsky, a text parsing library that uses parser combinators

Also:

• thiserror and miette for error handling/reporting
• tracing for logging
• clap for CLI argument parsing
• ptree for pretty printing of AST and IR
• tempfile for temporary files