Moonbit Compiler

This is a compiler for Moonbit language.

The official compiler uses OCaml and hand-crafted IR. This compiler attempts to leverage the power of MLIR and LLVM, enabling more optimizations.

As Moonbit language itself is unstable, this compiler might not always follow up the most recent changes. It is still under active development.

Any contributions are very welcome.

Supported features

The compiler is in a very early stage and is only capable of compiling a single file, with limited functionalities.

Supported language features include:

• variables of type Int only

• control flow via if and while

• functions, but not closures

Compiler Digest

Unlike Clang IR, we don't use a single dialect for every possible operations. Instead, we take advantage of various MLIR dialects that are already available, and treat moon dialect as a supplement.

As an example, take a look at the following source code.

fn main {
  let x = 1 + 2 * 3
}

It will be compiled to:

module {
  func.func @main() -> !moon.unit {
    %c1_i32 = arith.constant 1 : i32
    %c2_i32 = arith.constant 2 : i32
    %c3_i32 = arith.constant 3 : i32
    %0 = arith.muli %c2_i32, %c3_i32 : i32
    %1 = arith.addi %c1_i32, %0 : i32
    %2 = moon.get_unit() : () -> !moon.unit
    return %2 : !moon.unit
  }
}

Note that the last statement is automatically the return value, hence the get_unit operation. These useless instructions are eliminated via further transforms.