Koopa

Library for generating/parsing/optimizing Koopa IR.

For more details, please see the readme file of the koopa repository, and the documentation.

Usage

cargo add koopa

License

Copyright (C) 2021-2025 MaxXing. Licensed under GPLv3.

lib.rs:

Library for generating/parsing/optimizing Koopa IR.

Koopa IR is the next generation of education-oriented intermediate representations designed for compiler courses at Peking University.

Koopa IR

Here is a "Hello, world!" program in Koopa IR:

// `putchar` function in libc.
decl @putchar(i32): i32

// A helper function for printing strings (integer arrays).
fun @putstr(@arr: *i32) {
%entry:
  jump %loop_entry(@arr)

%loop_entry(%ptr: *i32):
  %cur = load %ptr
  br %cur, %loop_body, %end

%loop_body:
  call @putchar(%cur)
  %next = getptr %ptr, 1
  jump %loop_entry(%next)

%end:
  ret
}

// String "Hello, world!\n\0".
global @str = alloc [i32, 15], {
  72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33, 10, 0
}

// `main` function, the entry point of the program.
fun @main(): i32 {
%entry:
  %str = getelemptr @str, 0
  call @putstr(%str)
  ret 0
}

Koopa IR is a strongly-typed, SSA form based intermediate representation. It's simple but powerful enough to support compilation of code into machine instructions, or some advanced optimizations of it.

For more details, see the document of Koopa IR (Chinese).

Examples

See the examples directory, which contains three examples:

• opt: a simple Koopa IR optimizer.
• brainfuck: a brainfuck to Koopa IR compiler.
• interpreter: a simple Koopa IR interpreter.

And there are some more complex examples:

• kira-rs: The Kira compiler (Rust version), which compiles SysY language into Koopa IR and RISC-V assembly.
• kira-cpp: The Kira compiler (C++ version).

References

Koopa IR library is heavily influenced by LLVM and Cranelift.