hoangpq / ulisp

A compiler for a lisp-like language targeting LLVM IR, x86 assembly

ulisp

A compiler for a lisp-like language written in JavaScript targeting LLVM, x86 assembly.

Tutorials

1. Lisp to assembly
2. User-defined functions and variables
3. LLVM
4. LLVM conditionals and compiling fibonacci
5. LLVM system calls
6. An x86 upgrade

Example

The following program:

$ cat tests/fib.lisp
(def fib (n)
     (if (< n 2)
	 n
       (+ (fib (- n 1)) (fib (- n 2)))))

(def main ()
     (fib 8))

Returns 21 as its exit code when compiled:

$ node src/ulisp.js tests/fib.lisp
$ ./build/prog
$ echo $?
21

By generating this LLVM IR:

define i32 @fib(i32 %n) {
  %ifresult7 = alloca i32, align 4
  %sym8 = add i32 %n, 0
  %sym9 = add i32 2, 0
  %sym6 = icmp slt i32 %sym8, %sym9
  br i1 %sym6, label %iftrue10, label %iffalse11
iftrue10:
  %sym12 = add i32 %n, 0
  store i32 %sym12, i32* %ifresult7, align 4
  br label %ifend13
iffalse11:
  %sym18 = add i32 %n, 0
  %sym19 = add i32 1, 0
  %sym17 = sub i32 %sym18, %sym19
  %sym15 = call i32 @fib(i32 %sym17)
  %sym21 = add i32 %n, 0
  %sym22 = add i32 2, 0
  %sym20 = sub i32 %sym21, %sym22
  %sym16 = call i32 @fib(i32 %sym20)
  %sym14 = add i32 %sym15, %sym16
  store i32 %sym14, i32* %ifresult7, align 4
  br label %ifend13
ifend13:
  %sym5 = load i32, i32* %ifresult7, align 4
  ret i32 %sym5
}

define i32 @main() {
  %sym6 = add i32 8, 0
  %sym5 = call i32 @fib(i32 %sym6)
  ret i32 %sym5
}