A toy compiler for the untyped lambda calculus
To do:
- Test the generated assembly!!!
- Carry types through
- Do tail calls properly
- Separate into files
- Merge AST data types
Examples:
the Y combinator:
\f. (\x.x x) (\y.f (y y))
I first add explicit thunks:
\f. (\x. x () x) (\() y. f () (\(). (y () y)))
The continuation passing transform then sequentializes the operations:
(){
return: (f){
x = (){
return: (y){
forced_f = f()
thunk = (){
forced_y = y()
return: forced_y(y)
}
return: forced_f(thunk)
}
}
forced_x = x()
return: forced_x(x)
}
}
and then it is closure converted, with global labels.
Also, tuples are initialized in many steps through mutation,
here's just a smal portion:
x_code: (env, y) {
f = env[1]
code = f[0]
forced_f = code(f)
thunk = 2[]
thunk[0] := thunk_code
thunk[1] := y
code = forced_f[0]
return: code(forced_f, thunk)
}
and the corresponding assembly:
x_code:
subl $8, %esp
movl %eax, 0(%esp)
movl %ebx, 4(%esp)
movl 0(%esp), %eax
movl 4(%eax), %eax
subl $4, %esp
movl %eax, 0(%esp)
movl 0(%esp), %eax
movl 0(%eax), %eax
subl $4, %esp
movl %eax, 0(%esp)
movl 4(%esp), %eax
movl 0(%esp), %edi
call *%edi
subl $4, %esp
movl %eax, 0(%esp)
movl $2, %eax
call __malloc__
subl $4, %esp
movl %eax, 0(%esp)
movl 0(%esp), %eax
movl $thunk_code, %ebx
movl %ebx, 0(%eax)
movl 0(%esp), %eax
movl 20(%esp), %ebx
movl %ebx, 4(%eax)
movl 4(%esp), %eax
movl 0(%eax), %eax
subl $4, %esp
movl %eax, 0(%esp)
movl 8(%esp), %eax
movl 4(%esp), %ebx
movl 0(%esp), %edi
call *%edi
addl $28, %esp
ret