(define (codegen-not x si env)
(codegen-expr x si env)
- (emit "xorq $-1, %rax")
+ (emit "notq %rax")
(emit "andq $1, %rax"))
(define (range s n)
(inner-si (- si (* (length bindings) wordsize)))
(names (map car bindings))
(exprs (map cadr bindings))
- (inner-env (append (map cons names stack-offsets) env)))
- (for-each (lambda (expr offset)
+
+ ; recursive let bindings: build environment as we go
+ (inner-env (fold-left
+ (lambda (env name expr offset)
(codegen-expr expr inner-si env)
- (emit "movq %rax, ~a(%rsp)" offset))
- exprs stack-offsets)
- (for-each (lambda (form) (codegen-expr form inner-si inner-env)) body)))
+ (emit "movq %rax, ~a(%rsp)" offset)
+ (cons (cons name offset) env))
+ env names exprs stack-offsets)))
+ (for-each (lambda (form)
+ (codegen-expr form inner-si inner-env))
+ body)))
(define (codegen-var name si env)
+ (when (not (assoc name env))
+ (error #f (format "Variable ~a is not bound" name)))
(let ((offset (cdr (assoc name env))))
(emit "movq ~a(%rsp), %rax" offset)))
+(define cur-lambda 0)
+(define (fresh-lambda)
+ (set! cur-lambda (+ 1 cur-lambda))
+ (format "_lambda~a" (- cur-lambda 1)))
+
+ ; for now we can only call closures
+(define (codegen-call closure args si env)
+ (let* ((captured (caddr closure))
+ (label (cadr closure))
+ (argument-start (length captured)))
+
+ ; first move the captured variables into param registers
+ (for-each
+ (lambda (e i)
+ (emit "movq ~a(%rsp), ~a"
+ (cdr (assoc e env)) ; offset of the var
+ (param-register i)))
+ captured (range 0 (length captured)))
+
+
+ ; then codegen the arguments and move them into the next param registers
+ (for-each
+ (lambda (e i)
+ (begin
+ (codegen-expr e si env)
+ ; move result to correct param register
+ (emit "movq %rax, ~a" (param-register i))))
+ args (range argument-start (length args)))
+
+ ; now call
+ (emit "callq ~a" label)))
+
+
+(define (codegen-lambda l)
+ (let* ((label (car l))
+ (args (cadr l))
+ (captured (caddr l))
+ (body (cadddr l))
+ ; captured, then args
+ (vars (append captured args))
+
+ (param-registers (map param-register
+ (range 0 (length vars))))
+ (stack-offsets (map (lambda (i)
+ (* (- wordsize) i))
+ (range 0 (length vars))))
+
+ (copy-insts (map (lambda (r o)
+ (format "movq ~a, ~a(%rsp)"
+ r o))
+ param-registers stack-offsets))
+
+ (env (map cons vars stack-offsets)))
+ (emit "~a:" label)
+ (display "## lambda body: ")
+ (display body)
+ (newline)
+ (display "## environment: ")
+ (display env)
+ (newline)
+ (amd64-abi
+ (lambda ()
+ (for-each emit copy-insts)
+ (codegen-expr body (* (- wordsize) (length vars)) env)
+ )))) ; move args and capture vars to stack
+
(define (codegen-expr e si env)
- (cond ((app? e)
- (case (car e)
+ (case (ast-type e)
+ ('builtin e)
+ ('closure e)
+ ('app
+ (let ((callee (codegen-expr (car e) si env)))
+ (case callee
('+ (codegen-add (cdr e) si env))
('- (codegen-sub (cadr e) (caddr e) si env))
('* (codegen-mul (cadr e) (caddr e) si env))
('! (codegen-not (cadr e) si env))
('bool->int (codegen-expr (cadr e) si env))
- (else (error #f "can't handle anything else yet"))))
- ((let? e) (codegen-let
- (let-bindings e)
+ (else (codegen-call callee (cdr e) si env)))))
+
+ ('let (codegen-let (let-bindings e)
(let-body e)
si
env))
- ((var? e) (codegen-var e si env))
- ((boolean? e) (emit "movq $~a, %rax" (if e 1 0)))
- (else (emit "movq $~a, %rax" e))))
-(define (codegen program)
- (emit ".text")
- (emit ".p2align 4,,15")
- (emit ".globl _scheme_entry")
- (emit "_scheme_entry:")
+ ('var (codegen-var e si env))
+
+ ('string-literal (emit "movq ~a, %rax" label))
+ ('bool-literal (emit "movq $~a, %rax" (if e 1 0)))
+ ('int-literal (emit "movq $~a, %rax" e))
+
+ (else (error #f "don't know how to codegen this"))))
- ; handle incoming call from C
+
+(define (fold-map f x) (fold-left append '() (map f x)))
+
+(define (free-vars prog)
+ (define bound '())
+ (define (collect e)
+ (case (ast-type e)
+ ('builtin '()) ; do nothing
+ ('var (if (memq e bound) '() (list e)))
+ ('lambda
+ (set! bound (append (lambda-args e) bound))
+ (collect (lambda-body e)))
+
+ ('app (fold-map collect e))
+ ('let
+ (let ((bind-fvs (fold-map (lambda (a)
+ ((set! bound (cons (car a) bound))
+ (collect (cdr a))))
+ (let-bindings cadr)))
+ (body-fvs (fold-map collect (let-body e))))
+ (append bind-fvs body-fvs)))
+ (else '())))
+ (collect prog))
+
+ ; ((lambda (x) (+ x 1)) 42) => {lambda0: (x) (+ x 1)}, (@lambda0 42)
+(define (extract-lambdas program)
+ (define lambdas '())
+ (define (add-lambda e)
+ (let* ((label (fresh-lambda))
+ (args (lambda-args e))
+ (captured (free-vars e))
+ (body (extract (lambda-body e)))
+ (new-lambda (list label args captured body)))
+ (set! lambdas (cons new-lambda lambdas))
+ `(closure ,label ,captured))) ; todo: should we string->symbol?
+ (define (extract e)
+ (case (ast-type e)
+ ('lambda (add-lambda e))
+ ('let `(let
+ ,(map extract (let-bindings e))
+ ,@(map extract (let-body e))))
+ ('app (append (list (extract (car e)))
+ (map extract (cdr e))))
+ (else e)))
+ (let ((transformed (extract program)))
+ (cons lambdas transformed)))
+
+;(define (extract-strings program))
+
+(define (amd64-abi f)
+ ; preserve registers
(emit "push %rbp")
(emit "push %rbx")
(for-each (lambda (i)
(number->string i))))
'(12 13 14 15))
- ; our code goes here
- (codegen-expr program 0 '())
-
+ (f) ; call stuff
; restore preserved registers
(for-each (lambda (i)
(emit (string-append
'(15 14 13 12))
(emit "pop %rbx")
(emit "pop %rbp")
-
(emit "ret"))
-(define (compile-to-binary program)
+ ; 24(%rbp) mem arg 1
+ ; 16(%rbp) mem arg 0 prev frame
+ ; -----------------------
+ ; 8(%rbp) return address cur frame
+ ; 0(%rbp) prev %rbp
+ ; -8(%rbp) do what you want
+ ; ... do what you want
+ ; 0(%rsp) do what you want
+
+(define (param-register n)
+ (case n
+ (0 "%rdi")
+ (1 "%rsi")
+ (2 "%rdx")
+ (3 "%rcx")
+ (4 "%r8")
+ (5 "%r9")
+ (else (error #f "need to test out the below"))
+ (else (format "~a(%rsp)" (- n 6)))))
+
+(define (codegen program)
+ (let* ((extract-result (extract-lambdas program))
+ (lambdas (car extract-result))
+ (xform-prog (cdr extract-result)))
+ (emit ".text")
+ (emit ".p2align 4,,15")
+
+ (for-each codegen-lambda lambdas)
+
+ (emit ".globl _scheme_entry")
+ (emit "_scheme_entry:")
+
+
+ (amd64-abi
+ (lambda () (codegen-expr xform-prog 0 '())))))
+
+(define (compile-to-binary program output)
(when (not (eq? (typecheck program) 'int)) (error #f "not an int"))
(let ([tmp-path "/tmp/a.s"])
(when (file-exists? tmp-path) (delete-file tmp-path))
(with-output-to-file tmp-path
(lambda () (codegen program)))
- (system "clang -fomit-frame-pointer /tmp/a.s rts.c")))
+ (system (format "clang -fomit-frame-pointer /tmp/a.s rts.c -o ~a" output))))
projects / scheme.git / blobdiff