More WIP on closures

[scheme.git] / codegen.scm

diff --git a/codegen.scm b/codegen.scm
index 9b3878a2e947f3d3314c8c9c4bc96bca38a83a7f..571f1ef8498c0a662f3dfa7254b0cf2f535e4374 100644 (file)
--- a/codegen.scm
+++ b/codegen.scm
@@ -105,8 +105,25 @@
   (set! cur-lambda (+ 1 cur-lambda))
   (format "_lambda~a" (- cur-lambda 1)))
 
+; a closure on the heap looks like:
+; 0-x    x+0   x+4       x+12      x+20
+; label #vars var1....  var2....  var3....
+(define (codegen-closure label captured si env)
+  (let* ((heap-offsets (range 4 (length captured))) ; 4, 12, 20, etc.
+        (inner-si (- si (* (length captured) wordsize))))
+    (emit "movl $~a, (heap_start)")
+    (emit "add $4, (heap_start)")
+    (for-each (lambda (var-name new-offset)
+               (emit "movq ~a(%rbp), ~a(heap_start)" ; todo: do we need to copy this?
+                     (cdr (assoc var-name env))
+                     new-offset)
+               (emit "add $8, (heap_start)")
+             captured
+             stack-offsets)
+)
                                        ; for now we can only call closures
 (define (codegen-call closure args si env)
+;  (codegen-expr closure si env)
   (when (not (eq? (ast-type closure) 'closure))
     (error #f (format "~a is not a closure" closure)))
   (let* ((captured (caddr closure))
@@ -190,7 +207,7 @@
 (define (codegen-expr e si env)
   (case (ast-type e)
     ('builtin e)
-    ('closure e)
+    ('closure (codegen-closure (cadr e) (caddr e) si env))
     ('app
      (let ((callee (codegen-expr (car e) si env)))
        (case callee