X-Git-Url: https://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=codegen.scm;h=dd7950765c9ef375d443a110788a9146079fad20;hp=b90e7cdcefff689f56ce3b9cb911de408949b872;hb=d6b60d54bc90e5ebdc643d05d0b806ae7fd8aa7c;hpb=190fc656a7b4e12e6fcf640c56e6ff71b5a39e40

diff --git a/codegen.scm b/codegen.scm
index b90e7cd..dd79507 100644
--- a/codegen.scm
+++ b/codegen.scm
@@ -11,6 +11,10 @@
 
 (define wordsize 8)
 
+(define (stack-type? data-layouts type)
+  (if (assoc type data-layouts) #t #f))
+
+
 (define (type-size data-layouts type)
 
   (define (adt-size adt)
@@ -31,11 +35,25 @@
 	   (adt-size adt)
 	   (error #f "unknown size" type)))]))
 
+					; returns the size of an expression's result in bytes
+(define (expr-size e)
+  (if (eqv? (ast-type e) 'stack)
+      (cadr e)
+      wordsize))
+
 (define (on-stack? expr)
   (case (ast-type expr)
     ['stack (cadr expr)]
     [else #f]))
 
+; does a movsq for something on the stack
+(define (emit-stack-copy src dst size)
+  (emit "leaq ~a(%rbp), %rsi" (- src size))
+  (emit "leaq ~a(%rbp), %rdi" (- dst size))
+  (emit "movq $~a, %rcx" (/ size wordsize))
+  (emit "rep movsq"))	  
+  
+
 					; an environment consists of adt layouts in scope,
 					; and any bound variables.
 					; bound variables are an assoc list with their stack offset
@@ -118,7 +136,6 @@
     (and (eqv? (ast-type expr) 'closure)
 	 (memv name (caddr expr))))
 
-
   ;; (define (emit-scc scc env)
   ;;   ; acc is a pair of the env and list of touchups
   ;;   (define (emit-binding acc binding)
@@ -146,12 +163,31 @@
   ;; 	))
 
   ;;   (fold-left emit-binding (cons env '()) scc))))
-  
-  (let* ([stack-offsets (map (lambda (name x) ; assoc map of binding name to offset
-			       (cons name (- si (* x wordsize))))
-			     (map car bindings)
-			     (range 0 (length bindings)))]
-	 [inner-si (- si (* (length bindings) wordsize))]
+					; assoc map of binding name to size
+  (define stack-sizes
+    (map (lambda (binding) (cons (car binding) (expr-size (cadr binding))))
+	 bindings))
+
+					; assoc map of binding name to offset
+  (define stack-offsets
+					; 2  4  2  8  6
+    (let* ([totals                      ; 2  6  8  16 22
+	    (reverse (fold-left (lambda (acc x)
+				  (if (null? acc)
+				      (list x)
+				      (cons (+ x (car acc)) acc)))
+				'()
+				(map cdr stack-sizes)))]
+					; 0  2  6  8  16
+	   [relative-offsets (map - totals (map cdr stack-sizes))]
+	   [absolute-offsets (map (lambda (x) (- si x)) relative-offsets)])
+      (map cons (map car stack-sizes) absolute-offsets)))
+  
+  (let* (
+					; the stack index used when codegening binding body and main body
+					; -> stack ->
+					; [stack-offsets | inner-si]
+	 [inner-si (- si (fold-left + 0 (map cdr stack-sizes)))]
 
 	 [get-offset (lambda (n) (cdr (assoc n stack-offsets)))]
 	 
@@ -168,7 +204,8 @@
 		    [scc-env (make-env (env-data-layouts env) scc-binding-offsets)])
 	       (for-each 
 		(lambda (name)
-		  (let ([expr (cadr (assoc name bindings))])
+		  (let* ([expr (cadr (assoc name bindings))]
+			 [size (expr-size expr)])
 		    (emit "## generating ~a with scc-env ~a" name scc-env)
 		    (if (self-captive-closure? name expr)
 					; if self-captive, insert a flag into the environment to let
@@ -180,7 +217,11 @@
 				       (cons (cons name 'self-captive)
 					     (env-bindings scc-env))))
 			(codegen-expr expr inner-si scc-env))
-		    (emit "movq %rax, ~a(%rbp)" (get-offset name))))
+
+		    (if (on-stack? expr)
+						  ; copy over whatevers on the stack
+			(emit-stack-copy inner-si (get-offset name) size)
+			(emit "movq %rax, ~a(%rbp)" (get-offset name)))))
 		comps)
 	       scc-env))
 	   env
@@ -190,11 +231,16 @@
 		(codegen-expr form inner-si inner-env))
 	      body)))
 
-(define (codegen-var name si env)
-  (let ([binding (assoc name (env-bindings env))])
-    (if (not binding)
-	(error #f (format "Variable ~a is not bound" name))
-	(emit "movq ~a(%rbp), %rax" (cdr binding)))))
+(define (codegen-var e si env)
+  (let* ([stack-size (on-stack? e)]
+	 [name (if (on-stack? e) (caddr e) e)]
+	 [stack-offset (cdr (assoc name (env-bindings env)))])
+    (when (not stack-offset)
+      (error #f (format "Variable ~a is not bound" name)))
+
+    (if (on-stack? e)
+	(emit-stack-copy stack-offset si stack-size)
+	(emit "movq ~a(%rbp), %rax" stack-offset))))
 
 (define cur-lambda 0)
 (define (fresh-lambda)
@@ -363,31 +409,94 @@
     (emit "~a:" exit-label)))
 
 (define (data-tor env e)
-  (and (list? e)
+  (if (not (list? e)) #f    
       (assoc (car e) (flat-map data-tors (env-data-layouts env)))))
 
+					; returns the internal offset in bytes of a product within an ADT
+					; given the constructor layout
+					; constructor-layout: (foo (Int Bool))
+(define (data-product-offset data-layouts type sum index)
+  (let* ([products (cdr (assoc sum (cdr (assoc type data-layouts))))]
+	 [to-traverse (list-head products index)])
+    (fold-left
+     (lambda (acc t) (+ acc (type-size data-layouts t)))
+     wordsize ; skip the tag in the first word
+     to-traverse)))
+
+(define (data-sum-tag data-layouts type sum)
+
+  (define (go acc sums)
+    (when (null? sums) (error #f "data-sum-tag no sum for type" sum type))
+    (if (eqv? sum (car sums))
+	acc
+	(go (+ 1 acc) (cdr sums))))
+  (let* ([type-sums (cdr (assoc type data-layouts))])
+    (go 0 (map car type-sums))))
+
 (define (codegen-data-tor e si env)
 
+  (define dls (env-data-layouts env))
+
   (define (codegen-destructor tor)
-    (when (not (eqv? 'stack (ast-type (cadr e))))
-      (error #f "expected stack value"))
-    (let* ([stack-expr (cadr e)]
-	  [stack-body (caddr stack-expr)]
-	  [stack-type (cadr stack-expr)])
-      
-    (codegen-expr stack-body si env)
-    (let ([index (cadr tor)]
-	  [products 2]
-	  [to-traverse (list-head products index)]
-	  [offset (fold-left
-		   (lambda (acc t) (+ acc (type-size t)))
-		   wordsize ; skip tag in first word
-		   to-traverse)])
-      3
-      )))
+    (let* ([res (codegen-expr (cadr e) si env)]
+	   [info (cadr tor)]
+	   [type (car info)]
+	   [sum (cadr info)]
+   	   [index (caddr info)]
+   	   [product-type (cadddr info)]
+	   [product-type-size (type-size dls product-type)]
+
+	   [safe-space-offset (- si (type-size dls type))]
+
+	   [inner-offset (- si (data-product-offset dls type sum index))])
+      
+      (when (not (on-stack? (cadr e)))
+	(error #f "trying to destruct something that isn't a stack expression"))      
+      (emit "# deconstructing")
+
+      (if (stack-type? (env-data-layouts env) product-type)
+					; if copying from the stack, need to first copy
+					; to a safe space above to avoid overwriting
+					; the original result on the stack
+					; this is bad. please remove this in the rewrite.
+	  (begin
+	    (emit-stack-copy inner-offset safe-space-offset product-type-size)
+	    (emit-stack-copy safe-space-offset si product-type-size))
+	  (emit "movq ~a(%rbp), %rax" inner-offset))))
+
+  (define (codegen-constructor tor)
+    (let* ([info (cadr tor)]
+	   [type (car info)]
+	   [sum (cadr info)]
+	   [constructor (car e)]
+
+	   [args (cdr e)]
+
+	   [tag (data-sum-tag (env-data-layouts env)
+			      type
+			      sum)]
+
+	   [inner-si (- si (type-size dls type))]
+
+	   [product-types (cdr (assoc sum (cdr (assoc type dls))))]
+	   
+	   [insert-product
+	    (lambda (expr i product-type)
+	      (let ([dest-offset
+		     (- si (data-product-offset dls type sum i))]
+		    [product-size (type-size dls product-type)])
+		(codegen-expr expr inner-si env)
+		(if (on-stack? expr)
+		    (emit-stack-copy inner-si dest-offset product-size)
+		    (emit "movq %rax, ~a(%rbp)" dest-offset))))])
+	   
+					; emit the tag
+      (emit "movq $~a, ~a(%rbp)" tag si)     
+					; generate products
+      (for-each insert-product args (range 0 (length args)) product-types)))
   
   (let* ([tor (data-tor env e)]
-	 [constructor (eqv? 'constructor (cadr tor))])
+	 [constructor (eqv? 'constructor (caddr (cadr tor)))])
     (if constructor
 	(codegen-constructor tor)
 	(codegen-destructor tor))))
@@ -429,23 +538,27 @@
     ('static-string (emit "movq ~a@GOTPCREL(%rip), %rax"
 			  (cadr e)))
 
-    ('stack (error #f "stack value that needs explicit handling" e))
+    ('stack (case (ast-type (caddr e))
+	      ['var (codegen-var e si env)]
+	      [else (codegen-expr (caddr e) si env)]))
 
-    (else (error #f "don't know how to codegen this"))))
+    (else (error #f "don't know how to codegen this")))
+  (emit "# done ~a" e))
 
 					; takes in a expr annotated with types and returns a type-less AST
 					; with stack values wrapped
-(define (annotate-stack-values data-layout ann-e)
+(define (annotate-stack-values data-layouts ann-e)
   (define (stack-type? type)
-    (assoc type data-layout))
+    (assoc type data-layouts))
   (define (strip e)
     (ast-traverse strip (ann-expr e)))
   (let* ([e (ann-expr ann-e)]
 	 [type (ann-type ann-e)])
     (if (stack-type? type)
-	`(stack ,type ,(ast-traverse strip e))
+	`(stack ,(type-size data-layouts type)
+		,(ast-traverse (lambda (x) (annotate-stack-values data-layouts x)) e))
 	(ast-traverse (lambda (x)
-			(annotate-stack-values data-layout x))
+			(annotate-stack-values data-layouts x))
 		      e))))
 
 (define (free-vars prog)
@@ -612,7 +725,8 @@
   (set! cur-lambda 0)
   (let* ([data-layouts (program-data-layouts program)]
 
-	 [type-annotated (annotate-types program)]
+	 [pattern-matched (expand-pattern-matches program)]
+	 [type-annotated (annotate-types pattern-matched)]
 	 [stack-annotated (annotate-stack-values data-layouts
 						 type-annotated)]