X-Git-Url: https://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=codegen.scm;h=748781d9f4cde883830176a93c651172c8ec81f4;hp=dededbec01e0856b19703d8945e096e49b316aa5;hb=HEAD;hpb=006b94f5a24a794665788737fec8d54086284317

diff --git a/codegen.scm b/codegen.scm
index dededbe..748781d 100644
--- a/codegen.scm
+++ b/codegen.scm
@@ -1,6 +1,7 @@
 (load "typecheck.scm")
 (load "ast.scm")
 (load "platform.scm")
+(load "stdlib.scm")
 
 (define target host-os)
 
@@ -11,6 +12,13 @@
 
 (define wordsize 8)
 
+(define (stack-type? dls type)
+  (if (adt? dls type)      
+      (> (type-size dls type) wordsize)
+      #f))
+
+(define (adt? data-layouts type) (assoc type data-layouts))
+
 (define (type-size data-layouts type)
 
   (define (adt-size adt)
@@ -24,24 +32,59 @@
   
   (case type
     ['Int wordsize]
-    ['Bool wordsize]
     [else
      (let ([adt (assoc type data-layouts)])
        (if adt
 	   (adt-size adt)
 	   (error #f "unknown size" type)))]))
 
+(define (singletons dls)
+  (flat-map
+   (lambda (sums)
+     (fold-left append '()
+		(filter (lambda (x) (= 1 (length x))) sums)))
+   (map cdr dls)))
+
+(define (singleton? dls x)
+  (memv x (singletons dls)))
+
+					; returns the size of an expression's result in bytes
+(define (expr-size dls e)
+  (if (eqv? (ast-type e) 'stack)
+      (type-size dls (cadr e))
+      wordsize))
+
 (define (on-stack? expr)
   (case (ast-type expr)
     ['stack (cadr expr)]
     [else #f]))
 
+					; does a movsq for something on the stack
+					; src points to the start stack index, but not the top of that index
+					; likewise for dst
+					; | ...  |
+					; +------+ <-- to here
+					; | tag0 |
+					; +------+ <-- src (size = 16)
+					; |  42  |
+					; +------+ <-- start copying from here...
+(define (emit-stack-copy src dst size)
+  (let ([size-to-copy (- size wordsize)])
+    (emit "leaq ~a(%rbp), %rsi" (- src size-to-copy))
+    (emit "leaq ~a(%rbp), %rdi" (- dst size-to-copy))
+    (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
 (define make-env list)
 (define env-data-layouts car)
 (define env-bindings cadr)
+(define (env-append-bindings env bindings)
+  (make-env (env-data-layouts env)
+	    (append bindings (env-bindings env))))
 
 (define (codegen-add xs si env)
   (define (go ys)
@@ -118,7 +161,6 @@
     (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 +188,35 @@
   ;; 	))
 
   ;;   (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 dls (env-data-layouts env))
+  
+  (define stack-sizes
+    (map (lambda (binding) (cons (car binding) (expr-size dls (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 +233,8 @@
 		    [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 dls 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 +246,11 @@
 				       (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 +260,28 @@
 		(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-type (on-stack? e)]	 
+	 [name (if stack-type (caddr e) e)]
+
+	 [dls (env-data-layouts env)]
+	 
+				    
+	 [stack-offset (assoc name (env-bindings env))])
+
+    (when (and (not stack-offset) (not singleton?))
+      (error #f (format "Variable ~a is not bound" name)))
+
+    (cond
+     [(singleton? dls name)
+      					; singletons don't need to be in the environment
+					; just store the tag
+      (let ([tag (data-sum-tag (env-data-layouts env) name)])
+	(if (on-stack? e)
+	    (emit "movq $~a, ~a(%rbp)" tag si)
+	    (emit "movq $~a, %rax" tag)))]
+     [(on-stack? e) (emit-stack-copy (cdr stack-offset) si (type-size dls stack-type))]
+     [else (emit "movq ~a(%rbp), %rax" (cdr stack-offset))])))
 
 (define cur-lambda 0)
 (define (fresh-lambda)
@@ -293,9 +380,10 @@
 (define (codegen-lambda l)
   (let* ((label (car l))
 	 (stuff (cdr l))
-	 (captives (car stuff))
-	 (args (cadr stuff))
-	 (body (caddr stuff))
+	 (dls (car stuff))
+	 (captives (cadr stuff))
+	 (args (caddr stuff))
+	 (body (cadddr stuff))
 					; params = what actually gets passed
 	 (params (append captives args))
 
@@ -304,7 +392,7 @@
 			     (range 0 (length params))))
 
 	 [bindings (map cons params stack-offsets)]
-	 [env (make-env '() bindings)])
+	 [env (make-env dls bindings)])
     (emit "~a:" label)
 
     (display "## lambda captives: ")
@@ -362,6 +450,99 @@
     (codegen-expr else si env)
     (emit "~a:" exit-label)))
 
+(define (codegen-case switch cases si env)
+  (define dls (env-data-layouts env))
+  (define exit-label (fresh-label))
+
+
+					; checks if equal and returns assoc list of bindings
+  (define (check-equal jne-label type inner-offset x)
+
+					; TODO: tidy this up! comparibles and binds could be merged
+					; (foo a 2 (bar x)) -> ((2 Int 1) ((bar x) A 2))
+					; sum: foo
+    (define (comparibles sum)
+      (let ([product-types (cdr (assoc sum (cdr (assoc type dls))))])
+	(if (null? product-types)
+	    '()
+	    (filter (lambda (x) (not (eqv? 'var (ast-type (car x)))))
+		    (map (lambda (x t i) (list x t i))
+			 (cdr x)
+			 product-types
+			 (range 0 (length product-types)))))))
+    
+    (define (binds sum)
+      (let ([product-types (cdr (assoc sum (cdr (assoc type dls))))])
+	(if (null? product-types)
+	    '()
+	    (filter (lambda (x) (eqv? 'var (ast-type (car x))))
+		    (map (lambda (x i)
+			   (cons x
+				 (- inner-offset
+				    (data-product-offset dls type sum i))))
+			 (cdr x)
+			 (range 0 (length (cdr x))))))))
+	     
+
+    (if (adt? dls type)
+	(let* ([sum (if (list? x) (car x) x)] ; can sometimes be a singleton
+	       [tag (data-sum-tag dls sum)])
+					; the tag is at the top (beginning) of the adt on the stack
+	  (emit "cmpq $~a, ~a(%rbp)" tag inner-offset)
+	  (emit "jne ~a" jne-label)
+
+	  (append (binds sum)
+		  (flat-map
+		   (lambda (cmp) ; cmp = (x type index)
+		     (check-equal jne-label
+				  (cadr cmp)
+				  (- inner-offset (data-product-offset dls type sum (caddr cmp)))
+				  (car cmp)))
+		   (comparibles sum))))
+	(if (eqv? 'var (ast-type x))
+	    (list (cons x inner-offset))
+	    (begin
+	      (emit "cmpq $~a, ~a(%rbp)" x inner-offset)
+	      (emit "jne ~a" jne-label)
+	      '() ))))
+  
+  (define (codegen-adt-match type case)
+    (let* ([match (car case)]
+	   [expr (cadr case)]
+	   [next-section-label (fresh-label)]
+	   [inner-si (- si (type-size dls type))]
+	   [new-env (env-append-bindings env
+		     (check-equal next-section-label type si match))])
+
+
+      (codegen-expr expr inner-si new-env)
+      (emit "jmp ~a" exit-label)
+
+      (emit "~a:" next-section-label)))
+
+  (define (codegen-literal-match case)
+    (let* ([next-section-label (fresh-label)]
+	   [match (car case)]
+	   [val (if (singleton? dls match)
+		    (data-sum-tag dls match)
+		    match)])
+      (emit "cmpq $~a, %rax" val)
+      (emit "jne ~a" next-section-label)
+      (codegen-expr (cadr case) si env)
+      (emit "jmp ~a" exit-label)
+      (emit "~a:" next-section-label)))
+  
+					; generate the switch
+					; (and store it on the stack if not a stack value)
+  (codegen-expr switch si env)
+
+  (if (on-stack? switch)
+					; adt pattern match
+      (for-each (lambda (x) (codegen-adt-match (cadr switch) x)) cases)
+      (for-each codegen-literal-match cases))
+  (emit "~a:" exit-label))
+      
+
 (define (data-tor env e)
   (if (not (list? e)) #f    
       (assoc (car e) (flat-map data-tors (env-data-layouts env)))))
@@ -377,29 +558,48 @@
      wordsize ; skip the tag in the first word
      to-traverse)))
 
-(define (data-sum-tag data-layouts type sum)
+(define (data-sum-tag data-layouts 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))])
+  (let* ([all-sum-names (flat-map (lambda (x) (map (lambda (y) (cons (car y) (car x))) (cdr x))) data-layouts)]
+	 [type (cdr (assoc sum all-sum-names))]
+	 [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)
     (let* ([res (codegen-expr (cadr e) si env)]
 	   [info (cadr tor)]
-	   [index (caddr info)]
 	   [type (car info)]
-	   [sum (cadr info)])
-      (when (not (stack-expr? res))
-	(error #f "codegened something that wasn't a stack expression"))
-					;TODO handle stack types
-      (emit "movq ~a(%rbp), %rax"
-	    (- si (data-product-offset (env-data-layouts env) type sum index)))))				      
+	   [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)]
@@ -410,24 +610,26 @@
 	   [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)
-	      (let ([res (codegen-expr expr si env)]
-		    [stack-offset (- si (data-product-offset (env-data-layouts env)
-							     type sum
-							     i))])
-		(if (stack-expr? res)
-		    (error #f "todo: handle stack-exprs in stack exprs")
-		    (emit "movq %rax, ~a(%rbp)" stack-offset))))])
+	    (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)     
-      
-      (for-each insert-product args (range 0 (length args)))
-      (type-size (env-data-layouts env) type)))
+					; generate products
+      (for-each insert-product args (range 0 (length args)) product-types)))
   
   (let* ([tor (data-tor env e)]
 	 [constructor (eqv? 'constructor (caddr (cadr tor)))])
@@ -435,9 +637,6 @@
 	(codegen-constructor tor)
 	(codegen-destructor tor))))
 
-(define stack-expr? number?)
-
-					; returns a number if result was stored on stack 
 (define (codegen-expr e si env)
   (emit "# ~a" e)
   (case (ast-type e)
@@ -468,6 +667,7 @@
     ('var (codegen-var e si env))
 
     ('if (codegen-if (cadr e) (caddr e) (cadddr e) si env))
+    ('case (codegen-case (case-switch e) (case-cases e) si env))
     
     ('bool-literal (emit "movq $~a, %rax" (if e 1 0)))
     ('int-literal (emit "movq $~a, %rax" e))
@@ -475,27 +675,29 @@
     ('static-string (emit "movq ~a@GOTPCREL(%rip), %rax"
 			  (cadr e)))
 
-    ('stack (codegen-expr (caddr e) si env))
+    ('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 (stack-type? type)
-    (assoc type data-layout))
+(define (annotate-stack-values data-layouts ann-e)
   (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))
+    (if (stack-type? data-layouts type)
+	`(stack ,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)
-  (define bound '())
+(define (free-vars dls prog)
+  (define bound (singletons dls))
   (define (collect e)
     (case (ast-type e)
       ('builtin '()) ; do nothing
@@ -523,14 +725,14 @@
 					; outside of an immediate app
 					; but only one closure for each builtin
 
-(define (extract-lambdas program)
+(define (extract-lambdas dls program)
   (define lambdas '())
   (define (add-lambda e)
     (let* ((label (fresh-lambda))
 	   (args (lambda-args e))
-	   (captured (free-vars e))
+	   (captured (free-vars dls e))
 	   (body (extract (lambda-body e)))
-	   (new-lambda (cons label (list captured args body))))
+	   (new-lambda (cons label (list dls captured args body))))
       (set! lambdas (cons new-lambda lambdas))
       `(closure ,label ,captured))) ; todo: should we string->symbol?
 
@@ -564,7 +766,7 @@
 	   (captured '())
 	   (args (builtin-args e))
 	   (body `(,e ,@args))
-	   (new-lambda (cons label (list captured args body)))]
+	   (new-lambda (cons label (list dls captured args body)))]
       (set! lambdas (cons new-lambda lambdas))
       `(closure ,label ,captured)))
   
@@ -653,10 +855,11 @@
     (emit "movq heap_start@GOTPCREL(%rip), %rsi")
     (emit "movq %rax, (%rsi)")))
 
-(define (codegen program)
+(define (codegen program-without-stdlib)
   (set! cur-label 0)
   (set! cur-lambda 0)
-  (let* ([data-layouts (program-data-layouts program)]
+  (let* ([program (append stdlib program-without-stdlib)]
+	 [data-layouts (program-data-layouts program)]
 
 	 [pattern-matched (expand-pattern-matches program)]
 	 [type-annotated (annotate-types pattern-matched)]
@@ -665,13 +868,15 @@
 	 
 	 (strings-res (extract-strings stack-annotated))
 	 (strings (car strings-res))
-	 (lambdas-res (extract-lambdas (cdr strings-res)))
+	 (lambdas-res (extract-lambdas data-layouts (cdr strings-res)))
 	 (lambdas (car lambdas-res))
 	 (xform-prog (cdr lambdas-res)))
 
+					; verify pattern matches are total
+    (verify-cases data-layouts type-annotated)
+
     (emit "\t.global _start")
     (emit "\t.text")
-					;    (emit ".p2align 4,,15") is this needed?
 
     (for-each codegen-lambda lambdas)
 
@@ -680,7 +885,6 @@
     (initialize-heap)
 
     (emit "movq %rsp, %rbp")            ; set up the base pointer
-    
     (codegen-expr xform-prog (- wordsize) (make-env data-layouts '()))
 
 					; exit syscall