X-Git-Url: https://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=codegen.scm;h=748781d9f4cde883830176a93c651172c8ec81f4;hp=dd7950765c9ef375d443a110788a9146079fad20;hb=HEAD;hpb=1b7e2b53e68a39265fd7424910998d2607cc3815

diff --git a/codegen.scm b/codegen.scm
index dd79507..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)
 
@@ -11,9 +12,12 @@
 
 (define wordsize 8)
 
-(define (stack-type? data-layouts type)
-  (if (assoc type data-layouts) #t #f))
+(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)
 
@@ -28,17 +32,26 @@
   
   (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 e)
+(define (expr-size dls e)
   (if (eqv? (ast-type e) 'stack)
-      (cadr e)
+      (type-size dls (cadr e))
       wordsize))
 
 (define (on-stack? expr)
@@ -47,11 +60,20 @@
     [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)
-  (emit "leaq ~a(%rbp), %rsi" (- src size))
-  (emit "leaq ~a(%rbp), %rdi" (- 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"))	  
+    (emit "rep movsq")))
   
 
 					; an environment consists of adt layouts in scope,
@@ -60,6 +82,9 @@
 (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)
@@ -164,8 +189,12 @@
 
   ;;   (fold-left emit-binding (cons env '()) scc))))
 					; assoc map of binding name to size
+
+
+  (define dls (env-data-layouts env))
+  
   (define stack-sizes
-    (map (lambda (binding) (cons (car binding) (expr-size (cadr binding))))
+    (map (lambda (binding) (cons (car binding) (expr-size dls (cadr binding))))
 	 bindings))
 
 					; assoc map of binding name to offset
@@ -205,7 +234,7 @@
 	       (for-each 
 		(lambda (name)
 		  (let* ([expr (cadr (assoc name bindings))]
-			 [size (expr-size expr)])
+			 [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
@@ -232,15 +261,27 @@
 	      body)))
 
 (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)
+  (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-stack-copy stack-offset si stack-size)
-	(emit "movq ~a(%rbp), %rax" stack-offset))))
+	    (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)
@@ -339,9 +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))
 
@@ -350,7 +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: ")
@@ -408,6 +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)))))
@@ -423,14 +558,16 @@
      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)
@@ -473,7 +610,6 @@
 	   [args (cdr e)]
 
 	   [tag (data-sum-tag (env-data-layouts env)
-			      type
 			      sum)]
 
 	   [inner-si (- si (type-size dls type))]
@@ -531,6 +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))
@@ -548,21 +685,19 @@
 					; takes in a expr annotated with types and returns a type-less AST
 					; with stack values wrapped
 (define (annotate-stack-values data-layouts ann-e)
-  (define (stack-type? type)
-    (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-size data-layouts type)
+    (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-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
@@ -590,14 +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?
 
@@ -631,7 +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)))
   
@@ -720,10 +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)]
@@ -732,13 +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)
 
@@ -747,7 +885,6 @@
     (initialize-heap)
 
     (emit "movq %rsp, %rbp")            ; set up the base pointer
-    
     (codegen-expr xform-prog (- wordsize) (make-env data-layouts '()))
 
 					; exit syscall