-;;;
-;;; Stage 2: Optimization
-;;;
-
-(define (lift-variables! env)
- (let ((parent-env (ghil-env-parent env)))
- (for-each (lambda (v)
- (case (ghil-var-kind v)
- ((argument) (set! (ghil-var-kind v) 'local)))
- (set! (ghil-var-env v) parent-env)
- (ghil-env-add! parent-env v))
- (ghil-env-variables env))))
-
-;; Possible optimizations:
-;; * compile primitives specially
-;; * turn global-refs into primitive-refs
-;; * constant folding, propagation
-;; * procedure inlining
-;; * always when single call site
-;; * always for "trivial" procs
-;; * otherwise who knows
-;; * dead code elimination
-;; * degenerate case optimizations
-
-
-;; The premise of this, unused, approach to optimization is that you can
-;; determine the environment of a variable lexically, because they have
-;; been alpha-renamed. It makes the transformations *much* easier.
-;; Unfortunately it doesn't work yet.
-(define (optimize* x)
- (transform-record (<ghil> env loc) x
- ((quasiquote exp)
- (define (optimize-qq x)
- (cond ((list? x) (map optimize-qq x))
- ((pair? x) (cons (optimize-qq (car x)) (optimize-qq (cdr x))))
- ((record? x) (optimize x))
- (else x)))
- (-> (quasiquote (optimize-qq x))))
-
- ((unquote exp)
- (-> (unquote (optimize exp))))
-
- ((unquote-splicing exp)
- (-> (unquote-splicing (optimize exp))))
-
- ((set var val)
- (-> (set var (optimize val))))
-
- ((define var val)
- (-> (define var (optimize val))))
-
- ((if test then else)
- (-> (if (optimize test) (optimize then) (optimize else))))
-
- ((and exps)
- (-> (and (map optimize exps))))
-
- ((or exps)
- (-> (or (map optimize exps))))
-
- ((begin exps)
- (-> (begin (map optimize exps))))
-
- ((bind vars vals body)
- (-> (bind vars (map optimize vals) (optimize body))))
-
- ((mv-bind producer vars rest body)
- (-> (mv-bind (optimize producer) vars rest (optimize body))))
-
- ((inline inst args)
- (-> (inline inst (map optimize args))))
-
- ((call (proc (lambda vars (rest #f) meta body)) args)
- (-> (bind vars (optimize args) (optimize body))))
-
- ((call proc args)
- (-> (call (optimize proc) (map optimize args))))
-
- ((lambda vars rest meta body)
- (-> (lambda vars rest meta (optimize body))))
-
- ((mv-call producer (consumer (lambda vars rest meta body)))
- (-> (mv-bind (optimize producer) vars rest (optimize body))))
-
- ((mv-call producer consumer)
- (-> (mv-call (optimize producer) (optimize consumer))))
-
- ((values values)
- (-> (values (map optimize values))))
-
- ((values* values)
- (-> (values* (map optimize values))))
-
- (else
- (error "unrecognized GHIL" x))))
-
-(define (optimize x)
- (record-case x
- ((<ghil-set> env loc var val)
- (make-ghil-set env var (optimize val)))
-
- ((<ghil-define> env loc var val)
- (make-ghil-define env var (optimize val)))
-
- ((<ghil-if> env loc test then else)
- (make-ghil-if env loc (optimize test) (optimize then) (optimize else)))
-
- ((<ghil-and> env loc exps)
- (make-ghil-and env loc (map optimize exps)))
-
- ((<ghil-or> env loc exps)
- (make-ghil-or env loc (map optimize exps)))
-
- ((<ghil-begin> env loc exps)
- (make-ghil-begin env loc (map optimize exps)))
-
- ((<ghil-bind> env loc vars vals body)
- (make-ghil-bind env loc vars (map optimize vals) (optimize body)))
-
- ((<ghil-lambda> env loc vars rest meta body)
- (make-ghil-lambda env loc vars rest meta (optimize body)))
-
- ((<ghil-inline> env loc instruction args)
- (make-ghil-inline env loc instruction (map optimize args)))
-
- ((<ghil-call> env loc proc args)
- (let ((parent-env env))
- (record-case proc
- ;; ((@lambda (VAR...) BODY...) ARG...) =>
- ;; (@let ((VAR ARG) ...) BODY...)
- ((<ghil-lambda> env loc vars rest meta body)
- (cond
- ((not rest)
- (lift-variables! env)
- (make-ghil-bind parent-env loc (map optimize args)))
- (else
- (make-ghil-call parent-env loc (optimize proc) (map optimize args)))))
- (else
- (make-ghil-call parent-env loc (optimize proc) (map optimize args))))))
-
- ((<ghil-mv-call> env loc producer consumer)
- (record-case consumer
- ;; (mv-call PRODUCER (lambda ARGS BODY...)) =>
- ;; (mv-let PRODUCER ARGS BODY...)
- ((<ghil-lambda> env loc vars rest meta body)
- (lift-variables! env)
- (make-ghil-mv-bind producer vars rest body))
- (else
- (make-ghil-mv-call env loc (optimize producer) (optimize consumer)))))
-
- (else x)))
-
-\f
-;;;
-;;; Stage 3: Code generation
-;;;