diff options
-rw-r--r-- | module/language/tree-il/peval.scm | 144 |
1 files changed, 77 insertions, 67 deletions
diff --git a/module/language/tree-il/peval.scm b/module/language/tree-il/peval.scm index 0fd37fe6c..e744d8d19 100644 --- a/module/language/tree-il/peval.scm +++ b/module/language/tree-il/peval.scm @@ -99,46 +99,28 @@ (or (proc (vlist-ref vlist i)) (lp (1+ i))))))) +(define (singly-valued-expression? exp) + (match exp + (($ <const>) #t) + (($ <lexical-ref>) #t) + (($ <void>) #t) + (($ <lexical-ref>) #t) + (($ <primitive-ref>) #t) + (($ <module-ref>) #t) + (($ <toplevel-ref>) #t) + (($ <application> _ + ($ <primitive-ref> _ (? singly-valued-primitive?))) #t) + (($ <application> _ ($ <primitive-ref> _ 'values) (val)) #t) + (($ <lambda>) #t) + (else #f))) + (define (truncate-values x) "Discard all but the first value of X." - (let loop ((x x)) - (match x - (($ <const>) x) - (($ <lexical-ref>) x) - (($ <void>) x) - (($ <lexical-ref>) x) - (($ <primitive-ref>) x) - (($ <module-ref>) x) - (($ <toplevel-ref>) x) - (($ <conditional> src condition subsequent alternate) - (make-conditional src condition (loop subsequent) (loop alternate))) - (($ <application> _ ($ <primitive-ref> _ 'values) (first _ ...)) - first) - (($ <application> _ ($ <primitive-ref> _ 'values) (val)) - val) - (($ <application> src - (and prim ($ <primitive-ref> _ (? singly-valued-primitive?))) - args) - (make-application src prim (map loop args))) - (($ <application> src proc args) - (make-application src proc (map loop args))) - (($ <sequence> src (exps ... last)) - (make-sequence src (append exps (list (loop last))))) - (($ <lambda>) x) - (($ <dynlet> src fluids vals body) - (make-dynlet src fluids vals (loop body))) - (($ <let> src names gensyms vals body) - (make-let src names gensyms vals (loop body))) - (($ <letrec> src in-order? names gensyms vals body) - (make-letrec src in-order? names gensyms vals (loop body))) - (($ <fix> src names gensyms vals body) - (make-fix src names gensyms vals body)) - (($ <let-values> src exp body) - (make-let-values src exp (loop body))) - (else - (make-application (tree-il-src x) - (make-primitive-ref #f 'values) - (list x)))))) + (if (singly-valued-expression? x) + x + (make-application (tree-il-src x) + (make-primitive-ref #f 'values) + (list x)))) ;; Peval will do a one-pass analysis on the source program to determine ;; the set of assigned lexicals, and to identify unreferenced and @@ -315,13 +297,15 @@ (visit-count operand-visit-count set-operand-visit-count!) (residualize? operand-residualize? set-operand-residualize?!) (copyable? operand-copyable? set-operand-copyable?!) - (residual-value operand-residual-value set-operand-residual-value!) + (residual-value operand-residual-value %set-operand-residual-value!) (constant-value operand-constant-value set-operand-constant-value!)) (define* (make-operand var sym #:optional source visit) - ;; Bind SYM to VAR, with value SOURCE. - ;; Bound operands are considered copyable until we prove otherwise. - (let ((source (if source (truncate-values source) source))) + ;; Bind SYM to VAR, with value SOURCE. Bound operands are considered + ;; copyable until we prove otherwise. If we have a source expression, + ;; truncate it to one value. Copy propagation does not work on + ;; multiply-valued expressions. + (let ((source (and=> source truncate-values))) (%make-operand var sym visit source 0 #f (and source #t) #f #f))) (define (make-bound-operands vars syms sources visit) @@ -330,6 +314,17 @@ (define (make-unbound-operands vars syms) (map make-operand vars syms)) +(define (set-operand-residual-value! op val) + (%set-operand-residual-value! + op + (match val + (($ <application> src ($ <primitive-ref> _ 'values) (first)) + ;; The continuation of a residualized binding does not need the + ;; introduced `values' node, so undo the effects of truncation. + first) + (else + val)))) + (define* (visit-operand op counter ctx #:optional effort-limit size-limit) ;; Peval is O(N) in call sites of the source program. However, ;; visiting an operand can introduce new call sites. If we visit an @@ -454,26 +449,25 @@ top-level bindings from ENV and return the resulting expression." (set-operand-residual-value! op val)) (make-lexical-ref #f (var-name (operand-var op)) (operand-sym op))) - (define (apply-primitive name args) - ;; todo: further optimize commutative primitives - (catch #t - (lambda () - (call-with-values - (lambda () - (apply (module-ref the-scm-module name) args)) - (lambda results - (values #t results)))) - (lambda _ - (values #f '())))) - - (define (make-values src values) - (match values - ((single) single) ; 1 value - ((_ ...) ; 0, or 2 or more values - (make-application src (make-primitive-ref src 'values) - values)))) - (define (fold-constants src name args ctx) + (define (apply-primitive name args) + ;; todo: further optimize commutative primitives + (catch #t + (lambda () + (call-with-values + (lambda () + (apply (module-ref the-scm-module name) args)) + (lambda results + (values #t results)))) + (lambda _ + (values #f '())))) + + (define (make-values src values) + (match values + ((single) single) ; 1 value + ((_ ...) ; 0, or 2 or more values + (make-application src (make-primitive-ref src 'values) + values)))) (define (residualize-call) (make-application src (make-primitive-ref #f name) args)) (cond @@ -591,6 +585,9 @@ top-level bindings from ENV and return the resulting expression." (($ <primitive-ref>) #t) (($ <conditional> _ condition subsequent alternate) (and (loop condition) (loop subsequent) (loop alternate))) + (($ <application> _ ($ <primitive-ref> _ 'values) exps) + (and (not (null? exps)) + (every loop exps))) (($ <application> _ ($ <primitive-ref> _ name) args) (and (effect-free-primitive? name) (not (constructor-primitive? name)) @@ -711,7 +708,7 @@ top-level bindings from ENV and return the resulting expression." (let loop ((exp exp) (env vlist-null) ; vhash of gensym -> <operand> (counter #f) ; inlined call stack - (ctx 'value)) ; effect, value, test, operator, or call + (ctx 'values)) ; effect, value, values, test, operator, or call (define (lookup var) (cond ((vhash-assq var env) => cdr) @@ -721,6 +718,7 @@ top-level bindings from ENV and return the resulting expression." (loop exp env counter ctx)) (define (for-value exp) (visit exp 'value)) + (define (for-values exp) (visit exp 'values)) (define (for-test exp) (visit exp 'test)) (define (for-effect exp) (visit exp 'effect)) (define (for-call exp) (visit exp 'call)) @@ -766,7 +764,8 @@ top-level bindings from ENV and return the resulting expression." (let ((val (operand-constant-value op))) (log 'memoized-constant gensym val) (for-tail val))) - ((visit-operand op counter ctx recursive-effort-limit operand-size-limit) + ((visit-operand op counter (if (eq? ctx 'values) 'value ctx) + recursive-effort-limit operand-size-limit) => ;; If we end up deciding to residualize this value instead of ;; copying it, save that residualized value. @@ -789,7 +788,7 @@ top-level bindings from ENV and return the resulting expression." ;; It could be this constant is the result of folding. ;; If that is the case, cache it. This helps loop ;; unrolling get farther. - (if (eq? ctx 'value) + (if (or (eq? ctx 'value) (eq? ctx 'values)) (begin (log 'memoize-constant gensym val) (set-operand-constant-value! op val))) @@ -903,7 +902,7 @@ top-level bindings from ENV and return the resulting expression." ;; Peval the producer, then try to inline the consumer into ;; the producer. If that succeeds, peval again. Otherwise ;; reconstruct the let-values, pevaling the consumer. - (let ((producer (for-value producer))) + (let ((producer (for-values producer))) (or (match consumer (($ <lambda-case> src req #f #f #f () gensyms body #f) (cond @@ -1004,7 +1003,18 @@ top-level bindings from ENV and return the resulting expression." _ req #f rest #f () gensyms body #f))))) (for-tail (make-let-values src (make-application src producer '()) consumer))) - + (($ <application> src ($ <primitive-ref> _ 'values) exps) + (cond + ((null? exps) + (if (eq? ctx 'effect) + (make-void #f) + exp)) + (else + (let ((vals (map for-value exps))) + (if (and (memq ctx '(value test effect)) + (every singly-valued-expression? vals)) + (for-tail (make-sequence src (append (cdr vals) (list (car vals))))) + (make-application src (make-primitive-ref #f 'values) vals)))))) (($ <application> src orig-proc orig-args) ;; todo: augment the global env with specialized functions (let ((proc (visit orig-proc 'operator))) @@ -1205,7 +1215,7 @@ top-level bindings from ENV and return the resulting expression." ((operator) exp) (else (record-source-expression! exp - (make-lambda src meta (for-tail body)))))) + (make-lambda src meta (for-values body)))))) (($ <lambda-case> src req opt rest kw inits gensyms body alt) (let* ((vars (map lookup-var gensyms)) (new (fresh-gensyms vars)) |