diff options
author | Ludovic Courtès <ludo@gnu.org> | 2011-09-13 18:25:09 +0200 |
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committer | Ludovic Courtès <ludo@gnu.org> | 2011-09-13 18:25:09 +0200 |
commit | 61237fa4b96d020e96388cca4fd065ddf43bca60 (patch) | |
tree | 22af273af9fb30cb962565f1f7709577104a59e6 /module/language/tree-il/optimize.scm | |
parent | 1e8ace33d17a3156c184e8121eb291a7c9324ccc (diff) | |
download | guile-61237fa4b96d020e96388cca4fd065ddf43bca60.tar.gz |
peval: Use the right scope when replacing a lambda by a lexical-ref.
* module/language/tree-il/optimize.scm (peval)[maybe-unlambda]: New
procedures.
Use it to de-duplicate named lambdas. This fixes the scoping bug
described at <https://lists.gnu.org/archive/html/bug-guile/2011-09/msg00019.html>.
* test-suite/tests/tree-il.test ("partial evaluation"): Add tests to
reproduce the bug.
Diffstat (limited to 'module/language/tree-il/optimize.scm')
-rw-r--r-- | module/language/tree-il/optimize.scm | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/module/language/tree-il/optimize.scm b/module/language/tree-il/optimize.scm index 4453df3a3..104c4c265 100644 --- a/module/language/tree-il/optimize.scm +++ b/module/language/tree-il/optimize.scm @@ -174,6 +174,22 @@ it should be called before `fix-letrec'." (or (make-value-construction src value) orig))) (_ new))) + (define (maybe-unlambda orig new env) + ;; If NEW is a named lambda and ORIG is what it looked like before + ;; partial evaluation, then attempt to replace NEW with a lexical + ;; ref, to avoid code duplication. + (match new + (($ <lambda> src (= (cut assq-ref <> 'name) (? symbol? name)) + ($ <lambda-case> _ req opt rest kw inits gensyms body)) + ;; Look for NEW in the current environment, starting from the + ;; outermost frame. + (or (any (lambda (x) + (and (equal? (cdr x) new) + (make-lexical-ref src name (car x)))) + (vlist-fold cons '() env)) ; todo: optimize + new)) + (_ new))) + (catch 'match-error (lambda () (let loop ((exp exp) @@ -245,12 +261,15 @@ it should be called before `fix-letrec'." (make-conditional src condition (loop subsequent env calls) (loop alternate env calls))))) - (($ <application> src proc* orig-args) + (($ <application> src orig-proc orig-args) ;; todo: augment the global env with specialized functions - (let* ((proc (loop proc* env calls)) + (let* ((proc (loop orig-proc env calls)) + (proc* (maybe-unlambda orig-proc proc env)) (args (map (cut loop <> env calls) orig-args)) - (args* (map maybe-unconst orig-args args)) - (app (make-application src proc args*))) + (args* (map (cut maybe-unlambda <> <> env) + orig-args + (map maybe-unconst orig-args args))) + (app (make-application src proc* args*))) ;; If at least one of ARGS is static (to avoid infinite ;; inlining) and this call hasn't already been expanded ;; before (to avoid infinite recursion), then expand it @@ -294,17 +313,7 @@ it should be called before `fix-letrec'." (($ <toplevel-ref>) app)) - ;; There are no constant arguments, so don't substitute - ;; lambdas---i.e., prefer (lexical f) over an inline - ;; copy of `f'. - (let ((proc (if (lambda? proc) proc* proc)) - (args (map (lambda (raw evaled) - (if (lambda? evaled) - raw - evaled)) - orig-args - args))) - (make-application src proc args))))) + app))) (($ <lambda> src meta body) (make-lambda src meta (loop body env calls))) (($ <lambda-case> src req opt rest kw inits gensyms body alt) |