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authorAndy Wingo <wingo@pobox.com>2011-11-09 23:45:53 +0100
committerAndy Wingo <wingo@pobox.com>2011-11-09 23:45:53 +0100
commitfb135e12a473fd9a1612a59f904cfb90877fe775 (patch)
tree8a20716a5c5a62558d0ab859a71062a1cb56c617
parentacdf4fcc059df325f66698090359b3455725c865 (diff)
downloadguile-fb135e12a473fd9a1612a59f904cfb90877fe775.tar.gz
when leaving a non-tail let, allow bound vals to be collected
* module/language/tree-il/compile-glil.scm (flatten-lambda-case): Clear lexical stack slots at the end of a non-tail let, letrec, or fix. Fixes http://debbugs.gnu.org/9900. * test-suite/tests/gc.test ("gc"): Add test.
-rw-r--r--module/language/tree-il/compile-glil.scm22
-rw-r--r--test-suite/tests/gc.test28
2 files changed, 41 insertions, 9 deletions
diff --git a/module/language/tree-il/compile-glil.scm b/module/language/tree-il/compile-glil.scm
index 3daac7fca..de55026ab 100644
--- a/module/language/tree-il/compile-glil.scm
+++ b/module/language/tree-il/compile-glil.scm
@@ -237,6 +237,24 @@
(if (eq? context 'tail)
(emit-code #f (make-glil-call 'return 1)))))
+ ;; After lexical binding forms in non-tail context, call this
+ ;; function to clear stack slots, allowing their previous values to
+ ;; be collected.
+ (define (clear-stack-slots context syms)
+ (case context
+ ((push drop)
+ (for-each (lambda (v)
+ (and=>
+ ;; Can be #f if the var is labels-allocated.
+ (hashq-ref allocation v)
+ (lambda (h)
+ (pmatch (hashq-ref h self)
+ ((#t _ . ,n)
+ (emit-code #f (make-glil-void))
+ (emit-code #f (make-glil-lexical #t #f 'set n)))
+ (,loc (error "bad let var allocation" x loc))))))
+ syms))))
+
(record-case x
((<void>)
(case context
@@ -802,6 +820,7 @@
(,loc (error "bad let var allocation" x loc))))
(reverse gensyms))
(comp-tail body)
+ (clear-stack-slots context gensyms)
(emit-code #f (make-glil-unbind)))
((<letrec> src in-order? names gensyms vals body)
@@ -834,6 +853,7 @@
(,loc (error "bad letrec var allocation" x loc))))
(reverse gensyms))))
(comp-tail body)
+ (clear-stack-slots context gensyms)
(emit-code #f (make-glil-unbind)))
((<fix> src names gensyms vals body)
@@ -922,6 +942,7 @@
(comp-tail body)
(if new-RA
(emit-label new-RA))
+ (clear-stack-slots context gensyms)
(emit-code #f (make-glil-unbind))))
((<let-values> src exp body)
@@ -947,6 +968,7 @@
(,loc (error "bad let-values var allocation" x loc))))
(reverse gensyms))
(comp-tail body)
+ (clear-stack-slots context gensyms)
(emit-code #f (make-glil-unbind))))))
;; much trickier than i thought this would be, at first, due to the need
diff --git a/test-suite/tests/gc.test b/test-suite/tests/gc.test
index 57643e825..25dc5779d 100644
--- a/test-suite/tests/gc.test
+++ b/test-suite/tests/gc.test
@@ -16,8 +16,10 @@
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-(use-modules (ice-9 documentation)
- (test-suite lib))
+(define-module (test-suite tests gc)
+ #:use-module (ice-9 documentation)
+ #:use-module (test-suite lib)
+ #:use-module ((system base compile) #:select (compile)))
;;;
@@ -62,10 +64,8 @@
(add-hook! after-gc-hook thunk)
(gc)
(remove-hook! after-gc-hook thunk)
- foo)))
+ foo))
-
-(with-test-prefix "gc"
(pass-if "Unused modules are removed"
(let* ((guard (make-guardian))
(total 1000))
@@ -76,12 +76,22 @@
(stack-cleanup 20)
(gc)
- (gc) ;; twice: have to kill the weak vectors.
- (gc) ;; thrice: because the test doesn't succeed with only
- ;; one gc round. not sure why.
+ (gc) ;; twice: have to kill the weak vectors.
+ (gc) ;; thrice: because the test doesn't succeed with only
+ ;; one gc round. not sure why.
(= (let lp ((i 0))
(if (guard)
(lp (1+ i))
i))
- total))))
+ total)))
+
+ (pass-if "Lexical vars are collectable"
+ (procedure?
+ (compile
+ '(begin
+ (define guardian (make-guardian))
+ (let ((f (lambda () (display "test\n"))))
+ (guardian f))
+ (gc)(gc)(gc)
+ (guardian))))))