gc.c (define_final0): avoid duplicate blocks

This prevents excessive memory growth when a WeakRef
is repeatedly created

* gc.c (define_final0): avoid duplicate blocks
  [Bug #10537]
* test/test_weakref.rb (test_repeated_object_leak): new test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48820 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 14 insertions, 0 deletions

diff --git a/gc.c b/gc.c
index feb9c08059..1caa790202 100644
--- a/gc.c
+++ b/gc.c
@@ -2370,6 +2370,20 @@ define_final0(VALUE obj, VALUE block)
 
     if (st_lookup(finalizer_table, obj, &data)) {
 	table = (VALUE)data;
+
+	/* avoid duplicate block, table is usually small */
+	{
+	    const VALUE *ptr = RARRAY_CONST_PTR(table);
+	    long len = RARRAY_LEN(table);
+	    long i;
+
+	    for (i = 0; i < len; i++, ptr++) {
+		if (rb_funcall(*ptr, idEq, 1, block)) {
+		    return *ptr;
+		}
+	    }
+	}
+
 	rb_ary_push(table, block);
     }
     else {