variable.c: fix autoload object lifetimes and leak

We must not call normal Hash methods inside GC free callback,
either, however identity hash may be used.

[ruby-core:86935] [Bug #14742]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63389 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 19 insertions, 6 deletions

diff --git a/test/ruby/test_autoload.rb b/test/ruby/test_autoload.rb
index 6d51c16927..8311c40c35 100644
--- a/test/ruby/test_autoload.rb
+++ b/test/ruby/test_autoload.rb
@@ -335,6 +335,18 @@ p Foo::Bar
     end
   end
 
+  def test_no_leak
+    assert_no_memory_leak([], '', <<~'end;', 'many autoloads', timeout: 30)
+      200000.times do |i|
+        m = Module.new
+        m.instance_eval do
+          autoload :Foo, 'x'
+          autoload :Bar, i.to_s
+        end
+      end
+    end;
+  end
+
   def add_autoload(path)
     (@autoload_paths ||= []) << path
     ::Object.class_eval {autoload(:AutoloadTest, path)}
diff --git a/variable.c b/variable.c
index 6590567bf9..2d6fd22a70 100644
--- a/variable.c
+++ b/variable.c
@@ -1908,6 +1908,7 @@ autoload_c_free(void *ptr)
 {
     struct autoload_const *ac = ptr;
     list_del(&ac->cnode);
+    xfree(ac);
 }
 
 static size_t
@@ -1990,7 +1991,7 @@ rb_autoload_str(VALUE mod, ID id, VALUE file)
     }
     file = rb_fstring(file);
     if (!autoload_featuremap) {
-        autoload_featuremap = rb_hash_new();
+        autoload_featuremap = rb_hash_new_compare_by_id();
         rb_obj_hide(autoload_featuremap);
         rb_gc_register_mark_object(autoload_featuremap);
     }
@@ -2036,13 +2037,13 @@ autoload_delete(VALUE mod, ID id)
 	ele = get_autoload_data((VALUE)load, &ac);
 	VM_ASSERT(!list_empty(&ele->constants));
 
-	/* list_del_init to make list_del in autoload_c_free idempotent: */
+	/*
+	 * we must delete here to avoid "already initialized" warnings
+	 * with parallel autoload.  list_del_init makes list_del in
+	 * autoload_c_free idempotent
+	 */
 	list_del_init(&ac->cnode);
 
-	if (list_empty(&ele->constants)) {
-	    rb_hash_delete(autoload_featuremap, ele->feature);
-	}
-
 	if (tbl->num_entries == 0) {
 	    n = autoload;
 	    st_delete(RCLASS_IV_TBL(mod), &n, &val);