LibJS: Add MarkedValueList and use it for argument passing

A MarkedValueList is basically a Vector<JS::Value> that registers with
the Heap and makes sure that the stored values don't get GC'd.

Before this change, we were unsafely keeping Vector<JS::Value> in some
places, which is out-of-reach for the live reference finding logic
since Vector puts its elements on the heap by default.

We now pass all the JavaScript tests even when running with "js -g",
which does a GC on every heap allocation.

Libraries/LibJS/Runtime/MarkedValueList.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Noncopyable.h>
+#include <AK/Vector.h>
+#include <LibJS/Forward.h>
+#include <LibJS/Runtime/Value.h>
+
+namespace JS {
+
+class MarkedValueList {
+    AK_MAKE_NONCOPYABLE(MarkedValueList);
+
+public:
+    explicit MarkedValueList(Heap&);
+    MarkedValueList(MarkedValueList&&);
+    ~MarkedValueList();
+
+    MarkedValueList& operator=(MarkedValueList&&) = delete;
+
+    bool is_empty() const { return m_values.is_empty(); }
+    size_t size() const { return m_values.size(); }
+    void clear() { m_values.clear(); }
+    Vector<Value, 32>& values() { return m_values; }
+
+    void append(Value);
+
+private:
+    Heap& m_heap;
+    Vector<Value, 32> m_values;
+};
+
+}