--- /dev/null	2018-12-27 16:32:15.144191626 -0500
+++ new/test/hotspot/gtest/utilities/test_lockFreeStack.cpp	2019-01-15 17:45:52.566431415 -0500
@@ -0,0 +1,306 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "precompiled.hpp"
+#include "memory/allocation.inline.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/orderAccess.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/lockFreeStack.hpp"
+#include "threadHelper.inline.hpp"
+#include "unittest.hpp"
+#include <new>
+
+class LockFreeStackTestElement {
+  typedef LockFreeStackTestElement Element;
+
+  Element* volatile _entry;
+  Element* volatile _entry1;
+  size_t _id;
+
+  static Element* volatile* entry_ptr(Element& e) { return &e._entry; }
+  static Element* volatile* entry1_ptr(Element& e) { return &e._entry1; }
+
+public:
+  LockFreeStackTestElement(size_t id = 0) : _entry(), _entry1(), _id(id) {}
+  size_t id() const { return _id; }
+  void set_id(size_t value) { _id = value; }
+
+  typedef LockFreeStack<Element, &entry_ptr> Stack;
+  typedef LockFreeStack<Element, &entry1_ptr> Stack1;
+};
+
+typedef LockFreeStackTestElement Element;
+typedef Element::Stack Stack;
+typedef Element::Stack1 Stack1;
+
+static void initialize_ids(Element* elements, size_t size) {
+  for (size_t i = 0; i < size; ++i) {
+    elements[i].set_id(i);
+  }
+}
+
+class LockFreeStackTestBasics : public ::testing::Test {
+public:
+  LockFreeStackTestBasics();
+
+  static const size_t nelements = 10;
+  Element elements[nelements];
+  Stack stack;
+
+private:
+  void initialize();
+};
+
+const size_t LockFreeStackTestBasics::nelements;
+
+LockFreeStackTestBasics::LockFreeStackTestBasics() : stack() {
+  initialize_ids(elements, nelements);
+  initialize();
+}
+
+void LockFreeStackTestBasics::initialize() {
+  ASSERT_TRUE(stack.empty());
+  ASSERT_EQ(0u, stack.length());
+  ASSERT_TRUE(stack.pop() == NULL);
+  ASSERT_TRUE(stack.top() == NULL);
+
+  for (size_t id = 0; id < nelements; ++id) {
+    ASSERT_EQ(id, stack.length());
+    Element* e = &elements[id];
+    ASSERT_EQ(id, e->id());
+    stack.push(*e);
+    ASSERT_FALSE(stack.empty());
+    ASSERT_EQ(e, stack.top());
+  }
+}
+
+TEST_F(LockFreeStackTestBasics, push_pop) {
+  for (size_t i = nelements; i > 0; ) {
+    ASSERT_FALSE(stack.empty());
+    ASSERT_EQ(i, stack.length());
+    --i;
+    Element* e = stack.pop();
+    ASSERT_TRUE(e != NULL);
+    ASSERT_EQ(&elements[i], e);
+    ASSERT_EQ(i, e->id());
+  }
+  ASSERT_TRUE(stack.empty());
+  ASSERT_EQ(0u, stack.length());
+  ASSERT_TRUE(stack.pop() == NULL);
+}
+
+TEST_F(LockFreeStackTestBasics, prepend_one) {
+  Stack other_stack;
+  ASSERT_TRUE(other_stack.empty());
+  ASSERT_TRUE(other_stack.pop() == NULL);
+  ASSERT_EQ(0u, other_stack.length());
+  ASSERT_TRUE(other_stack.top() == NULL);
+  ASSERT_TRUE(other_stack.pop() == NULL);
+
+  other_stack.prepend(*stack.pop_all());
+  ASSERT_EQ(nelements, other_stack.length());
+  ASSERT_TRUE(stack.empty());
+  ASSERT_EQ(0u, stack.length());
+  ASSERT_TRUE(stack.pop() == NULL);
+  ASSERT_TRUE(stack.top() == NULL);
+
+  for (size_t i = nelements; i > 0; ) {
+    ASSERT_EQ(i, other_stack.length());
+    --i;
+    Element* e = other_stack.pop();
+    ASSERT_TRUE(e != NULL);
+    ASSERT_EQ(&elements[i], e);
+    ASSERT_EQ(i, e->id());
+  }
+  ASSERT_EQ(0u, other_stack.length());
+  ASSERT_TRUE(other_stack.pop() == NULL);
+}
+
+TEST_F(LockFreeStackTestBasics, prepend_two) {
+  Stack other_stack;
+  ASSERT_TRUE(other_stack.empty());
+  ASSERT_EQ(0u, other_stack.length());
+  ASSERT_TRUE(other_stack.top() == NULL);
+  ASSERT_TRUE(other_stack.pop() == NULL);
+
+  Element* top = stack.pop_all();
+  ASSERT_EQ(top, &elements[nelements - 1]);
+  other_stack.prepend(*top, elements[0]);
+
+  for (size_t i = nelements; i > 0; ) {
+    ASSERT_EQ(i, other_stack.length());
+    --i;
+    Element* e = other_stack.pop();
+    ASSERT_TRUE(e != NULL);
+    ASSERT_EQ(&elements[i], e);
+    ASSERT_EQ(i, e->id());
+  }
+  ASSERT_EQ(0u, other_stack.length());
+  ASSERT_TRUE(other_stack.pop() == NULL);
+}
+
+TEST_F(LockFreeStackTestBasics, two_stacks) {
+  Stack1 stack1;
+  ASSERT_TRUE(stack1.pop() == NULL);
+
+  for (size_t id = 0; id < nelements; ++id) {
+    stack1.push(elements[id]);
+  }
+  ASSERT_EQ(nelements, stack1.length());
+  Element* e0 = stack.top();
+  Element* e1 = stack1.top();
+  while (true) {
+    ASSERT_EQ(e0, e1);
+    if (e0 == NULL) break;
+    e0 = stack.next(*e0);
+    e1 = stack1.next(*e1);
+  }
+
+  for (size_t i = nelements; i > 0; ) {
+    ASSERT_EQ(i, stack.length());
+    ASSERT_EQ(i, stack1.length());
+    --i;
+    Element* e = stack.pop();
+    ASSERT_TRUE(e != NULL);
+    ASSERT_EQ(&elements[i], e);
+    ASSERT_EQ(i, e->id());
+
+    Element* e1 = stack1.pop();
+    ASSERT_TRUE(e1 != NULL);
+    ASSERT_EQ(&elements[i], e1);
+    ASSERT_EQ(i, e1->id());
+
+    ASSERT_EQ(e, e1);
+  }
+  ASSERT_EQ(0u, stack.length());
+  ASSERT_EQ(0u, stack1.length());
+  ASSERT_TRUE(stack.pop() == NULL);
+  ASSERT_TRUE(stack1.pop() == NULL);
+}
+
+class LockFreeStackTestThread : public JavaTestThread {
+  uint _id;
+  Stack* _from;
+  Stack* _to;
+  volatile size_t* _processed;
+  size_t _process_limit;
+  size_t _local_processed;
+  volatile bool _ready;
+
+public:
+  LockFreeStackTestThread(Semaphore* post,
+                          uint id,
+                          Stack* from,
+                          Stack* to,
+                          volatile size_t* processed,
+                          size_t process_limit) :
+    JavaTestThread(post),
+    _id(id),
+    _from(from),
+    _to(to),
+    _processed(processed),
+    _process_limit(process_limit),
+    _local_processed(0),
+    _ready(false)
+  {}
+
+  virtual void main_run() {
+    OrderAccess::release_store_fence(&_ready, true);
+    while (true) {
+      Element* e = _from->pop();
+      if (e != NULL) {
+        _to->push(*e);
+        Atomic::inc(_processed);
+        ++_local_processed;
+      } else if (OrderAccess::load_acquire(_processed) == _process_limit) {
+        tty->print_cr("thread %u processed " SIZE_FORMAT, _id, _local_processed);
+        return;
+      }
+    }
+  }
+
+  bool ready() const { return OrderAccess::load_acquire(&_ready); }
+};
+
+TEST_VM(LockFreeStackTest, stress) {
+  Semaphore post;
+  Stack initial_stack;
+  Stack start_stack;
+  Stack middle_stack;
+  Stack final_stack;
+  volatile size_t stage1_processed = 0;
+  volatile size_t stage2_processed = 0;
+
+  const size_t nelements = 10000;
+  Element* elements = NEW_C_HEAP_ARRAY(Element, nelements, mtOther);
+  for (size_t id = 0; id < nelements; ++id) {
+    ::new (&elements[id]) Element(id);
+    initial_stack.push(elements[id]);
+  }
+  ASSERT_EQ(nelements, initial_stack.length());
+
+  // - stage1 threads pop from start_stack and push to middle_stack.
+  // - stage2 threads pop from middle_stack and push to final_stack.
+  // - all threads in a stage count the number of elements processed in
+  //   their corresponding stageN_processed counter.
+
+  const uint stage1_threads = 2;
+  const uint stage2_threads = 2;
+  const uint nthreads = stage1_threads + stage2_threads;
+  LockFreeStackTestThread* threads[nthreads] = {};
+
+  for (uint i = 0; i < ARRAY_SIZE(threads); ++i) {
+    Stack* from = &start_stack;
+    Stack* to = &middle_stack;
+    volatile size_t* processed = &stage1_processed;
+    if (i >= stage1_threads) {
+      from = &middle_stack;
+      to = &final_stack;
+      processed = &stage2_processed;
+    }
+    threads[i] =
+      new LockFreeStackTestThread(&post, i, from, to, processed, nelements);
+    threads[i]->doit();
+    while (!threads[i]->ready()) {} // Wait until ready to start test.
+  }
+
+  // Transfer elements to start_stack to start test.
+  start_stack.prepend(*initial_stack.pop_all());
+
+  // Wait for all threads to complete.
+  for (uint i = 0; i < nthreads; ++i) {
+    post.wait();
+  }
+
+  // Verify expected state.
+  ASSERT_EQ(nelements, stage1_processed);
+  ASSERT_EQ(nelements, stage2_processed);
+  ASSERT_EQ(0u, initial_stack.length());
+  ASSERT_EQ(0u, start_stack.length());
+  ASSERT_EQ(0u, middle_stack.length());
+  ASSERT_EQ(nelements, final_stack.length());
+  while (final_stack.pop() != NULL) {}
+
+  FREE_C_HEAP_ARRAY(Element, elements);
+}