From fad25474a62eef8190cbe2eb46898fb46bd37b3b Mon Sep 17 00:00:00 2001
From: Anirudh Subramanian <anirudh2290@ufl.edu>
Date: Fri, 18 Oct 2019 03:12:41 +0000
Subject: [PATCH] Build dmlc-core with old thread_local implementation

---
 3rdparty/dmlc-core                    |  2 +-
 CMakeLists.txt                        |  3 +
 Makefile                              |  2 +
 tests/cpp/engine/thread_local_test.cc | 80 +++++++++++++++++++++++++++
 4 files changed, 86 insertions(+), 1 deletion(-)
 create mode 100644 tests/cpp/engine/thread_local_test.cc

diff --git a/3rdparty/dmlc-core b/3rdparty/dmlc-core
index 9088d2ee02cd..0e13243556d7 160000
--- a/3rdparty/dmlc-core
+++ b/3rdparty/dmlc-core
@@ -1 +1 @@
-Subproject commit 9088d2ee02cdfe393fd0569af4aefebe94f8b105
+Subproject commit 0e13243556d7de754a923c8f97998721d694f29b
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 70b09917de13..99ad34bed3dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -101,6 +101,9 @@ if("$ENV{VERBOSE}" STREQUAL "1")
   set(CMAKE_VERBOSE_MAKEFILE ON)
 endif()
 
+#Switch off modern thread local for dmlc-core, please see: https://github.com/dmlc/dmlc-core/issues/571#issuecomment-543467484
+add_definitions(-DDMLC_MODERN_THREAD_LOCAL=0)
+
 
 if(MSVC)
   add_definitions(-DWIN32_LEAN_AND_MEAN)
diff --git a/Makefile b/Makefile
index 0a1e355ee5e8..8339e97431cd 100644
--- a/Makefile
+++ b/Makefile
@@ -94,6 +94,8 @@ include $(DMLC_CORE)/make/dmlc.mk
 # all tge possible warning tread
 WARNFLAGS= -Wall -Wsign-compare
 CFLAGS = -DMSHADOW_FORCE_STREAM $(WARNFLAGS)
+# use old thread local implementation in DMLC-CORE
+CFLAGS += -DDMLC_MODERN_THREAD_LOCAL=0
 
 ifeq ($(DEV), 1)
 	CFLAGS += -g -Werror
diff --git a/tests/cpp/engine/thread_local_test.cc b/tests/cpp/engine/thread_local_test.cc
new file mode 100644
index 000000000000..24b689fa9a73
--- /dev/null
+++ b/tests/cpp/engine/thread_local_test.cc
@@ -0,0 +1,80 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2019 by Contributors
+ * \file engine_shutdown_test.cc
+ * \brief Tests engine shutdown for possible crashes
+*/
+#include <gtest/gtest.h>
+#include <time.h>
+#include <dmlc/logging.h>
+#include <dmlc/thread_group.h>
+#include <dmlc/omp.h>
+#include <mxnet/c_api.h>
+#include <mxnet/engine.h>
+#include <mxnet/ndarray.h>
+#include <dmlc/timer.h>
+#include <cstdio>
+#include <thread>
+#include <chrono>
+#include <vector>
+
+struct A {
+    std::vector<int> a;
+};
+int num_threads = 10;
+int num_elements = num_threads * 10;
+
+static int ThreadSafetyTest(int num, std::vector<int>* tmp_inputs, std::vector<int*>* res) {
+    A *ret = dmlc::ThreadLocalStore<A>::Get();
+    for (size_t i = num * 10; i < num * 10 + 10; ++i) {
+        (*tmp_inputs)[i] = i;
+    }
+    ret->a.clear();
+    ret->a.reserve(10);
+    for (size_t i = num * 10; i < num * 10 + 10; ++i) {
+        ret->a.push_back((*tmp_inputs)[i]);
+    }
+    (*res)[num] = dmlc::BeginPtr(ret->a);
+    return 0;
+}
+
+TEST(ThreadLocal, verify_thread_safety) {
+    std::vector<int> tmp_inputs;
+    tmp_inputs.resize(num_elements);
+    std::vector<int*> outputs;
+    outputs.resize(num_threads);
+    auto func = [&](int num) {
+        ThreadSafetyTest(num, &tmp_inputs, &outputs);
+    };
+    std::vector<std::thread> worker_threads(num_threads);
+    int count = 0;
+    for (auto&& i : worker_threads) {
+        i = std::thread(func, count);
+        count++;
+    }
+    for (auto&& i : worker_threads) {
+        i.join();
+    }
+
+    for (size_t i = 0; i < num_elements; i++) {
+        CHECK(outputs[i/10][i%10] == i);
+    }
+}