From 3cf1766d6291f59b9b236d52aa3756be19c25ec9 Mon Sep 17 00:00:00 2001
From: Yue Ni <niyue.com@gmail.com>
Date: Wed, 20 Sep 2023 10:44:02 +0800
Subject: [PATCH] Add minimum test case for verifying exported function
 registration only happens once.

---
 cpp/src/gandiva/CMakeLists.txt                |  1 +
 cpp/src/gandiva/exported_funcs.h              |  4 +--
 cpp/src/gandiva/exported_funcs_registry.cc    |  2 +-
 cpp/src/gandiva/exported_funcs_registry.h     |  4 +--
 .../gandiva/exported_funcs_registry_test.cc   | 28 +++++++++++++++++++
 5 files changed, 34 insertions(+), 5 deletions(-)
 create mode 100644 cpp/src/gandiva/exported_funcs_registry_test.cc

diff --git a/cpp/src/gandiva/CMakeLists.txt b/cpp/src/gandiva/CMakeLists.txt
index 732986478453d..6b6743bc8e52f 100644
--- a/cpp/src/gandiva/CMakeLists.txt
+++ b/cpp/src/gandiva/CMakeLists.txt
@@ -238,6 +238,7 @@ add_gandiva_test(internals-test
                  tree_expr_test.cc
                  encrypt_utils_test.cc
                  expr_decomposer_test.cc
+                 exported_funcs_registry_test.cc
                  expression_registry_test.cc
                  selection_vector_test.cc
                  lru_cache_test.cc
diff --git a/cpp/src/gandiva/exported_funcs.h b/cpp/src/gandiva/exported_funcs.h
index 9c110282095ea..82aa020a210c0 100644
--- a/cpp/src/gandiva/exported_funcs.h
+++ b/cpp/src/gandiva/exported_funcs.h
@@ -18,6 +18,7 @@
 #pragma once
 
 #include <vector>
+#include "gandiva/visibility.h"
 
 namespace gandiva {
 
@@ -61,6 +62,5 @@ class ExportedHashFunctions : public ExportedFuncsBase {
   void AddMappings(Engine* engine) const override;
 };
 
-void RegisterExportedFuncs();
-
+GANDIVA_EXPORT void RegisterExportedFuncs();
 }  // namespace gandiva
diff --git a/cpp/src/gandiva/exported_funcs_registry.cc b/cpp/src/gandiva/exported_funcs_registry.cc
index e30825cd4c090..78320f4e03a75 100644
--- a/cpp/src/gandiva/exported_funcs_registry.cc
+++ b/cpp/src/gandiva/exported_funcs_registry.cc
@@ -22,7 +22,7 @@
 namespace gandiva {
 
 void ExportedFuncsRegistry::AddMappings(Engine* engine) {
-  for (auto entry : registered()) {
+  for (const auto& entry : registered()) {
     entry->AddMappings(engine);
   }
 }
diff --git a/cpp/src/gandiva/exported_funcs_registry.h b/cpp/src/gandiva/exported_funcs_registry.h
index aa9c3e8359e06..639d1def15d10 100644
--- a/cpp/src/gandiva/exported_funcs_registry.h
+++ b/cpp/src/gandiva/exported_funcs_registry.h
@@ -21,6 +21,7 @@
 #include <vector>
 
 #include <gandiva/engine.h>
+#include <gandiva/visibility.h>
 
 namespace gandiva {
 
@@ -28,7 +29,7 @@ class ExportedFuncsBase;
 
 /// Registry for classes that export functions which can be accessed by
 /// LLVM/IR code.
-class ExportedFuncsRegistry {
+class GANDIVA_EXPORT ExportedFuncsRegistry {
  public:
   using list_type = std::vector<std::shared_ptr<ExportedFuncsBase>>;
 
@@ -40,7 +41,6 @@ class ExportedFuncsRegistry {
     return true;
   }
 
- private:
   static list_type& registered();
 };
 
diff --git a/cpp/src/gandiva/exported_funcs_registry_test.cc b/cpp/src/gandiva/exported_funcs_registry_test.cc
new file mode 100644
index 0000000000000..06d7f06018216
--- /dev/null
+++ b/cpp/src/gandiva/exported_funcs_registry_test.cc
@@ -0,0 +1,28 @@
+// 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.
+
+#include "gandiva/exported_funcs_registry.h"
+#include <gtest/gtest.h>
+#include "gandiva/exported_funcs.h"
+
+namespace gandiva {
+TEST(ExportedFuncsRegistry, RegistrationOnlyOnce) {
+  gandiva::RegisterExportedFuncs();
+  auto const& registered_list = ExportedFuncsRegistry::registered();
+  EXPECT_EQ(registered_list.size(), 6);
+}
+}  // namespace gandiva