Fix and test using RAII global state in main. (#168)

nvbench/main.cuh

@@ -111,9 +111,11 @@
 
 #ifndef NVBENCH_MAIN_INITIALIZE
 #define NVBENCH_MAIN_INITIALIZE(argc, argv)                                                        \
-  NVBENCH_MAIN_INITIALIZE_CUSTOM_PRE(argc, argv);                                                  \
-  nvbench::detail::main_initialize(argc, argv);                                                    \
-  NVBENCH_MAIN_INITIALIZE_CUSTOM_POST(argc, argv)
+  { /* Open a scope to ensure that the inner initialize/finalize hooks clean up in order. */       \
+    NVBENCH_MAIN_INITIALIZE_CUSTOM_PRE(argc, argv);                                                \
+    nvbench::detail::main_initialize(argc, argv);                                                  \
+    { /* Open a scope to ensure that the inner initialize/finalize hooks clean up in order. */     \
+      NVBENCH_MAIN_INITIALIZE_CUSTOM_POST(argc, argv)
 #endif
 
 #ifndef NVBENCH_MAIN_PARSE
@@ -146,8 +148,11 @@
 #ifndef NVBENCH_MAIN_FINALIZE
 #define NVBENCH_MAIN_FINALIZE()                                                                    \
   NVBENCH_MAIN_FINALIZE_CUSTOM_PRE();                                                              \
+  } /* Close a scope to ensure that the inner initialize/finalize hooks clean up in order. */      \
   nvbench::detail::main_finalize();                                                                \
-  NVBENCH_MAIN_FINALIZE_CUSTOM_POST()
+  NVBENCH_MAIN_FINALIZE_CUSTOM_POST();                                                             \
+  } /* Close a scope to ensure that the inner initialize/finalize hooks clean up in order. */      \
+  []() {}()
 #endif
 
 #ifndef NVBENCH_MAIN_CATCH_EXCEPTIONS

testing/CMakeLists.txt

@@ -8,6 +8,7 @@ set(test_srcs
   criterion_params.cu
   custom_main_custom_args.cu
   custom_main_custom_exceptions.cu
+  custom_main_global_state_raii.cu
   enum_type_list.cu
   entropy_criterion.cu
   float64_axis.cu

testing/custom_main_global_state_raii.cu

@@ -0,0 +1,121 @@
+/*
+ *  Copyright 2024 NVIDIA Corporation
+ *
+ *  Licensed under the Apache License, Version 2.0 with the LLVM exception
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.
+ *
+ *  You may obtain a copy of the License at
+ *
+ *      http://llvm.org/foundation/relicensing/LICENSE.txt
+ *
+ *  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 <nvbench/nvbench.cuh>
+
+#include <algorithm>
+#include <cstdlib>
+#include <cstdio>
+
+/******************************************************************************
+ * Test having global state that is initialized and finalized via RAII.
+ *****************************************************************************/
+
+struct raii
+{
+  const char m_ref_data[6];
+  char *m_data;
+  bool m_cuda;
+
+  const char *m_outer_data;
+  bool m_outer_cuda;
+
+  explicit raii(bool cuda, char *outer_data = nullptr, bool outer_cuda = false)
+      : m_ref_data{'a', 'b', 'c', '1', '2', '3'}
+      , m_data(nullptr)
+      , m_cuda(cuda)
+      , m_outer_data(outer_data)
+      , m_outer_cuda(outer_cuda)
+  {
+    if (m_cuda)
+    {
+      printf("(%p) RAII test: allocating device memory\n", this);
+      NVBENCH_CUDA_CALL(cudaMalloc(&m_data, 6));
+      NVBENCH_CUDA_CALL(cudaMemcpy(m_data, m_ref_data, 6, cudaMemcpyHostToDevice));
+    }
+    else
+    {
+      printf("(%p) RAII test: allocating host memory\n", this);
+      m_data = new char[6];
+      std::copy(m_ref_data, m_ref_data + 6, m_data);
+    }
+  }
+
+  ~raii()
+  {
+    this->verify();
+    if (m_cuda)
+    {
+      printf("(%p) RAII test: invalidating device memory\n", this);
+      NVBENCH_CUDA_CALL(cudaMemset(m_data, 0, 6));
+      printf("(%p) RAII test: freeing device memory\n", this);
+      NVBENCH_CUDA_CALL(cudaFree(m_data));
+    }
+    else
+    {
+      printf("(%p) RAII test: invalidating host memory\n", this);
+      std::fill(m_data, m_data + 6, '\0');
+      printf("(%p) RAII test: freeing host memory\n", this);
+      delete[] m_data;
+    }
+  }
+
+  void verify() noexcept
+  {
+    printf("(%p) RAII test: verifying instance state\n", this);
+    this->verify(m_cuda, m_data);
+    if (m_outer_data)
+    {
+      printf("(%p) RAII test: verifying outer state\n", this);
+      this->verify(m_outer_cuda, m_outer_data);
+    }
+  }
+
+  void verify(bool cuda, const char *data) noexcept
+  {
+    if (cuda)
+    {
+      char test_data[6];
+      NVBENCH_CUDA_CALL(cudaMemcpy(test_data, data, 6, cudaMemcpyDeviceToHost));
+      if (strncmp(test_data, m_ref_data, 6) != 0)
+      {
+        printf("(%p) RAII test failed: device data mismatch\n", this);
+        std::exit(1);
+      }
+    }
+    else
+    {
+      if (strncmp(data, m_ref_data, 6) != 0)
+      {
+        printf("(%p) RAII test failed: host data mismatch\n", this);
+        std::exit(1);
+      }
+    }
+  }
+};
+
+// These will be destroyed in the opposite order in which they are created:
+
+#undef NVBENCH_MAIN_INITIALIZE_CUSTOM_PRE
+#define NVBENCH_MAIN_INITIALIZE_CUSTOM_PRE(argc, argv) raii raii_outer(false);
+
+#undef NVBENCH_MAIN_INITIALIZE_CUSTOM_POST
+#define NVBENCH_MAIN_INITIALIZE_CUSTOM_POST(argc, argv)                                            \
+  [[maybe_unused]] raii raii_inner(true, raii_outer.m_data, raii_outer.m_cuda);
+
+NVBENCH_MAIN