[Offload] Implement olShutDown

offload/liboffload/src/OffloadImpl.cpp

@@ -148,19 +148,19 @@ constexpr ol_platform_backend_t pluginNameToBackend(StringRef Name) {
 #include "Shared/Targets.def"
 
 Error initPlugins() {
-  auto *Context = new OffloadContext{};
+  auto &Context = OffloadContext::get();
 
   // Attempt to create an instance of each supported plugin.
 #define PLUGIN_TARGET(Name)                                                    \
   do {                                                                         \
-    Context->Platforms.emplace_back(ol_platform_impl_t{                        \
+    Context.Platforms.emplace_back(ol_platform_impl_t{                         \
         std::unique_ptr<GenericPluginTy>(createPlugin_##Name()),               \
         pluginNameToBackend(#Name)});                                          \
   } while (false);
 #include "Shared/Targets.def"
 
   // Preemptively initialize all devices in the plugin
-  for (auto &Platform : Context->Platforms) {
+  for (auto &Platform : Context.Platforms) {
     // Do not use the host plugin - it isn't supported.
     if (Platform.BackendType == OL_PLATFORM_BACKEND_UNKNOWN)
       continue;
@@ -180,15 +180,13 @@ Error initPlugins() {
   }
 
   // Add the special host device
-  auto &HostPlatform = Context->Platforms.emplace_back(
+  auto &HostPlatform = Context.Platforms.emplace_back(
       ol_platform_impl_t{nullptr, OL_PLATFORM_BACKEND_HOST});
   HostPlatform.Devices.emplace_back(-1, nullptr, nullptr, InfoTreeNode{});
-  Context->HostDevice()->Platform = &HostPlatform;
+  Context.HostDevice()->Platform = &HostPlatform;
 
-  Context->TracingEnabled = std::getenv("OFFLOAD_TRACE");
-  Context->ValidationEnabled = !std::getenv("OFFLOAD_DISABLE_VALIDATION");
-
-  OffloadContextVal = Context;
+  Context.TracingEnabled = std::getenv("OFFLOAD_TRACE");
+  Context.ValidationEnabled = !std::getenv("OFFLOAD_DISABLE_VALIDATION");
 
   return Plugin::success();
 }
@@ -197,8 +195,10 @@ Error olInit_impl() {
   std::lock_guard<std::mutex> Lock{OffloadContextValMutex};
 
   std::optional<Error> InitResult;
-  if (!isOffloadInitialized())
+  if (!isOffloadInitialized()) {
+    OffloadContextVal = new OffloadContext{};
     InitResult = initPlugins();
+  }
 
   OffloadContext::get().RefCount++;