[OpenMP][NFC] Remove no-op __tgt_rtl_deinit_plugin

The order in which we deinit things, especially when shared libraries
are involved, is complicated. To simplify our lives the nextgen plugin
deinitializes the GenericPluginTy and subclasses automatically. The old
__tgt_rtl_deinit_plugin is not needed anymore.

Author: jdoerfert

openmp/libomptarget/include/omptargetplugin.h

@@ -23,9 +23,6 @@ extern "C" {
 // First method called on the plugin
 int32_t __tgt_rtl_init_plugin();
 
-// Last method called on the plugin
-int32_t __tgt_rtl_deinit_plugin();
-
 // Return the number of available devices of the type supported by the
 // target RTL.
 int32_t __tgt_rtl_number_of_devices(void);

openmp/libomptarget/include/rtl.h

@@ -32,7 +32,6 @@ struct __tgt_bin_desc;
 
 struct RTLInfoTy {
   typedef int32_t(init_plugin_ty)();
-  typedef int32_t(deinit_plugin_ty)();
   typedef int32_t(is_valid_binary_ty)(void *);
   typedef int32_t(is_valid_binary_info_ty)(void *, void *);
   typedef int32_t(is_data_exchangable_ty)(int32_t, int32_t);
@@ -90,7 +89,6 @@ struct RTLInfoTy {
 
   // Functions implemented in the RTL.
   init_plugin_ty *init_plugin = nullptr;
-  deinit_plugin_ty *deinit_plugin = nullptr;
   is_valid_binary_ty *is_valid_binary = nullptr;
   is_valid_binary_info_ty *is_valid_binary_info = nullptr;
   is_data_exchangable_ty *is_data_exchangable = nullptr;

openmp/libomptarget/plugins-nextgen/common/PluginInterface/PluginInterface.cpp

@@ -1632,17 +1632,6 @@ int32_t __tgt_rtl_init_plugin() {
   return OFFLOAD_SUCCESS;
 }
 
-int32_t __tgt_rtl_deinit_plugin() {
-  auto Err = Plugin::deinitIfNeeded();
-  if (Err) {
-    REPORT("Failure to deinitialize plugin " GETNAME(TARGET_NAME) ": %s\n",
-           toString(std::move(Err)).data());
-    return OFFLOAD_FAIL;
-  }
-
-  return OFFLOAD_SUCCESS;
-}
-
 int32_t __tgt_rtl_is_valid_binary(__tgt_device_image *TgtImage) {
   if (!Plugin::isActive())
     return false;

openmp/libomptarget/plugins-nextgen/common/PluginInterface/PluginInterface.h

@@ -1167,13 +1167,6 @@ class Plugin {
     return Error::success();
   }
 
-  // Deinitialize the plugin if needed. The plugin could have been deinitialized
-  // because the plugin library was exiting.
-  static Error deinitIfNeeded() {
-    // Do nothing. The plugin is deinitialized automatically.
-    return Plugin::success();
-  }
-
   /// Get a reference (or create if it was not created) to the plugin instance.
   static GenericPluginTy &get() {
     // This static variable will initialize the underlying plugin instance in

openmp/libomptarget/src/rtl.cpp

@@ -193,8 +193,6 @@ bool RTLsTy::attemptLoadRTL(const std::string &RTLName, RTLInfoTy &RTL) {
   DP("Registering RTL %s supporting %d devices!\n", Name, RTL.NumberOfDevices);
 
   // Optional functions
-  *((void **)&RTL.deinit_plugin) =
-      DynLibrary->getAddressOfSymbol("__tgt_rtl_deinit_plugin");
   *((void **)&RTL.is_valid_binary_info) =
       DynLibrary->getAddressOfSymbol("__tgt_rtl_is_valid_binary_info");
   *((void **)&RTL.deinit_device) =
@@ -598,14 +596,5 @@ void RTLsTy::unregisterLib(__tgt_bin_desc *Desc) {
 
   PM->TblMapMtx.unlock();
 
-  // TODO: Write some RTL->unload_image(...) function?
-  for (auto *R : UsedRTLs) {
-    if (R->deinit_plugin) {
-      if (R->deinit_plugin() != OFFLOAD_SUCCESS) {
-        DP("Failure deinitializing RTL %s!\n", R->RTLName.c_str());
-      }
-    }
-  }
-
   DP("Done unregistering library!\n");
 }