Merge pull request #1431 from zhaomaosu/fix-ocl-adapter-tear-down

[CL] Gracefully tear down adapter in case that some globals have been released

Author: kbenzie

source/adapters/opencl/adapter.cpp

@@ -15,18 +15,36 @@ struct ur_adapter_handle_t_ {
   std::mutex Mutex;
 };
 
-ur_adapter_handle_t_ adapter{};
+static ur_adapter_handle_t_ *adapter = nullptr;
+
+static void globalAdapterShutdown() {
+  if (cl_ext::ExtFuncPtrCache) {
+    delete cl_ext::ExtFuncPtrCache;
+    cl_ext::ExtFuncPtrCache = nullptr;
+  }
+  if (adapter) {
+    delete adapter;
+    adapter = nullptr;
+  }
+}
 
 UR_APIEXPORT ur_result_t UR_APICALL
 urAdapterGet(uint32_t NumEntries, ur_adapter_handle_t *phAdapters,
              uint32_t *pNumAdapters) {
   if (NumEntries > 0 && phAdapters) {
-    std::lock_guard<std::mutex> Lock{adapter.Mutex};
-    if (adapter.RefCount++ == 0) {
-      cl_ext::ExtFuncPtrCache = std::make_unique<cl_ext::ExtFuncPtrCacheT>();
+    // Sometimes urAdaterGet may be called after the library already been torn
+    // down, we also need to create a temporary handle for it.
+    if (!adapter) {
+      adapter = new ur_adapter_handle_t_();
+      atexit(globalAdapterShutdown);
     }
 
-    *phAdapters = &adapter;
+    std::lock_guard<std::mutex> Lock{adapter->Mutex};
+    if (adapter->RefCount++ == 0) {
+      cl_ext::ExtFuncPtrCache = new cl_ext::ExtFuncPtrCacheT();
+    }
+
+    *phAdapters = adapter;
   }
 
   if (pNumAdapters) {
@@ -37,14 +55,20 @@ urAdapterGet(uint32_t NumEntries, ur_adapter_handle_t *phAdapters,
 }
 
 UR_APIEXPORT ur_result_t UR_APICALL urAdapterRetain(ur_adapter_handle_t) {
-  ++adapter.RefCount;
+  ++adapter->RefCount;
   return UR_RESULT_SUCCESS;
 }
 
 UR_APIEXPORT ur_result_t UR_APICALL urAdapterRelease(ur_adapter_handle_t) {
-  std::lock_guard<std::mutex> Lock{adapter.Mutex};
-  if (--adapter.RefCount == 0) {
-    cl_ext::ExtFuncPtrCache.reset();
+  // Check first if the adapter is valid pointer
+  if (adapter) {
+    std::lock_guard<std::mutex> Lock{adapter->Mutex};
+    if (--adapter->RefCount == 0) {
+      if (cl_ext::ExtFuncPtrCache) {
+        delete cl_ext::ExtFuncPtrCache;
+        cl_ext::ExtFuncPtrCache = nullptr;
+      }
+    }
   }
   return UR_RESULT_SUCCESS;
 }
@@ -68,7 +92,7 @@ UR_APIEXPORT ur_result_t UR_APICALL urAdapterGetInfo(ur_adapter_handle_t,
   case UR_ADAPTER_INFO_BACKEND:
     return ReturnValue(UR_ADAPTER_BACKEND_OPENCL);
   case UR_ADAPTER_INFO_REFERENCE_COUNT:
-    return ReturnValue(adapter.RefCount.load());
+    return ReturnValue(adapter->RefCount.load());
   default:
     return UR_RESULT_ERROR_INVALID_ENUMERATION;
   }

source/adapters/opencl/common.hpp

@@ -349,7 +349,7 @@ struct ExtFuncPtrCacheT {
 // piTeardown to avoid issues with static destruction order (a user application
 // might have static objects that indirectly access this cache in their
 // destructor).
-inline std::unique_ptr<ExtFuncPtrCacheT> ExtFuncPtrCache;
+inline ExtFuncPtrCacheT *ExtFuncPtrCache;
 
 // USM helper function to get an extension function pointer
 template <typename T>