[llvm] [libsycl] implement methods of synchronization in event and queue classes (PR #205860)

[Kseniya Tikhomirova via llvm-commits]

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@@ -18,4 +19,24 @@ exception_list::iterator exception_list::begin() const { return MList.begin(); }
 
 exception_list::iterator exception_list::end() const { return MList.cend(); }
 
+void detail::addAsyncException(exception_list &List,
+                               const std::exception_ptr &Exception) {
+  List.MList.emplace_back(Exception);
+}
+
+void detail::defaultAsyncHandler(exception_list Exceptions) {
+  std::cerr << "Default async_handler caught exceptions:";
+  for (auto &EIt : Exceptions) {
+    try {
+      if (EIt) {
+        std::rethrow_exception(EIt);
+      }
+    } catch (const std::exception &E) {
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KseniyaTikhomirova wrote:

sycl::exception inherits std::exception and exception_list has generic value type: 
` using value_type = std::exception_ptr;`

so it is expected to catch std::exception here


https://github.com/llvm/llvm-project/pull/205860