Reverse the macro meaning

Author: denis-kabanov

sycl/include/CL/sycl/backend.hpp

@@ -74,7 +74,9 @@ auto get_native(const SyclObjectT &Obj)
   return Obj.template get_native<BackendName>();
 }
 
-#ifndef SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_CL_EVENT
+// define SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_VEC_CL_EVENT to correspond
+// SYCL 2020 spec and return vector<cl_event> from get_native instead of just cl_event
+#ifdef SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_VEC_CL_EVENT
 template <>
 inline backend_return_t<backend::opencl, event>
 get_native<backend::opencl, event>(const event &Obj) {
@@ -91,6 +93,23 @@ get_native<backend::opencl, event>(const event &Obj) {
   }
   return ReturnValue;
 }
+#else
+// Specialization for cl_event with deprecation message
+template <>
+__SYCL_DEPRECATED("get_native<backend::opencl, event>, which only returns "
+                  "cl_event is deprecated. "
+                  "According to SYCL 2020 spec, please define "
+                  "SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_VEC_CL_EVENT and "
+                  "use vector<cl_event> instead.")
+inline backend_return_t<backend::opencl, event> get_native<
+    backend::opencl, event>(const event &Obj) {
+  // TODO use SYCL 2020 exception when implemented
+  if (Obj.get_backend() != backend::opencl) {
+    throw runtime_error("Backends mismatch", PI_INVALID_OPERATION);
+  }
+  return reinterpret_cast<
+      typename detail::interop<backend::opencl, event>::type>(Obj.getNative());
+}
 #endif
 
 // Native handle of an accessor should be accessed through interop_handler

sycl/include/CL/sycl/detail/backend_traits_opencl.hpp

@@ -104,15 +104,7 @@ template <> struct BackendReturn<backend::opencl, device> {
   using type = cl_device_id;
 };
 
-#ifdef SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_CL_EVENT
-template <> struct interop<backend::opencl, event> { using type = cl_event; };
-template <> struct BackendInput<backend::opencl, event> {
-  using type = cl_event;
-};
-template <> struct BackendReturn<backend::opencl, event> {
-  using type = cl_event;
-};
-#else
+#ifdef SYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_VEC_CL_EVENT
 template <> struct interop<backend::opencl, event> {
   using type = std::vector<cl_event>;
   using value_type = cl_event;
@@ -125,6 +117,14 @@ template <> struct BackendReturn<backend::opencl, event> {
   using type = std::vector<cl_event>;
   using value_type = cl_event;
 };
+#else
+template <> struct interop<backend::opencl, event> { using type = cl_event; };
+template <> struct BackendInput<backend::opencl, event> {
+  using type = cl_event;
+};
+template <> struct BackendReturn<backend::opencl, event> {
+  using type = cl_event;
+};
 #endif
 
 template <> struct BackendInput<backend::opencl, queue> {

sycl/test/regression/check_vector_of_opencl_event.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify -DSYCL_GET_NATIVE_BACKEND_OPENCL_RETURN_T_VEC_CL_EVENT %s
 // expected-no-diagnostics
 //
 //===----------------------------------------------------------------------===//