[SYCL] Refactoring of accessor class + introduction of Requirement class.

The Requirement class is added as base non-templated class for accessor.
This class describes command group's requirement to memory object and
is used to build dependency graph in Scheduler.

Signed-off-by: Vlad Romanov <vlad.romanov@intel.com>

Author: romanovvlad

sycl/include/CL/sycl/access/access.hpp

@@ -97,6 +97,21 @@ struct DeviceValueType<dataT, access::target::host_buffer> {
   using type = dataT;
 };
 
+template <access::target accessTarget> struct TargetToAS {
+  constexpr static access::address_space AS =
+      access::address_space::global_space;
+};
+
+template <> struct TargetToAS<access::target::local> {
+  constexpr static access::address_space AS =
+      access::address_space::local_space;
+};
+
+template <> struct TargetToAS<access::target::constant_buffer> {
+  constexpr static access::address_space AS =
+      access::address_space::constant_space;
+};
+
 template <typename ElementType, access::address_space addressSpace>
 struct PtrValueType;
 

sycl/include/CL/sycl/accessor.hpp

@@ -6,6 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifdef SCHEDULER_20
+
+#include <CL/sycl/accessor2.hpp>
+
+#else
+
 #pragma once
 
 #include <type_traits>
@@ -1028,3 +1034,4 @@ struct hash<cl::sycl::accessor<T, Dimensions, AccessMode, AccessTarget,
   }
 };
 } // namespace std
+#endif // SCHEDULER_20