[SYCL] Support sycl_ext_oneapi_device_default_context (#20670)

Spec:
https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/proposed/sycl_ext_oneapi_device_default_context.asciidoc

Author: KornevNikita

sycl/include/sycl/device.hpp

@@ -38,6 +38,7 @@ namespace sycl {
 inline namespace _V1 {
 // Forward declarations
 class platform;
+class context;
 template <backend BackendName, class SyclObjectT>
 auto get_native(const SyclObjectT &Obj)
     -> backend_return_t<BackendName, SyclObjectT>;
@@ -353,6 +354,11 @@ class __SYCL_STANDALONE_DEBUG __SYCL_EXPORT device
     return profile.c_str();
   }
 
+  /// Shortcut for get_platform().khr_get_default_context().
+  ///
+  /// \return the default context
+  context ext_oneapi_get_default_context();
+
 // TODO: Remove this diagnostics when __SYCL_WARN_IMAGE_ASPECT is removed.
 #if defined(__clang__)
 #pragma clang diagnostic pop

sycl/source/device.cpp

@@ -336,5 +336,9 @@ detail::string device::ext_oneapi_cl_profile_impl() const {
   return detail::string{profile};
 }
 
+context device::ext_oneapi_get_default_context() {
+  return impl->get_platform().khr_get_default_context();
+}
+
 } // namespace _V1
 } // namespace sycl

sycl/source/feature_test.hpp.in

@@ -122,6 +122,7 @@ inline namespace _V1 {
 #define SYCL_EXT_ONEAPI_MEMORY_EXPORT 1
 #define SYCL_EXT_ONEAPI_CLOCK 1
 #define SYCL_EXT_ONEAPI_DEVICE_IS_INTEGRATED_GPU 1
+#define SYCL_EXT_ONEAPI_DEVICE_DEFAULT_CONTEXT 1
 // In progress yet
 #define SYCL_EXT_ONEAPI_ATOMIC16 0
 #define SYCL_KHR_DEFAULT_CONTEXT 1

sycl/test-e2e/Basic/ext_oneapi_get_default_context.cpp

@@ -0,0 +1,12 @@
+// RUN: %{build} -o %t.out
+// RUN: %{run} %t.out
+
+#include <sycl/detail/core.hpp>
+#include <sycl/platform.hpp>
+
+int main() {
+  sycl::device dev;
+  auto ctx1 = dev.ext_oneapi_get_default_context();
+  auto ctx2 = dev.get_platform().khr_get_default_context();
+  return !(ctx1 == ctx2);
+}

sycl/test/abi/sycl_symbols_linux.dump

@@ -3397,6 +3397,7 @@ _ZN4sycl3_V16device26ext_oneapi_architecture_isENS0_3ext6oneapi12experimental13a
 _ZN4sycl3_V16device26ext_oneapi_can_access_peerERKS1_NS0_3ext6oneapi11peer_accessE
 _ZN4sycl3_V16device29ext_oneapi_enable_peer_accessERKS1_
 _ZN4sycl3_V16device30ext_oneapi_disable_peer_accessERKS1_
+_ZN4sycl3_V16device30ext_oneapi_get_default_contextEv
 _ZN4sycl3_V16device32ext_oneapi_supports_cl_c_featureENS0_6detail11string_viewE
 _ZN4sycl3_V16deviceC1EP13_cl_device_id
 _ZN4sycl3_V16deviceC1ERKNS0_15device_selectorE

sycl/test/abi/sycl_symbols_windows.dump

@@ -3935,6 +3935,7 @@
 ?ext_oneapi_get_backend_content_view_impl@device_image_plain@detail@_V1@sycl@@IEBA?AU?$pair@PEBW4byte@std@@PEBW412@@std@@XZ
 ?ext_oneapi_get_backend_impl@device_image_plain@detail@_V1@sycl@@IEBA?AW4backend@34@XZ
 ?ext_oneapi_get_composite_devices@platform@_V1@sycl@@QEBA?AV?$vector@Vdevice@_V1@sycl@@V?$allocator@Vdevice@_V1@sycl@@@std@@@std@@XZ
+?ext_oneapi_get_default_context@device@_V1@sycl@@QEAA?AVcontext@23@XZ
 ?ext_oneapi_get_default_context@platform@_V1@sycl@@QEBA?AVcontext@23@XZ
 ?ext_oneapi_get_default_memory_pool@context@_V1@sycl@@QEBA?AVmemory_pool@experimental@oneapi@ext@23@AEBVdevice@23@W4alloc@usm@23@@Z
 ?ext_oneapi_get_device_global_address@kernel_bundle_plain@detail@_V1@sycl@@AEAAPEAXVstring_view@234@AEBVdevice@34@@Z