[UR][Offload] Implement urProgramGetGlobalVariablePointer

Author: RossBrunton

unified-runtime/source/adapters/offload/device.cpp

@@ -76,9 +76,10 @@ UR_APIEXPORT ur_result_t UR_APICALL urDeviceGetInfo(ur_device_handle_t hDevice,
     return ReturnValue(uint32_t{1});
   case UR_DEVICE_INFO_MAX_WORK_ITEM_DIMENSIONS:
     return ReturnValue(uint32_t{3});
+  case UR_DEVICE_INFO_GLOBAL_VARIABLE_SUPPORT:
+    return ReturnValue(true);
   // Unimplemented features
   case UR_DEVICE_INFO_PROGRAM_SET_SPECIALIZATION_CONSTANTS:
-  case UR_DEVICE_INFO_GLOBAL_VARIABLE_SUPPORT:
   case UR_DEVICE_INFO_USM_POOL_SUPPORT:
   case UR_DEVICE_INFO_COMMAND_BUFFER_SUPPORT_EXP:
   case UR_DEVICE_INFO_IMAGE_SUPPORT:

unified-runtime/source/adapters/offload/program.cpp

@@ -236,3 +236,27 @@ UR_APIEXPORT ur_result_t UR_APICALL urProgramSetSpecializationConstants(
     ur_program_handle_t, uint32_t, const ur_specialization_constant_info_t *) {
   return UR_RESULT_ERROR_UNSUPPORTED_FEATURE;
 }
+
+UR_APIEXPORT ur_result_t UR_APICALL urProgramGetGlobalVariablePointer(
+    ur_device_handle_t, ur_program_handle_t hProgram,
+    const char *pGlobalVariableName, size_t *pGlobalVariableSizeRet,
+    void **ppGlobalVariablePointerRet) {
+  ol_symbol_handle_t Symbol;
+  auto Err = olGetSymbol(hProgram->OffloadProgram, pGlobalVariableName,
+                         OL_SYMBOL_KIND_GLOBAL_VARIABLE, &Symbol);
+  if (Err && Err->Code == OL_ERRC_NOT_FOUND) {
+    return UR_RESULT_ERROR_INVALID_VALUE;
+  }
+  OL_RETURN_ON_ERR(Err);
+
+  if (pGlobalVariableSizeRet) {
+    OL_RETURN_ON_ERR(olGetSymbolInfo(Symbol,
+                                     OL_SYMBOL_INFO_GLOBAL_VARIABLE_SIZE,
+                                     sizeof(size_t), pGlobalVariableSizeRet));
+  }
+  OL_RETURN_ON_ERR(olGetSymbolInfo(Symbol,
+                                   OL_SYMBOL_INFO_GLOBAL_VARIABLE_ADDRESS,
+                                   sizeof(void *), ppGlobalVariablePointerRet));
+
+  return UR_RESULT_SUCCESS;
+}

unified-runtime/source/adapters/offload/ur_interface_loader.cpp

@@ -92,7 +92,7 @@ UR_DLLEXPORT ur_result_t UR_APICALL urGetProgramProcAddrTable(
   pDdiTable->pfnCreateWithNativeHandle = urProgramCreateWithNativeHandle;
   pDdiTable->pfnGetBuildInfo = nullptr;
   pDdiTable->pfnGetFunctionPointer = nullptr;
-  pDdiTable->pfnGetGlobalVariablePointer = nullptr;
+  pDdiTable->pfnGetGlobalVariablePointer = urProgramGetGlobalVariablePointer;
   pDdiTable->pfnGetInfo = urProgramGetInfo;
   pDdiTable->pfnGetNativeHandle = urProgramGetNativeHandle;
   pDdiTable->pfnLink = nullptr;

unified-runtime/test/conformance/program/urProgramGetGlobalVariablePointer.cpp

@@ -11,6 +11,8 @@ using urProgramGetGlobalVariablePointerTest = uur::urGlobalVariableTest;
 UUR_INSTANTIATE_DEVICE_TEST_SUITE(urProgramGetGlobalVariablePointerTest);
 
 TEST_P(urProgramGetGlobalVariablePointerTest, Success) {
+  // Our conformance tests don't generate binaries that contain externally visible globals on AMD
+  UUR_KNOWN_FAILURE_ON(uur::Offload{"gfx"});
   size_t global_variable_size = 0;
   void *global_variable_pointer;
   ASSERT_SUCCESS(urProgramGetGlobalVariablePointer(