[UR] Handle INVALID_VALUE in OCL urPlatformGet

Pre-commit MR for: oneapi-src/unified-runtime#2227

As there is a spec change in UR, adapter handling code has been updated -
it no longer tries to populate the platform list if it would be empty
(otherwise both "destination" pointers could be null, which is now
illegal).

This fixes a bug Intel tracks internally as URT-831

Author: RossBrunton

sycl/cmake/modules/FetchUnifiedRuntime.cmake

@@ -116,14 +116,24 @@ if(SYCL_UR_USE_FETCH_CONTENT)
       CACHE PATH "Path to external '${name}' adapter source dir" FORCE)
   endfunction()
 
-  set(UNIFIED_RUNTIME_REPO "https://github.com/oneapi-src/unified-runtime.git")
-  # commit c742ca49efb12380a35b8b0b467e6577ab8174ce
-  # Merge: 3a8bf2c5 504d3b63
-  # Author: Kenneth Benzie (Benie) <[email protected]>
-  # Date:   Mon Oct 21 11:55:23 2024 +0100
-  #     Merge pull request #2131 from Bensuo/ben/command-handle-fix
-  #     [EXP][CMDBUF] Make command handle behaviour consistent
-  set(UNIFIED_RUNTIME_TAG c742ca49efb12380a35b8b0b467e6577ab8174ce)
+  set(UNIFIED_RUNTIME_REPO "https://github.com/RossBrunton/unified-runtime.git")
+  # commit 9989d97bceeabd1e83949ff3c86ba34af94907d3
+  # Author: Ross Brunton <[email protected]>
+  # Date:   Mon Oct 21 16:35:45 2024 +0100
+  #     Handle INVALID_VALUE in OCL urPlatformGet
+  #
+  #     The OpenCL function clGetPlatformIDs may return CL_INVALID_VALUE, which
+  #     needs to be converted into appropriate UR returns as follows:
+  #
+  #     * If a non-null platforms list is provided, but the number of elements
+  #       in it is 0, then return UR_RESULT_ERROR_INVALID_SIZE.
+  #     * If neither platform or sizes outputs are provided, then return
+  #       UR_RESULT_ERROR_INVALID_VALUE.
+  #
+  #     This required a spec change.
+  #
+  #     This fixes a bug Intel are tracking internally as URT-831.
+  set(UNIFIED_RUNTIME_TAG 9989d97bceeabd1e83949ff3c86ba34af94907d3)
 
   set(UMF_BUILD_EXAMPLES OFF CACHE INTERNAL "EXAMPLES")
   # Due to the use of dependentloadflag and no installer for UMF and hwloc we need

sycl/source/detail/adapter.hpp

@@ -100,8 +100,10 @@ class Adapter {
       uint32_t platformCount = 0;
       call<UrApiKind::urPlatformGet>(&MAdapter, 1, 0, nullptr, &platformCount);
       UrPlatforms.resize(platformCount);
-      call<UrApiKind::urPlatformGet>(&MAdapter, 1, platformCount,
-                                     UrPlatforms.data(), nullptr);
+      if (platformCount) {
+        call<UrApiKind::urPlatformGet>(&MAdapter, 1, platformCount,
+                                       UrPlatforms.data(), nullptr);
+      }
       // We need one entry in this per platform
       LastDeviceIds.resize(platformCount);
     });