[llvm] [offload] Fix compatibility for level_zero 25.22.33944 (PR #214215)

[Jan Trusiłło via llvm-commits]

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@@ -177,16 +178,15 @@ class L0CmdListManagerTy {
                            ze_event_handle_t SignalEvent = nullptr,
                            uint32_t NumWaitEvents = 0,
                            ze_event_handle_t *WaitEvents = nullptr) {
-    auto zeCommandListAppendHost = Context.zeCommandListAppendHostFunction;
-    if (!zeCommandListAppendHost)
+    if (!api_helper::canCall<zeCommandListAppendHostFunction>())
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311Volt wrote:

It could be a good idea to introduce a second layer concerned only with whether a function is supported, and keep the current meaning of `canCall`, which is to ask if the symbol is available.

I would even go as far as to introduce a global per-symbol `isKnownUnsupported` flag (stored similarly to dlwrap pointers), which is `false` if the function ever returned `ZE_RESULT_ERROR_UNSUPPORTED_FEATURE`. This would keep fallbacks practically free in terms of runtime cost

https://github.com/llvm/llvm-project/pull/214215