[llvm] [Offload] Add device UID (PR #164391)

[Robert Imschweiler via llvm-commits]

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@@ -293,6 +294,12 @@ struct CUDADeviceTy : public GenericDeviceTy {
     if (auto Err = Plugin::check(Res, "error in cuDeviceGet: %s"))
       return Err;
 
+    CUuuid UUID = {0};
+    Res = cuDeviceGetUuid(&UUID, Device);
+    if (auto Err = Plugin::check(Res, "error in cuDeviceGetUuid: %s"))
+      return Err;
+    setDeviceUidFromVendorUid(toHex(UUID.bytes, true));
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ro-i wrote:

> Riiiight, well that API probably should've been implemented as to not rely on permanent storage but I guess that's moot

Unfortunately, OpenMP 6.0 explicitly specifies `const char *` (and in C wouldn't have `std::string` anyway).

>  Could probably just cache it at the OpenMP layer in a map of device pointers to strings and return the pointer and look it up if empty, then return it.

Urgh. Really?

https://github.com/llvm/llvm-project/pull/164391