[llvm] [Offload] Implement the remaining initial Offload API (PR #122106)

[Joseph Huber via llvm-commits]

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@@ -104,3 +104,15 @@ def : Function {
     Return<"OL_ERRC_INVALID_DEVICE">
   ];
 }
+
+def : Function {
+  let name = "olGetHostDevice";
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jhuber6 wrote:

In my mind, the platform is an implementation detail of the device. Something you can query, but the API just iterates over devices.

https://github.com/llvm/llvm-project/pull/122106