[llvm] [OFFLOAD] Add support for host offloading device (PR #171010)

[via llvm-commits]

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@@ -349,7 +350,7 @@ Error olGetPlatformInfoImplDetail(ol_platform_handle_t Platform,
                                   ol_platform_info_t PropName, size_t PropSize,
                                   void *PropValue, size_t *PropSizeRet) {
   InfoWriter Info(PropSize, PropValue, PropSizeRet);
-  bool IsHost = Platform->BackendType == OL_PLATFORM_BACKEND_HOST;
+  bool IsHost = Platform->Plugin == nullptr;
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fineg74 wrote:

They currently do not support host as an offloading target. Therefore host platform is always for true host. Since we can have host both as actual host and as an offloading target and both of them will have the same platform we rely on absence of plugin for the actual host

https://github.com/llvm/llvm-project/pull/171010