[llvm] [clang] [CUDA][HIP] Improve variable registration with the new driver (PR #73177)

[Yaxun Liu via cfe-commits]

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@@ -63,6 +63,12 @@ class CGCUDARuntime {
       OffloadGlobalSurfaceEntry = 0x2,
       /// Mark the entry as a texture variable.
       OffloadGlobalTextureEntry = 0x3,
+      /// Mark the entry as being extern.
+      OffloadGlobalExtern = 0x4,
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yxsamliu wrote:

once people start to use these enums, it is difficult to change them since it will break binary backward compatibility

https://github.com/llvm/llvm-project/pull/73177