[llvm] [DirectX] Adding support for Root Descriptors in obj2yaml/yaml2obj (PR #137259)

[via llvm-commits]

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@@ -580,7 +585,28 @@ struct ProgramSignatureElement {
 
 static_assert(sizeof(ProgramSignatureElement) == 32,
               "ProgramSignatureElement is misaligned");
+namespace RST0 {
+namespace v0 {
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joaosaffran wrote:

This is following the same pattern established in other parts of DXContainer, such as: https://github.com/llvm/llvm-project/blob/ea08dd8dc395e5f711f3acc542d3b4f0d4c8dfc0/llvm/include/llvm/BinaryFormat/DXContainer.h#L370. 

My understating for this original decision is, newer versions of DXContainer are superset of previous versions, meaning, they add new fields, structs and flags, don't remove nor modify existing definition.

https://github.com/llvm/llvm-project/pull/137259