[llvm] [DirectX] adding support in obj2yaml and yaml2obj to root constants (PR #127840)

[Chris B via llvm-commits]

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@@ -546,13 +560,75 @@ struct ProgramSignatureElement {
 static_assert(sizeof(ProgramSignatureElement) == 32,
               "ProgramSignatureElement is misaligned");
 
+struct RootConstants {
+  uint32_t ShaderRegister = 0;
+  uint32_t RegisterSpace = 0;
+  uint32_t Num32BitValues = 0;
+
+  RootConstants() = default;
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llvm-beanz wrote:

Why does this have a constructor? We generally don't have constructors for types that are encoded in binary files because the common usage is to just cast a pointer and read.

https://github.com/llvm/llvm-project/pull/127840