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

[Chris B via llvm-commits]

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@@ -13,11 +13,47 @@ using namespace llvm;
 using namespace llvm::mcdxbc;
 
 void RootSignatureDesc::write(raw_ostream &OS) const {
+  // Root signature header in dxcontainer has 6 uint_32t values.
+  const uint32_t HeaderSize = 24;
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llvm-beanz wrote:

We should get this using `sizeof` the structure.

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