[llvm] [DirectX] Moving Root Signature Metadata Parsing in to Shared Root Signature Metadata lib (PR #149221)

[Finn Plummer via llvm-commits]

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@@ -49,6 +51,49 @@ class MetadataBuilder {
   SmallVector<Metadata *> GeneratedMetadata;
 };
 
+enum class RootSignatureElementKind {
+  Error = 0,
+  RootFlags = 1,
+  RootConstants = 2,
+  SRV = 3,
+  UAV = 4,
+  CBV = 5,
+  DescriptorTable = 6,
+  StaticSamplers = 7
+};
+
+class MetadataParser {
+public:
+  MetadataParser(MDNode *Root) : Root(Root) {}
+
+  /// Iterates through root signature and converts them into MapT
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inbelic wrote:

nit: Can we specify what MapT is

https://github.com/llvm/llvm-project/pull/149221