[clang] [HLSL][RootSignature] Define and integrate rootsig clang attr and decl (PR #137690)

[Finn Plummer via cfe-commits]

================
@@ -3037,6 +3037,11 @@ void TextNodeDumper::VisitHLSLBufferDecl(const HLSLBufferDecl *D) {
   dumpName(D);
 }
 
+void TextNodeDumper::VisitHLSLRootSignatureDecl(
+    const HLSLRootSignatureDecl *D) {
+  dumpName(D);
----------------
inbelic wrote:

We could extend this to dump more info about the root elements. For instance, number of elements, or iterate through the types, etc.

https://github.com/llvm/llvm-project/pull/137690