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

[Finn Plummer via cfe-commits]

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

>From design we will block on https://github.com/llvm/llvm-project/issues/138025 such that we can provide sufficient testing.

We will go with an initial approach to just dump all information of the in-memory constructs and we can revisit this to maybe only print explicitly set parameters if this becomes to verbose/hard to debug with.

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