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

[Justin Bogner via cfe-commits]

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@@ -5209,6 +5211,92 @@ void Parser::ParseMicrosoftUuidAttributeArgs(ParsedAttributes &Attrs) {
   }
 }
 
+void Parser::ParseMicrosoftRootSignatureAttributeArgs(ParsedAttributes &Attrs) {
+  assert(Tok.is(tok::identifier) && "Not a Microsoft attribute list");
+  IdentifierInfo *RootSignatureIdent = Tok.getIdentifierInfo();
+  assert(RootSignatureIdent->getName() == "RootSignature" &&
+         "Not a Microsoft attribute list");
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bogner wrote:

The messages in these asserts aren't relevant to the problem... These should probably say something like "Expected RootSignature identifier"

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