[llvm] [DirectX] Remove custom error classes from RootSignature Metadata parser (PR #161921)

[Justin Bogner via llvm-commits]

================
@@ -81,8 +59,52 @@ template <class... Ts> struct OverloadedVisit : Ts... {
 };
 template <class... Ts> OverloadedVisit(Ts...) -> OverloadedVisit<Ts...>;
 
+struct FmtRange {
+  dxil::ResourceClass Type;
+  uint32_t Register;
+  uint32_t Space;
+
+  FmtRange(const mcdxbc::DescriptorRange &Range)
+      : Type(Range.RangeType), Register(Range.BaseShaderRegister),
+        Space(Range.RegisterSpace) {}
+};
+
+raw_ostream &operator<<(llvm::raw_ostream &OS, const FmtRange &Range) {
+  OS << getResourceClassName(Range.Type) << "(register=" << Range.Register
+     << ", space=" << Range.Space << ")";
+  return OS;
+}
+
+struct FmtMDNode {
+  const MDNode *Node;
+
+  FmtMDNode(const MDNode *Node) : Node(Node) {}
+};
+
+raw_ostream &operator<<(llvm::raw_ostream &OS, FmtMDNode Fmt) {
+  Fmt.Node->printTree(OS);
+  return OS;
+}
+
+static Error makeRSError(const Twine &Msg) {
+  return make_error<RootSignatureValidationError>(Msg);
+}
 } // namespace
 
+template <typename T, typename = std::enable_if_t<
+                          std::is_enum_v<T> &&
+                          std::is_same_v<std::underlying_type_t<T>, uint32_t>>>
+static Expected<T>
+extractEnumValue(MDNode *Node, unsigned int OpId, StringRef ErrText,
+                 llvm::function_ref<bool(uint32_t)> VerifyFn) {
+  if (std::optional<uint32_t> Val = extractMdIntValue(Node, OpId)) {
+    if (!VerifyFn(*Val))
+      return makeRSError(formatv("Invalid value for {0}: {1}", ErrText, Val));
+    return static_cast<T>(*Val);
+  }
+  return makeRSError(formatv("Invalid value for ShaderVisibility"));
----------------
bogner wrote:

This looks like a typo - this is used for lots of things other than ShaderVisibility
```suggestion
  return makeRSError(formatv("Invalid value for {0}", ErrText));
```

https://github.com/llvm/llvm-project/pull/161921