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

We have too many custom error classes that look too much alike when
error handling root signature metadata parser. This PR removes those
custom error classes and instead reuses `StringError` and a few
pre-formatted error messages.

Closes: [llvm#159429](llvm#159429)

---------

Co-authored-by: joaosaffran <[email protected]>

Author: joaosaffran

llvm/include/llvm/Frontend/HLSL/RootSignatureMetadata.h

@@ -27,160 +27,15 @@ class Metadata;
 
 namespace hlsl {
 namespace rootsig {
-
-template <typename T>
 class RootSignatureValidationError
-    : public ErrorInfo<RootSignatureValidationError<T>> {
-public:
-  static char ID;
-  StringRef ParamName;
-  T Value;
-
-  RootSignatureValidationError(StringRef ParamName, T Value)
-      : ParamName(ParamName), Value(Value) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Invalid value for " << ParamName << ": " << Value;
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class OffsetAppendAfterOverflow : public ErrorInfo<OffsetAppendAfterOverflow> {
-public:
-  static char ID;
-  dxil::ResourceClass Type;
-  uint32_t Register;
-  uint32_t Space;
-
-  OffsetAppendAfterOverflow(dxil::ResourceClass Type, uint32_t Register,
-                            uint32_t Space)
-      : Type(Type), Register(Register), Space(Space) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Range " << getResourceClassName(Type) << "(register=" << Register
-       << ", space=" << Space << ") "
-       << "cannot be appended after an unbounded range ";
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class ShaderRegisterOverflowError
-    : public ErrorInfo<ShaderRegisterOverflowError> {
-public:
-  static char ID;
-  dxil::ResourceClass Type;
-  uint32_t Register;
-  uint32_t Space;
-
-  ShaderRegisterOverflowError(dxil::ResourceClass Type, uint32_t Register,
-                              uint32_t Space)
-      : Type(Type), Register(Register), Space(Space) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Overflow for shader register range: " << getResourceClassName(Type)
-       << "(register=" << Register << ", space=" << Space << ").";
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class OffsetOverflowError : public ErrorInfo<OffsetOverflowError> {
-public:
-  static char ID;
-  dxil::ResourceClass Type;
-  uint32_t Register;
-  uint32_t Space;
-
-  OffsetOverflowError(dxil::ResourceClass Type, uint32_t Register,
-                      uint32_t Space)
-      : Type(Type), Register(Register), Space(Space) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Offset overflow for descriptor range: " << getResourceClassName(Type)
-       << "(register=" << Register << ", space=" << Space << ").";
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class TableSamplerMixinError : public ErrorInfo<TableSamplerMixinError> {
+    : public ErrorInfo<RootSignatureValidationError> {
 public:
   static char ID;
-  dxil::ResourceClass Type;
-  uint32_t Location;
-
-  TableSamplerMixinError(dxil::ResourceClass Type, uint32_t Location)
-      : Type(Type), Location(Location) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Samplers cannot be mixed with other "
-       << "resource types in a descriptor table, " << getResourceClassName(Type)
-       << "(location=" << Location << ")";
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class GenericRSMetadataError : public ErrorInfo<GenericRSMetadataError> {
-public:
-  LLVM_ABI static char ID;
-  StringRef Message;
-  MDNode *MD;
-
-  GenericRSMetadataError(StringRef Message, MDNode *MD)
-      : Message(Message), MD(MD) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << Message;
-    if (MD) {
-      OS << "\n";
-      MD->printTree(OS);
-    }
-  }
-
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class InvalidRSMetadataFormat : public ErrorInfo<InvalidRSMetadataFormat> {
-public:
-  LLVM_ABI static char ID;
-  StringRef ElementName;
+  std::string Msg;
 
-  InvalidRSMetadataFormat(StringRef ElementName) : ElementName(ElementName) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Invalid format for  " << ElementName;
-  }
+  RootSignatureValidationError(const Twine &Msg) : Msg(Msg.str()) {}
 
-  std::error_code convertToErrorCode() const override {
-    return llvm::inconvertibleErrorCode();
-  }
-};
-
-class InvalidRSMetadataValue : public ErrorInfo<InvalidRSMetadataValue> {
-public:
-  LLVM_ABI static char ID;
-  StringRef ParamName;
-
-  InvalidRSMetadataValue(StringRef ParamName) : ParamName(ParamName) {}
-
-  void log(raw_ostream &OS) const override {
-    OS << "Invalid value for " << ParamName;
-  }
+  void log(raw_ostream &OS) const override { OS << Msg; }
 
   std::error_code convertToErrorCode() const override {
     return llvm::inconvertibleErrorCode();