Support enum class in struct-backed type

example/ExampleDialect.td

@@ -367,7 +367,7 @@ def StructBackedType : DialectType<ExampleDialect, "struct.backed"> {
   let description = [{
     Test that a struct-backed type works correctly.
   }];
-  let typeArguments = (args AttrI32:$field0, AttrI32:$field1, AttrI32:$field2);
+  let typeArguments = (args AttrI32:$field0, AttrI8:$field1, AttrVectorKind:$field2);
   let representation = (repr_struct (IntegerType 41));
 
   let defaultGetterHasExplicitContextArgument = 1;

example/ExampleMain.cpp

@@ -149,7 +149,7 @@ void createFunctionExample(Module &module, const Twine &name) {
 
   b.create<xd::cpp::StringAttrOp>("Hello world!");
 
-  xd::cpp::StructBackedType *structBackedTy = xd::cpp::StructBackedType::get(bb->getContext(), 1, 0, 2);
+  xd::cpp::StructBackedType *structBackedTy = xd::cpp::StructBackedType::get(bb->getContext(), 1, 0, xd::cpp::VectorKind::BigEndian);
   auto *structBackedVal = b.create<xd::cpp::DummyStructBackedOutpOp>(structBackedTy, b.getInt32(42), "gen.struct.backed.val");
   b.create<xd::cpp::DummyStructBackedInpOp>(structBackedVal, "consume.struct.backed.val");
 

lib/TableGen/DialectType.cpp

@@ -201,17 +201,24 @@ void DialectType::emitDeclaration(raw_ostream &out, GenDialect *dialect) const {
     out << "      static bool classof(const ::llvm::Type *t);\n\n";
 
     unsigned fieldIdx = 1; // sentinel
+    auto getCastExpr = [&fmt](const NamedValue &argument,
+                              llvm::StringRef expr) -> std::string {
+      return tgfmt(cast<Attr>(argument.type)->getFromUnsigned(), &fmt, expr);
+    };
     for (const auto &argument : typeArguments()) {
       std::string camel = convertToCamelFromSnakeCase(argument.name, true);
       out << tgfmt(
-          R"(      unsigned get$0() const {
-        ::llvm::Type *elt = getElementType($1);
+          R"(      $0 get$1() const {
+        ::llvm::Type *elt = getElementType($2);
         if (elt->isStructTy())
-          return 0;
-        return ::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth();
+          return $3;
+        return $4;
       }
 )",
-          &fmt, camel, fieldIdx++);
+          &fmt, argument.type->getCppType(), camel, fieldIdx++,
+          getCastExpr(argument, "0"),
+          getCastExpr(argument,
+                      "::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth()"));
     }
 
     out << "    };\n\n";
@@ -307,14 +314,17 @@ void DialectType::emitDefinition(raw_ostream &out, GenDialect *dialect) const {
         "  $fields.push_back(::llvm::IntegerType::get($_context, $0));\n", &fmt,
         Twine(m_structSentinelBitWidth));
 
-    for (const auto &getterArg : getterArgs) {
+    for (const auto &[argument, getterArg] :
+         llvm::zip(typeArguments(), getterArgs)) {
+      std::string castExpr = tgfmt(cast<Attr>(argument.type)->getToUnsigned(),
+                                   &fmt, getterArg.name);
       out << tgfmt(R"(
   if ($0 == 0)
     $fields.push_back(::llvm::StructType::get($_context));
   else
     $fields.push_back(::llvm::IntegerType::get($_context, $0));
 )",
-                   &fmt, getterArg.name);
+                   &fmt, castExpr);
     }
     out << tgfmt("  auto *$st = ::llvm::StructType::create($_context, "
                  "$fields, $os.str(), /*isPacked=*/false);\n",

test/example/generated/ExampleDialect.cpp.inc

@@ -258,10 +258,10 @@ m_attributeLists[6] = argAttrList.addFnAttributes(context, attrBuilder);
 }
 }
 
-StructBackedType* StructBackedType::get(::llvm::LLVMContext & ctx, uint32_t field0, uint32_t field1, uint32_t field2) {
-
+StructBackedType* StructBackedType::get(::llvm::LLVMContext & ctx, uint32_t field0, uint8_t field1, VectorKind field2) {
 
 
+static_assert(sizeof(field2) <= sizeof(unsigned));
   std::string name; ::llvm::raw_string_ostream os(name);
   os << "struct.backed";
   os << '.' << (uint64_t)field0;
@@ -280,10 +280,10 @@ StructBackedType* StructBackedType::get(::llvm::LLVMContext & ctx, uint32_t fiel
   else
     fields.push_back(::llvm::IntegerType::get(ctx, field1));
 
-  if (field2 == 0)
+  if (static_cast<unsigned>(field2) == 0)
     fields.push_back(::llvm::StructType::get(ctx));
   else
-    fields.push_back(::llvm::IntegerType::get(ctx, field2));
+    fields.push_back(::llvm::IntegerType::get(ctx, static_cast<unsigned>(field2)));
   auto *st = ::llvm::StructType::create(ctx, fields, os.str(), /*isPacked=*/false);
   return static_cast<StructBackedType *>(st);
 }

test/example/generated/ExampleDialect.h.inc

@@ -58,27 +58,27 @@ namespace xd::cpp {
       using ::llvm::StructType::getElementType;
 
       static StructBackedType *get(
-  ::llvm::LLVMContext & ctx, uint32_t field0, uint32_t field1, uint32_t field2);
+  ::llvm::LLVMContext & ctx, uint32_t field0, uint8_t field1, VectorKind field2);
 
       static bool classof(const ::llvm::Type *t);
 
-      unsigned getField0() const {
+      uint32_t getField0() const {
         ::llvm::Type *elt = getElementType(1);
         if (elt->isStructTy())
           return 0;
         return ::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth();
       }
-      unsigned getField1() const {
+      uint8_t getField1() const {
         ::llvm::Type *elt = getElementType(2);
         if (elt->isStructTy())
           return 0;
         return ::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth();
       }
-      unsigned getField2() const {
+      VectorKind getField2() const {
         ::llvm::Type *elt = getElementType(3);
         if (elt->isStructTy())
-          return 0;
-        return ::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth();
+          return static_cast<VectorKind>(0);
+        return static_cast<VectorKind>(::llvm::cast<::llvm::IntegerType>(elt)->getBitWidth());
       }
     };