Support enum class in struct-backed type

We may use enumeration class in struct backed type, which makes struct type more
semantic. However, we need to force these values to be cast from integers to the
target type.

Author: GinShio

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());
       }
     };