[WebAssembly] Use ValType instead of integer types to model wasm tables (llvm#78012)

LLVM models some features found in the binary format with raw integers
and others with nested or enumerated types. This PR switches modeling of
tables and segments to use wasm::ValType rather than uint32_t. This NFC
change is in preparation for modeling more reference types, but IMO is
also cleaner and closer to the spec.

Author: dschuff

lld/wasm/InputFiles.cpp

@@ -320,7 +320,7 @@ void ObjFile::addLegacyIndirectFunctionTableIfNeeded(
   // it has an unexpected name or type, assume that it's not actually the
   // indirect function table.
   if (tableImport->Field != functionTableName ||
-      tableImport->Table.ElemType != uint8_t(ValType::FUNCREF)) {
+      tableImport->Table.ElemType != ValType::FUNCREF) {
     error(toString(this) + ": table import " + Twine(tableImport->Field) +
           " is missing a symbol table entry.");
     return;

lld/wasm/SymbolTable.cpp

@@ -676,7 +676,7 @@ Symbol *SymbolTable::addUndefinedTag(StringRef name,
 TableSymbol *SymbolTable::createUndefinedIndirectFunctionTable(StringRef name) {
   WasmLimits limits{0, 0, 0}; // Set by the writer.
   WasmTableType *type = make<WasmTableType>();
-  type->ElemType = uint8_t(ValType::FUNCREF);
+  type->ElemType = ValType::FUNCREF;
   type->Limits = limits;
   StringRef module(defaultModule);
   uint32_t flags = config->exportTable ? 0 : WASM_SYMBOL_VISIBILITY_HIDDEN;
@@ -690,7 +690,7 @@ TableSymbol *SymbolTable::createUndefinedIndirectFunctionTable(StringRef name) {
 TableSymbol *SymbolTable::createDefinedIndirectFunctionTable(StringRef name) {
   const uint32_t invalidIndex = -1;
   WasmLimits limits{0, 0, 0}; // Set by the writer.
-  WasmTableType type{uint8_t(ValType::FUNCREF), limits};
+  WasmTableType type{ValType::FUNCREF, limits};
   WasmTable desc{invalidIndex, type, name};
   InputTable *table = make<InputTable>(desc, nullptr);
   uint32_t flags = config->exportTable ? 0 : WASM_SYMBOL_VISIBILITY_HIDDEN;