Index: wasm/Driver.cpp
===================================================================
--- wasm/Driver.cpp
+++ wasm/Driver.cpp
@@ -458,7 +458,7 @@
     InputGlobal *StackPointer = make<InputGlobal>(Global, nullptr);
     StackPointer->Live = true;
 
-    static WasmSignature NullSignature = {{}, WASM_TYPE_NORESULT};
+    static WasmSignature NullSignature = {{}, {}};
 
     // Add synthetic symbols before any others
     WasmSym::CallCtors = Symtab->addSyntheticFunction(
Index: wasm/Writer.cpp
===================================================================
--- wasm/Writer.cpp
+++ wasm/Writer.cpp
@@ -991,7 +991,7 @@
     const WasmLinkingData &L = File->getWasmObj()->linkingData();
     for (const WasmInitFunc &F : L.InitFunctions) {
       FunctionSymbol *Sym = File->getFunctionSymbol(F.Symbol);
-      if (*Sym->FunctionType != WasmSignature{{}, WASM_TYPE_NORESULT})
+      if (*Sym->FunctionType != WasmSignature{{}, {}})
         error("invalid signature for init func: " + toString(*Sym));
       InitFunctions.emplace_back(WasmInitEntry{Sym, F.Priority});
     }
Index: wasm/WriterUtils.h
===================================================================
--- wasm/WriterUtils.h
+++ wasm/WriterUtils.h
@@ -35,7 +35,8 @@
 
 void writeU32(raw_ostream &OS, uint32_t Number, const Twine &Msg);
 
-void writeValueType(raw_ostream &OS, uint8_t Type, const Twine &Msg);
+void writeValueType(raw_ostream &OS, llvm::wasm::ValType Type,
+                    const Twine &Msg);
 
 void writeSig(raw_ostream &OS, const llvm::wasm::WasmSignature &Sig);
 
Index: wasm/WriterUtils.cpp
===================================================================
--- wasm/WriterUtils.cpp
+++ wasm/WriterUtils.cpp
@@ -19,15 +19,15 @@
 using namespace llvm::wasm;
 using namespace lld::wasm;
 
-static const char *valueTypeToString(uint8_t Type) {
+static const char *valueTypeToString(ValType Type) {
   switch (Type) {
-  case WASM_TYPE_I32:
+  case wasm::ValType::I32:
     return "i32";
-  case WASM_TYPE_I64:
+  case wasm::ValType::I64:
     return "i64";
-  case WASM_TYPE_F32:
+  case wasm::ValType::F32:
     return "f32";
-  case WASM_TYPE_F64:
+  case wasm::ValType::F64:
     return "f64";
   default:
     llvm_unreachable("invalid value type");
@@ -73,21 +73,20 @@
   support::endian::write(OS, Number, support::little);
 }
 
-void wasm::writeValueType(raw_ostream &OS, uint8_t Type, const Twine &Msg) {
-  writeU8(OS, Type, Msg + "[type: " + valueTypeToString(Type) + "]");
+void wasm::writeValueType(raw_ostream &OS, ValType Type, const Twine &Msg) {
+  writeU8(OS, static_cast<uint8_t>(Type),
+          Msg + "[type: " + valueTypeToString(Type) + "]");
 }
 
 void wasm::writeSig(raw_ostream &OS, const WasmSignature &Sig) {
   writeU8(OS, WASM_TYPE_FUNC, "signature type");
-  writeUleb128(OS, Sig.ParamTypes.size(), "param Count");
-  for (uint8_t ParamType : Sig.ParamTypes) {
+  writeUleb128(OS, Sig.Params.size(), "param Count");
+  for (ValType ParamType : Sig.Params) {
     writeValueType(OS, ParamType, "param type");
   }
-  if (Sig.ReturnType == WASM_TYPE_NORESULT) {
-    writeUleb128(OS, 0, "result Count");
-  } else {
-    writeUleb128(OS, 1, "result Count");
-    writeValueType(OS, Sig.ReturnType, "result type");
+  writeUleb128(OS, Sig.Returns.size(), "result Count");
+  if (Sig.Returns.size()) {
+    writeValueType(OS, Sig.Returns[0], "result type");
   }
 }
 
@@ -117,7 +116,8 @@
 }
 
 void wasm::writeGlobalType(raw_ostream &OS, const WasmGlobalType &Type) {
-  writeValueType(OS, Type.Type, "global type");
+  // TODO: Update WasmGlobalType to use ValType and remove this cast.
+  writeValueType(OS, ValType(Type.Type), "global type");
   writeU8(OS, Type.Mutable, "global mutable");
 }
 
@@ -195,16 +195,16 @@
 
 std::string lld::toString(const WasmSignature &Sig) {
   SmallString<128> S("(");
-  for (uint32_t Type : Sig.ParamTypes) {
+  for (ValType Type : Sig.Params) {
     if (S.size() != 1)
       S += ", ";
-    S += toString(static_cast<ValType>(Type));
+    S += toString(Type);
   }
   S += ") -> ";
-  if (Sig.ReturnType == WASM_TYPE_NORESULT)
+  if (Sig.Returns.size() == 0)
     S += "void";
   else
-    S += toString(static_cast<ValType>(Sig.ReturnType));
+    S += toString(Sig.Returns[0]);
   return S.str();
 }