[snapshot] Better typing for WasmCompiledModuleSerializer.

R=jgruber@chromium.org
BUG=v8:7509

Change-Id: If5f7829c4f42e6cb2a8f39d2ddb92a6b024c3506
Reviewed-on: https://chromium-review.googlesource.com/948492Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51734}

src/snapshot/code-serializer.cc

@@ -262,9 +262,7 @@ WasmCompiledModuleSerializer::WasmCompiledModuleSerializer(
 }
 
 std::unique_ptr<ScriptData> WasmCompiledModuleSerializer::SerializeWasmModule(
-    Isolate* isolate, Handle<Struct> input) {
-  Handle<WasmCompiledModule> compiled_module =
-      Handle<WasmCompiledModule>::cast(input);
+    Isolate* isolate, Handle<WasmCompiledModule> compiled_module) {
   WasmCompiledModuleSerializer wasm_cs(
       isolate, 0, isolate->native_context(),
       handle(compiled_module->shared()->module_bytes()));
@@ -272,11 +270,11 @@ std::unique_ptr<ScriptData> WasmCompiledModuleSerializer::SerializeWasmModule(
   return std::unique_ptr<ScriptData>(data);
 }
 
-MaybeHandle<Struct> WasmCompiledModuleSerializer::DeserializeWasmModule(
+MaybeHandle<WasmCompiledModule>
+WasmCompiledModuleSerializer::DeserializeWasmModule(
     Isolate* isolate, ScriptData* data, Vector<const byte> wire_bytes) {
-  MaybeHandle<Struct> nothing;
   if (!wasm::IsWasmCodegenAllowed(isolate, isolate->native_context())) {
-    return nothing;
+    return MaybeHandle<WasmCompiledModule>();
   }
   SerializedCodeData::SanityCheckResult sanity_check_result =
       SerializedCodeData::CHECK_SUCCESS;
@@ -285,7 +283,7 @@ MaybeHandle<Struct> WasmCompiledModuleSerializer::DeserializeWasmModule(
       isolate, data, 0, &sanity_check_result);
 
   if (sanity_check_result != SerializedCodeData::CHECK_SUCCESS) {
-    return nothing;
+    return MaybeHandle<WasmCompiledModule>();
   }
 
   // TODO(6792): No longer needed once WebAssembly code is off heap.
@@ -295,7 +293,7 @@ MaybeHandle<Struct> WasmCompiledModuleSerializer::DeserializeWasmModule(
                                                         wire_bytes);
 
   Handle<WasmCompiledModule> result;
-  if (!maybe_result.ToHandle(&result)) return nothing;
+  if (!maybe_result.ToHandle(&result)) return MaybeHandle<WasmCompiledModule>();
 
   WasmCompiledModule::ReinitializeAfterDeserialization(isolate, result);
   DCHECK(result->IsWasmCompiledModule());

src/snapshot/code-serializer.h

@@ -87,10 +87,9 @@ class CodeSerializer : public Serializer<> {
 
 class WasmCompiledModuleSerializer : public CodeSerializer {
  public:
-  // TODO(mstarzinger): Make these typed to {WasmCompiledModule} instead.
   static std::unique_ptr<ScriptData> SerializeWasmModule(
-      Isolate* isolate, Handle<Struct> compiled_module);
-  static MaybeHandle<Struct> DeserializeWasmModule(
+      Isolate* isolate, Handle<WasmCompiledModule> compiled_module);
+  static MaybeHandle<WasmCompiledModule> DeserializeWasmModule(
       Isolate* isolate, ScriptData* data, Vector<const byte> wire_bytes);
 
  protected:

src/wasm/wasm-serialization.cc

@@ -633,13 +633,8 @@ MaybeHandle<WasmCompiledModule> DeserializeNativeModule(
     Isolate* isolate, Vector<const byte> data, Vector<const byte> wire_bytes) {
   if (!FLAG_wasm_jit_to_native) {
     ScriptData script_data(data.start(), data.length());
-    Handle<Struct> compiled_module;
-    if (!WasmCompiledModuleSerializer::DeserializeWasmModule(
-             isolate, &script_data, wire_bytes)
-             .ToHandle(&compiled_module)) {
-      return {};
-    }
-    return Handle<WasmCompiledModule>::cast(compiled_module);
+    return WasmCompiledModuleSerializer::DeserializeWasmModule(
+        isolate, &script_data, wire_bytes);
   }
   if (!IsWasmCodegenAllowed(isolate, isolate->native_context())) {
     return {};