Fix SyntheticModule body descriptor

It was missing the name field.

Bug: chromium:1036641
Change-Id: I686a46adfccfd656422cddef340ded58b7a9c9b1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2000135
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65748}

src/objects/module.h

@@ -80,8 +80,8 @@ class Module : public HeapObject {
   static Handle<JSModuleNamespace> GetModuleNamespace(Isolate* isolate,
                                                       Handle<Module> module);
 
-// Layout description.
-  DEFINE_FIELD_OFFSET_CONSTANTS(Struct::kHeaderSize,
+  // Layout description.
+  DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize,
                                 TORQUE_GENERATED_MODULE_FIELDS)
 
   using BodyDescriptor =

src/objects/synthetic-module.h

@@ -40,9 +40,9 @@ class SyntheticModule
                               Handle<String> export_name,
                               Handle<Object> export_value);
 
-  using BodyDescriptor = SubclassBodyDescriptor<
-      Module::BodyDescriptor,
-      FixedBodyDescriptor<kExportNamesOffset, kSize, kSize>>;
+  using BodyDescriptor =
+      SubclassBodyDescriptor<Module::BodyDescriptor,
+                             FixedBodyDescriptor<kNameOffset, kSize, kSize>>;
 
  private:
   friend class Module;

test/cctest/test-api.cc

@@ -24015,6 +24015,34 @@ TEST(CreateSyntheticModuleGC) {
   }
 }
 
+TEST(CreateSyntheticModuleGCName) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::Isolate::Scope iscope(isolate);
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope cscope(context);
+
+  Local<Module> module;
+
+  {
+    v8::EscapableHandleScope inner_scope(isolate);
+    std::vector<v8::Local<v8::String>> export_names{v8_str("default")};
+    v8::Local<v8::String> module_name =
+        v8_str("CreateSyntheticModuleGCName-TestSyntheticModule");
+    module = inner_scope.Escape(v8::Module::CreateSyntheticModule(
+        isolate, module_name, export_names,
+        UnexpectedSyntheticModuleEvaluationStepsCallback));
+  }
+
+  CcTest::CollectAllGarbage();
+#ifdef VERIFY_HEAP
+  i::Handle<i::HeapObject> i_module =
+      i::Handle<i::HeapObject>::cast(v8::Utils::OpenHandle(*module));
+  i_module->HeapObjectVerify(reinterpret_cast<i::Isolate*>(isolate));
+#endif
+}
+
 TEST(SyntheticModuleSetExports) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();