[modules] Add partial support for debug-scopes.

src/debug/debug-scopes.cc

Index: src/debug/debug-scopes.cc
diff --git a/src/debug/debug-scopes.cc b/src/debug/debug-scopes.cc
index b9f93e25999d327412800cff65fcb96efdcdc1fe..be23e8a3e2ca263df60c0e44b42a5bb0f369739d 100644
--- a/src/debug/debug-scopes.cc
+++ b/src/debug/debug-scopes.cc
@@ -101,6 +101,8 @@ ScopeIterator::ScopeIterator(Isolate* isolate, FrameInspector* frame_inspector,
       // Language mode may be inherited from the eval caller.
       // Retrieve it from shared function info.
       info->set_language_mode(shared_info->language_mode());
+    } else if (scope_info->scope_type() == MODULE_SCOPE) {
+      info->set_module();
     } else {
       DCHECK(scope_info->scope_type() == SCRIPT_SCOPE);
     }
@@ -608,17 +610,10 @@ MaybeHandle<JSObject> ScopeIterator::MaterializeModuleScope() {
   Handle<Context> context = CurrentContext();
   DCHECK(context->IsModuleContext());
   Handle<ScopeInfo> scope_info(context->scope_info());
-
-  // Allocate and initialize a JSObject with all the members of the debugged
-  // module.
   Handle<JSObject> module_scope =
       isolate_->factory()->NewJSObjectWithNullProto();
-
-  // Fill all context locals.
   CopyContextLocalsToScopeObject(scope_info, context, module_scope);
-
-  // TODO(neis): Also collect stack locals as well as imports and exports.
-
+  CopyModuleVarsToScopeObject(scope_info, context, module_scope);
   return module_scope;
 }
 
@@ -789,6 +784,51 @@ void ScopeIterator::CopyContextLocalsToScopeObject(
   }
 }
 
+void ScopeIterator::CopyModuleVarsToScopeObject(Handle<ScopeInfo> scope_info,
+                                                Handle<Context> context,
+                                                Handle<JSObject> scope_object) {
+  Isolate* isolate = scope_info->GetIsolate();
+
+  int module_variable_count =
+      Smi::cast(scope_info->get(scope_info->ModuleVariableCountIndex()))
+          ->value();
+  for (int i = 0; i < module_variable_count; ++i) {
+    Handle<String> local_name;
+    bool is_export;
+    {
+      String* name;
+      int index;
+      scope_info->ModuleVariable(i, &name, &index);
+      CHECK(!ScopeInfo::VariableIsSynthetic(name));
+      local_name = handle(name, isolate);
+      is_export = index == Variable::kModuleExportIndex;
+    }
+
+    Handle<Object> value;
+    if (is_export) {
+      value =
+          Module::LoadExport(handle(context->module(), isolate), local_name);
+    } else {
+      Handle<ModuleInfo> module_info(scope_info->ModuleDescriptorInfo(),
+                                     isolate);
+      Handle<ModuleInfoEntry> entry =
+          ModuleInfo::LookupRegularImport(module_info, local_name);
+      Handle<String> import_name(String::cast(entry->import_name()), isolate);
+      int module_request = Smi::cast(entry->module_request())->value();
+      value = Module::LoadImport(handle(context->module(), isolate),
+                                 import_name, module_request);
+    }
+
+    // Reflect variables under TDZ as undefined in scope object.
+    if (value->IsTheHole(isolate)) continue;
+    // This should always succeed.
+    // TODO(verwaest): Use AddDataProperty instead.
+    JSObject::SetOwnPropertyIgnoreAttributes(scope_object, local_name, value,
+                                             NONE)
+        .Check();
+  }
+}
+
 void ScopeIterator::CopyContextExtensionToScopeObject(
     Handle<Context> context, Handle<JSObject> scope_object,
     KeyCollectionMode mode) {