[modules] Support exporting a local variable under multiple export names.

src/objects.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 19562 matching lines @@
 
 bool JSReceiver::HasProxyInPrototype(Isolate* isolate) {
   for (PrototypeIterator iter(isolate, this, kStartAtReceiver,
                               PrototypeIterator::END_AT_NULL);
        !iter.IsAtEnd(); iter.AdvanceIgnoringProxies()) {
     if (iter.GetCurrent<Object>()->IsJSProxy()) return true;
   }
   return false;
 }
 
-void Module::CreateExport(Handle<Module> module, Handle<String> name) {
+void Module::CreateExport(Handle<Module> module, Handle<FixedArray> names) {
+  DCHECK_LT(0, names->length());
   Isolate* isolate = module->GetIsolate();
   Handle<Cell> cell =
       isolate->factory()->NewCell(isolate->factory()->undefined_value());
   Handle<ObjectHashTable> exports(module->exports(), isolate);
-  DCHECK(exports->Lookup(name)->IsTheHole(isolate));
-  exports = ObjectHashTable::Put(exports, name, cell);
+  for (int i = 0, n = names->length(); i < n; ++i) {
+    Handle<String> name(String::cast(names->get(i)), isolate);
+    DCHECK(exports->Lookup(name)->IsTheHole(isolate));
+    exports = ObjectHashTable::Put(exports, name, cell);
+  }
   module->set_exports(*exports);
 }
 
 void Module::StoreExport(Handle<Module> module, Handle<String> name,
                          Handle<Object> value) {
   Handle<ObjectHashTable> exports(module->exports());
   Handle<Cell> cell(Cell::cast(exports->Lookup(name)));
   cell->set_value(*value);
 }
 
 Handle<Object> Module::LoadExport(Handle<Module> module, Handle<String> name) {
   Isolate* isolate = module->GetIsolate();
   Handle<ObjectHashTable> exports(module->exports(), isolate);
   Handle<Cell> cell(Cell::cast(exports->Lookup(name)));
   return handle(cell->value(), isolate);
 }
 
 }  // namespace internal
 }  // namespace v8