Collect list of requested modules in ModuleDescriptor while parsing

src/modules.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/modules.h"
 
 #include "src/ast-value-factory.h"
 
@@ skipping 17 matching lines @@
   ZoneHashMap::Entry* p =
       exports_->Lookup(key, export_name->hash(), !IsFrozen(), allocator);
   if (p == nullptr || p->value != nullptr) {
     *ok = false;
   }
 
   p->value = const_cast<AstRawString*>(local_name);
 }
 
 
+void ModuleDescriptor::AddModuleRequest(const AstRawString* module_specifier,
+                                        Zone* zone) {
+  // TODO(adamk): Avoid this O(N) operation on each insert by storing
+  // a HashMap, or by de-duping after parsing.
+  if (requested_modules_.Contains(module_specifier)) return;
+  requested_modules_.Add(module_specifier, zone);
+}
+
+
 const AstRawString* ModuleDescriptor::LookupLocalExport(
     const AstRawString* export_name, Zone* zone) {
   if (exports_ == nullptr) return nullptr;
   ZoneAllocationPolicy allocator(zone);
   ZoneHashMap::Entry* entry =
       exports_->Lookup(const_cast<AstRawString*>(export_name),
                        export_name->hash(), false, allocator);
   if (entry == nullptr) return nullptr;
   DCHECK_NOT_NULL(entry->value);
   return static_cast<const AstRawString*>(entry->value);
 }
 }
 }  // namespace v8::internal