Allow lookup of module exports by export name.

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"
 
 namespace v8 {
 namespace internal {
 
 
 void ModuleDescriptor::AddLocalExport(const AstRawString* export_name,
                                       const AstRawString* local_name,
                                       Zone* zone, bool* ok) {
   void* key = const_cast<AstRawString*>(export_name);
 
   ZoneAllocationPolicy allocator(zone);
 
   if (exports_ == nullptr) {
-    exports_ = new (zone->New(sizeof(ZoneHashMap)))
-        ZoneHashMap(ZoneHashMap::PointersMatch,
-                    ZoneHashMap::kDefaultHashMapCapacity, allocator);
+    exports_ = new (zone->New(sizeof(ZoneHashMap))) ZoneHashMap(
+        AstRawString::Compare, ZoneHashMap::kDefaultHashMapCapacity, allocator);
   }
 
   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);
 }
+
+
+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