Split TemplateHashMapImpl::Lookup into two methods

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) {
+  DCHECK(!IsFrozen());
   void* key = const_cast<AstRawString*>(export_name);
 
   ZoneAllocationPolicy allocator(zone);
 
   if (exports_ == nullptr) {
     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) {
+      exports_->LookupOrInsert(key, export_name->hash(), allocator);
+  DCHECK_NOT_NULL(p);
+  if (p->value != nullptr) {
+    // Duplicate export.
     *ok = false;
+    return;
   }
 
   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);
+  ZoneHashMap::Entry* entry = exports_->Lookup(
+      const_cast<AstRawString*>(export_name), export_name->hash());
   if (entry == nullptr) return nullptr;
   DCHECK_NOT_NULL(entry->value);
   return static_cast<const AstRawString*>(entry->value);
 }
 }
 }  // namespace v8::internal