- Use a map to lookup libraries by URL.

runtime/vm/object_store.h

Index: runtime/vm/object_store.h
diff --git a/runtime/vm/object_store.h b/runtime/vm/object_store.h
index b1426b4b1ba45012e66f5373439e381cca76bfb5..eb868fb767748896dcf44ee31ac74d08279da9b3 100644
--- a/runtime/vm/object_store.h
+++ b/runtime/vm/object_store.h
@@ -332,6 +332,11 @@ class ObjectStore {
     libraries_ = value.raw();
   }
 
+  RawArray* libraries_map() const { return libraries_map_; }
+  void set_libraries_map(const Array& value) {
+    libraries_map_ = value.raw();
+  }
+
   RawGrowableObjectArray* closure_functions() const {
     return closure_functions_;
   }
@@ -548,6 +553,7 @@ class ObjectStore {
   RawLibrary* typed_data_library_;
   RawLibrary* vmservice_library_;
   RawGrowableObjectArray* libraries_;
+  RawArray* libraries_map_;
   RawGrowableObjectArray* closure_functions_;
   RawGrowableObjectArray* pending_classes_;
   RawGrowableObjectArray* pending_deferred_loads_;