diff --git a/runtime/safe_map.h b/runtime/safe_map.h
index 0e5b503..49f80f3 100644
--- a/runtime/safe_map.h
+++ b/runtime/safe_map.h
@@ -19,6 +19,7 @@
 
 #include <map>
 #include <memory>
+#include <type_traits>
 
 #include "base/allocator.h"
 #include "base/logging.h"
@@ -124,6 +125,18 @@
     return result.first;
   }
 
+  template <typename CreateFn>
+  V GetOrCreate(const K& k, CreateFn create) {
+    static_assert(std::is_same<V, typename std::result_of<CreateFn()>::type>::value,
+                  "Argument `create` should return a value of type V.");
+    auto lb = lower_bound(k);
+    if (lb != end() && !key_comp()(k, lb->first)) {
+      return lb->second;
+    }
+    auto it = PutBefore(lb, k, create());
+    return it->second;
+  }
+
   bool Equals(const Self& rhs) const {
     return map_ == rhs.map_;
   }