diff --git a/source/blender/io/alembic/exporter/abc_archive.cc b/source/blender/io/alembic/exporter/abc_archive.cc
index a24226841a7..9bab50d7dd4 100644
--- a/source/blender/io/alembic/exporter/abc_archive.cc
+++ b/source/blender/io/alembic/exporter/abc_archive.cc
@@ -156,7 +156,7 @@ static void get_frames(double scene_fps,
 ABCArchive::ABCArchive(const Main *bmain,
                        const Scene *scene,
                        AlembicExportParams params,
-                       std::string filepath)
+                       const std::string &filepath)
     : archive(nullptr)
 {
   double scene_fps = FPS;
diff --git a/source/blender/io/alembic/exporter/abc_archive.h b/source/blender/io/alembic/exporter/abc_archive.h
index 6ece50b149f..877196102a7 100644
--- a/source/blender/io/alembic/exporter/abc_archive.h
+++ b/source/blender/io/alembic/exporter/abc_archive.h
@@ -36,7 +36,7 @@ class ABCArchive {
   ABCArchive(const Main *bmain,
              const Scene *scene,
              AlembicExportParams params,
-             std::string filepath);
+             const std::string &filepath);
   ~ABCArchive();
 
   uint32_t time_sampling_index_transforms() const;
diff --git a/source/blender/io/common/IO_abstract_hierarchy_iterator.h b/source/blender/io/common/IO_abstract_hierarchy_iterator.h
index 8d5c8faadc6..132df4519ee 100644
--- a/source/blender/io/common/IO_abstract_hierarchy_iterator.h
+++ b/source/blender/io/common/IO_abstract_hierarchy_iterator.h
@@ -263,7 +263,7 @@ class AbstractHierarchyIterator {
 
   void determine_export_paths(const HierarchyContext *parent_context);
   void determine_duplication_references(const HierarchyContext *parent_context,
-                                        std::string indent);
+                                        const std::string &indent);
 
   /* These three functions create writers and call their write() method. */
   void make_writers(const HierarchyContext *parent_context);
diff --git a/source/blender/io/common/intern/abstract_hierarchy_iterator.cc b/source/blender/io/common/intern/abstract_hierarchy_iterator.cc
index 97fcc8e2561..4842d973a0f 100644
--- a/source/blender/io/common/intern/abstract_hierarchy_iterator.cc
+++ b/source/blender/io/common/intern/abstract_hierarchy_iterator.cc
@@ -528,7 +528,7 @@ void AbstractHierarchyIterator::determine_export_paths(const HierarchyContext *p
 }
 
 void AbstractHierarchyIterator::determine_duplication_references(
-    const HierarchyContext *parent_context, std::string indent)
+    const HierarchyContext *parent_context, const std::string &indent)
 {
   ExportChildren children = graph_children(parent_context);