diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index a76bed3df..0162781c6 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -2514,7 +2514,8 @@ std::string cmLocalGenerator::GetObjectFileNameWithoutTarget(
   const char* fullPath = source.GetFullPath().c_str();
 
   // Try referencing the source relative to the source tree.
-  std::string relFromSource = this->ConvertToRelativePath(fullPath, START);
+  std::string relFromSource =
+    this->ConvertToRelativePath(this->GetCurrentSourceDirectory(), fullPath);
   assert(!relFromSource.empty());
   bool relSource = !cmSystemTools::FileIsFullPath(relFromSource.c_str());
   bool subSource = relSource && relFromSource[0] != '.';