diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index 106332892..e13006555 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -489,11 +489,10 @@ cmNinjaTargetGenerator
     cmLocalGenerator::RuleVariables compileObjectVars;
     std::string lang = language;
     compileObjectVars.Language = lang.c_str();
-    std::string escapedSourceFileName =
-      this->LocalGenerator->ConvertToOutputFormat(
-        sourceFileName.c_str(), cmLocalGenerator::SHELL);
 
-    if (!cmSystemTools::FileIsFullPath(escapedSourceFileName.c_str()))
+    std::string escapedSourceFileName = sourceFileName;
+
+    if (!cmSystemTools::FileIsFullPath(sourceFileName.c_str()))
       {
       escapedSourceFileName = cmSystemTools::CollapseFullPath(
         escapedSourceFileName.c_str(),
@@ -501,6 +500,10 @@ cmNinjaTargetGenerator
           GetHomeOutputDirectory());
       }
 
+    escapedSourceFileName =
+      this->LocalGenerator->ConvertToOutputFormat(
+        escapedSourceFileName.c_str(), cmLocalGenerator::SHELL);
+
     compileObjectVars.Source = escapedSourceFileName.c_str();
     compileObjectVars.Object = objectFileName.c_str();
     compileObjectVars.Flags = vars["FLAGS"].c_str();