diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 35ffe49..99c338c 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -896,7 +896,7 @@
     Res.push_back("-target-feature", Opts.Features[i]);
 }
 
-void CompilerInvocation::toArgs(std::vector<std::string> &Res) {
+void CompilerInvocation::toArgs(std::vector<std::string> &Res) const {
   ToArgsList List(Res);
   AnalyzerOptsToArgs(getAnalyzerOpts(), List);
   CodeGenOptsToArgs(getCodeGenOpts(), List);