diff --git a/llvm/lib/Support/SourceMgr.cpp b/llvm/lib/Support/SourceMgr.cpp
index 7652e18..83c7964 100644
--- a/llvm/lib/Support/SourceMgr.cpp
+++ b/llvm/lib/Support/SourceMgr.cpp
@@ -188,7 +188,7 @@
 // SMDiagnostic Implementation
 //===----------------------------------------------------------------------===//
 
-void SMDiagnostic::Print(const char *ProgName, raw_ostream &S) {
+void SMDiagnostic::Print(const char *ProgName, raw_ostream &S) const {
   if (ProgName && ProgName[0])
     S << ProgName << ": ";