2 files changed, 12 insertions, 0 deletions
diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp
index 31f56e99bf4..16cb111e2c2 100644
--- a/clang/lib/Basic/Diagnostic.cpp
+++ b/clang/lib/Basic/Diagnostic.cpp
@@ -65,6 +65,13 @@ static unsigned GetDefaultDiagMapping(unsigned DiagID) {
   return diag::MAP_FATAL;
 }
 
+/// getWarningOptionForDiag - Return the lowest-level warning option that
+/// enables the specified diagnostic.  If there is no -Wfoo flag that controls
+/// the diagnostic, this returns null.
+const char *Diagnostic::getWarningOptionForDiag(unsigned DiagID) {
+  return 0; //"Wfoo";
+}
+
 
 // Diagnostic classes.
 enum {
diff --git a/clang/lib/Frontend/TextDiagnosticPrinter.cpp b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
index c472a140cbf..24f66dac7f4 100644
--- a/clang/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/clang/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -308,6 +308,11 @@ void TextDiagnosticPrinter::HandleDiagnostic(Diagnostic::Level Level,
   llvm::SmallString<100> OutStr;
   Info.FormatDiagnostic(OutStr);
   OS.write(OutStr.begin(), OutStr.size());
+  
+  if (PrintDiagnosticOption)
+    if (const char *Option = Diagnostic::getWarningOptionForDiag(Info.getID()))
+      OS << " [-" << Option << ']';
+  
   OS << '\n';
   
   // If caret diagnostics are enabled and we have location, we want to