fix PR6814 - Only print [-pedantic] on a diagnostic if -pedantic 
actually turned it on.  If a diag is produced by a warning which
is an extension but defaults to on, and has no warning group, don't
print any option info.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101071 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Diagnostic.cpp b/lib/Basic/Diagnostic.cpp
index 1eeb25b..bd1d6e8 100644
--- a/lib/Basic/Diagnostic.cpp
+++ b/lib/Basic/Diagnostic.cpp
@@ -287,11 +287,18 @@
 }
 
 /// isBuiltinExtensionDiag - Determine whether the given built-in diagnostic
-/// ID is for an extension of some sort.
+/// ID is for an extension of some sort.  This also returns EnabledByDefault,
+/// which is set to indicate whether the diagnostic is ignored by default (in
+/// which case -pedantic enables it) or treated as a warning/error by default.
 ///
-bool Diagnostic::isBuiltinExtensionDiag(unsigned DiagID) {
-  return DiagID < diag::DIAG_UPPER_LIMIT &&
-         getBuiltinDiagClass(DiagID) == CLASS_EXTENSION;
+bool Diagnostic::isBuiltinExtensionDiag(unsigned DiagID,
+                                        bool &EnabledByDefault) {
+  if (DiagID >= diag::DIAG_UPPER_LIMIT ||
+      getBuiltinDiagClass(DiagID) != CLASS_EXTENSION)
+    return false;
+  
+  EnabledByDefault = StaticDiagInfo[DiagID].Mapping != diag::MAP_IGNORE;
+  return true;
 }
 
 
diff --git a/lib/Frontend/TextDiagnosticPrinter.cpp b/lib/Frontend/TextDiagnosticPrinter.cpp
index 4e91f8d..6c8137e 100644
--- a/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -796,8 +796,13 @@
       OutStr += " [-W";
       OutStr += Opt;
       OutStr += ']';
-    } else if (Diagnostic::isBuiltinExtensionDiag(Info.getID())) {
-      OutStr += " [-pedantic]";
+    } else {
+      // If the diagnostic is an extension diagnostic and not enabled by default
+      // then it must have been turned on with -pedantic.
+      bool EnabledByDefault;
+      if (Diagnostic::isBuiltinExtensionDiag(Info.getID(), EnabledByDefault) &&
+          !EnabledByDefault)
+        OutStr += " [-pedantic]";
     }
   }