Rejigger how -pedantic and -pedantic-errors work and their interaction
with other diagnostic mapping.  In the new scheme, -Wfoo or -Wno-foo or 
-Werror=foo all override the -pedantic options, and __extension__ 
robustly silences all extension diagnostics in their scope.

An added bonus of this change is that MAP_DEFAULT goes away, meaning that
per-diagnostic mapping information can now be stored in 2 bits, doubling
the density of the Diagnostic::DiagMapping array.  This also 
substantially simplifies Diagnostic::getDiagnosticLevel.

OTOH, this temporarily introduces some "macro intensive" code in 
Diagnostic.cpp.  This will be addressed in a later patch.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69154 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ExtensionRAIIObject.h b/lib/Parse/ExtensionRAIIObject.h
index 928d443..2b2bd3b 100644
--- a/lib/Parse/ExtensionRAIIObject.h
+++ b/lib/Parse/ExtensionRAIIObject.h
@@ -26,15 +26,13 @@
     void operator=(const ExtensionRAIIObject &);     // DO NOT IMPLEMENT
     ExtensionRAIIObject(const ExtensionRAIIObject&); // DO NOT IMPLEMENT
     Diagnostic &Diags;
-    bool OldState;
   public:
     ExtensionRAIIObject(Diagnostic &diags) : Diags(diags) {
-      OldState = Diags.getWarnOnExtensions();
-      Diags.setWarnOnExtensions(false);
+      Diags.IncrementAllExtensionsSilenced();
     }
     
     ~ExtensionRAIIObject() {
-      Diags.setWarnOnExtensions(OldState);
+      Diags.DecrementAllExtensionsSilenced();
     }
   };
 }