Enhance 'diagtool list-warnings' to report number of diagnostics covered directly under -Wpedantic, and enhance warning-flags.c test to test that this set does not grow.

llvm-svn: 159893

clang/test/Misc/warning-flags.c

@@ -177,3 +177,8 @@ CHECK-NEXT:   warn_use_out_of_scope_declaration
 CHECK-NEXT:   warn_weak_identifier_undeclared
 CHECK-NEXT:   warn_weak_import
 
+The list of warnings in -Wpedenatic should NEVER grow.
+
+CHECK: Number in -Wpedantic (not covered by other -W flags): 71
+
+

clang/tools/diagtool/ListWarnings.cpp

@@ -98,6 +98,10 @@ int ListWarnings::run(unsigned int argc, char **argv, llvm::raw_ostream &out) {
   out << "  Average number of diagnostics per flag: "
       << llvm::format("%.4g", avgDiagsPerFlag) << '\n';
     
+  out << "  Number in -Wpedantic (not covered by other -W flags): "
+      << flagHistogram.GetOrCreateValue("pedantic").getValue().size()
+      << '\n';
+  
   out << '\n';
   
   return 0;