Index: cfe/trunk/test/Misc/warning-flags-tree.c
===================================================================
--- cfe/trunk/test/Misc/warning-flags-tree.c
+++ cfe/trunk/test/Misc/warning-flags-tree.c
@@ -1,6 +1,6 @@
-// RUN: diagtool tree | FileCheck -strict-whitespace %s
-// RUN: diagtool tree -Weverything | FileCheck -strict-whitespace %s
-// RUN: diagtool tree everything | FileCheck -strict-whitespace %s
+// RUN: diagtool tree --internal | FileCheck -strict-whitespace %s
+// RUN: diagtool tree --internal -Weverything | FileCheck -strict-whitespace %s
+// RUN: diagtool tree --internal everything | FileCheck -strict-whitespace %s
 //
 // These three ways of running diagtool tree are the same:
 // they produce a tree for every top-level diagnostic flag.
@@ -29,8 +29,7 @@
 
 // RUN: not diagtool tree -Wthis-is-not-a-valid-flag
 
-
-// RUN: diagtool tree -Wgnu | FileCheck -strict-whitespace -check-prefix CHECK-GNU %s
+// RUN: diagtool tree --internal -Wgnu | FileCheck -strict-whitespace -check-prefix CHECK-GNU %s
 // CHECK-GNU: -Wgnu
 // CHECK-GNU:   -Wgnu-designator
 // CHECK-GNU:     ext_gnu_array_range
@@ -40,7 +39,7 @@
 // CHECK-GNU:     ext_vla
 // There are more GNU extensions but we don't need to check them all.
 
-// RUN: diagtool tree --flags-only -Wgnu | FileCheck -check-prefix CHECK-FLAGS-ONLY %s
+// RUN: diagtool tree -Wgnu | FileCheck -check-prefix CHECK-FLAGS-ONLY %s
 // CHECK-FLAGS-ONLY: -Wgnu
 // CHECK-FLAGS-ONLY:   -Wgnu-designator
 // CHECK-FLAGS-ONLY-NOT:     ext_gnu_array_range
Index: cfe/trunk/tools/diagtool/TreeView.cpp
===================================================================
--- cfe/trunk/tools/diagtool/TreeView.cpp
+++ cfe/trunk/tools/diagtool/TreeView.cpp
@@ -32,10 +32,10 @@
 public:
   llvm::raw_ostream &out;
   const bool ShowColors;
-  bool FlagsOnly;
+  bool Internal;
 
   TreePrinter(llvm::raw_ostream &out)
-      : out(out), ShowColors(hasColors(out)), FlagsOnly(false) {}
+      : out(out), ShowColors(hasColors(out)), Internal(false) {}
 
   void setColor(llvm::raw_ostream::Colors Color) {
     if (ShowColors)
@@ -54,10 +54,28 @@
     return Diags.isIgnored(DiagID, SourceLocation());
   }
 
+  static bool enabledByDefault(const GroupRecord &Group) {
+    for (const DiagnosticRecord &DR : Group.diagnostics()) {
+      if (isIgnored(DR.DiagID))
+        return false;
+    }
+
+    for (const GroupRecord &GR : Group.subgroups()) {
+      if (!enabledByDefault(GR))
+        return false;
+    }
+
+    return true;
+  }
+
   void printGroup(const GroupRecord &Group, unsigned Indent = 0) {
     out.indent(Indent * 2);
 
-    setColor(llvm::raw_ostream::YELLOW);
+    if (enabledByDefault(Group))
+      setColor(llvm::raw_ostream::GREEN);
+    else
+      setColor(llvm::raw_ostream::YELLOW);
+
     out << "-W" << Group.getName() << "\n";
     resetColor();
 
@@ -66,7 +84,7 @@
       printGroup(GR, Indent);
     }
 
-    if (!FlagsOnly) {
+    if (Internal) {
       for (const DiagnosticRecord &DR : Group.diagnostics()) {
         if (ShowColors && !isIgnored(DR.DiagID))
           setColor(llvm::raw_ostream::GREEN);
@@ -132,16 +150,16 @@
 };
 
 static void printUsage() {
-  llvm::errs() << "Usage: diagtool tree [--flags-only] [<diagnostic-group>]\n";
+  llvm::errs() << "Usage: diagtool tree [--internal] [<diagnostic-group>]\n";
 }
 
 int TreeView::run(unsigned int argc, char **argv, llvm::raw_ostream &out) {
   // First check our one flag (--flags-only).
-  bool FlagsOnly = false;
+  bool Internal = false;
   if (argc > 0) {
     StringRef FirstArg(*argv);
-    if (FirstArg.equals("--flags-only")) {
-      FlagsOnly = true;
+    if (FirstArg.equals("--internal")) {
+      Internal = true;
       --argc;
       ++argv;
     }
@@ -168,7 +186,7 @@
   }
 
   TreePrinter TP(out);
-  TP.FlagsOnly = FlagsOnly;
+  TP.Internal = Internal;
   TP.showKey();
   return ShowAll ? TP.showAll() : TP.showGroup(RootGroup);
 }