Implement .stats command printing out statistics about internal ADT

lib/MetaProcessor/MetaParser.cpp

@@ -112,11 +112,11 @@ namespace cling {
       || isXCommand(actionResult, resultValue)
       || isqCommand() || isUCommand(actionResult) || isICommand()
       || isOCommand() || israwInputCommand() || isprintASTCommand()
-      || isdynamicExtensionsCommand()
-      || ishelpCommand() || isfileExCommand() || isfilesCommand() || isClassCommand()
-      || isgCommand() || isTypedefCommand() || isprintIRCommand()
-      || isShellCommand(actionResult, resultValue)
-      || isstoreStateCommand() || iscompareStateCommand() || isundoCommand()
+      || isdynamicExtensionsCommand() || ishelpCommand() || isfileExCommand()
+      || isfilesCommand() || isClassCommand() || isgCommand()
+      || isTypedefCommand() || isprintIRCommand()
+      || isShellCommand(actionResult, resultValue) || isstoreStateCommand()
+      || iscompareStateCommand() || isstatsCommand() || isundoCommand()
       || isRedirectCommand(actionResult);
   }
 
@@ -404,6 +404,21 @@ namespace cling {
     return false;
   }
 
+  bool MetaParser::isstatsCommand() {
+    if (getCurTok().is(tok::ident) &&
+        getCurTok().getIdent().equals("stats")) {
+      consumeToken();
+      skipWhitespace();
+      if (!getCurTok().is(tok::ident))
+        return false; // FIXME: Issue proper diagnostics
+      std::string ident = getCurTok().getIdent();
+      consumeToken();
+      m_Actions->actOnstatsCommand(ident);
+      return true;
+    }
+    return false;
+  }
+
   bool MetaParser::isundoCommand() {
     if (getCurTok().is(tok::ident) &&
         getCurTok().getIdent().equals("undo")) {

lib/MetaProcessor/MetaParser.h

@@ -31,7 +31,7 @@ namespace cling {
   //                            PrintASTCommand | DynamicExtensionsCommand | HelpCommand |
   //                            FileExCommand | FilesCommand | ClassCommand |
   //                            GCommand | PrintIRCommand | StoreStateCommand | 
-  //                            CompareStateCommand | undoCommand
+  //                            CompareStateCommand | StatsCommand | undoCommand
   //                 LCommand := 'L' FilePath
   //                 >Command := '>' FilePath
   //                 qCommand := 'q'
@@ -44,6 +44,7 @@ namespace cling {
   //                 PrintIRCommand := 'printIR' [Constant]
   //                 StoreStateCommand := 'storeState' "Ident"
   //                 CompareStateCommand := 'compareState' "Ident"
+  //                 StatsCommand := 'stats' ['ast']
   //                 undoCommand := 'undo' [Constant]
   //                 DynamicExtensionsCommand := 'dynamicExtensions' [Constant]
   //                 HelpCommand := 'help'
@@ -93,6 +94,7 @@ namespace cling {
     bool isprintIRCommand();
     bool isstoreStateCommand();
     bool iscompareStateCommand();
+    bool isstatsCommand();
     bool isundoCommand();
     bool isdynamicExtensionsCommand();
     bool ishelpCommand();

lib/MetaProcessor/MetaSema.cpp

@@ -154,6 +154,12 @@ namespace cling {
     m_Interpreter.compareInterpreterState(name);
   }
 
+  void MetaSema::actOnstatsCommand(llvm::StringRef name) const {
+    if (name.equals("ast")) {
+      m_Interpreter.getCI()->getSema().getASTContext().PrintStats();
+    }
+  }
+
   void MetaSema::actOndynamicExtensionsCommand(SwitchMode mode/* = kToggle*/)
     const {
     if (mode == kToggle) {

lib/MetaProcessor/MetaSema.h

@@ -145,6 +145,12 @@ namespace cling {
     ///
     void actOncompareStateCommand(llvm::StringRef name) const;
 
+    ///\brief Show stats for various internal data structures.
+    ///
+    ///\param[in] name - Name of the structure.
+    ///
+    void actOnstatsCommand(llvm::StringRef name) const;
+
     ///\brief Switches on/off the experimental dynamic extensions (dynamic
     /// scopes) and late binding.
     ///