Scanner.cxx

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// @(#)root/utils/src:$Id$
// Author: Philippe Canal November 2011 ; originated from Zdenek Culik   16/04/2010 and Velislava Spasova.

/*************************************************************************
 * Copyright (C) 1995-2011, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/rootcint.            *
 *************************************************************************/

#include "Scanner.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/ADT/SmallSet.h"
#include "clang/Sema/Sema.h"
#include "clang/Frontend/CompilerInstance.h"

#include "cling/Interpreter/Interpreter.h"
#include "llvm/Support/Path.h"

#include "TClassEdit.h"

#include <iostream>
#include <sstream> // class ostringstream

#include "SelectionRules.h"

//#define DEBUG

#define SHOW_WARNINGS
// #define SHOW_TEMPLATE_INFO

// #define COMPLETE_TEMPLATES
// #define CHECK_TYPES

#define FILTER_WARNINGS
#define DIRECT_OUTPUT

// SHOW_WARNINGS - enable warnings
// SHOW_TEMPLATE_INFO - enable informations about encoutered tempaltes

// COMPLETE_TEMPLATES - process templates, not only specializations (instantiations)

// FILTER_WARNINGS -- do not repeat same type of warning
// DIRECT_OUTPUT -- output to std err with gcc compatible filename an line number

// #define SELECTION_DEBUG



namespace {

   class RPredicateIsSameNamespace
   {
   private:
      clang::NamespaceDecl *fTarget;
   public:
      RPredicateIsSameNamespace(clang::NamespaceDecl *target) : fTarget(target) {}

      bool operator()(const RScanner::AnnotatedNamespaceDecl& element)
      {
         return (fTarget == element);
      }
   };

template<class T>
inline static bool IsElementPresent(const std::vector<T> &v, const T &el){
   return std::find(v.begin(),v.end(),el) != v.end();
}

}

using namespace ROOT;
using namespace clang;

extern cling::Interpreter *gInterp;

const char* RScanner::fgClangDeclKey = "ClangDecl"; // property key used for connection with Clang objects
const char* RScanner::fgClangFuncKey = "ClangFunc"; // property key for demangled names

int RScanner::fgAnonymousClassCounter = 0;
int RScanner::fgBadClassCounter = 0;
int RScanner::fgAnonymousEnumCounter  = 0;

std::map <clang::Decl*, std::string> RScanner::fgAnonymousClassMap;
std::map <clang::Decl*, std::string> RScanner::fgAnonymousEnumMap;

////////////////////////////////////////////////////////////////////////////////
/// Regular constructor setting up the scanner to search for entities
/// matching the 'rules'.

RScanner::RScanner (SelectionRules &rules,
                    EScanType stype,
                    const cling::Interpreter &interpret,
                    ROOT::TMetaUtils::TNormalizedCtxt &normCtxt,
                    unsigned int verbose /* = 0 */) :
  fVerboseLevel(verbose),
  fSourceManager(0),
  fInterpreter(interpret),
  fRecordDeclCallback(0),
  fNormCtxt(normCtxt),
  fSelectionRules(rules),
  fScanType(stype),
  fFirstPass(true)
{
   // Build the cache for all selection rules
   fSelectionRules.FillCache();

   for (int i = 0; i <= fgDeclLast; i ++)
      fDeclTable [i] = false;

   for (int i = 0; i <= fgTypeLast; i ++)
      fTypeTable [i] = false;

   fLastDecl = 0;
}

////////////////////////////////////////////////////////////////////////////////

RScanner::~RScanner ()
{
}

////////////////////////////////////////////////////////////////////////////////

inline void* ToDeclProp(clang::Decl* item)
{
   /* conversion and type check used by AddProperty */
   return item;
}

////////////////////////////////////////////////////////////////////////////////

inline size_t APIntToSize(const llvm::APInt& num)
{
   return *num.getRawData();
}

////////////////////////////////////////////////////////////////////////////////

inline long APIntToLong(const llvm::APInt& num)
{
   return *num.getRawData();
}

////////////////////////////////////////////////////////////////////////////////

inline std::string APIntToStr(const llvm::APInt& num)
{
   return num.toString(10, true);
}

////////////////////////////////////////////////////////////////////////////////

inline std::string IntToStr(int num)
{
   std::string txt = "";
   txt += num;
   return txt;
}

////////////////////////////////////////////////////////////////////////////////

inline std::string IntToStd(int num)
{
   std::ostringstream stream;
   stream << num;
   return stream.str();
}

////////////////////////////////////////////////////////////////////////////////

inline std::string Message(const std::string &msg, const std::string &location)
{
   std::string loc = location;

#ifdef DIRECT_OUTPUT
   int n = loc.length ();
   while (n > 0 && loc [n] != ':')
      n--;
   if (n > 0)
      loc = loc.substr (0, n) + ":";
#endif

   if (loc == "")
      return msg;
   else
      return loc + " " + msg;
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::ShowInfo(const std::string &msg, const std::string &location) const
{
   const std::string message = Message(msg, location);
#ifdef DIRECT_OUTPUT
   std::cout << message << std::endl;
#else
   fReporter->Info("RScanner:ShowInfo", "CLR %s", message.Data());
#endif
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::ShowWarning(const std::string &msg, const std::string &location) const
{
#ifdef SHOW_WARNINGS
   const std::string message = Message(msg, location);
#ifdef DIRECT_OUTPUT
   std::cout << message << std::endl;
#else
   fReporter->Warning("RScanner:ShowWarning", "CLR %s", message.Data());
#endif
#endif
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::ShowError(const std::string &msg, const std::string &location) const
{
   const std::string message = Message(msg, location);
#ifdef DIRECT_OUTPUT
   std::cout << message << std::endl;
#else
   fReporter->Error("RScanner:ShowError", "CLR %s", message.Data());
#endif
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::ShowTemplateInfo(const std::string &msg, const std::string &location) const
{
#ifdef SHOW_TEMPLATE_INFO
   std::string loc = location;
   if (loc == "")
      loc = GetLocation (fLastDecl);
   ShowWarning(msg, loc);
#endif
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetSrcLocation(clang::SourceLocation L) const
{
   std::string location = "";
   llvm::raw_string_ostream stream(location);
   L.print(stream, *fSourceManager);
   return stream.str();
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetLocation(clang::Decl* D) const
{
   if (D == NULL)
   {
      return "";
   }
   else
   {
      std::string location = "";
      llvm::raw_string_ostream stream(location);
      D->getLocation().print(stream, *fSourceManager);
      return stream.str();
   }
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetName(clang::Decl* D) const
{
   std::string name = "";
   // std::string kind = D->getDeclKindName();

   if (clang::NamedDecl* ND = dyn_cast <clang::NamedDecl> (D)) {
      name = ND->getQualifiedNameAsString();
   }

   return name;
}

////////////////////////////////////////////////////////////////////////////////

inline std::string AddSpace(const std::string &txt)
{
   if (txt == "")
      return "";
   else
      return txt + " ";
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::DeclInfo(clang::Decl* D) const
{
   std::string location = GetLocation(D);
   std::string kind = D->getDeclKindName();
   std::string name = GetName(D);
   ShowInfo("Scan: " + kind + " declaration " + name, location);
}

////////////////////////////////////////////////////////////////////////////////
/// unknown - this kind of declaration was not known to programmer

void RScanner::UnknownDecl(clang::Decl* D, const std::string &txt) const
{
   std::string location = GetLocation(D);
   std::string kind = D->getDeclKindName();
   std::string name = GetName(D);
   ShowWarning("Unknown " + AddSpace(txt) + kind + " declaration " + name, location);
}

////////////////////////////////////////////////////////////////////////////////
/// unexpected - this kind of declaration is unexpected (in concrete place)

void RScanner::UnexpectedDecl(clang::Decl* D, const std::string &txt) const
{
   std::string location = GetLocation(D);
   std::string kind = D->getDeclKindName();
   std::string name = GetName(D);
   ShowWarning("Unexpected " + kind + " declaration " + name, location);
}

////////////////////////////////////////////////////////////////////////////////
/// unsupported - this kind of declaration is probably not used (in current version of C++)

void RScanner::UnsupportedDecl(clang::Decl* D, const std::string &txt) const
{
   std::string location = GetLocation(D);
   std::string kind = D->getDeclKindName();
   std::string name = GetName(D);
   ShowWarning("Unsupported " + AddSpace(txt) + kind + " declaration " + name, location);
}

////////////////////////////////////////////////////////////////////////////////
/// unimportant - this kind of declaration is not stored into reflex

void RScanner::UnimportantDecl(clang::Decl* D, const std::string &txt) const
{
}

////////////////////////////////////////////////////////////////////////////////
/// information about item, that should be implemented

void RScanner::UnimplementedDecl(clang::Decl* D, const std::string &txt)
{
   clang::Decl::Kind k = D->getKind();

   bool show = true;
#ifdef FILTER_WARNINGS
   if (k >= 0 || k <= fgDeclLast) {
      if (fDeclTable [k])
         show = false; // already displayed
      else
         fDeclTable [k] = true;
   }
#endif

   if (show)
   {
      std::string location = GetLocation(D);
      std::string kind = D->getDeclKindName();
      std::string name = GetName(D);
      std::string msg = "Unimplemented ";
      if (txt == "") {
         msg +=  "declaration";
      } else {
         msg += txt;
      }
      msg += ": ";
      msg += kind;
      msg += " ";
      msg += name;
      ShowWarning(msg,location);
   }
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::UnknownType(clang::QualType qual_type) const
{
   std::string location = GetLocation(fLastDecl);
   std::string kind = qual_type.getTypePtr()->getTypeClassName();
   ShowWarning("Unknown " + kind + " type " + qual_type.getAsString(), location);
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::UnsupportedType(clang::QualType qual_type) const
{
   std::string location = GetLocation(fLastDecl);
   std::string kind = qual_type.getTypePtr()->getTypeClassName();
   ShowWarning("Unsupported " + kind + " type " + qual_type.getAsString(), location);
}

////////////////////////////////////////////////////////////////////////////////
/// unimportant - this kind of declaration is not stored into reflex

void RScanner::UnimportantType(clang::QualType qual_type) const
{
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::UnimplementedType(clang::QualType qual_type)
{
   clang::Type::TypeClass k = qual_type.getTypePtr()->getTypeClass();

   bool show = true;
#ifdef FILTER_WARNINGS
   if (k >= 0 || k <= fgTypeLast) {
      if (fTypeTable [k])
         show = false; // already displayed
      else
         fTypeTable [k] = true;
   }
#endif

   if (show)
   {
      std::string location = GetLocation(fLastDecl);
      std::string kind = qual_type.getTypePtr()->getTypeClassName();
      ShowWarning("Unimplemented type: " + kind + " " + qual_type.getAsString(), location);
   }
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::UnimplementedType (const clang::Type* T)
{
   clang::Type::TypeClass k = T->getTypeClass();

   bool show = true;
#ifdef FILTER_WARNINGS
   if (k >= 0 || k <= fgTypeLast) {
      if (fTypeTable [k])
         show = false; // already displayed
      else
         fTypeTable [k] = true;
   }
#endif

   if (show)
   {
      std::string location = GetLocation(fLastDecl);
      std::string kind = T->getTypeClassName ();
      ShowWarning ("Unimplemented type: " + kind, location);
   }
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetClassName(clang::RecordDecl* D) const
{
   std::string cls_name = D->getQualifiedNameAsString();

   // NO if (cls_name == "")
   // NO if (D->isAnonymousStructOrUnion())
   // NO if (cls_name == "(anonymous)") {
   if (! D->getDeclName ()) {
      if (fgAnonymousClassMap.find (D) != fgAnonymousClassMap.end())
      {
         // already encountered anonymous class
         cls_name = fgAnonymousClassMap [D];
      }
      else
      {
         fgAnonymousClassCounter ++;
         cls_name = "_ANONYMOUS_CLASS_" + IntToStd(fgAnonymousClassCounter) + "_";  // !?
         fgAnonymousClassMap [D] = cls_name;
         // ShowInfo ("anonymous class " + cls_name, GetLocation (D));
      }
   }

   return cls_name;
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetEnumName(clang::EnumDecl* D) const
{
   std::string enum_name = D->getQualifiedNameAsString();

   if (! D->getDeclName ()) {
      if (fgAnonymousEnumMap.find (D) != fgAnonymousEnumMap.end())
      {
         // already encountered anonymous enumeration type
         enum_name = fgAnonymousEnumMap [D];
      }
      else
      {
         fgAnonymousEnumCounter ++;
         enum_name = "_ANONYMOUS_ENUM_" + IntToStd(fgAnonymousEnumCounter) + "_";  // !?
         fgAnonymousEnumMap [D] = enum_name;
         // ShowInfo ("anonymous enum " + enum_name, GetLocation (D));
      }
   }

   return enum_name;
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::ExprToStr(clang::Expr* expr) const
{
   clang::LangOptions lang_opts;
   clang::PrintingPolicy print_opts(lang_opts); // !?

   std::string text = "";
   llvm::raw_string_ostream stream(text);

   expr->printPretty(stream, NULL, print_opts);

   return stream.str();
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::ConvTemplateName(clang::TemplateName& N) const
{
   clang::LangOptions lang_opts;
   clang::PrintingPolicy print_opts(lang_opts);  // !?

   std::string text = "";
   llvm::raw_string_ostream stream(text);

   N.print(stream, print_opts);

   return stream.str();
}

#ifdef COMPLETE_TEMPLATES
////////////////////////////////////////////////////////////////////////////////

std::string RScanner::ConvTemplateParameterList(clang::TemplateParameterList* list) const
{
   std::string result = "";
   bool any = false;

   for (clang::TemplateParameterList::iterator I = list->begin(), E = list->end(); I != E; ++I) {
      if (any)
         result += ",";
      any = true;

      clang::NamedDecl * D = *I;

      switch (D->getKind()) {

         case clang::Decl::TemplateTemplateParm:
            UnimplementedDecl(dyn_cast <clang::TemplateTemplateParmDecl> (D), "template parameter");
            break;

         case clang::Decl::TemplateTypeParm:
         {
            clang::TemplateTypeParmDecl* P = dyn_cast <clang::TemplateTypeParmDecl> (D);

            if (P->wasDeclaredWithTypename())
               result += "typename ";
            else
               result += "class ";

            if (P->isParameterPack())
               result += "... ";

            result += P->getNameAsString();
         }
            break;

         case clang::Decl::NonTypeTemplateParm:
         {
            clang::NonTypeTemplateParmDecl* P = dyn_cast <clang::NonTypeTemplateParmDecl> (D);
            result += P->getType().getAsString();

            if (clang::IdentifierInfo* N = P->getIdentifier()) {
               result += " ";
               std::string s = N->getName();
               result += s;
            }

            if (P->hasDefaultArgument())
               result += " = " + ExprToStr(P->getDefaultArgument());
         }
            break;

         default:
            UnknownDecl(*I, "template parameter");
      }
   }

   // ShowInfo ("template parameters <" + result + ">");

   return "<" + result + ">";
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::ConvTemplateParams(clang::TemplateDecl* D)
{
   return ConvTemplateParameterList(D->getTemplateParameters());
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::ConvTemplateArguments(const clang::TemplateArgumentList& list)
{
   clang::LangOptions lang_opts;
   clang::PrintingPolicy print_opts(lang_opts);  // !?
   return clang::TemplateSpecializationType::PrintTemplateArgumentList
   (list.data(), list.size(), print_opts);
}
#endif // COMPLETE_TEMPLATES

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::FuncParameters(clang::FunctionDecl* D) const
{
   std::string result = "";

   for (clang::FunctionDecl::param_iterator I = D->param_begin(), E = D->param_end(); I != E; ++I) {
      clang::ParmVarDecl* P = *I;

      if (result != "")
         result += ";";  // semicolon, not comma, important

      std::string type = P->getType().getAsString();
      std::string name = P->getNameAsString();

      result += type + " " + name;

      // NO if (P->hasDefaultArg ()) // check hasUnparsedDefaultArg () and hasUninstantiatedDefaultArg ()
      if (P->getInit()) {
         std::string init_value = ExprToStr(P->getDefaultArg());
         result += "=" + init_value;
      }
   }

   return result;
}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::FuncParameterList(clang::FunctionDecl* D) const
{
   std::string result = "";

   for (clang::FunctionDecl::param_iterator I = D->param_begin(), E = D->param_end(); I != E; ++I) {
      clang::ParmVarDecl* P = *I;

      if (result != "")
         result += ",";

      std::string type = P->getType().getAsString();
      result += type;
   }

   return "(" + result + ")";
}

////////////////////////////////////////////////////////////////////////////////
/// This method visits a namespace node

bool RScanner::VisitNamespaceDecl(clang::NamespaceDecl* N)
{
   // We don't need to visit this while creating the big PCM
   if (fScanType == EScanType::kOnePCM)
      return true;

   // in case it is implicit we don't create a builder
   if(N && N->isImplicit()){
      return true;
   }

   bool ret = true;

   const ClassSelectionRule *selected = fSelectionRules.IsDeclSelected(N);
   if (selected) {

#ifdef SELECTION_DEBUG
      if (fVerboseLevel > 3) std::cout<<"\n\tSelected -> true";
#endif
      clang::DeclContext* primary_ctxt = N->getPrimaryContext();
      clang::NamespaceDecl* primary = llvm::dyn_cast<clang::NamespaceDecl>(primary_ctxt);

      RPredicateIsSameNamespace pred(primary);
      if ( find_if(fSelectedNamespaces.begin(),fSelectedNamespaces.end(),pred) == fSelectedNamespaces.end() ) {
         // The namespace is not already registered.

         if (fVerboseLevel > 0) {
            std::string qual_name;
            GetDeclQualName(N,qual_name);
            //      std::cout<<"\tSelected namespace -> " << qual_name << " ptr " << (void*)N <<   " decl ctxt " << (void*)N->getPrimaryContext() << " classname " <<primary->getNameAsString() << "\n";
            std::cout<<"\tSelected namespace -> " << qual_name << "\n";
         }
         fSelectedNamespaces.push_back(AnnotatedNamespaceDecl(primary,selected->GetIndex(),selected->RequestOnlyTClass()));
      }
      ret = true;
   }
   else {
#ifdef SELECTION_DEBUG
      if (fVerboseLevel > 3) std::cout<<"\n\tSelected -> false";
#endif
   }

   // DEBUG if(ret) std::cout<<"\n\tReturning true ...";
   // DEBUG else std::cout<<"\n\tReturning false ...";
   return ret;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::VisitRecordDecl(clang::RecordDecl* D)
{
   // This method visits a class node
   return TreatRecordDeclOrTypedefNameDecl(D);


}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::TreatRecordDeclOrTypedefNameDecl(clang::TypeDecl* typeDecl)
{
   // For every class is created a new class buider irrespectful of weather the
   // class is internal for another class declaration or not.
   // RecordDecls and TypedefDecls (or RecordDecls!) are treated.
   // We follow two different codepaths if the typeDecl is a RecordDecl or
   // a TypedefDecl. If typeDecl is a TypedefDecl, recordDecl becomes the
   // underlying RecordDecl.
   // This is done to leverage the selections rule matching in SelectionRules
   // which works basically with names.
   // At the end of the method, if the typedef name is matched, an AnnotatedRecordDecl
   // with the underlying RecordDecl is fed to the machinery.

   clang::RecordDecl* recordDecl = clang::dyn_cast<clang::RecordDecl>(typeDecl);
   clang::TypedefNameDecl* typedefNameDecl = clang::dyn_cast<clang::TypedefNameDecl>(typeDecl);

   // If typeDecl is not a RecordDecl, try to fetch the RecordDecl behind the TypedefDecl
   if (!recordDecl && typedefNameDecl) {
      recordDecl = ROOT::TMetaUtils::GetUnderlyingRecordDecl(typedefNameDecl->getUnderlyingType());
      }

   // If at this point recordDecl is still NULL, we have a problem
   if (!recordDecl) {
      ROOT::TMetaUtils::Warning("RScanner::TreatRecordDeclOrTypeNameDecl",
       "Could not cast typeDecl either to RecordDecl or could not get RecordDecl underneath typedef.\n");
      return true;
   }

   // Do not select unnamed records.
   if (!recordDecl->getIdentifier())
      return true;

   if (fScanType == EScanType::kOnePCM && ROOT::TMetaUtils::IsStdClass(*recordDecl))
      return true;


   // At this point, recordDecl must be a RecordDecl pointer.

   if (recordDecl && fRecordDeclCallback) {
      // Pass on any declaration.   This is usually used to record dependency.
      // Since rootcint see C++ compliant header files, we can assume that
      // if a forward declaration or declaration has been inserted, the
      // classes for which we are creating a dictionary will be using
      // them either directly or indirectly.   Any false positive can be
      // resolved by removing the spurrious dependency in the (user) header
      // files.
      std::string qual_name;
      GetDeclQualName(recordDecl,qual_name);
      fRecordDeclCallback(qual_name.c_str());
   }

   // in case it is implicit or a forward declaration, we are not interested.
   if(recordDecl && (recordDecl->isImplicit() || !recordDecl->isCompleteDefinition()) ) {
      return true;
   }

   // Never select the class templates themselves.
   const clang::CXXRecordDecl *cxxdecl = llvm::dyn_cast<clang::CXXRecordDecl>(recordDecl);
   if (cxxdecl && cxxdecl->getDescribedClassTemplate ()) {
      return true;
   }

   const ClassSelectionRule *selectedFromTypedef = typedefNameDecl ? fSelectionRules.IsDeclSelected(typedefNameDecl) : 0;

   const ClassSelectionRule *selectedFromRecDecl = fSelectionRules.IsDeclSelected(recordDecl);

   const ClassSelectionRule *selected = typedefNameDecl ? selectedFromTypedef : selectedFromRecDecl;

   if (! selected) return true; // early exit. Nothing more to be done.

   // Selected through typedef but excluded with concrete classname
   bool excludedFromRecDecl = false;
   if ( selectedFromRecDecl )
      excludedFromRecDecl = selectedFromRecDecl->GetSelected() == BaseSelectionRule::kNo;

   if (selected->GetSelected() == BaseSelectionRule::kYes && !excludedFromRecDecl) {
      // The record decl will results to be selected

      // Save the typedef
      if (selectedFromTypedef){
         if (!IsElementPresent(fSelectedTypedefs, typedefNameDecl))
            fSelectedTypedefs.push_back(typedefNameDecl);
         // Early exit here if we are not in presence of XML
         if (!fSelectionRules.IsSelectionXMLFile()) return true;
      }

      if (fSelectionRules.IsSelectionXMLFile() && selected->IsFromTypedef()) {
         if (!IsElementPresent(fSelectedTypedefs, typedefNameDecl))
            fSelectedTypedefs.push_back(typedefNameDecl);
         return true;
      }

      if (typedefNameDecl)
         ROOT::TMetaUtils::Info("RScanner::TreatRecordDeclOrTypedefNameDecl",
                                "Typedef is selected %s.\n", typedefNameDecl->getNameAsString().c_str());

      // For the case kNo, we could (but don't) remove the node from the pcm
      // For the case kDontCare, the rule is just a place holder and we are actually trying to exclude some of its children
      // (this is used only in the selection xml case).

      // Reject the selection of std::pair on the ground that it is trivial
      // and can easily be recreated from the AST information.
      if (recordDecl && recordDecl->getName() == "pair") {
         const clang::NamespaceDecl *nsDecl = llvm::dyn_cast<clang::NamespaceDecl>(recordDecl->getDeclContext());
         if (!nsDecl){
            ROOT::TMetaUtils::Error("RScanner::TreatRecordDeclOrTypedefNameDecl",
                                    "Cannot convert context of RecordDecl called pair into a namespace.\n");
            return true;
         }
         const clang::NamespaceDecl *nsCanonical = nsDecl->getCanonicalDecl();
         if (nsCanonical && nsCanonical == fInterpreter.getCI()->getSema().getStdNamespace()) {
            if (selected->HasAttributeFileName() || selected->HasAttributeFilePattern()) {
               return true;
            }
         }
      }

      // Insert in the selected classes if not already there
      // We need this check since the same class can be selected through its name or typedef
      bool rcrdDeclNotAlreadySelected = fselectedRecordDecls.insert((RecordDecl*)recordDecl->getCanonicalDecl()).second;

      auto declSelRuleMapIt = fDeclSelRuleMap.find(recordDecl->getCanonicalDecl());
      if (!fFirstPass &&
          !rcrdDeclNotAlreadySelected &&
          declSelRuleMapIt != fDeclSelRuleMap.end() &&
          declSelRuleMapIt->second != selected){
         std::string normName;
         TMetaUtils::GetNormalizedName(normName,
                                       recordDecl->getASTContext().getTypeDeclType(recordDecl),
                                       fInterpreter,
                                       fNormCtxt);

         auto previouslyMatchingRule = (const ClassSelectionRule*)declSelRuleMapIt->second;
         int previouslineno = previouslyMatchingRule->GetLineNumber();

         std::string cleanFileName =  llvm::sys::path::filename(selected->GetSelFileName());
         auto lineno = selected->GetLineNumber();
         auto rulesAreCompatible = SelectionRulesUtils::areEqual<ClassSelectionRule>(selected, previouslyMatchingRule, true /*moduloNameOrPattern*/);
         if (!rulesAreCompatible){
            std::stringstream message;
            if (lineno > 1) message << "Selection file " << cleanFileName << ", lines "
                                    << lineno << " and " << previouslineno << ". ";
            message << "Attempt to select a class "<< normName << " with two rules which have incompatible attributes. "
                    << "The attributes such as transiency might not be correctly propagated to the typesystem of ROOT.\n";
            selected->Print(message);
            message << "Conflicting rule already matched:\n";
            previouslyMatchingRule->Print(message);
            ROOT::TMetaUtils::Warning(0,"%s\n", message.str().c_str());
            }
         }

      fDeclSelRuleMap[recordDecl->getCanonicalDecl()]=selected;

      if(rcrdDeclNotAlreadySelected &&
         !fFirstPass){
          
          
         // Before adding the decl to the selected ones, check its access. 
         // We do not yet support I/O of private or protected classes.
         // See ROOT-7450
         // We exclude filename selections as they can come from aclic
         auto isFileSelection = selected->HasAttributeFileName() && 
                                selected->HasAttributePattern() &&
                                "*" == selected->GetAttributePattern();
         auto canDeclAccess = recordDecl->getCanonicalDecl()->getAccess();
         if (!isFileSelection && (AS_protected == canDeclAccess || AS_private == canDeclAccess)){
            std::string normName;
            TMetaUtils::GetNormalizedName(normName,
                                          recordDecl->getASTContext().getTypeDeclType(recordDecl),
                                          fInterpreter,
                                          fNormCtxt);            
            auto msg = "Class or struct %s was selected but its dictionary cannot be generated: "
                       "this is a private or protected class and this is not supported. No direct "
                       "I/O operation of %s instances will be possible.\n";
            ROOT::TMetaUtils::Warning(0,msg,normName.c_str(),normName.c_str());
            return true;
         }

         const std::string& name_value = selected->GetAttributeName();
         if (selected->HasAttributeName()) {
            ROOT::TMetaUtils::AnnotatedRecordDecl annRecDecl(selected->GetIndex(),
                                                            selected->GetRequestedType(),
                                                            recordDecl,
                                                            name_value.c_str(),
                                                            selected->RequestStreamerInfo(),
                                                            selected->RequestNoStreamer(),
                                                            selected->RequestNoInputOperator(),
                                                            selected->RequestOnlyTClass(),
                                                            selected->RequestedVersionNumber(),
                                                            fInterpreter,
                                                            fNormCtxt);
            fSelectedClasses.push_back(annRecDecl);



         } else {
            ROOT::TMetaUtils::AnnotatedRecordDecl annRecDecl(selected->GetIndex(),
                                                            recordDecl,
                                                            selected->RequestStreamerInfo(),
                                                            selected->RequestNoStreamer(),
                                                            selected->RequestNoInputOperator(),
                                                            selected->RequestOnlyTClass(),
                                                            selected->RequestedVersionNumber(),
                                                            fInterpreter,
                                                            fNormCtxt);
            fSelectedClasses.push_back(annRecDecl);
         }

         if (fVerboseLevel > 0) {
            std::string qual_name;
            GetDeclQualName(recordDecl,qual_name);
            std::string normName;
            TMetaUtils::GetNormalizedName(normName,
                                          recordDecl->getASTContext().getTypeDeclType(recordDecl),
                                          fInterpreter,
                                          fNormCtxt);
            std::string typedef_qual_name;
            std::string typedefMsg;
            if (typedefNameDecl){
               GetDeclQualName(typedefNameDecl,typedef_qual_name);
               typedefMsg = "(through typedef/alias " + typedef_qual_name + ") ";
            }

         std::cout <<"Selected class "
         << typedefMsg
         << "-> "
         << qual_name
         << " for ROOT: "
         << normName
         << "\n";
         }

      }
   }



   return true;
}

////////////////////////////////////////////////////////////////////////////////
/// Visitor for every TypedefNameDecl, i.e. aliases and typedefs
/// We check three conditions before trying to match the name:
/// 1) If we are creating a big PCM
/// 2) If the underlying decl is a RecordDecl
/// 3) If the typedef is eventually contained in the std namespace

bool RScanner::VisitTypedefNameDecl(clang::TypedefNameDecl* D)
{
   if (fScanType == EScanType::kOnePCM)
      return true;

   const clang::DeclContext *ctx = D->getDeclContext();

   bool isInStd=false;
   if (ctx) {
      const clang::NamedDecl *parent = llvm::dyn_cast<clang::NamedDecl> (ctx);
      isInStd = parent && 0 == parent->getQualifiedNameAsString().compare(0,5,"std::");
      }

   if (ROOT::TMetaUtils::GetUnderlyingRecordDecl(D->getUnderlyingType()) &&
       !isInStd){
      TreatRecordDeclOrTypedefNameDecl(D);
   }

    return true;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::VisitEnumDecl(clang::EnumDecl* D)
{
   if (fScanType == EScanType::kOnePCM)
      return true;

   if(fSelectionRules.IsDeclSelected(D) &&
      !IsElementPresent(fSelectedEnums, D)){ // Removal of duplicates.
      fSelectedEnums.push_back(D);
   }

   return true;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::VisitVarDecl(clang::VarDecl* D)
{
   if (!D->hasGlobalStorage() ||
       fScanType == EScanType::kOnePCM)
      return true;

   if(fSelectionRules.IsDeclSelected(D)){
      fSelectedVariables.push_back(D);
   }

   return true;
}

////////////////////////////////////////////////////////////////////////////////
/// Nothing to be done here

bool RScanner::VisitFieldDecl(clang::FieldDecl* D)
{
   return true;

//    bool ret = true;
//
//    if(fSelectionRules.IsDeclSelected(D)){
// #ifdef SELECTION_DEBUG
//       if (fVerboseLevel > 3) std::cout<<"\n\tSelected -> true";
// #endif
//
//       // if (fVerboseLevel > 0) {
// //      std::string qual_name;
// //      GetDeclQualName(D,qual_name);
// //      std::cout<<"\tSelected field -> " << qual_name << "\n";
//       // }
//    }
//    else {
// #ifdef SELECTION_DEBUG
//       if (fVerboseLevel > 3) std::cout<<"\n\tSelected -> false";
// #endif
//    }
//
//    return ret;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::VisitFunctionDecl(clang::FunctionDecl* D)
{
   if (fScanType == EScanType::kOnePCM)
      return true;

   if(clang::FunctionDecl::TemplatedKind::TK_FunctionTemplate == D->getTemplatedKind())
      return true;

   if(fSelectionRules.IsDeclSelected(D)){
      fSelectedFunctions.push_back(D);
   }

   return true;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::TraverseDeclContextHelper(DeclContext *DC)
{
   bool ret = true;

   if (!DC)
      return true;

   clang::Decl* D = dyn_cast<clang::Decl>(DC);
   // skip implicit decls
   if (D && D->isImplicit()){
      return true;
   }

   if (fScanType == EScanType::kOnePCM){
      const clang::NamespaceDecl *parent = llvm::dyn_cast<clang::NamespaceDecl> (DC);
      if (parent && 0 == parent->getQualifiedNameAsString().compare(0,5,"std::"))
         return true;
      }

   for (DeclContext::decl_iterator Child = DC->decls_begin(), ChildEnd = DC->decls_end();
        ret && (Child != ChildEnd); ++Child) {
      ret=TraverseDecl(*Child);
   }

   return ret;

}

////////////////////////////////////////////////////////////////////////////////

std::string RScanner::GetClassName(clang::DeclContext* DC) const
{
   clang::NamedDecl* N=dyn_cast<clang::NamedDecl>(DC);
   std::string ret;
   if(N && (N->getIdentifier()!=NULL))
      ret = N->getNameAsString().c_str();

   return ret;
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::GetDeclName(clang::Decl* D, std::string& name) const
{
   clang::NamedDecl* N = dyn_cast<clang::NamedDecl> (D);

   if (N) {
      name = N->getNameAsString();
      return true;
   }
   else {
      name = "UNNAMED";
      return false;
   }
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::GetDeclQualName(clang::Decl* D, std::string& qual_name) const
{
   clang::NamedDecl* N = dyn_cast<clang::NamedDecl> (D);

   if (N) {
      llvm::raw_string_ostream stream(qual_name);
      N->getNameForDiagnostic(stream,D->getASTContext().getPrintingPolicy(),true); // qual_name = N->getQualifiedNameAsString();
      return true;
   }
   else {
      return false;
   }
}

////////////////////////////////////////////////////////////////////////////////

bool RScanner::GetFunctionPrototype(clang::Decl* D, std::string& prototype) const {
   if (!D) {
      return false;
   }

   clang::FunctionDecl* F = dyn_cast<clang::FunctionDecl> (D);

   if (F) {

      prototype = "";
      for (clang::FunctionDecl::param_iterator I = F->param_begin(), E = F->param_end(); I != E; ++I) {
         clang::ParmVarDecl* P = *I;

         if (prototype != "")
            prototype += ",";

         //std::string type = P->getType().getAsString();
         std::string type = P->getType().getAsString();
         if (type.at(type.length()-1) == '*') {
            type.at(type.length()-2) = '*';
            type.erase(type.length()-1);
         }
         prototype += type;
      }

      prototype = "(" + prototype + ")";
      return true;
   }
   else {
      ShowWarning("can't convert Decl to FunctionDecl","");
      return false;
   }
}

////////////////////////////////////////////////////////////////////////////////

void RScanner::Scan(const clang::ASTContext &C)
{
   fSourceManager = &C.getSourceManager();

//    if (fVerboseLevel >= 3) fSelectionRules.PrintSelectionRules();

   if (fVerboseLevel > 0 && fSelectionRules.GetHasFileNameRule())  {
      std::cout<<"File name detected"<<std::endl;
   }

   if (fScanType == EScanType::kTwoPasses)
      TraverseDecl(C.getTranslationUnitDecl());

   fFirstPass=false;
   fselectedRecordDecls.clear();
   fSelectedEnums.clear();
   fSelectedTypedefs.clear();
   fSelectedFunctions.clear();
   TraverseDecl(C.getTranslationUnitDecl());

   // And finally resort the results according to the rule ordering.
   std::sort(fSelectedClasses.begin(),fSelectedClasses.end());
}


////////////////////////////////////////////////////////////////////////////////
/// Set the callback to the RecordDecl and return the previous one.

RScanner::DeclCallback RScanner::SetRecordDeclCallback(RScanner::DeclCallback callback)
{
   DeclCallback old = fRecordDeclCallback;
   fRecordDeclCallback = callback;
   return old;
}