cling::ForwardDeclPrinter: skip expr tmplt args

core/clingutils/res/TClingUtils.h

@@ -855,7 +855,7 @@ namespace AST2SourceTools {
 //______________________________________________________________________________
 const std::string Decls2FwdDecls(const std::vector<const clang::Decl*> &decls,
                                  bool (*ignoreFiles)(const clang::PresumedLoc&) ,
-                                 const cling::Interpreter& interp);
+                                 const cling::Interpreter& interp, std::string *logs);
 
 //______________________________________________________________________________
 int PrepareArgsForFwdDecl(std::string& templateArgs,

core/clingutils/src/TClingUtils.cxx

@@ -5105,7 +5105,10 @@ bool ROOT::TMetaUtils::IsHeaderName(const std::string &filename)
 
 ////////////////////////////////////////////////////////////////////////////////
 
-const std::string ROOT::TMetaUtils::AST2SourceTools::Decls2FwdDecls(const std::vector<const clang::Decl *> &decls, cling::Interpreter::IgnoreFilesFunc_t ignoreFiles, const cling::Interpreter &interp)
+const std::string ROOT::TMetaUtils::AST2SourceTools::Decls2FwdDecls(const std::vector<const clang::Decl *> &decls,
+                                                                    cling::Interpreter::IgnoreFilesFunc_t ignoreFiles,
+                                                                    const cling::Interpreter &interp,
+                                                                    std::string *logs)
 {
    clang::Sema &sema = interp.getSema();
    cling::Transaction theTransaction(sema);
@@ -5117,8 +5120,15 @@ const std::string ROOT::TMetaUtils::AST2SourceTools::Decls2FwdDecls(const std::v
    }
    std::string newFwdDecl;
    llvm::raw_string_ostream llvmOstr(newFwdDecl);
-   interp.forwardDeclare(theTransaction, sema.getPreprocessor(), sema.getASTContext(), llvmOstr, true, nullptr, ignoreFiles);
+
+   std::string locallogs;
+   llvm::raw_string_ostream llvmLogStr(locallogs);
+   interp.forwardDeclare(theTransaction, sema.getPreprocessor(), sema.getASTContext(), llvmOstr, true,
+                         logs ? &llvmLogStr : nullptr, ignoreFiles);
    llvmOstr.flush();
+   llvmLogStr.flush();
+   if (logs)
+      logs->swap(locallogs);
    return newFwdDecl;
 }
 

core/dictgen/src/rootcling_impl.cxx

@@ -3308,10 +3308,16 @@ static std::string GenerateFwdDeclString(const RScanner &scan,
 //    for (auto* VAR: scan.fSelectedVariables)
 //       selectedDecls.push_back(VAR);
 
+   std::string fwdDeclLogs;
+
    // The "R\"DICTFWDDCLS(\n" ")DICTFWDDCLS\"" pieces have been moved to
    // TModuleGenerator to be able to make the diagnostics more telling in presence
    // of an issue ROOT-6752.
-   fwdDeclString += Decls2FwdDecls(selectedDecls,IsLinkdefFile,interp);
+   fwdDeclString += Decls2FwdDecls(selectedDecls,IsLinkdefFile,interp, genreflex::verbose ? &fwdDeclLogs : nullptr);
+
+   if (genreflex::verbose && !fwdDeclLogs.empty())
+      std::cout << "Logs from forward decl printer: \n"
+         << fwdDeclLogs;
 
    // Functions
 //    for (auto const& fcnDeclPtr : scan.fSelectedFunctions){

interpreter/cling/lib/Interpreter/ForwardDeclPrinter.cpp

@@ -114,6 +114,7 @@ namespace cling {
     QT = utils::TypeName::GetFullyQualifiedType(QT, m_Ctx);
     Visit(QT.getTypePtr());
   }
+
   void ForwardDeclPrinter::Visit(clang::Decl *D) {
     auto Insert = m_Visited.insert(std::pair<const clang::Decl*, bool>(
                                              getCanonicalOrNamespace(D), true));
@@ -971,6 +972,10 @@ namespace cling {
                dyn_cast<TemplateTemplateParmDecl>(Param)) {
         Visit(TTPD);
         // FIXME: print the default argument, if present.
+        if (m_SkipFlag) {
+          skipDecl(TTPD, "template template param decl failed");
+          return;
+        }
       }
     }
 
@@ -1080,6 +1085,10 @@ namespace cling {
     for (const TemplateArgument& TA: iargs.asArray()) {
        VisitTemplateArgument(TA);
     }
+    if (m_SkipFlag) {
+      skipDecl(D, "template arguments failed");
+      return;
+    }
 
 //    Out() << "template <> ";
 //    VisitCXXRecordDecl(D->getCanonicalDecl());
@@ -1098,6 +1107,10 @@ namespace cling {
     Visit(D->getSpecializedTemplate());
     //Above code doesn't work properly
     //Must find better and more general way to print specializations
+    if (m_SkipFlag) {
+      skipDecl(D, "template specialization failed");
+      return;
+    }
   }
 
 
@@ -1107,6 +1120,10 @@ namespace cling {
 #define VISIT_DECL(WHAT, HOW) \
       case clang::Type::WHAT: \
         Visit(static_cast<const clang::WHAT##Type*>(typ)->HOW().getTypePtr()); \
+        if (m_SkipFlag) { \
+          skipDecl(nullptr, #WHAT " type failed"); \
+          return; \
+        } \
      break
       VISIT_DECL(ConstantArray, getElementType);
       VISIT_DECL(DependentSizedArray, getElementType);
@@ -1136,6 +1153,10 @@ namespace cling {
         const MemberPointerType* MPT
           = static_cast<const MemberPointerType*>(typ);
         Visit(MPT->getPointeeType().getTypePtr());
+        if (m_SkipFlag) {
+          skipDecl(nullptr, "pointee type failed");
+          return;
+        }
         Visit(MPT->getClass());
       }
       break;
@@ -1152,8 +1173,16 @@ namespace cling {
           = static_cast<const TemplateSpecializationType*>(typ);
         for (const TemplateArgument& TA: *TST) {
           VisitTemplateArgument(TA);
+          if (m_SkipFlag) {
+            skipDecl(nullptr, "template argument failed");
+            return;
+          }
         }
         VisitTemplateName(TST->getTemplateName());
+        if (m_SkipFlag) {
+          skipDecl(nullptr, "template specialization type failed");
+          return;
+        }
       }
       break;
 
@@ -1205,11 +1234,22 @@ namespace cling {
             return;
           }
         }
+        else {
+          std::string buf;
+          {
+            llvm::raw_string_ostream osbuf(buf);
+            TAExpr->printPretty(osbuf, nullptr, m_Policy);
+          }
+          Log() << "Visit(Type*): cannot forward declare template argument expression: "
+            << buf;
+          skipDecl(nullptr, nullptr);
+        }
       }
       break;
     default:
       Log() << "Visit(Type*): Unexpected TemplateSpecializationType "
             << TA.getKind() << '\n';
+      skipDecl(nullptr, nullptr);
       break;
     }
   }