[df] Extract function to retrieve deferred calls

Author: vepadulano

tree/dataframe/src/RLoopManager.cxx

@@ -112,6 +112,44 @@ std::unordered_map<std::string, std::string> &GetJitHelperNameMap()
    return map;
 }
 
+void DeclareAndRetrieveDeferredJitCalls(const std::string &codeToDeclare)
+{
+   // Step 1: Declare the DeferredJitCall functions to the interpreter
+   // We use ProcessLine to ensure meta functionality (e.g. autoloading) is
+   // processed when needed.
+   // If instead we used Declare, builds with runtime_cxxmodules=OFF would fail
+   // in jitted actions with custom helpers with errors like:
+   // error: 'MyHelperType' is an incomplete type
+   // return std::make_unique<Action_t>(Helper_t(std::move(*h)), bl, std::move(prevNode), colRegister);
+   //                                   ^
+   gInterpreter->ProcessLine(codeToDeclare.c_str());
+
+   // Step 2: Retrieve the declared functions as function pointers, cache them
+   // for later use in RunDeferredCalls
+   auto &funcMap = GetJitHelperFuncMap();
+   auto &nameMap = GetJitHelperNameMap();
+   auto clinfo = gInterpreter->ClassInfo_Factory("R_rdf");
+   assert(gInterpreter->ClassInfo_IsValid(clinfo));
+
+   for (auto &codeAndName : nameMap) {
+      if (auto it = funcMap.find(codeAndName.second); it == funcMap.end()) {
+         // fast fetch of the address via gInterpreter
+         // (faster than gInterpreter->Evaluate(function name, ret), ret->GetAsPointer())
+         // Retrieve the JIT helper function we registered via RegisterJitHelperCall
+         auto declid = gInterpreter->GetFunction(clinfo, codeAndName.second.c_str());
+         assert(declid);
+         auto minfo = gInterpreter->MethodInfo_Factory(declid);
+         assert(gInterpreter->MethodInfo_IsValid(minfo));
+         auto mname = gInterpreter->MethodInfo_GetMangledName(minfo);
+         auto res =
+            funcMap.insert({codeAndName.second, reinterpret_cast<JitHelperFunc_t>(gInterpreter->FindSym(mname))});
+         assert(res.second);
+         gInterpreter->MethodInfo_Delete(minfo);
+      }
+   }
+   gInterpreter->ClassInfo_Delete(clinfo);
+}
+
 void ThrowIfNSlotsChanged(unsigned int nSlots)
 {
    const auto currentSlots = RDFInternal::GetNSlots();
@@ -805,33 +843,7 @@ void RLoopManager::Jit()
    TStopwatch s;
    s.Start();
    if (!codeToDeclare.empty()) {
-      // This takes care of autoloading when needed
-      // If instead we used gInterpreter->Declare, builds with runtime_cxxmodules=OFF would fail in
-      // jitted actions with custom helpers with errors like:
-      // error: 'MyHelperType' is an incomplete type
-      // return std::make_unique<Action_t>(Helper_t(std::move(*h)), bl, std::move(prevNode), colRegister);
-      //                                   ^
-      gInterpreter->ProcessLine(codeToDeclare.c_str());
-      auto &funcMap = GetJitHelperFuncMap();
-      auto &nameMap = GetJitHelperNameMap();
-      auto clinfo = gInterpreter->ClassInfo_Factory("R_rdf");
-      assert(gInterpreter->ClassInfo_IsValid(clinfo));
-      for (auto &codeAndName : nameMap) {
-         JitHelperFunc_t &addr = funcMap[codeAndName.second];
-         if (!addr) {
-            // fast fetch of the address via gInterpreter
-            // (faster than gInterpreter->Evaluate(function name, ret), ret->GetAsPointer())
-            // Retrieve the JIT helper function we registered via RegisterJitHelperCall
-            auto declid = gInterpreter->GetFunction(clinfo, codeAndName.second.c_str());
-            assert(declid);
-            auto minfo = gInterpreter->MethodInfo_Factory(declid);
-            assert(gInterpreter->MethodInfo_IsValid(minfo));
-            auto mname = gInterpreter->MethodInfo_GetMangledName(minfo);
-            addr = reinterpret_cast<JitHelperFunc_t>(gInterpreter->FindSym(mname));
-            gInterpreter->MethodInfo_Delete(minfo);
-         }
-      }
-      gInterpreter->ClassInfo_Delete(clinfo);
+      DeclareAndRetrieveDeferredJitCalls(codeToDeclare);
    }
    if (!code.empty()) {
       RDFInternal::InterpreterCalc(code, "RLoopManager::Run");
@@ -887,11 +899,15 @@ void RLoopManager::Run(bool jit)
    // Change value of TTree::GetMaxTreeSize only for this scope. Revert when #6640 will be solved.
    MaxTreeSizeRAII ctxtmts;
 
+   R__LOG_INFO(RDFLogChannel()) << "Starting event loop number " << fNRuns << '.';
+
    ThrowIfNSlotsChanged(GetNSlots());
 
    if (jit)
       Jit();
 
+   // Called here since in a RunGraphs run, multiple RLoopManager runs could be
+   // triggered from different threads.
    RunDeferredCalls();
 
    InitNodes();