[flang][OpenMP] Set OpenMP attributes in MLIR module in bbc before lo… (#82774)

…wering

Right now attributes like OpenMP version or target attributes for
offload are set after lowering in bbc. The flang frontend sets them
before lowering, making them available in the lowering process.

This change sets them before lowering in bbc as well.

Author: kparzysz

flang/tools/bbc/bbc.cpp

@@ -360,7 +360,6 @@ static mlir::LogicalResult convertFortranSourceToMLIR(
       semanticsContext.targetCharacteristics(), parsing.allCooked(),
       targetTriple, kindMap, loweringOptions, envDefaults,
       semanticsContext.languageFeatures(), targetMachine);
-  burnside.lower(parseTree, semanticsContext);
   mlir::ModuleOp mlirModule = burnside.getModule();
   if (enableOpenMP) {
     if (enableOpenMPGPU && !enableOpenMPDevice) {
@@ -376,6 +375,7 @@ static mlir::LogicalResult convertFortranSourceToMLIR(
     setOffloadModuleInterfaceAttributes(mlirModule, offloadModuleOpts);
     setOpenMPVersionAttribute(mlirModule, setOpenMPVersion);
   }
+  burnside.lower(parseTree, semanticsContext);
   std::error_code ec;
   std::string outputName = outputFilename;
   if (!outputName.size())