[llvm-branch-commits] [flang] [MLIR][OpenMP] Add Lowering support for OpenMP Declare Mapper directive (PR #117046)

[Akash Banerjee via llvm-branch-commits]

TIFitis wrote:

@kiranchandramohan @kparzysz I guess I must be using the name mangler in an incorrect way then. I've added the code snippets I am using when lowering and later performing a lookup. Please let me know what would be the correct way of doing this.

When lowering DeclMapperOp:
```
static void
genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
       semantics::SemanticsContext &semaCtx, lower::pft::Evaluation &eval,
       const parser::OpenMPDeclareMapperConstruct &declareMapperConstruct) {
  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
  const auto &spec =
      std::get<parser::OmpDeclareMapperSpecifier>(declareMapperConstruct.t);
  const auto &mapperName{std::get<std::optional<parser::Name>>(spec.t)};
  std::string mapperNameStr;
  if (mapperName.has_value())
    mapperNameStr = mapperName->ToString();
  else
    mapperNameStr =
        "default_" + varType.declTypeSpec->derivedTypeSpec().name().ToString();

  // This is my current implementation.
  // It returns _QQFmy_mapper as mapperNameStr.
  mapperNameStr = converter.mangleName(*mapperName->symbol);

  auto declMapperOp = firOpBuilder.create<mlir::omp::DeclareMapperOp>(
      loc, mapperNameStr, mlirType);
  converter.getMLIRSymbolTable()->insert(declMapperOp);

  // This code produces the error:
  // LLVM ERROR: /home/akash/Documents/llvm-project/flang/lib/Lower/Mangler.cpp:184: not yet implemented: symbol mangling
  // mapperNameStr = converter.mangleName(*mapperName->symbol);
  
  // This code produces the error:
  // ** symbol not properly mapped **
  // symTable.lookupSymbol(mapperName->symbol).dump();
```

When trying to lookup DeclareMapper from the mapClause mapper:

```
      auto mapperIdName = mappers->front().v.id().symbol->name().ToString();
      mapperIdName = converter.mangleName(mapperIdName);

      // Here mapperIdName returns _QQFFtestmy_mapper which fails the
      // lookup inside the asser.

      // assert(converter.getMLIRSymbolTable()->lookup(mapperIdName) &&
      //        "mapper not found");
      mapperId = mlir::FlatSymbolRefAttr::get(&converter.getMLIRContext(),
                                              mapperIdName);
```

https://github.com/llvm/llvm-project/pull/117046