[flang-commits] [flang] [MLIR][OpenMP] Add Lowering support for implicitly linking to default declare mappers (PR #131006)

[Kareem Ergawy via flang-commits]

================
@@ -933,18 +933,42 @@ void ClauseProcessor::processMapObjects(
   mlir::FlatSymbolRefAttr mapperId;
   if (!mapperIdNameRef.empty() && !objects.empty()) {
     std::string mapperIdName = mapperIdNameRef.str();
-    if (mapperIdName == "default") {
-      const omp::Object &object = objects.front();
-      auto &typeSpec = object.sym()->owner().IsDerivedType()
-                           ? *object.sym()->owner().derivedTypeSpec()
-                           : object.sym()->GetType()->derivedTypeSpec();
-      mapperIdName = typeSpec.name().ToString() + ".default";
-      mapperIdName = converter.mangleName(mapperIdName, *typeSpec.GetScope());
+    if (mapperIdName == "implicit") {
+      if (!mlir::isa<mlir::omp::DeclareMapperOp>(
+              firOpBuilder.getRegion().getParentOp())) {
+        const omp::Object &object = objects.front();
+        const semantics::DerivedTypeSpec *typeSpec = nullptr;
+
+        if (object.sym()->owner().IsDerivedType())
+          typeSpec = object.sym()->owner().derivedTypeSpec();
+        else if (object.sym()->GetType() &&
+                 object.sym()->GetType()->category() ==
+                     semantics::DeclTypeSpec::TypeDerived)
+          typeSpec = &object.sym()->GetType()->derivedTypeSpec();
----------------
ergawy wrote:

Can you elaborate on why we need differnet approaches to find the `typeSpec` for implicit and default mappers? Can we extract the logic in one lambda for both cases?

Or, even better I think, it seems the logic for initializing `mapperIdName` and `mapperId` for both implicit and default cases is almost identical; with the exception that we assert if we did not find the default mapper AFAICT. Maybe this logic can be extracted in a lambda?

https://github.com/llvm/llvm-project/pull/131006