[flang-commits] [flang] [Flang][Lower][OpenMP] Add initial lowering of pointers/allocatables/target in map clauses to map_info and entries (PR #68600)

[via flang-commits]

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@@ -1752,11 +1754,82 @@ bool ClauseProcessor::processMap(
                                        semanticsContext, stmtCtx, ompObject,
                                        clauseLocation, asFortran, bounds);
 
+          auto checkIfStructComponent =
+              [](const Fortran::parser::OmpObject &ompObject) {
+                bool isComponent = false;
+                std::visit(
+                    Fortran::common::visitors{
+                        [&](const Fortran::parser::Designator &designator) {
+                          if (auto *structComp = Fortran::parser::Unwrap<
+                                  Fortran::parser::StructureComponent>(
+                                  designator)) {
+                            if (std::holds_alternative<Fortran::parser::Name>(
+                                    structComp->base.u))
+                              isComponent = true;
+                          }
+                        },
+                        [&](const Fortran::parser::Name &name) {}},
+                    ompObject.u);
+
+                return isComponent;
+              };
+
+          // TODO: Currently, it appears there's missing symbol information
+          // and bounds information for allocatables and pointers inside
+          // of derived types. The latter needs some additional support
+          // added to the bounds generation whereas the former appears
+          // that it could be a problem when referring to pointer members
+          // via an OpenMP map clause, for the moment we do not handle
+          // these cases and must emit an error.
+          if (checkIfStructComponent(ompObject) &&
+              Fortran::semantics::IsAllocatableOrPointer(
+                  *getOmpObjectSymbol(ompObject)))
+            TODO(currentLocation,
+                 "pointer members of derived types are currently unmapped");
+
+          if (Fortran::semantics::IsAllocatableOrPointer(
+                  *getOmpObjectSymbol(ompObject))) {
+            // We mimic what will eventually be a structure containing a
+            // pointer mapping for allocatables/pointers/target e.g.:
+            //
+            // !$omp target map(from:in, in%map_ptr)
----------------
agozillon wrote:

Sorry, some of my other example points might have been made without reading this! Too used to phabricator grouping up comments before submitting them all at once, need to manually do that now.

I think I understand what you mean, and in the case of allocatable I believe that's correct, perhaps in all cases it is, would it be correct in the example I provided in the comment I provided below (pointer remap on device)? or would this be a case where a tofrom mapping for the descriptor would make sense (the example is a slightly simplified test case we have in an old bug report, so perhaps it's invalid OpenMP)? That's the only case where I think having some kind of from mapping for the descriptor would make sense, and perhaps I'm completely wrong. 

https://github.com/llvm/llvm-project/pull/68600