[llvm-branch-commits] [Flang][OpenMP] Derived type explicit allocatable member mapping (PR #111192)

[Kareem Ergawy via llvm-branch-commits]

================
@@ -58,21 +67,62 @@ class MapInfoFinalizationPass
            /*corresponding local alloca=*/fir::AllocaOp>
       localBoxAllocas;
 
-  void genDescriptorMemberMaps(mlir::omp::MapInfoOp op,
-                               fir::FirOpBuilder &builder,
-                               mlir::Operation *target) {
-    mlir::Location loc = op.getLoc();
-    mlir::Value descriptor = op.getVarPtr();
+  /// getMemberUserList gathers all users of a particular MapInfoOp that are
+  /// other MapInfoOp's and places them into the mapMemberUsers list, which
+  /// records the map that the current argument MapInfoOp "op" is part of
+  /// alongside the placement of "op" in the recorded users members list. The
+  /// intent of the generated list is to find all MapInfoOp's that may be
+  /// considered parents of the passed in "op" and in which it shows up in the
+  /// member list, alongside collecting the placement information of "op" in its
+  /// parents member list.
+  void
+  getMemberUserList(mlir::omp::MapInfoOp op,
+                    llvm::SmallVectorImpl<ParentAndPlacement> &mapMemberUsers) {
----------------
ergawy wrote:

In what scenario will `mapMemberUsers` end up with more than one element?

As a test (just to learn more about the changes), I modified this function as follows and none of the tests failed:
```diff
--- a/flang/lib/Optimizer/OpenMP/MapInfoFinalization.cpp
+++ b/flang/lib/Optimizer/OpenMP/MapInfoFinalization.cpp
@@ -81,8 +81,10 @@ class MapInfoFinalizationPass
     for (auto *users : op->getUsers())
       if (auto map = mlir::dyn_cast_if_present<mlir::omp::MapInfoOp>(users))
         for (auto [i, mapMember] : llvm::enumerate(map.getMembers()))
-          if (mapMember.getDefiningOp() == op)
+          if (mapMember.getDefiningOp() == op) {
             mapMemberUsers.push_back({map, i});
+            break;
+          }
   }
 
   llvm::SmallVector<int64_t>
```

Also, `mapMemberUsers[0]` is the only element used below (in `genDescriptorMemberMaps`).

https://github.com/llvm/llvm-project/pull/111192