[flang-commits] [flang] [flang][mlir] Add flang to mlir lowering for groupprivate (PR #180934)

[Sergio Afonso via flang-commits]

================
@@ -783,6 +783,115 @@ static void threadPrivatizeVars(lower::AbstractConverter &converter,
   }
 }
 
+// Translate a semantics-layer device_type to the MLIR enum used by
+// omp.groupprivate.
+static mlir::omp::DeclareTargetDeviceType
+toMLIRDeclareTargetDeviceType(Fortran::common::OmpDeviceType deviceType) {
+  switch (deviceType) {
+  case Fortran::common::OmpDeviceType::Any:
+    return mlir::omp::DeclareTargetDeviceType::any;
+  case Fortran::common::OmpDeviceType::Host:
+    return mlir::omp::DeclareTargetDeviceType::host;
+  case Fortran::common::OmpDeviceType::Nohost:
+    return mlir::omp::DeclareTargetDeviceType::nohost;
+  }
+  llvm_unreachable("invalid OmpDeviceType");
+}
+
+static void groupprivatizeVars(lower::AbstractConverter &converter,
+                               lower::pft::Evaluation &eval) {
+  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
+  mlir::Location currentLocation = converter.getCurrentLocation();
+  mlir::OpBuilder::InsertionGuard guard(firOpBuilder);
+  firOpBuilder.setInsertionPointToStart(firOpBuilder.getAllocaBlock());
+
+  auto module = converter.getModuleOp();
+
+  // Create a groupprivate operation for the symbol.
+  auto genGroupprivateOp = [&](const semantics::Symbol &sym) -> mlir::Value {
+    std::string globalName = converter.mangleName(sym);
+    fir::GlobalOp global = module.lookupSymbol<fir::GlobalOp>(globalName);
+    if (!global) {
+      return mlir::Value();
+    }
+
+    // The device_type modifier was recorded on the symbol during semantic
+    // analysis.
+    mlir::omp::DeclareTargetDeviceType deviceTypeEnum =
+        mlir::omp::DeclareTargetDeviceType::any;
+    Fortran::common::visit(
+        [&](auto &&details) {
+          using TypeD = llvm::remove_cvref_t<decltype(details)>;
+          if constexpr (std::is_base_of_v<semantics::WithOmpDeclarative,
+                                          TypeD>) {
+            if (auto dt = details.ompGroupprivateDeviceType())
+              deviceTypeEnum = toMLIRDeclareTargetDeviceType(*dt);
+          }
+        },
+        sym.GetUltimate().details());
+    mlir::omp::DeclareTargetDeviceTypeAttr deviceTypeAttr =
+        mlir::omp::DeclareTargetDeviceTypeAttr::get(firOpBuilder.getContext(),
+                                                    deviceTypeEnum);
+
+    // omp.groupprivate takes a flat symbol reference and returns
+    // the address of the per-team copy of the global variable.
----------------
skatrak wrote:

```suggestion
    // the address of the per-contention group copy of the global variable.
```

https://github.com/llvm/llvm-project/pull/180934