[flang][acc] Ensure fir.class is handled in type categorization

fir.class is treated similarly as fir.box - but it has one key
distinction which is that it doesn't hold an element type. Thus
the categorization logic was mishandling this case for this reason
(and also the fact that it assumed that a base object is always a
fir.ref).

This PR improves this handling and adds appropriate test exercising
both a class and a class field to ensure categorization works.

Author: Razvan Lupusoru

flang/lib/Optimizer/OpenACC/FIROpenACCTypeInterfaces.cpp

@@ -320,8 +320,13 @@ template <>
 mlir::acc::VariableTypeCategory
 OpenACCMappableModel<fir::BaseBoxType>::getTypeCategory(mlir::Type type,
                                                         mlir::Value var) const {
+  // Class-type does not behave like a normal box because it does not hold an
+  // element type. Thus special handle it here.
+  if (mlir::isa<fir::ClassType>(type))
+    return mlir::acc::VariableTypeCategory::composite;
 
   mlir::Type eleTy = fir::dyn_cast_ptrOrBoxEleTy(type);
+  assert(eleTy && "expect to be able to unwrap the element type");
 
   // If the type enclosed by the box is a mappable type, then have it
   // provide the type category.
@@ -346,7 +351,7 @@ OpenACCMappableModel<fir::BaseBoxType>::getTypeCategory(mlir::Type type,
   return mlir::acc::VariableTypeCategory::nonscalar;
 }
 
-static mlir::TypedValue<mlir::acc::PointerLikeType>
+static mlir::Value
 getBaseRef(mlir::TypedValue<mlir::acc::PointerLikeType> varPtr) {
   // If there is no defining op - the unwrapped reference is the base one.
   mlir::Operation *op = varPtr.getDefiningOp();
@@ -372,7 +377,7 @@ getBaseRef(mlir::TypedValue<mlir::acc::PointerLikeType> varPtr) {
           })
           .Default([&](mlir::Operation *) { return varPtr; });
 
-  return mlir::cast<mlir::TypedValue<mlir::acc::PointerLikeType>>(baseRef);
+  return baseRef;
 }
 
 static mlir::acc::VariableTypeCategory
@@ -384,10 +389,17 @@ categorizePointee(mlir::Type pointer,
   // value would both be represented as !fir.ref<f32>. We do not want to treat
   // such a reference as a scalar. Thus unwrap interior pointer calculations.
   auto baseRef = getBaseRef(varPtr);
-  mlir::Type eleTy = baseRef.getType().getElementType();
 
-  if (auto mappableTy = mlir::dyn_cast<mlir::acc::MappableType>(eleTy))
-    return mappableTy.getTypeCategory(varPtr);
+  if (auto mappableTy =
+          mlir::dyn_cast<mlir::acc::MappableType>(baseRef.getType()))
+    return mappableTy.getTypeCategory(baseRef);
+
+  // It must be a pointer-like type since it is not a MappableType.
+  auto ptrLikeTy = mlir::cast<mlir::acc::PointerLikeType>(baseRef.getType());
+  mlir::Type eleTy = ptrLikeTy.getElementType();
+
+  if (auto mappableEleTy = mlir::dyn_cast<mlir::acc::MappableType>(eleTy))
+    return mappableEleTy.getTypeCategory(varPtr);
 
   if (isScalarLike(eleTy))
     return mlir::acc::VariableTypeCategory::scalar;

flang/test/Fir/OpenACC/openacc-type-categories-class.f90

@@ -0,0 +1,18 @@
+module mm
+  type, public :: polyty
+    real :: field
+  end type
+contains
+  subroutine init(this)
+    class(polyty), intent(inout) :: this
+    !$acc enter data copyin(this, this%field)
+  end subroutine
+end module
+
+! RUN: bbc -fopenacc -emit-hlfir %s -o - | fir-opt -pass-pipeline='builtin.module(test-fir-openacc-interfaces)' --mlir-disable-threading 2>&1 | FileCheck %s
+! CHECK: Visiting: {{.*}} acc.copyin {{.*}} {name = "this", structured = false}
+! CHECK: Mappable: !fir.class<!fir.type<_QMmmTpolyty{field:f32}>>
+! CHECK: Type category: composite
+! CHECK: Visiting: {{.*}} acc.copyin {{.*}} {name = "this%field", structured = false}
+! CHECK: Pointer-like: !fir.ref<f32>
+! CHECK: Type category: composite

flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp

@@ -6,12 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/Dialect/OpenACC/OpenACC.h"
 #include "mlir/IR/Builders.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Support/LLVM.h"
+#include "flang/Optimizer/Dialect/FIRDialect.h"
+#include "flang/Optimizer/HLFIR/HLFIRDialect.h"
 #include "flang/Optimizer/Support/DataLayout.h"
+#include "mlir/Dialect/DLTI/DLTI.h"
 
 using namespace mlir;
 
@@ -25,6 +29,11 @@ struct TestFIROpenACCInterfaces
   StringRef getDescription() const final {
     return "Test FIR implementation of the OpenACC interfaces.";
   }
+  void getDependentDialects(::mlir::DialectRegistry &registry) const override {
+    registry.insert<fir::FIROpsDialect, hlfir::hlfirDialect,
+        mlir::arith::ArithDialect, mlir::acc::OpenACCDialect,
+        mlir::DLTIDialect>();
+  }
   void runOnOperation() override {
     mlir::ModuleOp mod = getOperation();
     auto datalayout =