[mlir][OpenACC] indicate if destruction is needed in generatePrivateInit

Author: jeanPerier

flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h

@@ -57,8 +57,8 @@ struct OpenACCMappableModel
                                   mlir::Location loc,
                                   mlir::TypedValue<mlir::acc::MappableType> var,
                                   llvm::StringRef varName,
-                                  mlir::ValueRange extents,
-                                  mlir::Value initVal) const;
+                                  mlir::ValueRange extents, mlir::Value initVal,
+                                  bool &needsDestroy) const;
 };
 
 } // namespace fir::acc

flang/lib/Lower/OpenACC.cpp

@@ -978,15 +978,18 @@ static RecipeOp genRecipeOp(
   auto mappableTy = mlir::dyn_cast<mlir::acc::MappableType>(ty);
   assert(mappableTy &&
          "Expected that all variable types are considered mappable");
+  bool needsDestroy = false;
   auto retVal = mappableTy.generatePrivateInit(
       builder, loc,
       mlir::cast<mlir::TypedValue<mlir::acc::MappableType>>(
           initBlock->getArgument(0)),
       initName,
       initBlock->getArguments().take_back(initBlock->getArguments().size() - 1),
-      initValue);
+      initValue, needsDestroy);
   mlir::acc::YieldOp::create(builder, loc,
                              retVal ? retVal : initBlock->getArgument(0));
+  // TODO: insert destruction when needed.
+  (void)needsDestroy;
   return recipe;
 }
 

flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp

@@ -548,7 +548,8 @@ template <typename Ty>
 mlir::Value OpenACCMappableModel<Ty>::generatePrivateInit(
     mlir::Type type, mlir::OpBuilder &builder, mlir::Location loc,
     mlir::TypedValue<mlir::acc::MappableType> var, llvm::StringRef varName,
-    mlir::ValueRange extents, mlir::Value initVal) const {
+    mlir::ValueRange extents, mlir::Value initVal, bool &needsDestroy) const {
+  needsDestroy = false;
   mlir::Value retVal;
   mlir::Type unwrappedTy = fir::unwrapRefType(type);
   mlir::ModuleOp mod = builder.getInsertionBlock()
@@ -615,9 +616,11 @@ mlir::Value OpenACCMappableModel<Ty>::generatePrivateInit(
       mlir::Value firClass =
           fir::EmboxOp::create(builder, loc, boxTy, allocatedScalar);
       fir::StoreOp::create(builder, loc, firClass, retVal);
+      needsDestroy = true;
     } else if (mlir::isa<fir::SequenceType>(innerTy)) {
       hlfir::Entity source = hlfir::Entity{var};
-      auto [temp, cleanup] = hlfir::createTempFromMold(loc, firBuilder, source);
+      auto [temp, cleanupFlag] =
+          hlfir::createTempFromMold(loc, firBuilder, source);
       if (fir::isa_ref_type(type)) {
         // When the temp is created - it is not a reference - thus we can
         // end up with a type inconsistency. Therefore ensure storage is created
@@ -636,6 +639,9 @@ mlir::Value OpenACCMappableModel<Ty>::generatePrivateInit(
       } else {
         retVal = temp;
       }
+      // If heap was allocated, a destroy is required later.
+      if (cleanupFlag)
+        needsDestroy = true;
     } else {
       TODO(loc, "Unsupported boxed type for OpenACC private-like recipe");
     }
@@ -667,23 +673,23 @@ template mlir::Value
 OpenACCMappableModel<fir::BaseBoxType>::generatePrivateInit(
     mlir::Type type, mlir::OpBuilder &builder, mlir::Location loc,
     mlir::TypedValue<mlir::acc::MappableType> var, llvm::StringRef varName,
-    mlir::ValueRange extents, mlir::Value initVal) const;
+    mlir::ValueRange extents, mlir::Value initVal, bool &needsDestroy) const;
 
 template mlir::Value
 OpenACCMappableModel<fir::ReferenceType>::generatePrivateInit(
     mlir::Type type, mlir::OpBuilder &builder, mlir::Location loc,
     mlir::TypedValue<mlir::acc::MappableType> var, llvm::StringRef varName,
-    mlir::ValueRange extents, mlir::Value initVal) const;
+    mlir::ValueRange extents, mlir::Value initVal, bool &needsDestroy) const;
 
 template mlir::Value OpenACCMappableModel<fir::HeapType>::generatePrivateInit(
     mlir::Type type, mlir::OpBuilder &builder, mlir::Location loc,
     mlir::TypedValue<mlir::acc::MappableType> var, llvm::StringRef varName,
-    mlir::ValueRange extents, mlir::Value initVal) const;
+    mlir::ValueRange extents, mlir::Value initVal, bool &needsDestroy) const;
 
 template mlir::Value
 OpenACCMappableModel<fir::PointerType>::generatePrivateInit(
     mlir::Type type, mlir::OpBuilder &builder, mlir::Location loc,
     mlir::TypedValue<mlir::acc::MappableType> var, llvm::StringRef varName,
-    mlir::ValueRange extents, mlir::Value initVal) const;
+    mlir::ValueRange extents, mlir::Value initVal, bool &needsDestroy) const;
 
 } // namespace fir::acc

mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td

@@ -274,6 +274,12 @@ def OpenACC_MappableTypeInterface : TypeInterface<"MappableType"> {
         The `initVal` can be empty - it is primarily needed for reductions
         to ensure the variable is also initialized with appropriate value.
 
+        The `needsDestroy` out-parameter is set by implementations to indicate
+        that destruction code must be generated after the returned private
+        variable usages, typically in the destroy region of recipe operations
+        (for example, when heap allocations or temporaries requiring cleanup
+        are created during initialization).
+
         If the return value is empty, it means that recipe body was not
         successfully generated.
       }],
@@ -284,7 +290,8 @@ def OpenACC_MappableTypeInterface : TypeInterface<"MappableType"> {
                     "::mlir::TypedValue<::mlir::acc::MappableType>":$var,
                     "::llvm::StringRef":$varName,
                     "::mlir::ValueRange":$extents,
-                    "::mlir::Value":$initVal),
+                    "::mlir::Value":$initVal,
+                    "bool &":$needsDestroy),
       /*methodBody=*/"",
       /*defaultImplementation=*/[{
         return {};