[flang] Make adapt.valuebyref attribute work again (#73658)

This got "lost" in the HLFIR transformation. This patch applies the old
attribute to the AssociateOp that needs it, and forwards it to the
AllocaOp that is generated when lowering to FIR.

Author: Leporacanthicus

flang/include/flang/Lower/ConvertExpr.h

@@ -225,15 +225,6 @@ mlir::Value createSubroutineCall(AbstractConverter &converter,
                                  SymMap &symMap, StatementContext &stmtCtx,
                                  bool isUserDefAssignment);
 
-// Attribute for an alloca that is a trivial adaptor for converting a value to
-// pass-by-ref semantics for a VALUE parameter. The optimizer may be able to
-// eliminate these.
-inline mlir::NamedAttribute getAdaptToByRefAttr(fir::FirOpBuilder &builder) {
-  return {mlir::StringAttr::get(builder.getContext(),
-                                fir::getAdaptToByRefAttrName()),
-          builder.getUnitAttr()};
-}
-
 mlir::Value addCrayPointerInst(mlir::Location loc, fir::FirOpBuilder &builder,
                                mlir::Value ptrVal, mlir::Type ptrTy,
                                mlir::Type pteTy);

flang/include/flang/Optimizer/Builder/HLFIRTools.h

@@ -239,11 +239,11 @@ fir::FortranVariableOpInterface genDeclare(mlir::Location loc,
 /// Generate an hlfir.associate to build a variable from an expression value.
 /// The type of the variable must be provided so that scalar logicals are
 /// properly typed when placed in memory.
-hlfir::AssociateOp genAssociateExpr(mlir::Location loc,
-                                    fir::FirOpBuilder &builder,
-                                    hlfir::Entity value,
-                                    mlir::Type variableType,
-                                    llvm::StringRef name);
+hlfir::AssociateOp
+genAssociateExpr(mlir::Location loc, fir::FirOpBuilder &builder,
+                 hlfir::Entity value, mlir::Type variableType,
+                 llvm::StringRef name,
+                 std::optional<mlir::NamedAttribute> attr = std::nullopt);
 
 /// Get the raw address of a variable (simple fir.ref/fir.ptr, or fir.heap
 /// value). The returned value should be used with care, it does not contain any

flang/include/flang/Optimizer/Dialect/FIROps.h

@@ -38,10 +38,6 @@ mlir::ParseResult parseSelector(mlir::OpAsmParser &parser,
                                 mlir::OpAsmParser::UnresolvedOperand &selector,
                                 mlir::Type &type);
 
-static constexpr llvm::StringRef getAdaptToByRefAttrName() {
-  return "adapt.valuebyref";
-}
-
 static constexpr llvm::StringRef getNormalizedLowerBoundAttrName() {
   return "normalized.lb";
 }

flang/include/flang/Optimizer/Dialect/FIROpsSupport.h

@@ -141,6 +141,22 @@ inline std::optional<std::int64_t> getIntIfConstant(mlir::Value value) {
   return {};
 }
 
+static constexpr llvm::StringRef getAdaptToByRefAttrName() {
+  return "adapt.valuebyref";
+}
+
+// Attribute for an alloca that is a trivial adaptor for converting a value to
+// pass-by-ref semantics for a VALUE parameter. The optimizer may be able to
+// eliminate these.
+// Template is used to avoid compiler errors in places that don't include
+// FIRBuilder.h
+template <typename Builder>
+inline mlir::NamedAttribute getAdaptToByRefAttr(Builder &builder) {
+  return {mlir::StringAttr::get(builder.getContext(),
+                                fir::getAdaptToByRefAttrName()),
+          builder.getUnitAttr()};
+}
+
 } // namespace fir
 
 #endif // FORTRAN_OPTIMIZER_DIALECT_FIROPSSUPPORT_H

flang/include/flang/Optimizer/HLFIR/HLFIROps.td

@@ -660,7 +660,7 @@ def hlfir_AssociateOp : hlfir_Op<"associate", [AttrSizedOperandSegments,
     AnyFortranValue:$source,
     Optional<AnyShapeOrShiftType>:$shape,
     Variadic<AnyIntegerType>:$typeparams,
-    Builtin_StringAttr:$uniq_name,
+    OptionalAttr<Builtin_StringAttr>:$uniq_name,
     OptionalAttr<fir_FortranVariableFlagsAttr>:$fortran_attrs
   );
 
@@ -672,9 +672,13 @@ def hlfir_AssociateOp : hlfir_Op<"associate", [AttrSizedOperandSegments,
   }];
 
   let builders = [
-    OpBuilder<(ins "mlir::Value":$source, "llvm::StringRef":$uniq_name,
+    OpBuilder<(ins "mlir::Value":$source, CArg<"llvm::StringRef", "{}">:$uniq_name,
       CArg<"mlir::Value", "{}">:$shape, CArg<"mlir::ValueRange", "{}">:$typeparams,
-      CArg<"fir::FortranVariableFlagsAttr", "{}">:$fortran_attrs)>];
+      CArg<"fir::FortranVariableFlagsAttr", "{}">:$fortran_attrs)>,
+    OpBuilder<(ins "mlir::Value":$memref, CArg<"mlir::Value", "{}">:$shape,
+      CArg<"mlir::ValueRange", "{}">:$typeparams, 
+      CArg<"fir::FortranVariableFlagsAttr", "{}">:$fortran_attrs,
+      CArg<"llvm::ArrayRef<mlir::NamedAttribute>", "{}">:$attributes)>];
 
   let extraClassDeclaration = [{
     /// Override FortranVariableInterface default implementation

flang/lib/Lower/Bridge.cpp

@@ -2083,10 +2083,10 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     assert(sym && "There must be a symbol to bind");
     mlir::Type toTy = genType(*sym);
     // FIXME: this should be a "per iteration" temporary.
-    mlir::Value tmp = builder->createTemporary(
-        loc, toTy, toStringRef(sym->name()),
-        llvm::ArrayRef<mlir::NamedAttribute>{
-            Fortran::lower::getAdaptToByRefAttr(*builder)});
+    mlir::Value tmp =
+        builder->createTemporary(loc, toTy, toStringRef(sym->name()),
+                                 llvm::ArrayRef<mlir::NamedAttribute>{
+                                     fir::getAdaptToByRefAttr(*builder)});
     mlir::Value cast = builder->createConvert(loc, toTy, inducVar);
     builder->create<fir::StoreOp>(loc, cast, tmp);
     addSymbol(*sym, tmp, /*force=*/true);

flang/lib/Lower/ConvertCall.cpp

@@ -12,6 +12,7 @@
 
 #include "flang/Lower/ConvertCall.h"
 #include "flang/Lower/Allocatable.h"
+#include "flang/Lower/ConvertExpr.h"
 #include "flang/Lower/ConvertExprToHLFIR.h"
 #include "flang/Lower/ConvertVariable.h"
 #include "flang/Lower/CustomIntrinsicCall.h"
@@ -958,8 +959,9 @@ static PreparedDummyArgument preparePresentUserCallActualArgument(
       // Make a copy in a temporary.
       auto copy = builder.create<hlfir::AsExprOp>(loc, entity);
       mlir::Type storageType = entity.getType();
+      mlir::NamedAttribute byRefAttr = fir::getAdaptToByRefAttr(builder);
       hlfir::AssociateOp associate = hlfir::genAssociateExpr(
-          loc, builder, hlfir::Entity{copy}, storageType, "adapt.valuebyref");
+          loc, builder, hlfir::Entity{copy}, storageType, "", byRefAttr);
       entity = hlfir::Entity{associate.getBase()};
       // Register the temporary destruction after the call.
       preparedDummy.pushExprAssociateCleanUp(associate);
@@ -986,8 +988,9 @@ static PreparedDummyArgument preparePresentUserCallActualArgument(
     // The actual is an expression value, place it into a temporary
     // and register the temporary destruction after the call.
     mlir::Type storageType = converter.genType(expr);
+    mlir::NamedAttribute byRefAttr = fir::getAdaptToByRefAttr(builder);
     hlfir::AssociateOp associate = hlfir::genAssociateExpr(
-        loc, builder, entity, storageType, "adapt.valuebyref");
+        loc, builder, entity, storageType, "", byRefAttr);
     entity = hlfir::Entity{associate.getBase()};
     preparedDummy.pushExprAssociateCleanUp(associate);
     if (mustSetDynamicTypeToDummyType) {
@@ -1395,8 +1398,9 @@ static std::optional<hlfir::EntityWithAttributes> genCustomIntrinsicRefCore(
     CallContext &callContext) {
   auto &builder = callContext.getBuilder();
   const auto &loc = callContext.loc;
-  assert(intrinsic && Fortran::lower::intrinsicRequiresCustomOptionalHandling(
-                          callContext.procRef, *intrinsic, callContext.converter));
+  assert(intrinsic &&
+         Fortran::lower::intrinsicRequiresCustomOptionalHandling(
+             callContext.procRef, *intrinsic, callContext.converter));
 
   // helper to get a particular prepared argument
   auto getArgument = [&](std::size_t i, bool loadArg) -> fir::ExtendedValue {

flang/lib/Lower/ConvertExpr.cpp

@@ -358,8 +358,7 @@ placeScalarValueInMemory(fir::FirOpBuilder &builder, mlir::Location loc,
   mlir::Value val = builder.createConvert(loc, storageType, valBase);
   mlir::Value temp = builder.createTemporary(
       loc, storageType,
-      llvm::ArrayRef<mlir::NamedAttribute>{
-          Fortran::lower::getAdaptToByRefAttr(builder)});
+      llvm::ArrayRef<mlir::NamedAttribute>{fir::getAdaptToByRefAttr(builder)});
   builder.create<fir::StoreOp>(loc, val, temp);
   return fir::substBase(exv, temp);
 }
@@ -2401,19 +2400,18 @@ class ScalarExprLowering {
       mlir::Value len = charBox->getLen();
       mlir::Value zero = builder.createIntegerConstant(loc, len.getType(), 0);
       len = builder.create<mlir::arith::SelectOp>(loc, isPresent, len, zero);
-      mlir::Value temp = builder.createTemporary(
-          loc, type, /*name=*/{},
-          /*shape=*/{}, mlir::ValueRange{len},
-          llvm::ArrayRef<mlir::NamedAttribute>{
-              Fortran::lower::getAdaptToByRefAttr(builder)});
+      mlir::Value temp =
+          builder.createTemporary(loc, type, /*name=*/{},
+                                  /*shape=*/{}, mlir::ValueRange{len},
+                                  llvm::ArrayRef<mlir::NamedAttribute>{
+                                      fir::getAdaptToByRefAttr(builder)});
       return fir::CharBoxValue{temp, len};
     }
     assert((fir::isa_trivial(type) || type.isa<fir::RecordType>()) &&
            "must be simple scalar");
-    return builder.createTemporary(
-        loc, type,
-        llvm::ArrayRef<mlir::NamedAttribute>{
-            Fortran::lower::getAdaptToByRefAttr(builder)});
+    return builder.createTemporary(loc, type,
+                                   llvm::ArrayRef<mlir::NamedAttribute>{
+                                       fir::getAdaptToByRefAttr(builder)});
   }
 
   template <typename A>
@@ -4752,10 +4750,10 @@ class ArrayExprLowering {
         } else {
           // Store scalar value in a temp to fulfill VALUE attribute.
           mlir::Value val = fir::getBase(asScalar(*expr));
-          mlir::Value temp = builder.createTemporary(
-              loc, val.getType(),
-              llvm::ArrayRef<mlir::NamedAttribute>{
-                  Fortran::lower::getAdaptToByRefAttr(builder)});
+          mlir::Value temp =
+              builder.createTemporary(loc, val.getType(),
+                                      llvm::ArrayRef<mlir::NamedAttribute>{
+                                          fir::getAdaptToByRefAttr(builder)});
           builder.create<fir::StoreOp>(loc, val, temp);
           operands.emplace_back(
               [=](IterSpace iters) -> ExtValue { return temp; });
@@ -5843,10 +5841,10 @@ class ArrayExprLowering {
           base = builder.create<fir::ArrayFetchOp>(
               loc, eleTy, arrLd, iters.iterVec(), arrLdTypeParams);
         }
-        mlir::Value temp = builder.createTemporary(
-            loc, base.getType(),
-            llvm::ArrayRef<mlir::NamedAttribute>{
-                Fortran::lower::getAdaptToByRefAttr(builder)});
+        mlir::Value temp =
+            builder.createTemporary(loc, base.getType(),
+                                    llvm::ArrayRef<mlir::NamedAttribute>{
+                                        fir::getAdaptToByRefAttr(builder)});
         builder.create<fir::StoreOp>(loc, base, temp);
         return fir::factory::arraySectionElementToExtendedValue(
             builder, loc, extMemref, temp, slice);

flang/lib/Lower/OpenMP.cpp

@@ -2104,7 +2104,7 @@ createAndSetPrivatizedLoopVar(Fortran::lower::AbstractConverter &converter,
       loc, tempTy, /*pinned=*/true, /*lengthParams=*/mlir::ValueRange{},
       /*shapeParams*/ mlir::ValueRange{},
       llvm::ArrayRef<mlir::NamedAttribute>{
-          Fortran::lower::getAdaptToByRefAttr(firOpBuilder)});
+          fir::getAdaptToByRefAttr(firOpBuilder)});
   converter.bindSymbol(*sym, temp);
   firOpBuilder.restoreInsertionPoint(insPt);
   mlir::Value cvtVal = firOpBuilder.createConvert(loc, tempTy, indexVal);

flang/lib/Optimizer/Builder/Character.cpp

@@ -14,6 +14,7 @@
 #include "flang/Optimizer/Builder/DoLoopHelper.h"
 #include "flang/Optimizer/Builder/FIRBuilder.h"
 #include "flang/Optimizer/Builder/Todo.h"
+#include "flang/Optimizer/Dialect/FIROpsSupport.h"
 #include "llvm/Support/Debug.h"
 #include <optional>