[flang] Do not pass derived type by descriptor when not needed

[jeanPerier]

Summary

A missing "!" in the call interface lowering caused all derived type
arguments without length parameters that require and explicit interface
to be passed via fir.box (runtime descriptor).

This was not the intent: there is no point passing a simple derived type
scalars or explicit shapes by descriptor just because they have an attribute
like TARGET. This would actually be problematic with existing code that is
not always 100% compliant: some code implicitly calls procedures with
TARGET dummy attributes (this is not something a compiler can enforce
if the call and procedure definition are not in the same file).

Add a Scope::IsDerivedTypeWithLengthParameter to avoid passing derived
types with only kind parameters by descriptor. There is no point, the
callee knows about the kind parameter values.

[clementval]

LGTM

flang/include/flang/Semantics/scope.h

bool IsSubmodule() const {
     return kind_ == Kind::Module && symbol_->get<ModuleDetails>().isSubmodule();
   }
   bool IsDerivedType() const { return kind_ == Kind::DerivedType; }
   bool IsStmtFunction() const;
   bool IsParameterizedDerivedType() const;
   bool IsParameterizedDerivedTypeInstantiation() const {
     return kind_ == Kind::DerivedType && !symbol_;
   }
+  /// Does this derived type have at least one kind parameter ?
   bool IsDerivedTypeWithKindParameter() const;
+  /// Does this derived type have at least one length parameter ?
+  bool IsDerivedTypeWithLengthParameter() const;
   Symbol *symbol() { return symbol_; }
   const Symbol *symbol() const { return symbol_; }
   SemanticsContext &context() const { return context_; }
 
   inline const Symbol *GetSymbol() const;
   const Scope *GetDerivedTypeParent() const;
   const Scope &GetDerivedTypeBase() const;
   inline std::optional<SourceName> GetName() const;

flang/lib/Lower/CallInterface.cpp

bool dummyRequiresBox(
     if ((obj.type.attrs() & shapeRequiringBox).any())
       // Need to pass shape/coshape info in fir.box.
       return true;
     if (obj.type.type().IsPolymorphic())
       // Need to pass dynamic type info in fir.box.
       return true;
     if (const Fortran::semantics::DerivedTypeSpec *derived =
             Fortran::evaluate::GetDerivedTypeSpec(obj.type.type()))
-      // Need to pass type parameters in fir.box if any.
-      return derived->parameters().empty();
+      if (const Fortran::semantics::Scope *scope = derived->scope())
+        // Need to pass length type parameters in fir.box if any.
+        return scope->IsDerivedTypeWithLengthParameter();
     return false;
   }
 
   mlir::Type
   translateDynamicType(const Fortran::evaluate::DynamicType &dynamicType) {
     Fortran::common::TypeCategory cat = dynamicType.category();
     // DERIVED
     if (cat == Fortran::common::TypeCategory::Derived) {

flang/lib/Semantics/scope.cpp

llvm::raw_ostream &operator<<(llvm::raw_ostream &os, const Scope &scope) {
   }
   return os;
 }
 
 bool Scope::IsStmtFunction() const {
   return symbol_ && symbol_->test(Symbol::Flag::StmtFunction);
 }
 
-bool Scope::IsParameterizedDerivedType() const {
-  if (!IsDerivedType()) {
+template <common::TypeParamAttr... ParamAttr> struct IsTypeParamHelper {
+  static_assert(sizeof...(ParamAttr) == 0, "must have one or zero template");
+  static bool IsParam(const Symbol &symbol) {
+    return symbol.has<TypeParamDetails>();
+  }
+};
+
+template <common::TypeParamAttr ParamAttr> struct IsTypeParamHelper<ParamAttr> {
+  static bool IsParam(const Symbol &symbol) {
+    if (const auto *typeParam{symbol.detailsIf<TypeParamDetails>()}) {
+      return typeParam->attr() == ParamAttr;
+    }
     return false;
   }
-  if (const Scope * parent{GetDerivedTypeParent()}) {
-    if (parent->IsParameterizedDerivedType()) {
+};
+
+template <common::TypeParamAttr... ParamAttr>
+static bool IsParameterizedDerivedTypeHelper(const Scope &scope) {
+  if (scope.IsDerivedType()) {
+    if (const Scope * parent{scope.GetDerivedTypeParent()}) {
+      if (IsParameterizedDerivedTypeHelper<ParamAttr...>(*parent)) {
         return true;
       }
     }
-  for (const auto &pair : symbols_) {
-    if (pair.second->has<TypeParamDetails>()) {
+    for (const auto &nameAndSymbolPair : scope) {
+      if (IsTypeParamHelper<ParamAttr...>::IsParam(*nameAndSymbolPair.second)) {
         return true;
       }
     }
-  return false;
   }
-
-bool Scope::IsDerivedTypeWithKindParameter() const {
-  if (!IsDerivedType()) {
-    return false;
-  }
-  if (const Scope * parent{GetDerivedTypeParent()}) {
-    if (parent->IsDerivedTypeWithKindParameter()) {
-      return true;
-    }
-  }
-  for (const auto &pair : symbols_) {
-    if (const auto *typeParam{pair.second->detailsIf<TypeParamDetails>()}) {
-      if (typeParam->attr() == common::TypeParamAttr::Kind) {
-        return true;
-      }
-    }
-  }
-  return false;
+
+bool Scope::IsParameterizedDerivedType() const {
+  return IsParameterizedDerivedTypeHelper<>(*this);
+bool Scope::IsDerivedTypeWithLengthParameter() const {
+  return IsParameterizedDerivedTypeHelper<common::TypeParamAttr::Len>(*this);
+bool Scope::IsDerivedTypeWithKindParameter() const {
+  return IsParameterizedDerivedTypeHelper<common::TypeParamAttr::Kind>(*this);
 }
 
 const DeclTypeSpec *Scope::FindInstantiatedDerivedType(
     const DerivedTypeSpec &spec, DeclTypeSpec::Category category) const {
   DeclTypeSpec type{category, spec};
   if (const auto *result{FindType(type)}) {
     return result;
   } else if (IsGlobal()) {

flang/test/Lower/default-initialization.f90

subroutine intent_out(x)
     ! CHECK: %[[xboxNone:.*]] = fir.convert %[[xbox]]
     ! CHECK: fir.call @_FortranAInitialize(%[[xboxNone]], %{{.*}}, %{{.*}}) : (!fir.box<none>, !fir.ref<i8>, i32) -> none
     type(t), intent(out) :: x
   end subroutine
 
   ! Test that optional intent(out) are default initialized only when
   ! present.
   ! CHECK-LABEL: func @_QMtest_dinitPintent_out_optional(
-  ! CHECK-SAME: %[[x:.*]]: !fir.box<!fir.type<_QMtest_dinitTt{i:i32}>> {fir.bindc_name = "x", fir.optional})
+  ! CHECK-SAME: %[[x:.*]]: !fir.ref<!fir.type<_QMtest_dinitTt{i:i32}>> {fir.bindc_name = "x", fir.optional})
   subroutine intent_out_optional(x)
-    ! CHECK: %[[isPresent:.*]] = fir.is_present %[[x]] : (!fir.box<!fir.type<_QMtest_dinitTt{i:i32}>>) -> i1
+    ! CHECK: %[[isPresent:.*]] = fir.is_present %[[x]] : (!fir.ref<!fir.type<_QMtest_dinitTt{i:i32}>>) -> i1
     ! CHECK: fir.if %[[isPresent]] {
-      ! CHECK: %[[xboxNone:.*]] = fir.convert %[[x]]
+      ! CHECK: %[[xbox:.*]] = fir.embox %[[x]] : (!fir.ref<!fir.type<_QMtest_dinitTt{i:i32}>>) -> !fir.box<!fir.type<_QMtest_dinitTt{i:i32}>>
+      ! CHECK: %[[xboxNone:.*]] = fir.convert %[[xbox]]
       ! CHECK: fir.call @_FortranAInitialize(%[[xboxNone]], %{{.*}}, %{{.*}}) : (!fir.box<none>, !fir.ref<i8>, i32) -> none
     ! CHECK: }
     type(t), intent(out), optional :: x
   end subroutine
 
   ! Test local equivalences where one entity has default initialization
   ! CHECK-LABEL: func @_QMtest_dinitPlocal_eq()
   subroutine local_eq()

flang/test/Lower/dummy-argument-derived.f90

+! Test lowering of derived type dummy arguments
+! RUN: bbc -emit-fir %s -o - | FileCheck %s
+module type_defs
+  type simple_type
+    integer :: i
+  end type
+  type with_kind(k)
+    integer, kind :: k
+    real(k) :: x
+  end type
+end module
+
+! -----------------------------------------------------------------------------
+!     Test passing of derived type arguments that do not require a
+!     fir.box (runtime descriptor).
+! -----------------------------------------------------------------------------
+
+! Test simple type scalar with no attribute.
+! CHECK-LABEL: func @_QPtest1(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.type<_QMtype_defsTsimple_type{i:i32}>> {fir.bindc_name = "a"}) {
+subroutine test1(a)
+  use type_defs
+  type(simple_type) :: a
+end subroutine
+
+! Test simple type explicit array with no attribute.
+! CHECK-LABEL: func @_QPtest2(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.array<100x!fir.type<_QMtype_defsTsimple_type{i:i32}>>> {fir.bindc_name = "a"}) {
+subroutine test2(a)
+  use type_defs
+  type(simple_type) :: a(100)
+end subroutine
+
+! Test simple type scalar with TARGET attribute.
+! CHECK-LABEL: func @_QPtest3(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.type<_QMtype_defsTsimple_type{i:i32}>> {fir.bindc_name = "a", fir.target}) {
+subroutine test3(a)
+  use type_defs
+  type(simple_type), target :: a
+end subroutine
+
+! Test simple type explicit array with TARGET attribute.
+! CHECK-LABEL: func @_QPtest4(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.array<100x!fir.type<_QMtype_defsTsimple_type{i:i32}>>> {fir.bindc_name = "a", fir.target}) {
+subroutine test4(a)
+  use type_defs
+  type(simple_type), target :: a(100)
+end subroutine
+
+! Test kind parametrized derived type scalar with no attribute.
+! CHECK-LABEL: func @_QPtest1k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.type<_QMtype_defsTwith_kindK4{x:f32}>> {fir.bindc_name = "a"}) {
+subroutine test1k(a)
+  use type_defs
+  type(with_kind(4)) :: a
+end subroutine
+
+! Test kind parametrized derived type explicit array with no attribute.
+! CHECK-LABEL: func @_QPtest2k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.array<100x!fir.type<_QMtype_defsTwith_kindK4{x:f32}>>> {fir.bindc_name = "a"}) {
+subroutine test2k(a)
+  use type_defs
+  type(with_kind(4)) :: a(100)
+end subroutine
+
+! Test kind parametrized derived type scalar with TARGET attribute.
+! CHECK-LABEL: func @_QPtest3k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.type<_QMtype_defsTwith_kindK4{x:f32}>> {fir.bindc_name = "a", fir.target}) {
+subroutine test3k(a)
+  use type_defs
+  type(with_kind(4)), target :: a
+end subroutine
+
+! Test kind parametrized derived type explicit array with TARGET attribute.
+! CHECK-LABEL: func @_QPtest4k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.ref<!fir.array<100x!fir.type<_QMtype_defsTwith_kindK4{x:f32}>>> {fir.bindc_name = "a", fir.target}) {
+subroutine test4k(a)
+  use type_defs
+  type(with_kind(4)), target :: a(100)
+end subroutine
+
+! -----------------------------------------------------------------------------
+!     Test passing of derived type arguments that require a fir.box (runtime descriptor).
+! -----------------------------------------------------------------------------
+
+! Test simple type assumed shape array with no attribute.
+! CHECK-LABEL: func @_QPtest5(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.box<!fir.array<?x!fir.type<_QMtype_defsTsimple_type{i:i32}>>> {fir.bindc_name = "a"}) {
+subroutine test5(a)
+  use type_defs
+  type(simple_type) :: a(:)
+end subroutine
+
+! Test simple type assumed shape array with TARGET attribute.
+! CHECK-LABEL: func @_QPtest6(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.box<!fir.array<?x!fir.type<_QMtype_defsTsimple_type{i:i32}>>> {fir.bindc_name = "a", fir.target}) {
+subroutine test6(a)
+  use type_defs
+  type(simple_type), target :: a(:)
+end subroutine
+
+! Test kind parametrized derived type assumed shape array with no attribute.
+! CHECK-LABEL: func @_QPtest5k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.box<!fir.array<?x!fir.type<_QMtype_defsTwith_kindK4{x:f32}>>> {fir.bindc_name = "a"}) {
+subroutine test5k(a)
+  use type_defs
+  type(with_kind(4)) :: a(:)
+end subroutine
+
+! Test kind parametrized derived type assumed shape array with TARGET attribute.
+! CHECK-LABEL: func @_QPtest6k(
+! CHECK-SAME:  %[[VAL_0:.*]]: !fir.box<!fir.array<?x!fir.type<_QMtype_defsTwith_kindK4{x:f32}>>> {fir.bindc_name = "a", fir.target}) {
+subroutine test6k(a)
+  use type_defs
+  type(with_kind(4)), target :: a(:)
+end subroutine