[flang] Fix fir.dispatch_table generation with derived-type parameter with kind type parameter

[clementval]

Summary

When generating the fir.dispatch_table operation, the name of the parent
derived-type needs to be mangled. For this the type instantiation
DerivedTypeSpec needs to be retrieved to have the correct kind type parameters.

[clementval]

@klausler Is it ok to modify FindParentComponent like this or is there a better way to retrieve the parent type instantiation DerivedTypeSpec from a DerivedTypeSpec?

[jeanPerier]

flang/lib/Evaluate/type.cpp

213–214

Looking at the comment same as typeSymbol_.scope() unless PDT here: https://github.com/llvm/llvm-project/blob/main/flang/include/flang/Semantics/type.h#L310, I think using derived.scope() should be enough, but I did not check that this comment was honored.

[klausler]

flang/lib/Evaluate/type.cpp

213–214

If "derived" is not a PDT instantiation the two scopes should be the same. If it is a PDT instantiation, "derived" will have its own scope for all of the object and pointer components, including the parent; generics and bindings are still found in the original scope.

In any case, yes, "derived.scope()" should not be null outside error recovery situations.

Please always use braces around "if" statement bodies here, thanks.

[PeteSteinfeld]

Aside from Peter's comment on adding braces, all builds and tests correctly and looks good.

[clementval]

clang-format + if braces

flang/lib/Evaluate/type.cpp

const semantics::DerivedTypeSpec *GetDerivedTypeSpec(const DynamicType &type) {
   } else {
     return nullptr;
   }
 }
 
 static const semantics::Symbol *FindParentComponent(
     const semantics::DerivedTypeSpec &derived) {
   const semantics::Symbol &typeSymbol{derived.typeSymbol()};
-  if (const semantics::Scope * scope{typeSymbol.scope()}) {
+  const semantics::Scope *scope{derived.scope()};
+  if (!scope) {
+    scope = typeSymbol.scope();
+  }
+  if (scope) {
     const auto &dtDetails{typeSymbol.get<semantics::DerivedTypeDetails>()};
     if (auto extends{dtDetails.GetParentComponentName()}) {
       if (auto iter{scope->find(*extends)}; iter != scope->cend()) {
         if (const Symbol & symbol{*iter->second};
             symbol.test(Symbol::Flag::ParentComp)) {
           return &symbol;
         }
       }

flang/test/Fir/dispatch.f90

module dispatch1
   end type
 
   type, extends(a1) :: a2
     integer b
   contains
     procedure :: a1_proc => a2_proc
   end type
 
+  type ty_kind(i, j)
+    integer, kind :: i, j
+    integer :: a(i)
+  end Type
+
+  type, extends(ty_kind) :: ty_kind_ex
+    integer :: b(j)
+  end type
+  type(ty_kind(10,20)) :: tk1
+  type(ty_kind_ex(10,20)) :: tke1
 contains
 
   subroutine display1_p1(this)
     class(p1) :: this
     print*,'call display1_p1'
   end subroutine
 
   subroutine display2_p1(this)

 ! CHECK-LABEL: _QMdispatch1Pno_pass_array
 ! CHECK-LABEL: _QMdispatch1Pno_pass_array_allocatable
 ! CHECK-LABEL: _QMdispatch1Pno_pass_array_pointer
 ! CHECK-LABEL: _QMdispatch1Pcall_a1_proc
 
 ! Check the layout of the binding table. This is easier to do in FIR than in 
 ! LLVM IR.
 
+! BT-LABEL: fir.dispatch_table @_QMdispatch1Tty_kindK10K20
+! BT-LABEL: fir.dispatch_table @_QMdispatch1Tty_kind_exK10K20 extends("_QMdispatch1Tty_kindK10K20")
+
 ! BT-LABEL: fir.dispatch_table @_QMdispatch1Tp1 {
 ! BT: fir.dt_entry "aproc", @_QMdispatch1Paproc
 ! BT: fir.dt_entry "display1", @_QMdispatch1Pdisplay1_p1
 ! BT: fir.dt_entry "display2", @_QMdispatch1Pdisplay2_p1
 ! BT: fir.dt_entry "get_value", @_QMdispatch1Pget_value_p1
 ! BT: fir.dt_entry "proc_nopass", @_QMdispatch1Pproc_nopass_p1
 ! BT: fir.dt_entry "proc_pass", @_QMdispatch1Pproc_pass_p1
 ! BT: fir.dt_entry "proc_with_values", @_QMdispatch1Pproc_p1