[flang] simplify derived type info table format

[jeanPerier]

Summary

• Replace class(*) member by a c_ptr member to avoid having to handle polymorphic components in the type info table generation. Polymorphic entity handling will require these very tables to be lowered properly. Note: keep the init as NullPointer/Designators. This is technically invalid Fortran, the init should have c_ptr type. But wrapping this in a C_LOC intrinsic call would make runtime generation and lowering more complex with no real benefits.

• ComponentIterator is crashing when used on the generated derived types in GetScope. This patch makes GetScope more robust, but it is not entirely clear to me why this is only happening with the generated derived types.

• The type of generated character globals was incorrect because Scope::FindType was matching character types with different length. Add a CharacterTypeSpec == operator to fix this.

[PeteSteinfeld]

All builds, tests, and looks good.

[klausler]

flang/include/flang/Semantics/tools.h

463

The "true" part of the conditional expression needs no DEREF protection.

[jeanPerier]

DEREF only the false part of introduced ternary.

flang/include/flang/Semantics/tools.h

public:
       void set_component(const Symbol &component) { component_ = &component; }
       bool visited() const { return visited_; }
       void set_visited(bool yes) { visited_ = yes; }
       bool descended() const { return descended_; }
       void set_descended(bool yes) { descended_ = yes; }
       name_iterator &nameIterator() { return nameIterator_; }
       name_iterator nameEnd() { return nameEnd_; }
       const Symbol &GetTypeSymbol() const { return derived_->typeSymbol(); }
-      const Scope &GetScope() const { return DEREF(derived_->scope()); }
+      const Scope &GetScope() const {
+        return derived_->scope() ? *derived_->scope()
+                                 : DEREF(GetTypeSymbol().scope());
+      }
       bool operator==(const ComponentPathNode &that) const {
         return &*derived_ == &*that.derived_ &&
             nameIterator_ == that.nameIterator_ &&
             component_ == that.component_;
       }
 
     private:
       common::Reference<const DerivedTypeSpec> derived_;

flang/include/flang/Semantics/type.h

 };
 
 class CharacterTypeSpec : public IntrinsicTypeSpec {
 public:
   CharacterTypeSpec(ParamValue &&length, KindExpr &&kind)
       : IntrinsicTypeSpec(TypeCategory::Character, std::move(kind)),
         length_{std::move(length)} {}
   const ParamValue &length() const { return length_; }
+  bool operator==(const CharacterTypeSpec &that) const {
+    return kind() == that.kind() && length_ == that.length_;
+  }
   std::string AsFortran() const;
 
 private:
   ParamValue length_;
   friend llvm::raw_ostream &operator<<(
       llvm::raw_ostream &os, const CharacterTypeSpec &x);
 };
 

flang/module/__fortran_type_info.f90

type :: Component ! data components, incl. object pointers
     integer(1) :: kind
     integer(1) :: rank
     integer(1) :: __padding0(4)
     integer(kind=int64) :: offset
     type(Value) :: characterLen ! for category == Character
     type(DerivedType), pointer :: derived ! for category == Derived
     type(Value), pointer :: lenValue(:) ! (SIZE(derived%lenParameterKind))
     type(Value), pointer :: bounds(:, :) ! (2, rank): lower, upper
-    class(*), pointer :: initialization
+    type(__builtin_c_ptr) :: initialization
   end type
 
   type :: ProcPtrComponent ! procedure pointer components
     character(len=:), pointer :: name
     integer(kind=int64) :: offset
     type(__builtin_c_funptr) :: initialization
   end type
 

flang/test/Semantics/typeinfo01.f90

contains
   subroutine s1(x)
 !CHECK: .c.t.1, SAVE, TARGET: ObjectEntity type: TYPE(component) shape: 0_8:3_8 init:[component::component(name=.n.allocatable,genre=3_1,category=1_1,kind=4_1,rank=1_1,offset=0_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=NULL()),component(name=.n.automatic,genre=4_1,category=1_1,kind=4_1,rank=1_1,offset=96_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=.b.t.1.automatic,initialization=NULL()),component(name=.n.chauto,genre=4_1,category=3_1,kind=1_1,rank=0_1,offset=72_8,characterlen=value(genre=3_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=NULL()),component(name=.n.pointer,genre=2_1,category=1_1,kind=4_1,rank=0_1,offset=48_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=target)]
 !CHECK: .dt.t.1, SAVE, TARGET: ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t,sizeinbytes=144_8,parent=NULL(),uninstantiated=.dt.t,kindparameter=NULL(),lenparameterkind=.lpk.t.1,component=.c.t.1,procptr=NULL(),special=NULL())
 !CHECK: .lpk.t.1, SAVE, TARGET: ObjectEntity type: INTEGER(1) shape: 0_8:0_8 init:[INTEGER(1)::8_1]
 !CHECK: .b.t.1.automatic, SAVE, TARGET: ObjectEntity type: TYPE(value) shape: 0_8:1_8,0_8:0_8 init:reshape([value::value(genre=2_1,value=1_8),value(genre=3_1,value=0_8)],shape=[2,1])
     type(t(*)), intent(in) :: x
   end subroutine
 end module
+
+module m12
+  type :: t1
+    integer :: n
+    integer :: n2
+    integer :: n_3
+    ! CHECK: .n.n, SAVE, TARGET: ObjectEntity type: CHARACTER(1_8,1) init:"n"
+    ! CHECK: .n.n2, SAVE, TARGET: ObjectEntity type: CHARACTER(2_8,1) init:"n2"
+    ! CHECK: .n.n_3, SAVE, TARGET: ObjectEntity type: CHARACTER(3_8,1) init:"n_3"
+  end type
+end module