[PATCH] Emit Fortran CHARACTER types as DW_TAG_string_type

[PATCH] Emit Fortran CHARACTER types as DW_TAG_string_type

[Jakub Jelinek]

Hi!

The Dwarf3 standard says Fortran CHARACTER types should be represented
as DW_TAG_string_type (but as it has no DW_AT_type, IMHO only kind=1
characters can use it) and this patch implements that.  Testcase e.g.
subroutine foo (e, f)
  character (len=1) :: c
  character (len=8) :: d
  character (len=*) :: e
  character (len=*) :: f (1:7, 8:10)
  c = 'c'
  d = 'd'
  e = 'e'
  f = 'f'
end subroutine foo
  character (len=4) :: g, h (1:7, 8:10)
  g = 'g'
  h = 'h'
  call foo (g, h)
end

gdb I have handles the constant DW_TAG_string_type DIEs well (and obviously
it is much nicer than what it printed for DW_TAG_array_type DIEs), but the
non-constant ones with DW_AT_string_length don't seem to be working right,
but IMHO what GCC emits with this patch looks correct.

2008-08-22  Jakub Jelinek  <jakub@redhat.com>

	* dwarf2out.c (add_subscript_info): Stop on Fortran TYPE_STRING_FLAG
	types.
	(gen_array_type_die): Emit DW_TAG_string_type for Fortran character
	types.

--- gcc/dwarf2out.c.jj	2008-08-22 13:39:21.000000000 +0200
+++ gcc/dwarf2out.c	2008-08-22 17:49:10.000000000 +0200
@@ -12037,6 +12037,9 @@ add_subscript_info (dw_die_ref type_die,
     {
       tree domain = TYPE_DOMAIN (type);
 
+      if (TYPE_STRING_FLAG (type) && is_fortran ())
+	break;
+
       /* Arrays come in three flavors: Unspecified bounds, fixed bounds,
 	 and (in GNU C only) variable bounds.  Handle all three forms
 	 here.  */
@@ -12570,7 +12573,40 @@ gen_array_type_die (tree type, dw_die_re
 
   bool collapse_nested_arrays = !is_ada ();
   tree element_type;
-  
+
+  /* Emit DW_TAG_string_type for Fortran character types (with kind 1 only, as
+     DW_TAG_string_type doesn't have DW_AT_type attribute).  */
+  if (TYPE_STRING_FLAG (type)
+      && TREE_CODE (type) == ARRAY_TYPE
+      && is_fortran ()
+      && TYPE_MODE (TREE_TYPE (type)) == TYPE_MODE (char_type_node))
+    {
+      HOST_WIDE_INT size;
+
+      array_die = new_die (DW_TAG_string_type, scope_die, type);
+      add_name_attribute (array_die, type_tag (type));
+      equate_type_number_to_die (type, array_die);
+      size = int_size_in_bytes (type);
+      if (size >= 0)
+	add_AT_unsigned (array_die, DW_AT_byte_size, size);
+      else if (TYPE_DOMAIN (type) != NULL_TREE
+	       && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) != NULL_TREE
+	       && DECL_P (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
+	{
+	  tree szdecl = TYPE_MAX_VALUE (TYPE_DOMAIN (type));
+	  dw_loc_descr_ref loc = loc_descriptor_from_tree (szdecl);
+
+	  size = int_size_in_bytes (TREE_TYPE (szdecl));
+	  if (loc && size > 0)
+	    {
+	      add_AT_loc (array_die, DW_AT_string_length, loc);
+	      if (size != DWARF2_ADDR_SIZE)
+		add_AT_unsigned (array_die, DW_AT_byte_size, size);
+	    }
+	}
+      return;
+    }
+
   /* ??? The SGI dwarf reader fails for array of array of enum types
      (e.g. const enum machine_mode insn_operand_mode[2][10]) unless the inner
      array type comes before the outer array type.  We thus call gen_type_die
@@ -12597,7 +12633,8 @@ gen_array_type_die (tree type, dw_die_re
   /* For Fortran multidimensional arrays use DW_ORD_col_major ordering.  */
   if (is_fortran ()
       && TREE_CODE (type) == ARRAY_TYPE
-      && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
+      && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE
+      && !TYPE_STRING_FLAG (TREE_TYPE (type)))
     add_AT_unsigned (array_die, DW_AT_ordering, DW_ORD_col_major);
 
 #if 0
@@ -12625,8 +12662,12 @@ gen_array_type_die (tree type, dw_die_re
   element_type = TREE_TYPE (type);
   if (collapse_nested_arrays)
     while (TREE_CODE (element_type) == ARRAY_TYPE)
-      element_type = TREE_TYPE (element_type);
-  
+      {
+	if (TYPE_STRING_FLAG (element_type) && is_fortran ())
+	  break;
+	element_type = TREE_TYPE (element_type);
+      }
+
 #ifndef MIPS_DEBUGGING_INFO
   gen_type_die (element_type, context_die);
 #endif

	Jakub

Re: [PATCH] Emit Fortran CHARACTER types as DW_TAG_string_type

[Jason Merrill]

It seems like this patch uses DW_TAG_string_type for kind 1 CHARACTERs, 
which makes sense, and leaves other CHARACTERs as DW_TAG_array_types, 
which seems reasonable until the standards issue is cleared up, but then 
also removes the array size/subscript information from those 
DW_TAG_array_types, which I don't understand.

Jason

Re: [PATCH] Emit Fortran CHARACTER types as DW_TAG_string_type

[Jakub Jelinek]

On Fri, Aug 22, 2008 at 01:58:17PM -0400, Jason Merrill wrote:
> It seems like this patch uses DW_TAG_string_type for kind 1 CHARACTERs, 
> which makes sense, and leaves other CHARACTERs as DW_TAG_array_types, 
> which seems reasonable until the standards issue is cleared up, but then 
> also removes the array size/subscript information from those 
> DW_TAG_array_types, which I don't understand.

You're right, I should have done the break in add_subscript_info only
for dimension_number > 0.  The rest is IMHO correct.  Even for kind 4
CHARACTER types IMHO we don't want character (kind=4,len=10) :: x (2:5,2:8)
be represented as 3 dimensional array, but 2 dimensional array of
1 dimensional arrays (when we can't use DW_TAG_string_type), to at least
hint the debugger it is not integer (kind=4) :: x (2:5,2:8,10).

2008-08-22  Jakub Jelinek  <jakub@redhat.com>

	* dwarf2out.c (add_subscript_info): Stop on Fortran TYPE_STRING_FLAG
	types.
	(gen_array_type_die): Emit DW_TAG_string_type for Fortran character
	types.

--- gcc/dwarf2out.c.jj	2008-08-22 13:39:21.000000000 +0200
+++ gcc/dwarf2out.c	2008-08-22 17:49:10.000000000 +0200
@@ -12037,6 +12037,9 @@ add_subscript_info (dw_die_ref type_die,
     {
       tree domain = TYPE_DOMAIN (type);
 
+      if (TYPE_STRING_FLAG (type) && is_fortran () && dimension_number > 0)
+	break;
+
       /* Arrays come in three flavors: Unspecified bounds, fixed bounds,
 	 and (in GNU C only) variable bounds.  Handle all three forms
 	 here.  */
@@ -12570,7 +12573,40 @@ gen_array_type_die (tree type, dw_die_re
 
   bool collapse_nested_arrays = !is_ada ();
   tree element_type;
-  
+
+  /* Emit DW_TAG_string_type for Fortran character types (with kind 1 only, as
+     DW_TAG_string_type doesn't have DW_AT_type attribute).  */
+  if (TYPE_STRING_FLAG (type)
+      && TREE_CODE (type) == ARRAY_TYPE
+      && is_fortran ()
+      && TYPE_MODE (TREE_TYPE (type)) == TYPE_MODE (char_type_node))
+    {
+      HOST_WIDE_INT size;
+
+      array_die = new_die (DW_TAG_string_type, scope_die, type);
+      add_name_attribute (array_die, type_tag (type));
+      equate_type_number_to_die (type, array_die);
+      size = int_size_in_bytes (type);
+      if (size >= 0)
+	add_AT_unsigned (array_die, DW_AT_byte_size, size);
+      else if (TYPE_DOMAIN (type) != NULL_TREE
+	       && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) != NULL_TREE
+	       && DECL_P (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
+	{
+	  tree szdecl = TYPE_MAX_VALUE (TYPE_DOMAIN (type));
+	  dw_loc_descr_ref loc = loc_descriptor_from_tree (szdecl);
+
+	  size = int_size_in_bytes (TREE_TYPE (szdecl));
+	  if (loc && size > 0)
+	    {
+	      add_AT_loc (array_die, DW_AT_string_length, loc);
+	      if (size != DWARF2_ADDR_SIZE)
+		add_AT_unsigned (array_die, DW_AT_byte_size, size);
+	    }
+	}
+      return;
+    }
+
   /* ??? The SGI dwarf reader fails for array of array of enum types
      (e.g. const enum machine_mode insn_operand_mode[2][10]) unless the inner
      array type comes before the outer array type.  We thus call gen_type_die
@@ -12597,7 +12633,8 @@ gen_array_type_die (tree type, dw_die_re
   /* For Fortran multidimensional arrays use DW_ORD_col_major ordering.  */
   if (is_fortran ()
       && TREE_CODE (type) == ARRAY_TYPE
-      && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
+      && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE
+      && !TYPE_STRING_FLAG (TREE_TYPE (type)))
     add_AT_unsigned (array_die, DW_AT_ordering, DW_ORD_col_major);
 
 #if 0
@@ -12625,8 +12662,12 @@ gen_array_type_die (tree type, dw_die_re
   element_type = TREE_TYPE (type);
   if (collapse_nested_arrays)
     while (TREE_CODE (element_type) == ARRAY_TYPE)
-      element_type = TREE_TYPE (element_type);
-  
+      {
+	if (TYPE_STRING_FLAG (element_type) && is_fortran ())
+	  break;
+	element_type = TREE_TYPE (element_type);
+      }
+
 #ifndef MIPS_DEBUGGING_INFO
   gen_type_die (element_type, context_die);
 #endif

	Jakub

Re: [PATCH] Emit Fortran CHARACTER types as DW_TAG_string_type

[Jason Merrill]

OK.

Jason