Make range types inherit signed-ness from base type

I ran across this comment in valprint.c:

      /* FIXME: create_static_range_type does not set the unsigned bit in a
         range type (I think it probably should copy it from the target
         type), so we won't print values which are too large to
         fit in a signed integer correctly.  */

It seems to me that a range type ought to inherit its signed-ness from
the underlying type, so this patch implements this change, and removes
the comment.  (It was also copied into m2-valprint.c.)

I also remove the comment about handling ranges of enums, because I
think that comment is incorrect.

gdb/ChangeLog
2020-10-17  Tom Tromey  <tom@tromey.com>

	* valprint.c (generic_value_print): Remove comment.
	* m2-valprint.c (m2_value_print_inner): Remove comment.
	* gdbtypes.c (create_range_type): Set TYPE_UNSIGNED from base
	type.

4 files changed, 8 insertions, 27 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9ed6493..fc4b716 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2020-10-17  Tom Tromey  <tom@tromey.com>
+
+	* valprint.c (generic_value_print): Remove comment.
+	* m2-valprint.c (m2_value_print_inner): Remove comment.
+	* gdbtypes.c (create_range_type): Set TYPE_UNSIGNED from base
+	type.
+
 2020-10-17  Tom de Vries  <tdevries@suse.de>
 
 	PR symtab/26317
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 43c05d3..e7d9e4c 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -950,16 +950,7 @@ create_range_type (struct type *result_type, struct type *index_type,
 
   result_type->set_bounds (bounds);
 
-  if (low_bound->kind () == PROP_CONST && low_bound->const_val () >= 0)
-    result_type->set_is_unsigned (true);
-
-  /* Ada allows the declaration of range types whose upper bound is
-     less than the lower bound, so checking the lower bound is not
-     enough.  Make sure we do not mark a range type whose upper bound
-     is negative as unsigned.  */
-  if (high_bound->kind () == PROP_CONST && high_bound->const_val () < 0)
-    result_type->set_is_unsigned (false);
-
+  result_type->set_is_unsigned (index_type->is_unsigned ());
   result_type->set_endianity_is_not_default
     (index_type->endianity_is_not_default ());
 
diff --git a/gdb/m2-valprint.c b/gdb/m2-valprint.c
index 9f5ce7e..c285543 100644
--- a/gdb/m2-valprint.c
+++ b/gdb/m2-valprint.c
@@ -448,13 +448,6 @@ m2_value_print_inner (struct value *val, struct ui_file *stream, int recurse,
 	  m2_value_print_inner (v, stream, recurse, options);
 	  break;
 	}
-      /* FIXME: create_static_range_type does not set the unsigned bit in a
-         range type (I think it probably should copy it from the target
-         type), so we won't print values which are too large to
-         fit in a signed integer correctly.  */
-      /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
-         print with the target type, though, because the size of our type
-         and the target type might differ).  */
       /* FALLTHROUGH */
 
     case TYPE_CODE_REF:
diff --git a/gdb/valprint.c b/gdb/valprint.c
index 0749f38..dd70a1a 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -893,16 +893,6 @@ generic_value_print (struct value *val, struct ui_file *stream, int recurse,
       break;
 
     case TYPE_CODE_RANGE:
-      /* FIXME: create_static_range_type does not set the unsigned bit in a
-         range type (I think it probably should copy it from the
-         target type), so we won't print values which are too large to
-         fit in a signed integer correctly.  */
-      /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
-         print with the target type, though, because the size of our
-         type and the target type might differ).  */
-
-      /* FALLTHROUGH */
-
     case TYPE_CODE_INT:
       generic_value_print_int (val, stream, options);
       break;