Re: [rfc][19/37] Eliminate builtin_type_ macros: Ada range type handling

Ulrich Weigand
2008-09-09T22:32:19Z

Joel Brobecker wrote:

> First, I need to correct myself - ranges are not just for integral
> types. You can have a range over any discrete type, which means
> things like this:
>
> type Digit is (Zero, One, Two, ...);
> subtype Binary is Digit range (Zero .. One);
>
> In this case, Binary would be defined as a subrange of the enumeration
> type. However, after thinking about it awhile, I don't think that
> enumeration types are that different from integral types in terms
> of comparison and range check.

Yes, value_less etc. should be able to handle enumeration (and range)
types fine.

> That being said:
>
> > Well, the only effect going through GDB values to perform the
> > comparison has is to do the appropriate type promotions. However, if
> > this doesn't actually apply for Ada, I'm wondering why we don't simply
> > do the comparison on integral LONGEST values directly, like in the
> > patch below?
>
> The only problem that I see is when the base type of the range type
> is unsigned. value_less is supposed to be able to handle such cases,
> whereas converting the bounds to a LONGEST might cause some problems,
> no?

I see. We'd need to compare either LONGEST or ULONGEST to take care
of signed vs. unsigned types. value_less already does this ...

So I guess your original proposal to use the range type itself is
the simplest solution. Implemented by the patch below.

Bye,
Ulrich

ChangeLog:

* ada-lang.c (ada_array_length): Use builtin_type_int32 instead
of builtin_type_int.
(ada_evaluate_subexp) [UNOP_IN_RANGE]: Use operand range type
instead of builtin_type_int.

Index: gdb-head/gdb/ada-lang.c
===================================================================
--- gdb-head.orig/gdb/ada-lang.c
+++ gdb-head/gdb/ada-lang.c
@@ -2623,7 +2623,7 @@ ada_array_length (struct value *arr, int
}
else
return
- value_from_longest (builtin_type_int,
+ value_from_longest (builtin_type_int32,
value_as_long (desc_one_bound (desc_bounds (arr),
n, 1))
- value_as_long (desc_one_bound (desc_bounds (arr),
@@ -8860,9 +8860,8 @@ ada_evaluate_subexp (struct type *expect
return value_from_longest (type, (LONGEST) 1);

case TYPE_CODE_RANGE:
- arg2 = value_from_longest (builtin_type_int, TYPE_LOW_BOUND (type));
- arg3 = value_from_longest (builtin_type_int,
- TYPE_HIGH_BOUND (type));
+ arg2 = value_from_longest (type, TYPE_LOW_BOUND (type));
+ arg3 = value_from_longest (type, TYPE_HIGH_BOUND (type));
binop_promote (exp->language_defn, exp->gdbarch, &arg1, &arg2);
binop_promote (exp->language_defn, exp->gdbarch, &arg1, &arg3);
type = language_bool_type (exp->language_defn, exp->gdbarch);