diff options
Diffstat (limited to 'gcc/ada/trans.c')
| -rw-r--r-- | gcc/ada/trans.c | 51 |
1 files changed, 30 insertions, 21 deletions
diff --git a/gcc/ada/trans.c b/gcc/ada/trans.c index 9e59373..8bec775 100644 --- a/gcc/ada/trans.c +++ b/gcc/ada/trans.c @@ -1181,33 +1181,42 @@ Attribute_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, int attribute) else /* attribute == Attr_Range_Length || attribute == Attr_Length */ { - tree gnu_compute_type; - if (pa && pa->length) { gnu_result = pa->length; break; } + else + { + tree gnu_compute_type + = signed_or_unsigned_type_for + (0, get_base_type (gnu_result_type)); + + tree index_type + = TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)); + tree lb + = convert (gnu_compute_type, TYPE_MIN_VALUE (index_type)); + tree hb + = convert (gnu_compute_type, TYPE_MAX_VALUE (index_type)); + + /* We used to compute the length as max (hb - lb + 1, 0), + which could overflow for some cases of empty arrays, e.g. + when lb == index_type'first. + + We now compute it as (hb < lb) ? 0 : hb - lb + 1, which + could overflow as well, but only for extremely large arrays + which we expect never to encounter in practice. */ - gnu_compute_type - = signed_or_unsigned_type_for (0, - get_base_type (gnu_result_type)); - - gnu_result - = build_binary_op - (MAX_EXPR, gnu_compute_type, - build_binary_op - (PLUS_EXPR, gnu_compute_type, - build_binary_op - (MINUS_EXPR, gnu_compute_type, - convert (gnu_compute_type, - TYPE_MAX_VALUE - (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)))), - convert (gnu_compute_type, - TYPE_MIN_VALUE - (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))))), - convert (gnu_compute_type, integer_one_node)), - convert (gnu_compute_type, integer_zero_node)); + gnu_result + = build3 + (COND_EXPR, gnu_compute_type, + build_binary_op (LT_EXPR, gnu_compute_type, hb, lb), + convert (gnu_compute_type, integer_zero_node), + build_binary_op + (PLUS_EXPR, gnu_compute_type, + build_binary_op (MINUS_EXPR, gnu_compute_type, hb, lb), + convert (gnu_compute_type, integer_one_node))); + } } /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are |