Re: [PATCH 2/2] Change ptype/o to print bit offset

[Tom Tromey <tromey@adacore.com>]

>>>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:

>> /*    5: 0   |     4 */        unsigned int y : 3;
>> /*    5: 3   |     4 */        unsigned int z : 3;
>> /* XXX  2-bit padding  */
>> /* XXX  3-byte padding */

Eli> This loses information, because now the bits part is just a trivial
Eli> conversion of the field size in the declaration.  The current display
Eli> shows something that cannot be trivially gleaned by looking at the
Eli> bitfield sizes.

Eli> I'm not objecting to the change, I'm just saying we lose something
Eli> here.

We don't actually lose anything here, because the padding is spelled out
explicitly in the comments that are printed.


Also, consider an example like this, from an Ada test case:

/* offset    |  size */  type = struct aggregates__nested_packed {
/*    0: 5   |     1 */    <range type> q000 : 3;
/*    0:23   |     8 */    struct aggregates__packed_rec {
/*    0      |     4 */        integer packed_array_assign_w;
/*    4: 5   |     1 */        <range type> packed_array_assign_x : 3;
/*    4: 2   |     1 */        <range type> packed_array_assign_y : 3;
/* XXX  2-bit padding  */
/* XXX  3-byte padding */

                               /* total size (bytes):    8 */
                           } r000 : 38;

The "0:23" here is, IMO, actively confusing.

Tom