Re: Question Regarding Int Cast Error in GDB Python

[Vacha Bhavsar via Gdb <gdb@sourceware.org>]

Hi,

We chose this particular cast just to stay aligned with the
existing method of testing in QEMU which also uses this cast
but for 64bit integers.

qemu/tests/tcg/aarch64/gdbstub/test-sve.py at
b86307ecef9222c335ebd0ed4da2b243e86f779e · qemu/qemu
<https://github.com/qemu/qemu/blob/b86307ecef9222c335ebd0ed4da2b243e86f779e/tests/tcg/aarch64/gdbstub/test-sve.py>
https://lists.gnu.org/archive/html/qemu-devel/2025-08/msg01815.html


However, since we have seen that this issue only occurs with the
specific indiciated version of gdb, and does not fail for example with
gdb16.3, we have implemented a workaround to avoid the
casting in the case of gdb-multiarch 15.0.50.20240403-0ubuntu1.

Thank you for confirming this is a known issue!


Thanks,
Vacha

On Tue, Aug 26, 2025 at 4:49 PM Luis <luis.machado.foss@gmail.com> wrote:

> Hi,
>
> On 8/25/25 14:29, Vacha Bhavsar wrote:
> > Hi,
> >
> > Apologies, it seems I pasted the wrong snippet in the original email.
> > The code in my reply just prior to this is the correct code. The snippet
> > that
> > should have been included in the first email, which causes the error, is
> > the one below:
> >
> > v = gdb.parse_and_eval(reg)
> > report(str(v.type) == "uint128_t", "size of %s" % (reg))
>
> Right, so gdb doesn't like casting integers to/from 8+ bytes. That's a
> limitation currently. But why are you considering this particular cast?
> To optimize the checks instead of using the byte vectors?
>