Richard Henderson <rth(a)redhat.com> writes:
On 04/23/2014 03:17 AM, Petr Machata wrote:
> Wouldn't something like this get us off the hook as well?
>
> - (var) |= (typeof (var)) __s.i << ((nth) * 7); \
> + (var) |= (typeof (var)) \
> + (((uint64_t) (typeof (var)) __s.i) << ((nth) * 7)); \
>
> We are really only using the bitfield trick to avoid having to
> sign-extend by hand, but we can shift unsigned without losing anything.
It gets us off the hook, but might introduce a 64-bit shift where
only a 32-bit shift was required.
Good point, but get_sleb128_step is only used from __libdw_get_sleb128,
where the type is int64_t. This macro is not safe for outside use
anyway, as it uses its parameters more than once.
Hmm, should we maybe #undef it after __libdw_get_sleb128, so that it's
clear that it's for local use only?
Thanks,
PM