On Sun, 27 Oct 2024, Arnd Bergmann wrote:
On Sun, Oct 27, 2024, at 06:16, Finn Thain wrote:
Right. And I don't think the problem is going to go away. One solution
that is sometimes raised is better tooling. I'm not sure how that would
No. You don’t understand the problem: applications are being
written that require natural alignment for at least 32-bit and
smaller quantities, some possibly for all quantities even. We
need these applications to work, and we cannot redesign them
(it’s common for them to store flags in the lowest pointer bits
and do other awful things).
Could you please, if you cannot believe it yourself, accept the
word of those actually doing the porting that it is direly needed
in the current Linux ecosystem. Thank you.
That struct is just 12 bytes for you then?
Right. i686 and m68k agree on that.
The other ones that have misaligned 'long long' variables are
arc
arm (OABI only)
csky
microblaze
nios2
openrisc
superh
i386
Okaaay. So, all “old” platforms or with low distro support.
For Debian, we have superh and i386, out of these. It is
entirely possible that Qt et al. can work with this, but
these all have natural alignment for quantities ≤ 32 bits.
Does Gentoo support more of them? Debian used to have arm
OABI, but that’s ages ago. I know things like OpenADK support
them, but that is very chiefly embedded.
The 32-bit architectures that use a natural 8-byte
alignment are
arm (EABI)
parisc
mips
powerpc
riscv
s390
sparc
xtensa
That’s majoritily represented in Debian. And ideally, we’d
use that for all new architectures.
I have a feeling that GCC’s -malign-int will only push us
into the former. I have no idea whether it’s feasible to
also change GCC for this; that will probably depend on both
the other “what parts of the toolchain need changing” and
whether GCC can be switched with little effort.
bye,
//mirabilos
--
22:20⎜<asarch> The crazy that persists in his craziness becomes a master
22:21⎜<asarch> And the distance between the craziness and geniality is
only measured by the success 18:35⎜<asarch> "Psychotics are consistently
inconsistent. The essence of sanity is to be inconsistently inconsistent
