[Qemu-devel] [PATCH 0/2] slirp: fix -Waddress-of-packed-member warnings

[Peter Maydell]

These patches fix the clang -Waddress-of-packed-member warnings
in the slirp code. For slirp, the structs marked as packed
are already naturally packed/aligned, so adding the 'packed'
attribute doesn't change their layout but means the compiler
has to assume they might be misaligned. Instead, for the structs
which map to on-the-wire packet formats, we add build time
assertions that they have the sizes we think they should.

The 'struct ipq' and 'struct ipasfrag' aren't on-the-wire
packet representations, so it's not clear why they were
marked packed in the first place. (They contain host pointers
and so have a size that depends on the host.) Here we just
assert the only thing that's documented as a layout restriction:
that struct ipq's frag_link and struct ipasfrag's ipf_link
are at the same offset.

Together, this fixes all the -Waddress-of-packed-member warnings
in slirp, which I think was the only set remaining without
patches at least being on-list. (Some of the block/ warning fixes
are still working their way through the relevant trees.)

thanks
-- PMM

Peter Maydell (2):
  slirp: Avoid marking naturally packed structs as QEMU_PACKED
  slirp: Don't mark struct ipq or struct ipasfrag as packed

 slirp/ip.h       |  7 +++++--
 slirp/ip6.h      | 12 ++++++++++--
 slirp/ip6_icmp.h | 20 +++++++++++++++-----
 3 files changed, 30 insertions(+), 9 deletions(-)

-- 
2.20.1