On 25 May 2017 at 13:54, Ben Pfaff <[email protected]> wrote:
> On Thu, May 25, 2017 at 01:18:21PM -0700, Joe Stringer wrote:
>> On 25 May 2017 at 10:42, Ben Pfaff <[email protected]> wrote:
>> > On Tue, May 23, 2017 at 04:02:15PM -0700, Joe Stringer wrote:
>> >> Clang 4.0 complains:
>> >>
>> >> ../tests/test-hash.c:160:16: error: taking address of packed member 'b' of
>> >> class or structure 'offset_ovs_u128' may result in an unaligned pointer 
>> >> value
>> >>       [-Werror,-Waddress-of-packed-member]
>> >>         in0 = &in0_data.b;
>> >>
>> >> Rework the 128-bit hash test to have a separate function for setting
>> >> bits in the 32-bit offset u128 structure.
>> >>
>> >> Signed-off-by: Joe Stringer <[email protected]>
>> >
>> > How about something like this, to reduce code duplication?  I have not
>> > tested it with Clang 4.0.
>> >
>> > diff --git a/tests/test-hash.c b/tests/test-hash.c
>> > index d1beead36ed5..f02f0218c71f 100644
>> > --- a/tests/test-hash.c
>> > +++ b/tests/test-hash.c
>> > @@ -153,14 +153,13 @@ check_hash_bytes128(void (*hash)(const void *, 
>> > size_t, uint32_t, ovs_u128 *),
>> >          OVS_PACKED(struct offset_ovs_u128 {
>> >              uint32_t a;
>> >              ovs_u128 b;
>> > -        }) in0_data;
>> > -        ovs_u128 *in0, in1;
>> > +        }) in0;
>> > +        ovs_u128 in1;
>> >          ovs_u128 out0, out1;
>> >
>> > -        in0 = &in0_data.b;
>> > -        set_bit128(in0, i, n_bits);
>> >          set_bit128(&in1, i, n_bits);
>> > -        hash(in0, sizeof(ovs_u128), 0, &out0);
>> > +        in0.b = in1;
>> > +        hash(&in0.b, sizeof(ovs_u128), 0, &out0);
>> >          hash(&in1, sizeof(ovs_u128), 0, &out1);
>> >          if (!ovs_u128_equals(out0, out1)) {
>> >              printf("%s hash not the same for non-64 aligned data "
>>
>> Thanks, this looks like a much better approach and it satisfies clang
>> 4.0. Will you propose this formally or shall I? The 256B version needs
>> a slight variation on this as well.
>
> I was hoping that you would propose it formally.

OK, I can do that.
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