On 3/7/19 10:34 AM, Jan Beulich wrote: > While I've not observed this myself, gcc 9 (imo validly) reportedly may > complain > > trace.c: In function '__trace_hypercall': > trace.c:826:19: error: taking address of packed member of 'struct > <anonymous>' may result in an unaligned pointer value > [-Werror=address-of-packed-member] > 826 | uint32_t *a = d.args;
Wait, is this saying that in this case (i.e., with a single uint32_t before args), you *do* get an unaligned pointer value, or just that if the struct changes in the future that the pointer value may become un-aligned? If the latter, I disagree that the warning is valid. If at some point in the future, 'op' changes to be (say) 16 bits, then *that* is when the compiler should complain; and that's when we can either add in our own padding, or change the algorithm not to require a pointer to args[]. -George _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
