Le 30/04/2019 à 22:28, Laurent Vivier a écrit :
> Le 30/04/2019 à 22:09, Alistair Francis a écrit :
>> Fix this warning with GCC 9 on Fedora 30:
>> hw/usb/dev-mtp.c:1715:36: error: taking address of packed member of ‘struct
>> <anonymous>’ may result in an unaligned pointer value
>> [-Werror=address-of-packed-member]
>> 1715 | dataset->filename);
>> | ~~~~~~~^~~~~~~~~~
>>
>> Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
>> ---
>> hw/usb/dev-mtp.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
>> index 99548b012d..6de85d99e6 100644
>> --- a/hw/usb/dev-mtp.c
>> +++ b/hw/usb/dev-mtp.c
>> @@ -1711,9 +1711,22 @@ static void usb_mtp_write_metadata(MTPState *s,
>> uint64_t dlen)
>> assert(!s->write_pending);
>> assert(p != NULL);
>>
>> +/*
>> + * We are about to access a packed struct. We are confident that the pointer
>> + * address won't be unalligned, so we ignore GCC warnings.
>> + */
>> +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9, 0)
>> +#pragma GCC diagnostic push
>> +#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
>> +#endif
>> +
>> filename = utf16_to_str(MIN(dataset->length, filename_chars),
>> dataset->filename);
>>
>> +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9, 0)
>> +#pragma GCC diagnostic pop
>> +#endif
>> +
>> if (strchr(filename, '/')) {
>> usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans,
>> 0, 0, 0, 0);
>>
>
> You should move and use PRAGMA_DISABLE_PACKED_WARNING and
> PRAGMA_REENABLE_PACKED_WARNING from linux-user/qemu.h.
>
> It has laready been very well tested :)
Oh, they are for clang and a false positive, so forget my comment (and
the following one)
Thanks,
Laurent
