Re: [PATCH] qcow2: Silence clang -m32 compiler warning

[Hanna Reitz <hreitz@redhat.com>]

On 11.10.21 18:24, Eric Blake wrote:
> On Mon, Oct 11, 2021 at 05:50:31PM +0200, Hanna Reitz wrote:
>> With -m32, size_t is generally only a uint32_t.  That makes clang
>> complain that in the assertion
>>
>>    assert(qiov->size <= INT64_MAX);
>>
>> the range of the type of qiov->size (size_t) is too small for any of its
>> values to ever exceed INT64_MAX.
> Yep, I'm not surprised that we hit that.
>
>> Cast qiov->size to uint64_t to silence clang.
>>
>> Fixes: f7ef38dd1310d7d9db76d0aa16899cbc5744f36d
>>         ("block: use int64_t instead of uint64_t in driver read
>>         handlers")
>> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
>> ---
>> I don't know whether this is the best possible solution, or whether we
>> should care about this at all (I personally think it's basically just
>> wrong for clang to warn about always-true conditions in assertions), but
>> I thought I might as well just send this patch as the basis for a
>> discussion.
> I agree that the compiler is overly noisy, but the fix is simple
> enough that I'm fine with it as written.

Well, I just hope clang won’t become even more clever in the future and 
realize the cast has no real effect...

> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> Since the original went through my tree, I'm happy to take this one
> through my NBD tree as well.

Thanks!

Hanna