On Fri, Jun 09, 2023 at 06:15:44PM +0200, Daniel Vacek wrote:
> On Fri, Jun 9, 2023 at 6:01 PM Jason Gunthorpe <jgg@xxxxxxxx> wrote:
> >
> > On Fri, Jun 09, 2023 at 05:31:47PM +0200, Daniel Vacek wrote:
> > > Our customer reported the below warning whe using Clang v16.0.4 and C++20,
> > > on a code that includes the header "/usr/include/infiniband/verbs.h":
> > >
> > > error: bitwise operation between different enumeration types ('ibv_access_flags' and
> > > 'ib_uverbs_access_flags') is deprecated [-Werror,-Wdeprecated-enum-enum-conversion]
> > > mem->mr = ibv_reg_mr(dev->pd, (void*)start, len, IBV_ACCESS_LOCAL_WRITE);
> > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > /usr/include/infiniband/verbs.h:2514:19: note: expanded from macro 'ibv_reg_mr'
> > > ((access) & IBV_ACCESS_OPTIONAL_RANGE) == 0))
> > > ~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
> > > 1 error generated.
> > >
> > > According to the article "Clang 11 warning: Bitwise operation between different
> > > enumeration types is deprecated":
> > >
> > > C++20's P1120R0 deprecated bitwise operations between different enums. Such code is
> > > likely to become ill-formed in C++23. Clang 11 warns about such cases. It should be fixed.
> >
> > There should be a cast to an integer in the macro, we can't know what
> > the user will pass in there and it may not be that enum.
>
> Hmm, if the user passes a definition from the header files at least we
> should be consistent I'd say, which is this case. No one was passing
> any custom values here.
> If you cast to an integer here you may start silently hiding possible
> errors. If the user passes any custom value, IMO, it's his
> responsibility to make it right.
The signature of the API is to accept an int, we cannot demand any
more of that from the user. The macro wiped out the type cast to an
int, it should put it back.
Jason
