On Tue, 24 Nov 2020 at 12:52, <marcandre.lur...@redhat.com> wrote:
>
> From: Marc-André Lureau <marcandre.lur...@redhat.com>
>
> Hi,
>
> Since commit efc6c07 ("configure: Add a test for the minimum compiler version=
> "),
> QEMU explicitely depends on GCC >= 4.8.You need to be a bit cautious about removing QEMU_GNUC_PREREQ() checks, because clang advertises itself as GCC 4.2 via the __GNUC__ and __GNUC_MINOR__ macros that QEMU_GNUC_PREREQ() tests, and so unless the code has explicitly handled clang via a different ifdef or feature test clang will be using the fallback codepath in cases like this. So you also need to find out whether all our supported versions of clang are OK with the gcc-4.4-and-up version of the code before removing any particular ifdef. Compare this previous (not-applied) patchset from Philippe: https://patchew.org/QEMU/20200928125859.734287-1-phi...@redhat.com/ which dealt with two of these ifdefs, one of which is "clearly OK" and the other of which is "needs more analysis". The path forward I think is along those lines -- we need one patch per ifdef we're trying to remove, and the commit message can then include the information about why in this case it is OK for clang too (or switch the ifdef to check for something else, eg one of clang's feature-specific test macros). thanks -- PMM
