Re: [dpdk-dev] [dpdk-stable] [PATCH v5 1/2] mk: fix cross build errors

[Thomas Monjalon <thomas@monjalon.net>]

30/05/2018 04:45, Gavin Hu:
> From: Bruce Richardson <bruce.richardson@intel.com>
> > On Tue, May 29, 2018 at 04:45:55PM +0200, Thomas Monjalon wrote:
> > > 28/05/2018 15:24, Bruce Richardson:
> > > > Would a simpler solution for this not be to put "-Wno-implicit-
> > fallthrough"
> > > > for pmdinfogen? GCC will not give a warning for an unrecognised "-Wno"
> > > > flag when compiling, unless there are other errors. This means we
> > > > can just use the flag without bothering with version checks.
> > >
> > > No, it does not work.
> > > I have this error with clang 5.0.1:
> > >     error: unknown warning option '-Wno-format-truncation'
> > >
> > Yes, you still need to check for GCC to use the flag, just not for a specific
> > version of GCC.
> >
> > /Bruce
> [Gavin Hu] Hi Thomas, '-Wno-format-truncation' is applied to gcc only, not to clang.
> Gcc, icc and clang have their own WERROR_FLAGS, they should not mix up with each other.

Now I understand what we missed from the beginning: I am testing with meson.
This flag is added unconditionnaly in config/meson.build.

> @Bruce,
> Yes, in this sense, I am really concerned about to add -Wno-implicit-fallthrough option in the pmdinfogen Makefile, as it impacts not only gcc, but also clang and icc.
> Maybe this not a best solution, as maybe it is not supported by all compilers. So should I fall back to the previous patch which check for the gcc version and apply the options for gcc only?