On Fri, Jan 22, 2021 at 12:20:55AM +0100, Thomas Monjalon wrote: > 21/01/2021 16:15, Bruce Richardson: > > On Thu, Jan 21, 2021 at 10:36:18AM +0100, Thomas Monjalon wrote: > > > 21/01/2021 10:33, Bruce Richardson: > > > > On Thu, Jan 21, 2021 at 10:25:07AM +0100, David Marchand wrote: > > > > > Is rte_byteorder.h inclusion in rte_mbuf.h still necessary? > > > > > > > > > Good question. The checks I was doing were only for missing headers. > > > > Checking for superfluous headers is more complicated and not something > > > > I've > > > > looked at. I know it was previously suggested to use the > > > > "include-what-you-use" tool on DPDK, if anyone wants to attempt that. > > > > > > I would love having an integration of include-what-you-use in our build > > > system. > > > I don't know whether it's trivial or difficult with meson. > > > > > > > Did some initial investigation here, and here are some basic instructions > > based on how I got it running on my Ubuntu 20.10 system. The positive is > > that "iwyu_tool" can run on DPDK build dirs without any extra work on our > > part. > > I had looked at it recently but didn't try thinking meson was not compatible. > Thank you, it works :) > > > 1. Install iwyu from Ubuntu packaging. > > 2. Install clang-9 package: > > * This is not a dependency of iwyu, but probably should be > > * The version of clang installed *must* match that used to build iwyu > > [I had clang-10 installed which didn't work for this] > > * If you get errors about missing standard headers e.g. stddef.h, > > the version mismatch is likely the issue. > > 3. Configure a clang build of DPDK: > > * CC=clang meson <args> build-clang > > 4. "iwyu_tool" supports the build database format used by meson, so just > > run: "iwyu_tool -p build-clang" > > > > Be warned, this runs really slowly and produces lots of output! > > We need to filter only reports of useless includes > and do the cleaning... > > The difficult part is that some includes may be useless on Linux > but required on FreeBSD. > And that some "useless" includes in headers are required by the corresponding C file which then needs the include added there. :-(
However, thinking a bit more after sending that email yesterday and looking at the results, I came to the same conclusion as you - we should use it to primarily remove unused headers. That will be slowed down by the need for additional fixup, but it's doable if someone has a bit of time. /Bruce
