[dpdk-dev] [PATCH v6 0/8] add checking of header includes

[David Marchand]

On Wed, Jan 27, 2021 at 6:33 PM Bruce Richardson
<bruce.richardson at intel.com> wrote:
>
> As a general principle, each header file should include any other
> headers it needs to provide data type definitions or macros. For
> example, any header using the uintX_t types in structures or function
> prototypes should include "stdint.h" to provide those type definitions.
>
> In practice, while many, but not all, headers in DPDK did include all
> necessary headers, it was never actually checked that each header could
> be included in a C file and compiled without having any compiler errors
> about missing definitions.  The script "check-includes.sh" could be used
> for this job, but it was not called out in the documentation, so many
> contributors may not have been aware of it's existance. It also was
> difficult to run from a source-code directory, as the script did not
> automatically allow finding of headers from one DPDK library directory
> to another [this was probably based on running it on a build created by
> the "make" build system, where all headers were in a single directory].
> To attempt to have a build-system integrated replacement, this patchset
> adds a "chkincs" app in the buildtools directory to verify this on an
> ongoing basis.
>
> This chkincs app does nothing when run, and is not installed as part of
> a DPDK "ninja install", it's for build-time checking only. Its source
> code consists of one C file per public DPDK header, where that C file
> contains nothing except an include for that header.  Therefore, if any
> header is added to the lib folder which fails to compile when included
> alone, the build of chkincs will fail with a suitable error message.
> Since this compile checking is not needed on most builds of DPDK, the
> building of chkincs is disabled by default, but can be enabled by the
> "test_includes" meson option. To catch errors with patch submissions,
> the final patch of this series enables it for a single build in
> test-meson-builds script.
>
> Future work could involve doing similar checks on headers for C++
> compatibility, which was something done by the check-includes.sh script
> but which is missing here.
>
> V6:
> * Added release notes updates for:
>    - renamed, no-longer-installed header files
>    - new "check_includes" build option
>    - removal of old check_includes script
> * Included acks from previous versions

I have some comments, see replies on patches.
I can address them if you are ok, and I would take this series for
-rc2 without needing a respin.

Sidenote: I like how we are hiding API by simply not exporting headers.
We need more cleanups like this.
Ethdev has been cleaned; this will probably remove the need for the
ABI exception on eth_dev_ops.
Eventdev, other driver classes and bus drivers will probably be the
next to look at.


-- 
David Marchand