[v3] build: add definitions for use as meson subproject

  To allow other projects to easily use DPDK as a subproject, add in the
necessary dependency definitions. Slightly different definitions are
necessary for static and shared builds, since for shared builds the
drivers should not be linked in, and the internal meson dependency
objects are more complete.

To use DPDK as a subproject fallback i.e. use installed DPDK if present,
otherwise the shipped one, the following meson statement can be used:

libdpdk = dependency('libdpdk', fallback: ['dpdk', 'dpdk_dep'])

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 buildtools/subproject/meson.build | 21 +++++++++++++++++++++
 drivers/meson.build               |  4 ++++
 lib/meson.build                   |  2 ++
 meson.build                       |  6 ++++++
 4 files changed, 33 insertions(+)
 create mode 100644 buildtools/subproject/meson.build
  

Currently utilizing this in an upcoming set of changes for TLDK and all
seems to be working for fallback dependency support under both shared and
static linkage.

Reviewed-by: Ben Magistro <koncept1@gmail.com>
Tested-by: Ben Magistro <koncept1@gmail.com>

On Fri, May 6, 2022 at 10:43 AM Bruce Richardson <bruce.richardson@intel.com>
wrote:

> To allow other projects to easily use DPDK as a subproject, add in the
> necessary dependency definitions. Slightly different definitions are
> necessary for static and shared builds, since for shared builds the
> drivers should not be linked in, and the internal meson dependency
> objects are more complete.
>
> To use DPDK as a subproject fallback i.e. use installed DPDK if present,
> otherwise the shipped one, the following meson statement can be used:
>
> libdpdk = dependency('libdpdk', fallback: ['dpdk', 'dpdk_dep'])
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  buildtools/subproject/meson.build | 21 +++++++++++++++++++++
>  drivers/meson.build               |  4 ++++
>  lib/meson.build                   |  2 ++
>  meson.build                       |  6 ++++++
>  4 files changed, 33 insertions(+)
>  create mode 100644 buildtools/subproject/meson.build
>
> diff --git a/buildtools/subproject/meson.build
> b/buildtools/subproject/meson.build
> new file mode 100644
> index 0000000000..3192efaa40
> --- /dev/null
> +++ b/buildtools/subproject/meson.build
> @@ -0,0 +1,21 @@
> +# SPDX-License-Identifier: BSD-3-Clause
> +# Copyright(c) 2022 Intel Corporation
> +
> +message('DPDK subproject linking: ' + get_option('default_library'))
> +if get_option('default_library') == 'static'
> +    dpdk_dep = declare_dependency(
> +            version: meson.project_version(),
> +            dependencies: dpdk_static_lib_deps,
> +            # static library deps in DPDK build don't include "link_with"
> parameters,
> +            # so explicitly link-in both libs and drivers
> +            link_with: dpdk_static_libraries,
> +            link_whole: dpdk_drivers,
> +            link_args: dpdk_extra_ldflags)
> +else
> +    dpdk_dep = declare_dependency(
> +            version: meson.project_version(),
> +            # shared library deps include all necessary linking parameters
> +            dependencies: dpdk_shared_lib_deps)
> +endif
> +
> +libdpdk_dep = dpdk_dep
> diff --git a/drivers/meson.build b/drivers/meson.build
> index 1d8123b00c..db4d9c73bd 100644
> --- a/drivers/meson.build
> +++ b/drivers/meson.build
> @@ -245,6 +245,10 @@ foreach subpath:subdirs
>
>          set_variable('shared_@0@'.format(lib_name), shared_dep)
>          set_variable('static_@0@'.format(lib_name), static_dep)
> +        # for drivers, we only need to add dependency objects for static
> libs,
> +        # shared lib drivers are not linked in
> +        dpdk_static_lib_deps += static_dep
> +
>          dependency_name = ''.join(lib_name.split('rte_'))
>          if developer_mode
>              message('drivers/@0@: Defining dependency "@1@"'.format(
> diff --git a/lib/meson.build b/lib/meson.build
> index 24adbe44c9..c648f7d800 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -266,6 +266,8 @@ foreach l:libraries
>
>      set_variable('shared_rte_' + name, shared_dep)
>      set_variable('static_rte_' + name, static_dep)
> +    dpdk_shared_lib_deps += shared_dep
> +    dpdk_static_lib_deps += static_dep
>      if developer_mode
>          message('lib/@0@: Defining dependency "@1@"'.format(l, name))
>      endif
> diff --git a/meson.build b/meson.build
> index 937f6110c0..6085e32a79 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -36,6 +36,8 @@ dpdk_build_root = meson.current_build_dir()
>  dpdk_conf = configuration_data()
>  dpdk_libraries = []
>  dpdk_static_libraries = []
> +dpdk_shared_lib_deps = []
> +dpdk_static_lib_deps = []
>  dpdk_chkinc_headers = []
>  dpdk_driver_classes = []
>  dpdk_drivers = []
> @@ -103,6 +105,10 @@ configure_file(output: build_cfg,
>  # build pkg-config files for dpdk
>  subdir('buildtools/pkg-config')
>
> +if meson.is_subproject()
> +    subdir('buildtools/subproject')
> +endif
> +
>  # final output, list all the libs and drivers to be built
>  # this does not affect any part of the build, for information only.
>  output_message = '\n=================\nLibraries
> Enabled\n=================\n'
> --
> 2.34.1
>
>
  

21/05/2022 02:54, Ben Magistro:
> Currently utilizing this in an upcoming set of changes for TLDK and all
> seems to be working for fallback dependency support under both shared and
> static linkage.
> 
> Reviewed-by: Ben Magistro <koncept1@gmail.com>
> Tested-by: Ben Magistro <koncept1@gmail.com>
> 
> On Fri, May 6, 2022 at 10:43 AM Bruce Richardson <bruce.richardson@intel.com>
> wrote:
> 
> > To allow other projects to easily use DPDK as a subproject, add in the
> > necessary dependency definitions. Slightly different definitions are
> > necessary for static and shared builds, since for shared builds the
> > drivers should not be linked in, and the internal meson dependency
> > objects are more complete.
> >
> > To use DPDK as a subproject fallback i.e. use installed DPDK if present,
> > otherwise the shipped one, the following meson statement can be used:
> >
> > libdpdk = dependency('libdpdk', fallback: ['dpdk', 'dpdk_dep'])
> >
> > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>

Applied, thanks.