Re: [Qemu-devel] [PATCH 6/7] vhost-user-scsi: convert to Meson

[Markus Armbruster <armbru@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> The libiscsi pkg-config information is extracted from config-host.mak and
> used to link vhost-user-blk.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  .gitignore                            | 2 +-
>  Makefile                              | 3 ---
>  Makefile.objs                         | 3 ---
>  contrib/vhost-user-scsi/Makefile.objs | 1 -
>  contrib/vhost-user-scsi/meson.build   | 3 +++
>  meson.build                           | 3 +++
>  6 files changed, 7 insertions(+), 8 deletions(-)
>  delete mode 100644 contrib/vhost-user-scsi/Makefile.objs
>  create mode 100644 contrib/vhost-user-scsi/meson.build
>
> diff --git a/.gitignore b/.gitignore
> index 20637a1..3934eff 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -63,7 +63,7 @@
>  /qemu-version.h.tmp
>  /module_block.h
>  /scsi/qemu-pr-helper
> -/vhost-user-scsi
> +/contrib/vhost-user-scsi/vhost-user-scsi
>  /contrib/vhost-user-blk/vhost-user-blk
>  /fsdev/virtfs-proxy-helper
>  *.tmp
> diff --git a/Makefile b/Makefile
> index da290fa..bff097c 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -426,7 +426,6 @@ dummy := $(call unnest-vars,, \
>                  ivshmem-client-obj-y \
>                  ivshmem-server-obj-y \
>                  rdmacm-mux-obj-y \
> -                vhost-user-scsi-obj-y \
>                  vhost-user-input-obj-y \
>                  vhost-user-gpu-obj-y \
>                  qga-vss-dll-obj-y \
> @@ -629,8 +628,6 @@ ivshmem-client$(EXESUF): $(ivshmem-client-obj-y) $(COMMON_LDADDS)
>  ivshmem-server$(EXESUF): $(ivshmem-server-obj-y) $(COMMON_LDADDS)
>  	$(call LINK, $^)
>  endif
> -vhost-user-scsi$(EXESUF): $(vhost-user-scsi-obj-y) contrib/libvhost-user/libvhost-user.a
> -	$(call LINK, $^)
>  
>  rdmacm-mux$(EXESUF): LIBS += "-libumad"
>  rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS)
> diff --git a/Makefile.objs b/Makefile.objs
> index 644e2bd..adf2f92 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -116,9 +116,6 @@ qga-vss-dll-obj-y = qga/
>  elf2dmp-obj-y = contrib/elf2dmp/
>  ivshmem-client-obj-$(CONFIG_IVSHMEM) = contrib/ivshmem-client/
>  ivshmem-server-obj-$(CONFIG_IVSHMEM) = contrib/ivshmem-server/
> -vhost-user-scsi.o-cflags := $(LIBISCSI_CFLAGS)
> -vhost-user-scsi.o-libs := $(LIBISCSI_LIBS)
> -vhost-user-scsi-obj-y = contrib/vhost-user-scsi/

The casual reader may wonder what these variables do.  The %.o: %.c rule
in rules.mak passes $($@-cflags) to $(CC).

With meson, ...

>  rdmacm-mux-obj-y = contrib/rdmacm-mux/
>  vhost-user-input-obj-y = contrib/vhost-user-input/
>  vhost-user-gpu-obj-y = contrib/vhost-user-gpu/
> diff --git a/contrib/vhost-user-scsi/Makefile.objs b/contrib/vhost-user-scsi/Makefile.objs
> deleted file mode 100644
> index e83a38a..0000000
> --- a/contrib/vhost-user-scsi/Makefile.objs
> +++ /dev/null
> @@ -1 +0,0 @@
> -vhost-user-scsi-obj-y = vhost-user-scsi.o
> diff --git a/contrib/vhost-user-scsi/meson.build b/contrib/vhost-user-scsi/meson.build
> new file mode 100644
> index 0000000..b80398c
> --- /dev/null
> +++ b/contrib/vhost-user-scsi/meson.build
> @@ -0,0 +1,3 @@
> +executable('vhost-user-scsi', files('vhost-user-scsi.c'),
> +           link_with: libvhost_user,
> +           dependencies: [glib, libiscsi])

... we instead name dependencies, which ...

> diff --git a/meson.build b/meson.build
> index c4cad8f..bc7fbea 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -10,6 +10,9 @@ add_project_arguments(config_host['QEMU_INCLUDES'].split(),
>  
>  glib = declare_dependency(compile_args: config_host['GLIB_CFLAGS'].split(),
>                            link_args: config_host['GLIB_LIBS'].split())
> +libiscsi = declare_dependency(compile_args: config_host['LIBISCSI_CFLAGS'].split(),
> +                          link_args: config_host['LIBISCSI_LIBS'].split())

... we define here.  Less magical.

Note that there's also glib dependency, which works the same (see
previous patch).  With Make, we add GLib flags to QEMU_CFLAGS and LIBS,
so they get used for everything unless overridden.

>  
>  subdir('contrib/libvhost-user')
>  subdir('contrib/vhost-user-blk')
> +subdir('contrib/vhost-user-scsi')