[PATCH v2 10/15] qemu-common: introduce a common subproject

[marcandre . lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Add a new meson subproject to provide common code and scripts for QEMU
and tools. Initially, it will offer QAPI/QMP code generation and
common utilities.

libvhost-user & libvduse will make use of the subproject to avoid having
include/ links to common headers.

The other targeted user is qemu-ga, which will also be converted to a
subproject (so it can be built, moved, released etc independent from QEMU).

Other projects such as qemu-storage-daemon could be built standalone
eventually in the future.

Note that with meson subprojects are "global". Projects will share
subprojects 
(https://mesonbuild.com/Subprojects.html#subprojects-depending-on-other-subprojects).
We will add extra subprojects/ links to allow standalone subproject
compilation though.

This initial commit simply set the stage to build and link against it.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 meson.build                                              | 9 ++++++++-
 .../qemu-common/include}/qemu/help-texts.h               | 0
 linux-user/meson.build                                   | 4 ++--
 subprojects/libvduse/meson.build                         | 2 ++
 subprojects/libvduse/subprojects/qemu-common             | 1 +
 subprojects/libvhost-user/meson.build                    | 2 ++
 subprojects/libvhost-user/subprojects/qemu-common        | 1 +
 subprojects/qemu-common/meson.build                      | 8 ++++++++
 8 files changed, 24 insertions(+), 3 deletions(-)
 rename {include => subprojects/qemu-common/include}/qemu/help-texts.h (100%)
 create mode 120000 subprojects/libvduse/subprojects/qemu-common
 create mode 120000 subprojects/libvhost-user/subprojects/qemu-common
 create mode 100644 subprojects/qemu-common/meson.build

diff --git a/meson.build b/meson.build
index bc5569ace159..254eb1263a66 100644
--- a/meson.build
+++ b/meson.build
@@ -167,6 +167,10 @@ if 'dtrace' in get_option('trace_backends')
   endif
 endif
 
+add_project_arguments('-I' + meson.current_source_dir() / 
'subprojects/qemu-common/include',
+  language: ['c', 'cpp', 'objc'],
+)
+
 if get_option('iasl') == ''
   iasl = find_program('iasl', required: false)
 else
@@ -1577,6 +1581,9 @@ if libbpf.found() and not cc.links('''
   endif
 endif
 
+qemu_common = subproject('qemu-common')
+qemu_common = qemu_common.get_variable('qemu_common_dep')
+
 #################
 # config-host.h #
 #################
@@ -3052,7 +3059,7 @@ util_ss.add_all(trace_ss)
 util_ss = util_ss.apply(config_all, strict: false)
 libqemuutil = static_library('qemuutil',
                              sources: util_ss.sources() + stub_ss.sources() + 
genh,
-                             dependencies: [util_ss.dependencies(), libm, 
threads, glib, socket, malloc, pixman])
+                             dependencies: [util_ss.dependencies(), libm, 
threads, glib, socket, malloc, pixman, qemu_common])
 qemuutil = declare_dependency(link_with: libqemuutil,
                               sources: genh + version_res,
                               dependencies: [event_loop_base])
diff --git a/include/qemu/help-texts.h 
b/subprojects/qemu-common/include/qemu/help-texts.h
similarity index 100%
rename from include/qemu/help-texts.h
rename to subprojects/qemu-common/include/qemu/help-texts.h
diff --git a/linux-user/meson.build b/linux-user/meson.build
index de4320af053c..fc6cdb55d657 100644
--- a/linux-user/meson.build
+++ b/linux-user/meson.build
@@ -7,7 +7,7 @@ linux_user_ss = ss.source_set()
 common_user_inc += include_directories('include/host/' / host_arch)
 common_user_inc += include_directories('include')
 
-linux_user_ss.add(files(
+linux_user_ss.add([files(
   'elfload.c',
   'exit.c',
   'fd-trans.c',
@@ -20,7 +20,7 @@ linux_user_ss.add(files(
   'thunk.c',
   'uaccess.c',
   'uname.c',
-))
+), qemu_common])
 linux_user_ss.add(rt)
 
 linux_user_ss.add(when: 'TARGET_HAS_BFLT', if_true: files('flatload.c'))
diff --git a/subprojects/libvduse/meson.build b/subprojects/libvduse/meson.build
index ba08f5ee1a03..841509ecb996 100644
--- a/subprojects/libvduse/meson.build
+++ b/subprojects/libvduse/meson.build
@@ -2,6 +2,8 @@ project('libvduse', 'c',
         license: 'GPL-2.0-or-later',
         default_options: ['c_std=gnu99'])
 
+qemu_common = subproject('qemu-common')
+
 libvduse = static_library('vduse',
                           files('libvduse.c'),
                           c_args: '-D_GNU_SOURCE')
diff --git a/subprojects/libvduse/subprojects/qemu-common 
b/subprojects/libvduse/subprojects/qemu-common
new file mode 120000
index 000000000000..4c1c87018a7a
--- /dev/null
+++ b/subprojects/libvduse/subprojects/qemu-common
@@ -0,0 +1 @@
+../../qemu-common
\ No newline at end of file
diff --git a/subprojects/libvhost-user/meson.build 
b/subprojects/libvhost-user/meson.build
index 39825d9404ae..73355908e072 100644
--- a/subprojects/libvhost-user/meson.build
+++ b/subprojects/libvhost-user/meson.build
@@ -5,6 +5,8 @@ project('libvhost-user', 'c',
 threads = dependency('threads')
 glib = dependency('glib-2.0')
 
+qemu_common = subproject('qemu-common')
+
 vhost_user = static_library('vhost-user',
                             files('libvhost-user.c'),
                             dependencies: threads,
diff --git a/subprojects/libvhost-user/subprojects/qemu-common 
b/subprojects/libvhost-user/subprojects/qemu-common
new file mode 120000
index 000000000000..4c1c87018a7a
--- /dev/null
+++ b/subprojects/libvhost-user/subprojects/qemu-common
@@ -0,0 +1 @@
+../../qemu-common
\ No newline at end of file
diff --git a/subprojects/qemu-common/meson.build 
b/subprojects/qemu-common/meson.build
new file mode 100644
index 000000000000..8969b08473ef
--- /dev/null
+++ b/subprojects/qemu-common/meson.build
@@ -0,0 +1,8 @@
+project('qemu-common', 'c',
+  license: 'GPL-2.0-or-later',
+  default_options: ['c_std=gnu11']
+)
+
+qemu_common_dep = declare_dependency(
+  include_directories: include_directories('include'),
+)
-- 
2.37.0.rc0