libqemuutil, qapi, trace: convert to meson

This shows how to do some "computations" in meson.build using its array
and dictionary data structures, and also a basic usage of the sourceset
module for conditional compilation.

Notice the new "if have_system" part of util/meson.build, which fixes
a bug in the old build system was buggy: util/dbus.c was built even for
non-softmmu builds, but the dependency on -lgio was lost when the linking
was done through libqemuutil.a.  Because all of its users required gio
otherwise, the bug was hidden.  Meson instead propagates libqemuutil's
dependencies down to its users, and shows the problem.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

qapi/Makefile.objs

@@ -1,25 +1,4 @@
-util-obj-y = qapi-visit-core.o qapi-dealloc-visitor.o qobject-input-visitor.o
-util-obj-y += qobject-output-visitor.o qmp-registry.o qmp-dispatch.o
-util-obj-y += string-input-visitor.o string-output-visitor.o
-util-obj-y += opts-visitor.o qapi-clone-visitor.o
-util-obj-y += qmp-event.o
-util-obj-y += qapi-util.o
-
-QAPI_COMMON_MODULES = audio authz block-core block char common control crypto
-QAPI_COMMON_MODULES += dump error introspect job machine migration misc
-QAPI_COMMON_MODULES += net pragma qdev qom rdma rocker run-state sockets tpm
-QAPI_COMMON_MODULES += trace transaction ui
 QAPI_TARGET_MODULES = machine-target misc-target
-QAPI_MODULES = $(QAPI_COMMON_MODULES) $(QAPI_TARGET_MODULES)
-
-util-obj-y += qapi-builtin-types.o
-util-obj-y += $(QAPI_COMMON_MODULES:%=qapi-types-%.o)
-util-obj-y += qapi-builtin-visit.o
-util-obj-y += $(QAPI_COMMON_MODULES:%=qapi-visit-%.o)
-util-obj-y += qapi-emit-events.o
-util-obj-y += $(QAPI_COMMON_MODULES:%=qapi-events-%.o)
-
-common-obj-y = $(QAPI_COMMON_MODULES:%=qapi-commands-%.o)
 
 obj-y = qapi-introspect.o
 obj-y += $(QAPI_TARGET_MODULES:%=qapi-types-%.o)
@@ -34,5 +13,3 @@ obj-y += qapi-init-commands.o
 
 QAPI_MODULES_STORAGE_DAEMON = block-core char common control crypto
 QAPI_MODULES_STORAGE_DAEMON += introspect job qom sockets pragma transaction
-
-storage-daemon-obj-y += $(QAPI_MODULES_STORAGE_DAEMON:%=qapi-commands-%.o)

qapi/meson.build

@@ -0,0 +1,121 @@
+util_ss.add(files(
+  'opts-visitor.c',
+  'qapi-clone-visitor.c',
+  'qapi-dealloc-visitor.c',
+  'qapi-util.c',
+  'qapi-visit-core.c',
+  'qmp-dispatch.c',
+  'qmp-event.c',
+  'qmp-registry.c',
+  'qobject-input-visitor.c',
+  'qobject-output-visitor.c',
+  'string-input-visitor.c',
+  'string-output-visitor.c',
+))
+
+qapi_all_modules = [
+  'audio',
+  'authz',
+  'block-core',
+  'block',
+  'char',
+  'common',
+  'control',
+  'crypto',
+  'dump',
+  'error',
+  'introspect',
+  'job',
+  'machine',
+  'machine-target',
+  'migration',
+  'misc',
+  'misc-target',
+  'net',
+  'pragma',
+  'qdev',
+  'qom',
+  'rdma',
+  'rocker',
+  'run-state',
+  'sockets',
+  'tpm',
+  'trace',
+  'transaction',
+  'ui',
+]
+
+qapi_storage_daemon_modules = [
+  'block-core',
+  'char',
+  'common',
+  'control',
+  'crypto',
+  'introspect',
+  'job',
+  'qom',
+  'sockets',
+  'pragma',
+  'transaction',
+]
+
+qapi_nonmodule_outputs = [
+  'qapi-introspect.c', 'qapi-introspect.h',
+  'qapi-types.c', 'qapi-types.h',
+  'qapi-visit.h', 'qapi-visit.c',
+  'qapi-commands.h', 'qapi-commands.c',
+  'qapi-init-commands.h', 'qapi-init-commands.c',
+  'qapi-events.h', 'qapi-events.c',
+  'qapi-emit-events.c', 'qapi-emit-events.h',
+]
+
+# First build all sources
+qapi_util_outputs = [
+  'qapi-builtin-types.c', 'qapi-builtin-visit.c',
+  'qapi-builtin-types.h', 'qapi-builtin-visit.h',
+]
+
+qapi_inputs = []
+qapi_specific_outputs = []
+foreach module : qapi_all_modules
+  qapi_inputs += [ files(module + '.json') ]
+  qapi_module_outputs = [
+    'qapi-types-@0@.c'.format(module),
+    'qapi-types-@0@.h'.format(module),
+    'qapi-visit-@0@.c'.format(module),
+    'qapi-visit-@0@.h'.format(module),
+    'qapi-events-@0@.c'.format(module),
+    'qapi-events-@0@.h'.format(module),
+    'qapi-commands-@0@.c'.format(module),
+    'qapi-commands-@0@.h'.format(module),
+  ]
+  if module.endswith('-target')
+    qapi_specific_outputs += qapi_module_outputs
+  else
+    qapi_util_outputs += qapi_module_outputs
+  endif
+endforeach
+
+qapi_files = custom_target('shared QAPI source files',
+  output: qapi_util_outputs + qapi_specific_outputs + qapi_nonmodule_outputs + ['qapi-doc.texi'],
+  input: [ files('qapi-schema.json') ],
+  command: [ qapi_gen, '-o', 'qapi', '-b', '@INPUT0@' ],
+  depend_files: [ qapi_inputs, qapi_gen_depends ])
+
+# Now go through all the outputs and add them to the right sourceset.
+# These loops must be synchronized with the output of the above custom target.
+
+i = 0
+foreach output : qapi_util_outputs
+  if output.endswith('.h')
+    genh += qapi_files[i]
+  endif
+  util_ss.add(qapi_files[i])
+  i = i + 1
+endforeach
+
+# These are still handled by the Makefile
+i += qapi_nonmodule_outputs.length()
+i += qapi_specific_outputs.length()
+
+qapi_doc_texi = qapi_files[i]