plugins/loader: compile loader only once

There is very little in loader that is different between builds save
for a tiny user/system mode difference in the plugin_info structure.
Create two new files, user and system to hold mode specific helpers
and move loader into common_ss.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250304222439.2035603-26-alex.bennee@linaro.org>

plugins/loader.c

@@ -31,9 +31,6 @@
 #include "qemu/memalign.h"
 #include "hw/core/cpu.h"
 #include "exec/tb-flush.h"
-#ifndef CONFIG_USER_ONLY
-#include "hw/boards.h"
-#endif
 
 #include "plugin.h"
 
@@ -300,14 +297,8 @@ int qemu_plugin_load_list(QemuPluginList *head, Error **errp)
     info->target_name = target_name();
     info->version.min = QEMU_PLUGIN_MIN_VERSION;
     info->version.cur = QEMU_PLUGIN_VERSION;
-#ifndef CONFIG_USER_ONLY
-    MachineState *ms = MACHINE(qdev_get_machine());
-    info->system_emulation = true;
-    info->system.smp_vcpus = ms->smp.cpus;
-    info->system.max_vcpus = ms->smp.max_cpus;
-#else
-    info->system_emulation = false;
-#endif
+
+    qemu_plugin_fillin_mode_info(info);
 
     QTAILQ_FOREACH_SAFE(desc, head, entry, next) {
         int err;

plugins/meson.build

@@ -57,8 +57,13 @@ if host_os == 'windows'
     command: dlltool_cmd
   )
 endif
+
+user_ss.add(files('user.c'))
+system_ss.add(files('system.c'))
+
+common_ss.add(files('loader.c'))
+
 specific_ss.add(files(
-  'loader.c',
   'core.c',
   'api.c',
 ))

plugins/plugin.h

@@ -119,4 +119,10 @@ struct qemu_plugin_scoreboard *plugin_scoreboard_new(size_t element_size);
 
 void plugin_scoreboard_free(struct qemu_plugin_scoreboard *score);
 
+/**
+ * qemu_plugin_fillin_mode_info() - populate mode specific info
+ * info: pointer to qemu_info_t structure
+ */
+void qemu_plugin_fillin_mode_info(qemu_info_t *info);
+
 #endif /* PLUGIN_H */

plugins/system.c

@@ -0,0 +1,24 @@
+/*
+ * QEMU Plugin system-emulation helpers
+ *
+ * Helpers that are specific to system emulation.
+ *
+ * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
+ * Copyright (C) 2019-2025, Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/plugin.h"
+#include "hw/boards.h"
+
+#include "plugin.h"
+
+void qemu_plugin_fillin_mode_info(qemu_info_t *info)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    info->system_emulation = true;
+    info->system.smp_vcpus = ms->smp.cpus;
+    info->system.max_vcpus = ms->smp.max_cpus;
+}

plugins/user.c

@@ -0,0 +1,19 @@
+/*
+ * QEMU Plugin user-mode helpers
+ *
+ * Helpers that are specific to user-mode.
+ *
+ * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
+ * Copyright (C) 2019-2025, Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/plugin.h"
+#include "plugin.h"
+
+void qemu_plugin_fillin_mode_info(qemu_info_t *info)
+{
+    info->system_emulation = false;
+}