[PATCH v3 008/114] target-info: replace QOM registration with a constructor list

[Yonggang Luo <luoyonggang@xxxxxxxxx>]

Replace MODULE_INIT_TARGET_INFO and target_info_qom_set_target with a
constructor list. target_info_init builds a TargetInfoNode;
target_info_list_add inserts it, sorted by target_arch, before main().
target_info() starts as an "unknown" TargetInfo and target_info_select
sets the current entry. target-info.c moves into libqom.

Signed-off-by: Yonggang Luo <luoyonggang@xxxxxxxxx>
---
 include/qemu/module.h           |  1 -
 include/qemu/target-info-def.h  | 56 ++++++++++++++++++++++++++++++---
 include/qemu/target-info-init.h | 53 -------------------------------
 include/qemu/target-info-qom.h  | 30 ------------------
 include/qemu/target-info.h      | 11 +++++++
 meson.build                     |  6 ++--
 system/vl.c                     |  4 ---
 target-info-def.c               |  1 -
 target-info-qom.c               | 55 --------------------------------
 target-info.c                   | 56 ++++++++++++++++++++++++++++++++-
 tests/qtest/fuzz/fuzz.c         |  3 --
 11 files changed, 120 insertions(+), 156 deletions(-)
 delete mode 100644 include/qemu/target-info-init.h
 delete mode 100644 include/qemu/target-info-qom.h
 delete mode 100644 target-info-qom.c

diff --git a/include/qemu/module.h b/include/qemu/module.h
index fccf017bf9e..9885ac9afb3 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -43,7 +43,6 @@ typedef enum {
     MODULE_INIT_MIGRATION,
     MODULE_INIT_BLOCK,
     MODULE_INIT_OPTS,
-    MODULE_INIT_TARGET_INFO,
     MODULE_INIT_QOM,
     MODULE_INIT_TRACE,
     MODULE_INIT_XEN_BACKEND,
diff --git a/include/qemu/target-info-def.h b/include/qemu/target-info-def.h
index ebd88463aea..25dc7c508d3 100644
--- a/include/qemu/target-info-def.h
+++ b/include/qemu/target-info-def.h
@@ -11,8 +11,10 @@
 
 #include "qapi/qapi-types-common.h"
 #include "qapi/qapi-types-machine.h"
+#include "qemu/queue.h"
+#include "qemu/target-info.h"
 
-typedef struct TargetInfo {
+struct TargetInfo {
     /* runtime equivalent of TARGET_NAME definition */
     const char *target_name;
     /* related to TARGET_ARCH definition */
@@ -30,13 +32,57 @@ typedef struct TargetInfo {
     unsigned page_bits_init;
     /* runtime equivalent of TARGET_PAGE_BITS_VARY definition */
     bool page_bits_vary;
-} TargetInfo;
+};
+
+typedef struct TargetInfoNode TargetInfoNode;
+typedef QLIST_HEAD(, TargetInfoNode) TargetInfoList;
+
+struct TargetInfoNode {
+    const TargetInfo *info;
+    QLIST_ENTRY(TargetInfoNode) next;
+};
+
+/**
+ * target_info_list:
+ *
+ * TargetInfo is a static list, not a QOM type. Constructors insert
+ * entries before main(), so type_init can use it.
+ *
+ * Returns: registered TargetInfoNode list head, sorted by
+ *          info->target_arch. The list is owned by target-info
+ *          and must not be modified. Iterate with
+ *          QLIST_FOREACH(..., next) and use node->info.
+ */
+const TargetInfoList *target_info_list(void);
 
 /**
- * target_info:
+ * target_info_select:
+ * @ti: TargetInfo to make current
  *
- * Returns: The TargetInfo structure definition for this target binary.
+ * Sets target_info() to @ti.
+ */
+void target_info_select(const TargetInfo *ti);
+
+/**
+ * target_info_list_add:
+ * @node: static TargetInfoNode whose info points at a const TargetInfo
+ *
+ * Inserts @node into target_info_list(), sorted by info->target_arch.
+ * Sets target_info() to the first list entry.
+ */
+void target_info_list_add(TargetInfoNode *node);
+
+/*
+ * Register @ti before main(). Linked into the executable, not a DSO.
+ * @ti is a unique identifier in this translation unit.
  */
-const TargetInfo *target_info(void);
+#define target_info_init(ti)                                            \
+    static TargetInfoNode ti##_node = {                                 \
+        .info = &(ti),                                                  \
+    };                                                                  \
+    static void __attribute__((constructor)) do_qemu_init_##ti(void)    \
+    {                                                                   \
+        target_info_list_add(&ti##_node);                               \
+    }
 
 #endif
diff --git a/include/qemu/target-info-init.h b/include/qemu/target-info-init.h
deleted file mode 100644
index b7024c9faef..00000000000
--- a/include/qemu/target-info-init.h
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * QEMU target info initialization
- *
- * Copyright (c) Qualcomm
- *
- * SPDX-License-Identifier: GPL-2.0-or-later
- *
- * This file is included by each file defining a TargetInfo structure and is
- * responsible for registering it.
- */
-
-#ifndef QEMU_TARGET_INFO_INIT_H
-#define QEMU_TARGET_INFO_INIT_H
-
-#define DEFINE_TARGET_INFO_TYPE(info)                                       \
-static void do_qemu_init_target_info(void)                                  \
-{                                                                           \
-    type_register_static(&info);                                            \
-}                                                                           \
-module_init(do_qemu_init_target_info, MODULE_INIT_TARGET_INFO)
-
-#ifdef COMPILING_PER_TARGET
-#ifdef CONFIG_USER_ONLY
-
-/*
- * User mode does not support multiple targets in the same binary, so just
- * define target_info().
- */
-#define target_info_init(ti_var)        \
-const TargetInfo *target_info(void)     \
-{                                       \
-    return &ti_var;                     \
-}
-
-#else /* CONFIG_USER_ONLY */
-
-#include "qemu/target-info-qom.h"
-#include "qom/object.h"
-
-#define target_info_init(ti_var)                                            \
-static const TypeInfo target_info_qom_target_type_info = {                  \
-    .name =  TYPE_TARGET_INFO"-"TARGET_NAME,                                \
-    .parent = TYPE_TARGET_INFO,                                             \
-    .instance_size = sizeof(TargetInfoQom),                                 \
-    .class_size = sizeof(TargetInfoQomClass),                               \
-    .class_data = &ti_var,                                                  \
-};                                                                          \
-DEFINE_TARGET_INFO_TYPE(target_info_qom_target_type_info)
-
-#endif /* CONFIG_USER_ONLY */
-#endif /* COMPILING_PER_TARGET */
-
-#endif /* QEMU_TARGET_INFO_INIT_H */
diff --git a/include/qemu/target-info-qom.h b/include/qemu/target-info-qom.h
deleted file mode 100644
index 0f6772e65c3..00000000000
--- a/include/qemu/target-info-qom.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * QEMU target info QOM types
- *
- * Copyright (c) Qualcomm
- *
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-#ifndef QEMU_TARGET_INFO_QOM_H
-#define QEMU_TARGET_INFO_QOM_H
-
-#include "qemu/target-info-def.h"
-#include "qom/object.h"
-
-#define TYPE_TARGET_INFO "target-info"
-
-typedef struct TargetInfoQom {
-    Object parent_obj;
-} TargetInfoQom;
-
-typedef struct TargetInfoQomClass {
-    ObjectClass parent_class;
-    const TargetInfo *target_info;
-} TargetInfoQomClass;
-
-OBJECT_DECLARE_TYPE(TargetInfoQom, TargetInfoQomClass, TARGET_INFO)
-
-void target_info_qom_set_target(void);
-
-#endif /* QEMU_TARGET_INFO_QOM_H */
diff --git a/include/qemu/target-info.h b/include/qemu/target-info.h
index c09e5d2a3ec..c48973f20be 100644
--- a/include/qemu/target-info.h
+++ b/include/qemu/target-info.h
@@ -9,6 +9,17 @@
 #ifndef QEMU_TARGET_INFO_H
 #define QEMU_TARGET_INFO_H
 
+#include <stdbool.h>
+
+typedef struct TargetInfo TargetInfo;
+
+/**
+ * target_info:
+ *
+ * Returns: The TargetInfo structure definition for the selected target.
+ */
+const TargetInfo *target_info(void);
+
 /**
  * target_name:
  *
diff --git a/meson.build b/meson.build
index 20345860c9f..9a6a80fd0c8 100644
--- a/meson.build
+++ b/meson.build
@@ -3777,6 +3777,9 @@ if enable_modules
   modulecommon = declare_dependency(objects: 
libmodulecommon.extract_all_objects(recursive: false), compile_args: 
'-DBUILD_DSO')
 endif
 
+qom_ss.add(files(
+  'target-info.c',
+))
 qom_ss = qom_ss.apply({})
 libqom = static_library('qom', qom_ss.sources() + genh,
                         dependencies: [qom_ss.dependencies()],
@@ -3871,9 +3874,6 @@ endif
 common_ss.add(pagevary)
 system_ss.add(files('page-vary-system.c'))
 
-common_ss.add(files('target-info.c'))
-system_ss.add(files('target-info-qom.c'))
-
 if 'CONFIG_TCG' in config_all_accel
   subdir('contrib/plugins')
 endif
diff --git a/system/vl.c b/system/vl.c
index dc883de8274..37cb4838188 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -28,7 +28,6 @@
 #include "qemu/units.h"
 #include "qemu/module.h"
 #include "qemu/target-info.h"
-#include "qemu/target-info-qom.h"
 #include "exec/cpu-common.h"
 #include "exec/page-vary.h"
 #include "hw/core/qdev-properties.h"
@@ -2930,9 +2929,6 @@ void qemu_init(int argc, char **argv)
 
     os_setup_limits();
 
-    module_call_init(MODULE_INIT_TARGET_INFO);
-    target_info_qom_set_target();
-
     module_init_info(qemu_modinfo);
     module_allow_arch(target_name());
 
diff --git a/target-info-def.c b/target-info-def.c
index f167f5f2ac1..954298b56d0 100644
--- a/target-info-def.c
+++ b/target-info-def.c
@@ -9,7 +9,6 @@
 #include "qemu/osdep.h"
 #include "qemu/target-info.h"
 #include "qemu/target-info-def.h"
-#include "qemu/target-info-init.h"
 #include "cpu-qom.h"
 #include "cpu-param.h"
 #include "exec/page-vary.h"
diff --git a/target-info-qom.c b/target-info-qom.c
deleted file mode 100644
index 2b38673a3f8..00000000000
--- a/target-info-qom.c
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * QEMU binary/target API (QOM types)
- *
- *  Copyright (c) Linaro
- *
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-#include "qemu/osdep.h"
-#include "qapi/error.h"
-#include "qom/object.h"
-#include "qemu/target-info-def.h"
-#include "qemu/target-info-init.h"
-#include "qemu/target-info-qom.h"
-
-static void target_info_qom_class_init(ObjectClass *oc, const void * data)
-{
-    TargetInfoQomClass *klass = TARGET_INFO_CLASS(oc);
-    klass->target_info = data;
-}
-
-static const TypeInfo target_info_parent_type = {
-    .name = TYPE_TARGET_INFO,
-    .parent = TYPE_OBJECT,
-    .instance_size = sizeof(TargetInfoQom),
-    .class_size = sizeof(TargetInfoQomClass),
-    /* use class_base_init so children classes can set class_data accordingly 
*/
-    .class_base_init = target_info_qom_class_init,
-    /* children classes will be concrete, which allows to easily query them
-     * without listing this parent class also */
-    .abstract = true,
-};
-
-DEFINE_TARGET_INFO_TYPE(target_info_parent_type)
-
-static const TargetInfo *target_info_ptr;
-
-const TargetInfo *target_info(void)
-{
-    return target_info_ptr;
-}
-
-void target_info_qom_set_target(void)
-{
-    g_autoptr(GSList) targets = object_class_get_list(TYPE_TARGET_INFO, false);
-
-    size_t num_found = g_slist_length(targets);
-    if (num_found != 1) {
-        error_setg(&error_fatal, num_found == 0 ?
-                                 "no target-info is available" :
-                                 "more than one target-info is available");
-    }
-
-    target_info_ptr = TARGET_INFO_CLASS(targets->data)->target_info;
-}
diff --git a/target-info.c b/target-info.c
index 9abe72b1f55..6e66f48e1ff 100644
--- a/target-info.c
+++ b/target-info.c
@@ -10,7 +10,61 @@
 #include "qemu/target-info.h"
 #include "qemu/target-info-qapi.h"
 #include "qemu/target-info-def.h"
-#include "qapi/error.h"
+#include "exec/page-vary.h"
+
+static const TargetInfo target_info_default = {
+    .target_arch = SYS_EMU_TARGET__MAX,
+    .target_name = "unknown",
+    .long_bits = 64,
+    .endianness = ENDIAN_MODE_LITTLE,
+    .page_bits_init = TARGET_PAGE_BITS_MIN,
+};
+
+static const TargetInfo *target_info_ptr = &target_info_default;
+static TargetInfoList target_infos = QLIST_HEAD_INITIALIZER(target_infos);
+
+const TargetInfo *target_info(void)
+{
+    g_assert(target_info_ptr != NULL);
+    return target_info_ptr;
+}
+
+const TargetInfoList *target_info_list(void)
+{
+    return &target_infos;
+}
+
+void target_info_select(const TargetInfo *ti)
+{
+    g_assert(ti != NULL);
+    target_info_ptr = ti;
+}
+
+void target_info_list_add(TargetInfoNode *node)
+{
+    const TargetInfo *info;
+    TargetInfoNode *cur, *prev = NULL;
+
+    g_assert(node && node->info);
+    info = node->info;
+    QLIST_FOREACH(cur, &target_infos, next) {
+        if (info->target_arch < cur->info->target_arch) {
+            QLIST_INSERT_BEFORE(cur, node, next);
+            break;
+        }
+        prev = cur;
+    }
+    if (!cur) {
+        if (prev) {
+            QLIST_INSERT_AFTER(prev, node, next);
+        } else {
+            QLIST_INSERT_HEAD(&target_infos, node, next);
+        }
+    }
+
+    /* Single-target default: the first list entry. */
+    target_info_select(QLIST_FIRST(&target_infos)->info);
+}
 
 const char *target_name(void)
 {
diff --git a/tests/qtest/fuzz/fuzz.c b/tests/qtest/fuzz/fuzz.c
index a3a131c80f8..d2355989616 100644
--- a/tests/qtest/fuzz/fuzz.c
+++ b/tests/qtest/fuzz/fuzz.c
@@ -22,7 +22,6 @@
 #include "system/runstate.h"
 #include "qemu/main-loop.h"
 #include "qemu/rcu.h"
-#include "qemu/target-info-qom.h"
 #include "tests/qtest/libqtest.h"
 #include "tests/qtest/libqos/qgraph.h"
 #include "fuzz.h"
@@ -173,8 +172,6 @@ int LLVMFuzzerInitialize(int *argc, char ***argv, char 
***envp)
 
     /* Initialize qgraph and modules */
     qos_graph_init();
-    module_call_init(MODULE_INIT_TARGET_INFO);
-    target_info_qom_set_target();
     module_call_init(MODULE_INIT_FUZZ_TARGET);
     module_call_init(MODULE_INIT_QOM);
     module_call_init(MODULE_INIT_LIBQOS);
-- 
2.52.0.windows.1