[PATCH v2 01/18] modules: add metadata macros, add qxl module annotations

[Gerd Hoffmann <kraxel@redhat.com>]

Stealing an idea from the linux kernel:  Place module metadata
in an .modinfo elf section.  This patch adds macros and qxl module
annotations as example.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 include/qemu/module.h | 22 ++++++++++++++++++++++
 hw/display/qxl.c      |  4 ++++
 2 files changed, 26 insertions(+)

diff --git a/include/qemu/module.h b/include/qemu/module.h
index 944d403cbd15..d3cab3c25a2f 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -73,4 +73,26 @@ bool module_load_one(const char *prefix, const char *lib_name, bool mayfail);
 void module_load_qom_one(const char *type);
 void module_load_qom_all(void);
 
+/*
+ * macros to store module metadata in a .modinfo section.
+ * qemu-modinfo utility will collect the metadata.
+ *
+ * Use "objdump -t -s -j .modinfo ${module}.so" to inspect.
+ */
+
+#define ___PASTE(a, b) a##b
+#define __PASTE(a, b) ___PASTE(a, b)
+
+#define modinfo(kind, value)                             \
+    static const char __PASTE(kind, __LINE__)[]          \
+        __attribute__((__used__))                        \
+        __attribute__((section(".modinfo")))             \
+        __attribute__((aligned(1)))                      \
+        = stringify(kind) "=" value
+
+#define module_obj(name) modinfo(obj, name)
+#define module_dep(name) modinfo(dep, name)
+#define module_arch(name) modinfo(arch, name)
+#define module_opts(name) modinfo(opts, name)
+
 #endif
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index 6e1f8ff1b2a7..84f99088e0a0 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -2522,6 +2522,7 @@ static const TypeInfo qxl_primary_info = {
     .parent        = TYPE_PCI_QXL,
     .class_init    = qxl_primary_class_init,
 };
+module_obj("qxl-vga");
 
 static void qxl_secondary_class_init(ObjectClass *klass, void *data)
 {
@@ -2538,6 +2539,7 @@ static const TypeInfo qxl_secondary_info = {
     .parent        = TYPE_PCI_QXL,
     .class_init    = qxl_secondary_class_init,
 };
+module_obj("qxl");
 
 static void qxl_register_types(void)
 {
@@ -2547,3 +2549,5 @@ static void qxl_register_types(void)
 }
 
 type_init(qxl_register_types)
+
+module_dep("ui-spice-core");
-- 
2.31.1