[PATCH 01/10] modules: Provide macros making it easier to identify module exports

[Christophe de Dinechin]

In order to facilitate the move of large chunks of functionality to
load modules, it is simpler to create a wrapper with the same name
that simply relays the implementation. For efficiency, this is
typically done using inline functions in the header for the
corresponding functionality. In that case, we rename the actual
implementation by appending _implementation to its name. This makes it
easier to select which function you want to put a breakpoint on.

Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
---
 include/qemu/module.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/include/qemu/module.h b/include/qemu/module.h
index 011ae1ae76..1922a0293c 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -39,6 +39,30 @@ static void __attribute__((constructor)) do_qemu_init_ ## 
function(void)    \
 }
 #endif
 
+#ifdef CONFIG_MODULES
+/* Identify which functions are replaced by a callback stub */
+#ifdef MODULE_STUBS
+#define MODIFACE(Ret,Name,Args)                                         \
+    Ret (*Name)Args;                                                    \
+    extern Ret Name##_implementation Args
+#else /* !MODULE_STUBS */
+#define MODIFACE(Ret,Name,Args)                                         \
+    extern Ret (*Name)Args;                                             \
+    extern Ret Name##_implementation Args
+#endif /* MODULE_STUBS */
+
+#define MODIMPL(Ret,Name,Args)                                          \
+    static void __attribute__((constructor)) Name##_register(void)      \
+    {                                                                   \
+        Name = Name##_implementation;                                   \
+    }                                                                   \
+    Ret Name##_implementation Args
+#else /* !CONFIG_MODULES */
+/* When not using a module, such functions are called directly */
+#define MODIFACE(Ret,Name,Args)         Ret Name Args
+#define MODIMPL(Ret,Name,Args)          Ret Name Args
+#endif /* CONFIG_MODULES */
+
 typedef enum {
     MODULE_INIT_MIGRATION,
     MODULE_INIT_BLOCK,
-- 
2.26.2