rust: cleanup module_init!, use it from #[derive(Object)]

Remove the duplicate code by using the module_init! macro; at the same time,
simplify how module_init! is used, by taking inspiration from the implementation
of #[derive(Object)].

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 27 insertions, 38 deletions

diff --git a/rust/qemu-api/src/definitions.rs b/rust/qemu-api/src/definitions.rs
index 3323a66..064afe6 100644
--- a/rust/qemu-api/src/definitions.rs
+++ b/rust/qemu-api/src/definitions.rs
@@ -29,51 +29,40 @@ pub trait Class {
 
 #[macro_export]
 macro_rules! module_init {
-    ($func:expr, $type:expr) => {
-        #[used]
-        #[cfg_attr(
-            not(any(target_vendor = "apple", target_os = "windows")),
-            link_section = ".init_array"
-        )]
-        #[cfg_attr(target_vendor = "apple", link_section = "__DATA,__mod_init_func")]
-        #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
-        pub static LOAD_MODULE: extern "C" fn() = {
-            extern "C" fn __load() {
-                unsafe {
-                    $crate::bindings::register_module_init(Some($func), $type);
-                }
-            }
-
-            __load
-        };
-    };
-    (qom: $func:ident => $body:block) => {
-        // NOTE: To have custom identifiers for the ctor func we need to either supply
-        // them directly as a macro argument or create them with a proc macro.
-        #[used]
-        #[cfg_attr(
-            not(any(target_vendor = "apple", target_os = "windows")),
-            link_section = ".init_array"
-        )]
-        #[cfg_attr(target_vendor = "apple", link_section = "__DATA,__mod_init_func")]
-        #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
-        pub static LOAD_MODULE: extern "C" fn() = {
-            extern "C" fn __load() {
-                unsafe extern "C" fn $func() {
+    ($type:ident => $body:block) => {
+        const _: () = {
+            #[used]
+            #[cfg_attr(
+                not(any(target_vendor = "apple", target_os = "windows")),
+                link_section = ".init_array"
+            )]
+            #[cfg_attr(target_vendor = "apple", link_section = "__DATA,__mod_init_func")]
+            #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
+            pub static LOAD_MODULE: extern "C" fn() = {
+                extern "C" fn init_fn() {
                     $body
                 }
 
-                unsafe {
-                    $crate::bindings::register_module_init(
-                        Some($func),
-                        $crate::bindings::module_init_type::MODULE_INIT_QOM,
-                    );
+                extern "C" fn ctor_fn() {
+                    unsafe {
+                        $crate::bindings::register_module_init(
+                            Some(init_fn),
+                            $crate::bindings::module_init_type::$type,
+                        );
+                    }
                 }
-            }
 
-            __load
+                ctor_fn
+            };
         };
     };
+
+    // shortcut because it's quite common that $body needs unsafe {}
+    ($type:ident => unsafe $body:block) => {
+        $crate::module_init! {
+            $type => { unsafe { $body } }
+        }
+    };
 }
 
 #[macro_export]