Use ptr::addr_of! to avoid creating references to block ISAs

madsmtm · Jan 7, 2024 · b733009 · b733009
1 parent 498904a
commit b733009
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Showing 4 changed files with 15 additions and 10 deletions.
diff --git a/crates/block2/src/concrete_block.rs b/crates/block2/src/concrete_block.rs
@@ -215,7 +215,7 @@ impl<A, R, F> ConcreteBlock<A, R, F> {
     /// correct arguments.
     unsafe fn with_invoke(invoke: unsafe extern "C" fn(), closure: F) -> Self {
         let layout = abi::Block_layout {
-            isa: unsafe { &ffi::_NSConcreteStackBlock },
+            isa: unsafe { ptr::addr_of!(ffi::_NSConcreteStackBlock) },
             flags: Self::FLAGS,
             reserved: 0,
             invoke: Some(invoke),

diff --git a/crates/block2/src/debug.rs b/crates/block2/src/debug.rs
@@ -11,11 +11,14 @@ struct Isa(*const ffi::Class);
 
 impl Isa {
     fn is_global(self) -> bool {
-        ptr::eq(unsafe { &ffi::_NSConcreteGlobalBlock }, self.0)
+        ptr::eq(
+            unsafe { ptr::addr_of!(ffi::_NSConcreteGlobalBlock) },
+            self.0,
+        )
     }
 
     fn is_stack(self) -> bool {
-        ptr::eq(unsafe { &ffi::_NSConcreteStackBlock }, self.0)
+        ptr::eq(unsafe { ptr::addr_of!(ffi::_NSConcreteStackBlock) }, self.0)
     }
 }
 
@@ -216,13 +219,13 @@ mod tests {
 
     #[test]
     fn test_isa() {
-        let isa = Isa(unsafe { &ffi::_NSConcreteGlobalBlock });
+        let isa = Isa(unsafe { ptr::addr_of!(ffi::_NSConcreteGlobalBlock) });
         assert!(isa.is_global());
         assert!(!isa.is_stack());
-        let isa = Isa(unsafe { &ffi::_NSConcreteStackBlock });
+        let isa = Isa(unsafe { ptr::addr_of!(ffi::_NSConcreteStackBlock) });
         assert!(!isa.is_global());
         assert!(isa.is_stack());
-        let isa = Isa(unsafe { &ffi::private::_NSConcreteMallocBlock });
+        let isa = Isa(unsafe { ptr::addr_of!(ffi::private::_NSConcreteMallocBlock) });
         assert!(!isa.is_global());
         assert!(!isa.is_stack());
         let isa = Isa(ptr::null());

diff --git a/crates/block2/src/ffi.rs b/crates/block2/src/ffi.rs
@@ -153,9 +153,11 @@ mod tests {
 
     #[test]
     fn test_linkable() {
-        println!("{:p}", unsafe { &_NSConcreteGlobalBlock });
-        println!("{:p}", unsafe { &_NSConcreteStackBlock });
-        println!("{:p}", unsafe { &private::_NSConcreteMallocBlock });
+        println!("{:?}", unsafe { ptr::addr_of!(_NSConcreteGlobalBlock) });
+        println!("{:?}", unsafe { ptr::addr_of!(_NSConcreteStackBlock) });
+        println!("{:?}", unsafe {
+            ptr::addr_of!(private::_NSConcreteMallocBlock)
+        });
         println!("{:p}", _Block_copy as unsafe extern "C" fn(_) -> _);
         println!(
             "{:p}",

diff --git a/crates/block2/src/global.rs b/crates/block2/src/global.rs
@@ -171,7 +171,7 @@ macro_rules! global_block {
         #[allow(unused_unsafe)]
         $vis static $name: $crate::GlobalBlock<($($t,)*) $(, $r)?> = unsafe {
             let mut layout = $crate::GlobalBlock::<($($t,)*) $(, $r)?>::__DEFAULT_LAYOUT;
-            layout.isa = &$crate::ffi::_NSConcreteGlobalBlock;
+            layout.isa = ::core::ptr::addr_of!($crate::ffi::_NSConcreteGlobalBlock);
             layout.invoke = ::core::option::Option::Some({
                 unsafe extern "C" fn inner(_: *mut $crate::__Block_layout, $($a: $t),*) $(-> $r)? {
                     $body