build: Use core::mem::offset_of!

Signed-off-by: Akira Moroo <[email protected]>

src/boot.rs

@@ -247,6 +247,6 @@ mod tests {
         assert_eq!(mem::size_of::<E820Entry>(), 20);
         assert_eq!(mem::size_of::<Params>(), 4096);
 
-        assert_eq!(offset_of!(Params, hdr), HEADER_START);
+        assert_eq!(core::mem::offset_of!(Params, hdr), HEADER_START);
     }
 }

src/common.rs

@@ -1,27 +1,17 @@
 // SPDX-License-Identifier: Apache-2.0
 // Copyright © 2019 Intel Corporation
 
-#[macro_export]
-macro_rules! offset_of {
-    ($container:ty, $field:ident) => {
-        #[allow(deref_nullptr)]
-        unsafe {
-            &(*(core::ptr::null() as *const $container)).$field as *const _ as usize
-        }
-    };
-}
-
 #[macro_export]
 macro_rules! container_of {
     ($ptr:ident, $container:ty, $field:ident) => {{
-        (($ptr as usize) - offset_of!($container, $field)) as *const $container
+        (($ptr as usize) - core::mem::offset_of!($container, $field)) as *const $container
     }};
 }
 
 #[macro_export]
 macro_rules! container_of_mut {
     ($ptr:ident, $container:ty, $field:ident) => {{
-        (($ptr as usize) - offset_of!($container, $field)) as *mut $container
+        (($ptr as usize) - core::mem::offset_of!($container, $field)) as *mut $container
     }};
 }
 

src/efi/mod.rs

@@ -4,7 +4,7 @@
 use core::{
     cell::SyncUnsafeCell,
     ffi::c_void,
-    mem::{size_of, transmute},
+    mem::{offset_of, size_of, transmute},
     ptr::null_mut,
     slice::from_raw_parts,
 };