Use ptr::addr_of when available

3 files changed, 26 insertions, 4 deletions

diff --git a/build.rs b/build.rs
index c4982111e7..0e40178638 100644
--- a/build.rs
+++ b/build.rs
@@ -72,6 +72,10 @@ fn main() {
         println!("cargo:rustc-cfg=libc_cfg_target_vendor");
     }
 
+    if rustc_minor_ver >= 51 || rustc_dep_of_std {
+        println!("cargo:rustc-cfg=libc_ptr_addr_of");
+    }
+
     // #[thread_local] is currently unstable
     if rustc_dep_of_std {
         println!("cargo:rustc-cfg=libc_thread_local");
diff --git a/src/macros.rs b/src/macros.rs
index 1871cfafda..d52c4ad81e 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -341,3 +341,19 @@ macro_rules! deprecated_mach {
         )*
     }
 }
+
+#[allow(unused_macros)]
+#[cfg(not(libc_ptr_addr_of))]
+macro_rules! ptr_addr_of {
+    ($place:expr) => {
+        &$place
+    };
+}
+
+#[allow(unused_macros)]
+#[cfg(libc_ptr_addr_of)]
+macro_rules! ptr_addr_of {
+    ($place:expr) => {
+        ::core::ptr::addr_of!($place)
+    };
+}
diff --git a/src/wasi.rs b/src/wasi.rs
index a41ec47696..7d49450d09 100644
--- a/src/wasi.rs
+++ b/src/wasi.rs
@@ -352,10 +352,12 @@ pub const _SC_PAGE_SIZE: ::c_int = _SC_PAGESIZE;
 pub const _SC_IOV_MAX: c_int = 60;
 pub const _SC_SYMLOOP_MAX: c_int = 173;
 
-pub static CLOCK_MONOTONIC: clockid_t = unsafe { clockid_t(&_CLOCK_MONOTONIC) };
-pub static CLOCK_PROCESS_CPUTIME_ID: clockid_t = unsafe { clockid_t(&_CLOCK_PROCESS_CPUTIME_ID) };
-pub static CLOCK_REALTIME: clockid_t = unsafe { clockid_t(&_CLOCK_REALTIME) };
-pub static CLOCK_THREAD_CPUTIME_ID: clockid_t = unsafe { clockid_t(&_CLOCK_THREAD_CPUTIME_ID) };
+pub static CLOCK_MONOTONIC: clockid_t = unsafe { clockid_t(ptr_addr_of!(_CLOCK_MONOTONIC)) };
+pub static CLOCK_PROCESS_CPUTIME_ID: clockid_t =
+    unsafe { clockid_t(ptr_addr_of!(_CLOCK_PROCESS_CPUTIME_ID)) };
+pub static CLOCK_REALTIME: clockid_t = unsafe { clockid_t(ptr_addr_of!(_CLOCK_REALTIME)) };
+pub static CLOCK_THREAD_CPUTIME_ID: clockid_t =
+    unsafe { clockid_t(ptr_addr_of!(_CLOCK_THREAD_CPUTIME_ID)) };
 
 #[cfg_attr(
     feature = "rustc-dep-of-std",