cleanup: Mark private padding fields as Padding

src/fuchsia/mod.rs

@@ -478,7 +478,7 @@ s! {
         #[cfg(target_endian = "little")]
         pub f_fsid: c_ulong,
         #[cfg(all(target_pointer_width = "32", not(target_arch = "x86_64")))]
-        __f_unused: c_int,
+        __f_unused: Padding<c_int>,
         #[cfg(target_endian = "big")]
         pub f_fsid: c_ulong,
         pub f_flag: c_ulong,
@@ -520,7 +520,7 @@ s! {
         pub ssi_syscall: i32,
         pub ssi_call_addr: u64,
         pub ssi_arch: u32,
-        _pad: [u8; 28],
+        _pad: Padding<[u8; 28]>,
     }
 
     pub struct itimerspec {

src/new/musl/sys/socket.rs

@@ -10,16 +10,16 @@ s! {
         pub msg_namelen: crate::socklen_t,
         pub msg_iov: *mut crate::iovec,
         #[cfg(all(target_pointer_width = "64", target_endian = "big"))]
-        __pad1: c_int,
+        __pad1: Padding<c_int>,
         pub msg_iovlen: c_int,
         #[cfg(all(target_pointer_width = "64", target_endian = "little"))]
-        __pad1: c_int,
+        __pad1: Padding<c_int>,
         pub msg_control: *mut c_void,
         #[cfg(all(target_pointer_width = "64", target_endian = "big"))]
-        __pad2: c_int,
+        __pad2: Padding<c_int>,
         pub msg_controllen: crate::socklen_t,
         #[cfg(all(target_pointer_width = "64", target_endian = "little"))]
-        __pad2: c_int,
+        __pad2: Padding<c_int>,
         pub msg_flags: c_int,
     }
 

src/new/netbsd/utmpx_.rs

@@ -46,7 +46,7 @@ s! {
         pub ut_exit: __exit_status, // FIXME(netbsd): when anonymous struct are supported
         pub ut_ss: crate::sockaddr_storage,
         pub ut_tv: crate::timeval,
-        ut_pad: [u8; _UTX_PADSIZE],
+        ut_pad: Padding<[u8; _UTX_PADSIZE]>,
     }
 
     pub struct __exit_status {

src/types.rs

@@ -22,6 +22,18 @@ impl<T: Copy> Default for Padding<T> {
     }
 }
 
+impl<T: Copy> Padding<T> {
+    /// Const constructor for uninitialized padding in const contexts.
+    // FIXME: Change this into zeroed() and use MaybeUninit::zeroed()
+    // when we depend on rustc 1.75.0.
+    #[allow(unused)]
+    pub(crate) const fn uninit() -> Self {
+        // We can still safely use uninit here, since padding are is something
+        // that can are not meant to be read or written anyways.
+        Self(MaybeUninit::uninit())
+    }
+}
+
 impl<T: Copy> fmt::Debug for Padding<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Taken frmo `MaybeUninit`'s debug implementation

src/unix/bsd/apple/b64/x86_64/mod.rs

@@ -10,8 +10,8 @@ s! {
     // FIXME(1.0): This should not implement `PartialEq`
     #[allow(unpredictable_function_pointer_comparisons)]
     pub struct malloc_zone_t {
-        _reserved1: *mut c_void,
-        _reserved2: *mut c_void,
+        _reserved1: Padding<*mut c_void>,
+        _reserved2: Padding<*mut c_void>,
         pub size:
             Option<unsafe extern "C" fn(zone: *mut malloc_zone_t, ptr: *const c_void) -> size_t>,
         pub malloc:

src/unix/bsd/apple/mod.rs

@@ -1313,7 +1313,7 @@ s! {
         pub ut_type: c_short,
         pub ut_tv: crate::timeval,
         pub ut_host: [c_char; _UTX_HOSTSIZE],
-        ut_pad: [u32; 16],
+        ut_pad: Padding<[u32; 16]>,
     }
 
     pub struct sigevent {

src/unix/bsd/freebsdlike/dragonfly/mod.rs

@@ -215,7 +215,7 @@ s! {
         pub cr_uid: crate::uid_t,
         pub cr_ngroups: c_short,
         pub cr_groups: [crate::gid_t; 16],
-        __cr_unused1: *mut c_void,
+        __cr_unused1: Padding<*mut c_void>,
     }
 
     pub struct stack_t {
@@ -260,8 +260,8 @@ s! {
         pub cp_sys: u64,
         pub cp_intr: u64,
         pub cp_idel: u64,
-        cp_unused01: u64,
-        cp_unused02: u64,
+        cp_unused01: Padding<u64>,
+        cp_unused02: Padding<u64>,
         pub cp_sample_pc: u64,
         pub cp_sample_sp: u64,
         pub cp_msg: [c_char; 32],
@@ -382,8 +382,8 @@ s! {
         pub vm_daddr: *mut c_char,
         pub vm_maxsaddr: *mut c_char,
         pub vm_minsaddr: *mut c_char,
-        _unused1: c_int,
-        _unused2: c_int,
+        _unused1: Padding<c_int>,
+        _unused2: Padding<c_int>,
         pub vm_pagesupply: c_int,
         pub vm_holdcnt: c_uint,
         pub vm_refcnt: c_uint,

src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs

@@ -226,10 +226,10 @@ s! {
         pub st_ino: crate::ino_t,
         pub st_nlink: crate::nlink_t,
         pub st_mode: crate::mode_t,
-        st_padding0: i16,
+        st_padding0: Padding<i16>,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        st_padding1: i32,
+        st_padding1: Padding<i32>,
         pub st_rdev: crate::dev_t,
         #[cfg(target_arch = "x86")]
         st_atim_ext: i32,

src/unix/bsd/freebsdlike/freebsd/freebsd13/mod.rs

@@ -239,10 +239,10 @@ s! {
         pub st_ino: crate::ino_t,
         pub st_nlink: crate::nlink_t,
         pub st_mode: crate::mode_t,
-        st_padding0: i16,
+        st_padding0: Padding<i16>,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        st_padding1: i32,
+        st_padding1: Padding<i32>,
         pub st_rdev: crate::dev_t,
         #[cfg(target_arch = "x86")]
         st_atim_ext: i32,

src/unix/bsd/freebsdlike/freebsd/freebsd14/mod.rs

@@ -240,10 +240,10 @@ s! {
         pub st_ino: crate::ino_t,
         pub st_nlink: crate::nlink_t,
         pub st_mode: crate::mode_t,
-        st_padding0: i16,
+        st_padding0: Padding<i16>,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        st_padding1: i32,
+        st_padding1: Padding<i32>,
         pub st_rdev: crate::dev_t,
         #[cfg(target_arch = "x86")]
         st_atim_ext: i32,

src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs

@@ -242,10 +242,10 @@ s! {
         pub st_ino: crate::ino_t,
         pub st_nlink: crate::nlink_t,
         pub st_mode: crate::mode_t,
-        st_padding0: i16,
+        st_padding0: Padding<i16>,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        st_padding1: i32,
+        st_padding1: Padding<i32>,
         pub st_rdev: crate::dev_t,
         #[cfg(target_arch = "x86")]
         st_atim_ext: i32,

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -346,7 +346,7 @@ s! {
         m_ceilings: [u32; 2],
         m_rb_link: crate::uintptr_t,
         #[cfg(target_pointer_width = "32")]
-        m_pad: u32,
+        m_pad: Padding<u32>,
         m_spare: [u32; 2],
     }
 
@@ -1616,7 +1616,7 @@ s_no_extra_traits! {
     }
 
     pub union __c_anonymous_cr_pid {
-        __cr_unused: *mut c_void,
+        __cr_unused: Padding<*mut c_void>,
         pub cr_pid: crate::pid_t,
     }
 
@@ -1684,7 +1684,7 @@ s_no_extra_traits! {
     }
 
     pub struct in_addr_4in6 {
-        _ia46_pad32: [u32; 3],
+        _ia46_pad32: Padding<[u32; 3]>,
         pub ia46_addr4: crate::in_addr,
     }
 

src/unix/bsd/netbsdlike/netbsd/mod.rs

@@ -230,16 +230,16 @@ s! {
             target_arch = "x86",
             target_arch = "x86_64"
         ))]
-        ptm_pad1: [u8; 3],
+        ptm_pad1: Padding<[u8; 3]>,
         // actually a union with a non-unused, 0-initialized field
-        ptm_unused: __pthread_spin_t,
+        ptm_unused: Padding<__pthread_spin_t>,
         #[cfg(any(
             target_arch = "sparc",
             target_arch = "sparc64",
             target_arch = "x86",
             target_arch = "x86_64"
         ))]
-        ptm_pad2: [u8; 3],
+        ptm_pad2: Padding<[u8; 3]>,
         ptm_owner: crate::pthread_t,
         ptm_waiters: *mut u8,
         ptm_recursed: c_uint,
@@ -1281,9 +1281,9 @@ cfg_if! {
         pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
             ptm_magic: 0x33330003,
             ptm_errorcheck: 0,
-            ptm_pad1: [0; 3],
-            ptm_unused: 0,
-            ptm_pad2: [0; 3],
+            ptm_pad1: Padding::uninit(),
+            ptm_unused: Padding::uninit(),
+            ptm_pad2: Padding::uninit(),
             ptm_waiters: 0 as *mut _,
             ptm_owner: 0,
             ptm_recursed: 0,
@@ -1293,7 +1293,7 @@ cfg_if! {
         pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
             ptm_magic: 0x33330003,
             ptm_errorcheck: 0,
-            ptm_unused: 0,
+            ptm_unused: Padding::uninit(),
             ptm_waiters: 0 as *mut _,
             ptm_owner: 0,
             ptm_recursed: 0,

src/unix/bsd/netbsdlike/openbsd/aarch64.rs

@@ -4,7 +4,7 @@ pub type ucontext_t = sigcontext;
 
 s! {
     pub struct sigcontext {
-        __sc_unused: c_int,
+        __sc_unused: Padding<c_int>,
         pub sc_mask: c_int,
         pub sc_sp: c_ulong,
         pub sc_lr: c_ulong,

src/unix/bsd/netbsdlike/openbsd/mod.rs

@@ -616,16 +616,16 @@ s! {
         pub d_reclen: u16,
         pub d_type: u8,
         pub d_namlen: u8,
-        __d_padding: [u8; 4],
+        __d_padding: Padding<[u8; 4]>,
         pub d_name: [c_char; 256],
     }
 
     pub struct sockaddr_storage {
         pub ss_len: u8,
         pub ss_family: crate::sa_family_t,
-        __ss_pad1: [u8; 6],
-        __ss_pad2: i64,
-        __ss_pad3: [u8; 240],
+        __ss_pad1: Padding<[u8; 6]>,
+        __ss_pad2: Padding<i64>,
+        __ss_pad3: Padding<[u8; 240]>,
     }
 
     pub struct siginfo_t {
@@ -634,9 +634,9 @@ s! {
         pub si_errno: c_int,
         pub si_addr: *mut c_char,
         #[cfg(target_pointer_width = "32")]
-        __pad: [u8; 112],
+        __pad: Padding<[u8; 112]>,
         #[cfg(target_pointer_width = "64")]
-        __pad: [u8; 108],
+        __pad: Padding<[u8; 108]>,
     }
 
     pub struct lastlog {

src/unix/bsd/netbsdlike/openbsd/riscv64.rs

@@ -4,7 +4,7 @@ pub type ucontext_t = sigcontext;
 
 s! {
     pub struct sigcontext {
-        __sc_unused: c_int,
+        __sc_unused: Padding<c_int>,
         pub sc_mask: c_int,
         pub sc_ra: c_long,
         pub sc_sp: c_long,

src/unix/bsd/netbsdlike/openbsd/x86_64.rs

@@ -32,7 +32,7 @@ s! {
         pub sc_rsp: c_long,
         pub sc_ss: c_long,
         pub sc_fpstate: *mut fxsave64,
-        __sc_unused: c_int,
+        __sc_unused: Padding<c_int>,
         pub sc_mask: c_int,
         pub sc_cookie: c_long,
     }
@@ -42,15 +42,15 @@ s! {
         pub fx_fcw: u16,
         pub fx_fsw: u16,
         pub fx_ftw: u8,
-        __fx_unused1: u8,
+        __fx_unused1: Padding<u8>,
         pub fx_fop: u16,
         pub fx_rip: u64,
         pub fx_rdp: u64,
         pub fx_mxcsr: u32,
         pub fx_mxcsr_mask: u32,
         pub fx_st: [[u64; 2]; 8],
         pub fx_xmm: [[u64; 2]; 16],
-        __fx_unused3: [u8; 96],
+        __fx_unused3: Padding<[u8; 96]>,
     }
 }
 

src/unix/cygwin/mod.rs

@@ -468,7 +468,7 @@ s! {
         __d_version: u32,
         pub d_ino: ino_t,
         pub d_type: c_uchar,
-        __d_unused1: [c_uchar; 3],
+        __d_unused1: Padding<[c_uchar; 3]>,
         __d_internal1: u32,
         pub d_name: [c_char; 256],
     }

src/unix/haiku/mod.rs

@@ -292,14 +292,14 @@ s! {
     pub struct pthread_mutex_t {
         flags: u32,
         lock: i32,
-        unused: i32,
+        unused: Padding<i32>,
         owner: i32,
         owner_count: i32,
     }
 
     pub struct pthread_cond_t {
         flags: u32,
-        unused: i32,
+        unused: Padding<i32>,
         mutex: *mut c_void,
         waiter_count: i32,
         lock: i32,
@@ -495,7 +495,7 @@ s! {
         pub ut_user: [c_char; 32],
         pub ut_line: [c_char; 16],
         pub ut_host: [c_char; 128],
-        __ut_reserved: [c_char; 64],
+        __ut_reserved: Padding<[c_char; 64]>,
     }
 }
 
@@ -1090,13 +1090,13 @@ pub const PTHREAD_STACK_MIN: size_t = 8192;
 pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
     flags: 0,
     lock: 0,
-    unused: -42,
+    unused: Padding::uninit(),
     owner: -1,
     owner_count: 0,
 };
 pub const PTHREAD_COND_INITIALIZER: pthread_cond_t = pthread_cond_t {
     flags: 0,
-    unused: -42,
+    unused: Padding::uninit(),
     mutex: 0 as *mut _,
     waiter_count: 0,
     lock: 0,

src/unix/haiku/native.rs

@@ -422,10 +422,10 @@ s! {
         pub model: u32,
         pub family: u32,
         pub tpe: u32,
-        __reserved_0: u32,
+        __reserved_0: Padding<u32>,
         pub extended_model: u32,
         pub extended_family: u32,
-        __reserved_1: u32,
+        __reserved_1: Padding<u32>,
         pub brand_index: u32,
         pub clflush: u32,
         pub logical_cpus: u32,