message: Add padding on 64-bits only
diff: @@ -295,6 +295,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  "S_IFLNK"
  };
  + // FIXME: use Scalar::to_u16
  let mode = this.eval_libc(mode_name)?.to_bits(Size::from_bits(16))? as u16;
  let size = metadata.len();
  @@ -316,6 +317,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  let blksize_t_layout = this.libc_ty_layout("blksize_t")?;
  let uint32_t_layout = this.libc_ty_layout("uint32_t")?;
  + // We need to add 32 bits of padding after `st_rdev` if we are in a 64-bit platform. To do
  + // this, we store `st_rdev` as a `c_long` instead of a `dev_t`.
  + let st_rdev_layout = if this.tcx.sess.target.ptr_width == 64 {
  + long_layout
  + } else {
  + dev_t_layout
  + };
  +
  let imms = [
  immty_from_uint_checked(0u128, dev_t_layout)?, // st_dev
  immty_from_uint_checked(mode, mode_t_layout)?, // st_mode
  @@ -323,8 +332,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  immty_from_uint_checked(0u128, ino_t_layout)?, // st_ino
  immty_from_uint_checked(0u128, uid_t_layout)?, // st_uid
  immty_from_uint_checked(0u128, gid_t_layout)?, // st_gid
  - immty_from_uint_checked(0u128, dev_t_layout)?, // st_rdev
  - immty_from_uint_checked(0u128, dev_t_layout)?, // padding
  + immty_from_uint_checked(0u128, st_rdev_layout)?, // st_rdev
  immty_from_uint_checked(access_sec, time_t_layout)?, // st_atime
  immty_from_uint_checked(access_nsec, long_layout)?, // st_atime_nsec
  immty_from_uint_checked(modified_sec, time_t_layout)?, // st_mtime
  