1 files changed, 43 insertions, 0 deletions
diff --git a/library/std/src/sys/sgx/rwlock/tests.rs b/library/std/src/sys/sgx/rwlock/tests.rs
new file mode 100644
index 00000000000..05b36c633f8
--- /dev/null
+++ b/library/std/src/sys/sgx/rwlock/tests.rs
@@ -0,0 +1,43 @@
+use super::*;
+use crate::mem::{self, MaybeUninit};
+use core::array::FixedSizeArray;
+
+// Verify that the bytes of initialized RWLock are the same as in
+// libunwind. If they change, `src/UnwindRustSgx.h` in libunwind needs to
+// be changed too.
+#[test]
+fn test_c_rwlock_initializer() {
+    #[rustfmt::skip]
+    const RWLOCK_INIT: &[u8] = &[
+        /* 0x00 */ 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x10 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x20 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x30 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x40 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x50 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x60 */ 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x70 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+        /* 0x80 */ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+    ];
+
+    #[inline(never)]
+    fn zero_stack() {
+        test::black_box(MaybeUninit::<[RWLock; 16]>::zeroed());
+    }
+
+    #[inline(never)]
+    unsafe fn rwlock_new(init: &mut MaybeUninit<RWLock>) {
+        init.write(RWLock::new());
+    }
+
+    unsafe {
+        // try hard to make sure that the padding/unused bytes in RWLock
+        // get initialized as 0. If the assertion below fails, that might
+        // just be an issue with the test code and not with the value of
+        // RWLOCK_INIT.
+        zero_stack();
+        let mut init = MaybeUninit::<RWLock>::zeroed();
+        rwlock_new(&mut init);
+        assert_eq!(mem::transmute::<_, [u8; 144]>(init.assume_init()).as_slice(), RWLOCK_INIT)
+    };
+}