1 files changed, 31 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 000000000..479996115
--- /dev/null
+++ b/library/std/src/sys/sgx/rwlock/tests.rs
@@ -0,0 +1,31 @@
+use super::*;
+
+// Verify that the byte pattern libunwind uses to initialize an RwLock is
+// equivalent to the value of RwLock::new(). If the value changes,
+// `src/UnwindRustSgx.h` in libunwind needs to be changed too.
+#[test]
+fn test_c_rwlock_initializer() {
+    #[rustfmt::skip]
+    const C_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,
+    ];
+
+    // For the test to work, we need the padding/unused bytes in RwLock to be
+    // initialized as 0. In practice, this is the case with statics.
+    static RUST_RWLOCK_INIT: RwLock = RwLock::new();
+
+    unsafe {
+        // If the assertion fails, that not necessarily an issue with the value
+        // of C_RWLOCK_INIT. It might just be an issue with the way padding
+        // bytes are initialized in the test code.
+        assert_eq!(&crate::mem::transmute_copy::<_, [u8; 144]>(&RUST_RWLOCK_INIT), C_RWLOCK_INIT);
+    };
+}