1 files changed, 75 insertions, 0 deletions
diff --git a/tests/codegen/external-no-mangle-fns.rs b/tests/codegen/external-no-mangle-fns.rs
new file mode 100644
index 000000000..70349b2ec
--- /dev/null
+++ b/tests/codegen/external-no-mangle-fns.rs
@@ -0,0 +1,75 @@
+// compile-flags: -C no-prepopulate-passes
+// `#[no_mangle]`d functions always have external linkage, i.e., no `internal` in their `define`s
+
+#![crate_type = "lib"]
+#![no_std]
+
+// CHECK: define{{( dso_local)?}} void @a()
+#[no_mangle]
+fn a() {}
+
+// CHECK: define{{( dso_local)?}} void @b()
+#[no_mangle]
+pub fn b() {}
+
+mod private {
+    // CHECK: define{{( dso_local)?}} void @c()
+    #[no_mangle]
+    fn c() {}
+
+    // CHECK: define{{( dso_local)?}} void @d()
+    #[no_mangle]
+    pub fn d() {}
+}
+
+const HIDDEN: () = {
+    // CHECK: define{{( dso_local)?}} void @e()
+    #[no_mangle]
+    fn e() {}
+
+    // CHECK: define{{( dso_local)?}} void @f()
+    #[no_mangle]
+    pub fn f() {}
+};
+
+// The surrounding item should not accidentally become external
+// CHECK-LABEL: ; external_no_mangle_fns::x
+// CHECK-NEXT: ; Function Attrs:
+// CHECK-NEXT: define internal
+#[inline(never)]
+fn x() {
+    // CHECK: define{{( dso_local)?}} void @g()
+    #[no_mangle]
+    fn g() {
+        x();
+    }
+
+    // CHECK: define{{( dso_local)?}} void @h()
+    #[no_mangle]
+    pub fn h() {}
+
+    // side effect to keep `x` around
+    unsafe {
+        core::ptr::read_volatile(&42);
+    }
+}
+
+// CHECK: define{{( dso_local)?}} void @i()
+#[no_mangle]
+#[inline]
+fn i() {}
+
+// CHECK: define{{( dso_local)?}} void @j()
+#[no_mangle]
+#[inline]
+pub fn j() {}
+
+// CHECK: define{{( dso_local)?}} void @k()
+#[no_mangle]
+#[inline(always)]
+fn k() {}
+
+// CHECK: define{{( dso_local)?}} void @l()
+#[no_mangle]
+#[inline(always)]
+pub fn l() {}