From 7bf4e9977ebfd1de31b3daea3cec327f61ee1685 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Ber=C3=A1nek?= <berykubik@gmail.com>
Date: Mon, 3 Mar 2025 10:34:26 +0100
Subject: [PATCH] Add test for garbage collection of encapsulation symbols
---
.../ui/linking/no-gc-encapsulation-symbols.rs | 25 +++++++++++++++++++
1 file changed, 25 insertions(+)
create mode 100644 tests/ui/linking/no-gc-encapsulation-symbols.rs
diff --git a/tests/ui/linking/no-gc-encapsulation-symbols.rs b/tests/ui/linking/no-gc-encapsulation-symbols.rs
new file mode 100644
index 0000000000000..36d69969199ce
--- /dev/null
+++ b/tests/ui/linking/no-gc-encapsulation-symbols.rs
@@ -0,0 +1,25 @@
+// This test checks that encapsulation symbols are not garbage collected by the linker.
+// LLD will remove them by default, so this test checks that we pass `-znostart-stop-gc` to LLD
+// to avoid that behavior. Without that flag, the test should fail.
+// This test is inspired by the behavior of the linkme crate.
+//
+//@ build-pass
+//@ only-x86_64-unknown-linux-gnu
+
+unsafe extern "Rust" {
+ // The __start_ section name is magical for the linker,
+ // It will put link sections named EXTERNFNS after it.
+ #[link_name = "__start_EXTERNFNS"]
+ static SECTION_START: fn();
+}
+
+#[used]
+#[unsafe(link_section = "EXTERNFNS")]
+static EXTERN_FN_LOCAL: fn() = extern_fn;
+
+fn extern_fn() {}
+
+fn main() {
+ // We need to reference the SECTION_START symbol to avoid it being garbage collected
+ let slice = unsafe { SECTION_START };
+}