naked functions: add run-make test for DCE

Author: folkertdev

tests/run-make/naked-dead-code-elimination/main.rs

@@ -0,0 +1,24 @@
+use std::arch::naked_asm;
+
+#[unsafe(naked)]
+#[no_mangle]
+extern "C" fn used() {
+    naked_asm!("ret")
+}
+
+#[unsafe(naked)]
+#[no_mangle]
+extern "C" fn unused() {
+    naked_asm!("ret")
+}
+
+#[unsafe(naked)]
+#[link_section = "foobar"]
+#[no_mangle]
+extern "C" fn unused_link_section() {
+    naked_asm!("ret")
+}
+
+fn main() {
+    used();
+}

tests/run-make/naked-dead-code-elimination/rmake.rs

@@ -0,0 +1,10 @@
+//@ needs-asm-support
+
+use run_make_support::symbols::object_contains_any_symbol;
+use run_make_support::{bin_name, rustc};
+
+fn main() {
+    rustc().input("main.rs").opt().run();
+    let mut unused = vec!["unused", "unused_link_section"];
+    assert!(!object_contains_any_symbol(bin_name("main"), &unused));
+}