add codegen test for the #[instruction_set] attribute

Author: folkertdev

tests/codegen/naked-fn/instruction-set.rs

@@ -0,0 +1,43 @@
+//@ compile-flags: --target armv5te-none-eabi
+//@ needs-llvm-components: arm
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items, rustc_attrs, naked_functions)]
+#![no_core]
+
+#[rustc_builtin_macro]
+macro_rules! asm {
+    () => {};
+}
+
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+
+// CHECK-LABEL: test_unspecified:
+// CHECK: .arm
+#[no_mangle]
+#[naked]
+unsafe extern "C" fn test_unspecified() {
+    asm!("bx lr", options(noreturn));
+}
+
+// CHECK-LABEL: test_thumb:
+// CHECK: .thumb
+// CHECK: .thumb_func
+#[no_mangle]
+#[naked]
+#[instruction_set(arm::t32)]
+unsafe extern "C" fn test_thumb() {
+    asm!("bx lr", options(noreturn));
+}
+
+// CHECK-LABEL: test_arm:
+// CHECK: .arm
+#[no_mangle]
+#[naked]
+#[instruction_set(arm::t32)]
+unsafe extern "C" fn test_arm() {
+    asm!("bx lr", options(noreturn));
+}