Implement global_asm! using an external assembler

Fixes #1061

2 files changed, 24 insertions, 0 deletions

diff --git a/example/mini_core.rs b/example/mini_core.rs
index a8db81fa06d..94336154748 100644
--- a/example/mini_core.rs
+++ b/example/mini_core.rs
@@ -562,6 +562,10 @@ pub macro line() { /* compiler built-in */ }
 #[rustc_macro_transparency = "semitransparent"]
 pub macro cfg() { /* compiler built-in */ }
 
+#[rustc_builtin_macro]
+#[rustc_macro_transparency = "semitransparent"]
+pub macro global_asm() { /* compiler built-in */ }
+
 pub static A_STATIC: u8 = 42;
 
 #[lang = "panic_location"]
diff --git a/example/mini_core_hello_world.rs b/example/mini_core_hello_world.rs
index 12c6638dd92..d83fb2aece9 100644
--- a/example/mini_core_hello_world.rs
+++ b/example/mini_core_hello_world.rs
@@ -284,6 +284,26 @@ fn main() {
 
     #[cfg(not(jit))]
     test_tls();
+
+    #[cfg(not(jit))]
+    unsafe {
+        global_asm_test();
+    }
+}
+
+#[cfg(not(jit))]
+extern "C" {
+    fn global_asm_test();
+}
+
+#[cfg(not(jit))]
+global_asm! {
+    "
+    .global global_asm_test
+    global_asm_test:
+    // comment that would normally be removed by LLVM
+    ret
+    "
 }
 
 #[repr(C)]