From e76bfae7eb4405091625b973f1fbe1e8859afb15 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Wed, 25 Sep 2013 04:40:45 -0400
Subject: [PATCH] add `noreturn` attribute to functions returning !

Closes #9317
---
 src/librustc/middle/trans/base.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index 49b4d711f86..822f9e32d93 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -220,6 +220,12 @@ pub fn decl_rust_fn(ccx: &mut CrateContext, inputs: &[ty::t], output: ty::t,
     let llfn = decl_cdecl_fn(ccx.llmod, name, llfty);
 
     match ty::get(output).sty {
+        // functions returning bottom may unwind, but can never return normally
+        ty::ty_bot => {
+            unsafe {
+                llvm::LLVMAddFunctionAttr(llfn, lib::llvm::NoReturnAttribute as c_uint)
+            }
+        }
         // `~` pointer return values never alias because ownership is transferred
         ty::ty_uniq(*) |
         ty::ty_evec(_, ty::vstore_uniq) => {