From a3f378754b63d222f1679b901f7d90d6d4c32aaa Mon Sep 17 00:00:00 2001
From: bjorn3 <bjorn3@users.noreply.github.com>
Date: Fri, 17 Jan 2020 20:33:27 +0100
Subject: [PATCH] Warn when using LTO

---
 src/lib.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index cc7c0bb5a63..77ffd46f6f2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -162,7 +162,11 @@ impl<'clif, 'tcx, B: Backend + 'static> CodegenCx<'clif, 'tcx, B> {
 struct CraneliftCodegenBackend;
 
 impl CodegenBackend for CraneliftCodegenBackend {
-    fn init(&self, _sess: &Session) {}
+    fn init(&self, sess: &Session) {
+        if sess.lto() != rustc_session::config::Lto::No {
+            sess.warn("LTO is not supported. You may get a linker error.");
+        }
+    }
 
     fn metadata_loader(&self) -> Box<dyn MetadataLoader + Sync> {
         Box::new(crate::metadata::CraneliftMetadataLoader)