From 1af3e0a65e5c390ce46c4be9d3b9132768278ce9 Mon Sep 17 00:00:00 2001
From: Gary Guo <gary@garyguo.net>
Date: Sun, 24 Apr 2022 22:32:05 +0100
Subject: [PATCH] Ensure `#[used]` symbols are preserved in LTO

---
 compiler/rustc_codegen_llvm/src/back/lto.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 6bc242b46e043..da8d574abfe2d 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -56,7 +56,7 @@ fn prepare_lto(
     };
 
     let symbol_filter = &|&(ref name, info): &(String, SymbolExportInfo)| {
-        if info.level.is_below_threshold(export_threshold) {
+        if info.level.is_below_threshold(export_threshold) || info.used {
             Some(CString::new(name.as_str()).unwrap())
         } else {
             None