From c9276ea042bda9f11e4ca26428d57ea3701f7bc0 Mon Sep 17 00:00:00 2001
From: Ao Li <leeleo3x@gmail.com>
Date: Fri, 5 Jan 2024 15:59:11 -0500
Subject: [PATCH] Pass LLVM error message back to pass wrapper.

---
 compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index cf3f526400d..76eb6bfaef7 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -787,7 +787,9 @@ LLVMRustOptimize(
     for (auto PluginPath: Plugins) {
       auto Plugin = PassPlugin::Load(PluginPath.str());
       if (!Plugin) {
-        LLVMRustSetLastError(("Failed to load pass plugin" + PluginPath.str()).c_str());
+        auto Err = Plugin.takeError();
+        auto ErrMsg = llvm::toString(std::move(Err));
+        LLVMRustSetLastError(ErrMsg.c_str());
         return LLVMRustResult::Failure;
       }
       Plugin->registerPassBuilderCallbacks(PB);