[llvm] Fix potential Out-of-order Evaluation in DebugInfo (PR #124385)

[Elvin Wang via llvm-commits]

https://github.com/NaiveWang created https://github.com/llvm/llvm-project/pull/124385

In DebugTypeInfoRemoval, DenseMap Replacements's assignment's rvalue is a recursive function that may access Replacements itself. Since C++17 such an "right to left" order cannot get guaranteed. This change is to separate 1 line into 2, avoid such a case.

>From 9b12e06da755ea145312312cebb4977f5bc217fa Mon Sep 17 00:00:00 2001
From: Elvin Wang <wanhzhiwen at gmail.com>
Date: Fri, 24 Jan 2025 18:59:51 -0800
Subject: [PATCH] Fix potential Out-of-order Evaluation in DebugInfo

In DebugTypeInfoRemoval, DenseMap Replacements's assignment's rvalue is a recursive function that may access Replacements itself. Since C++17 such an "right to left" order cannot get guaranteed.
This change is to separate 1 line into 2.
---
 llvm/lib/IR/DebugInfo.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index 4ce518009bd3ea..f4080ce532ef38 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -798,7 +798,8 @@ class DebugTypeInfoRemoval {
 
       return getReplacementMDNode(N);
     };
-    Replacements[N] = doRemap(N);
+    auto value = doRemap(N);
+    Replacements[N] = value;
   }
 
   /// Do the remapping traversal.