[compiler-rt] [UBSan] Wrap Location variants in anonymous union (PR #168866)

[Benjamin Stott via llvm-commits]

https://github.com/BStott6 created https://github.com/llvm/llvm-project/pull/168866

(Addresses the FIXME)

>From a362bdcc1715146752a38487b6facd9433406497 Mon Sep 17 00:00:00 2001
From: BStott <Benjamin.Stott at sony.com>
Date: Thu, 20 Nov 2025 12:08:53 +0000
Subject: [PATCH] [UBSan] Wrap Location variants in anonymous union

---
 compiler-rt/lib/ubsan/ubsan_diag.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/compiler-rt/lib/ubsan/ubsan_diag.h b/compiler-rt/lib/ubsan/ubsan_diag.h
index c836647c98f3c..d37bc309fdd0a 100644
--- a/compiler-rt/lib/ubsan/ubsan_diag.h
+++ b/compiler-rt/lib/ubsan/ubsan_diag.h
@@ -37,10 +37,11 @@ class Location {
 
 private:
   LocationKind Kind;
-  // FIXME: In C++11, wrap these in an anonymous union.
-  SourceLocation SourceLoc;
-  MemoryLocation MemoryLoc;
-  const SymbolizedStack *SymbolizedLoc;  // Not owned.
+  union {
+    SourceLocation SourceLoc;
+    MemoryLocation MemoryLoc;
+    const SymbolizedStack *SymbolizedLoc; // Not owned.
+  };
 
 public:
   Location() : Kind(LK_Null) {}