From 950f1de70bbfff9d4581c3102d2107ca6a4512a7 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas@devlieghere.com>
Date: Mon, 6 Apr 2026 13:25:34 -0700
Subject: [PATCH] [lldb] Fix UUID thombstone Key (#190551)

This changes `DenseMapInfo<UUID>::getTombstoneKey()` to return a 1-byte
`{0xFF}` sentinel instead of the empty, default constructed UUID().
Returning the same key for the empty and tombstone value apparently
violates the `DenseMap` invariant.
---
 lldb/include/lldb/Utility/UUID.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lldb/include/lldb/Utility/UUID.h b/lldb/include/lldb/Utility/UUID.h
index 8c8fc41e63d5..c64dd573d9bd 100644
--- a/lldb/include/lldb/Utility/UUID.h
+++ b/lldb/include/lldb/Utility/UUID.h
@@ -112,6 +112,7 @@ private:
   friend bool operator>=(const UUID &LHS, const UUID &RHS) {
     return !(LHS < RHS);
   }
+  friend struct llvm::DenseMapInfo<UUID>;
 };
 } // namespace lldb_private
 
@@ -124,7 +125,9 @@ template <> struct DenseMapInfo<lldb_private::UUID> {
     return lldb_private::UUID();
   }
   static inline lldb_private::UUID getTombstoneKey() {
-    return lldb_private::UUID();
+    lldb_private::UUID key;
+    key.m_bytes = {0xFF};
+    return key;
   }
   static unsigned getHashValue(lldb_private::UUID uuid) {
     return DenseMapInfo<llvm::ArrayRef<uint8_t>>::getHashValue(uuid.GetBytes());