[llvm] 6bcdcb3 - [DWARFLinker] Make synthetic type names deterministic under threading (#209553)

[via llvm-commits]

Author: Jonas Devlieghere
Date: 2026-07-19T15:58:34-05:00
New Revision: 6bcdcb39c57ea926d3082ec3ecae74bf59b4658e

URL: https://github.com/llvm/llvm-project/commit/6bcdcb39c57ea926d3082ec3ecae74bf59b4658e
DIFF: https://github.com/llvm/llvm-project/commit/6bcdcb39c57ea926d3082ec3ecae74bf59b4658e.diff

LOG: [DWARFLinker] Make synthetic type names deterministic under threading (#209553)

Added: 
    

Modified: 
    llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp

Removed: 
    


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diff  --git a/llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp b/llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp
index b5be5d498ed3e..c3d8a2489de9a 100644
--- a/llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp
+++ b/llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp
@@ -405,10 +405,13 @@ Error SyntheticTypeNameBuilder::addDIETypeName(
   // Check if DIE already has a name.
   if (!TypeEntryPtr) {
     size_t NameStart = SyntheticName.size();
-    if (AssignNameToTypeDescriptor) {
-      if (Error Err = addParentName(*UnitEntryPair))
-        return Err;
-    }
+    // Prepend the parent scope so this name matches the key the type is
+    // stored under in the pool (the getKey() branch below). Otherwise the
+    // same type gets 
diff erent names depending on whether it already has a
+    // pool entry, which races under parallel assignment and breaks
+    // deterministic deduplication.
+    if (Error Err = addParentName(*UnitEntryPair))
+      return Err;
     addTypePrefix(UnitEntryPair->DieEntry);
 
     if (ChildIndex) {