[PATCH] D74161: Fix MSAN failure on Function destruction

[Antonio Maiorano via Phabricator via llvm-commits]

amaiorano updated this revision to Diff 243017.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D74161/new/

https://reviews.llvm.org/D74161

Files:
  llvm/lib/IR/Value.cpp


Index: llvm/lib/IR/Value.cpp
===================================================================
--- llvm/lib/IR/Value.cpp
+++ llvm/lib/IR/Value.cpp
@@ -83,13 +83,17 @@
   // reference and something is wrong.  This code is here to print out where
   // the value is still being referenced.
   //
-  if (!use_empty()) {
+  // Note that use_empty() cannot be called here, as it eventually downcasts
+  // 'this' to GlobalValue (derived class of Value), but GlobalValue has already
+  // been destructed, so accessing it is UB.
+  //
+  if (!materialized_use_empty()) {
     dbgs() << "While deleting: " << *VTy << " %" << getName() << "\n";
     for (auto *U : users())
       dbgs() << "Use still stuck around after Def is destroyed:" << *U << "\n";
   }
 #endif
-  assert(use_empty() && "Uses remain when a value is destroyed!");
+  assert(materialized_use_empty() && "Uses remain when a value is destroyed!");

   // If this value is named, destroy the name.  This should not be in a symtab
   // at this point.


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