[PATCH] D74161: Fix MSAN failure on Function destruction

[Antonio Maiorano via Phabricator via llvm-commits]

amaiorano created this revision.
amaiorano added a reviewer: eugenis.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

When Function is destroyed, GlobalValue base class is destroyed, then
Value destructor would call use_empty, which ultimately attempts to
downcast 'this' to GlobalValue. This is UB, and is caught my MSAN as
accessing uninitialized memory.

Call materialized_use_empty, which doesn't call
assertModuleIsMaterializedImpl().


Repository:
  rG LLVM Github Monorepo

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
@@ -83,7 +83,7 @@
   // reference and something is wrong.  This code is here to print out where
   // the value is still being referenced.
   //
-  if (!use_empty()) {
+  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";


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