[PATCH] D137408: [StructurizeCFG][DebugInfo] Avoid use-after-free

[Juan Manuel Martinez Caamaño via Phabricator via llvm-commits]

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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D137408

Files:
  llvm/lib/Transforms/Scalar/StructurizeCFG.cpp


Index: llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
+++ llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
@@ -856,7 +856,12 @@
   BasicBlock *Flow = BasicBlock::Create(Context, FlowBlockName,
                                         Func, Insert);
   FlowSet.insert(Flow);
-  TermDL[Flow] = TermDL[Dominator];
+
+  // use a temporary variable to avoid a use-after-free if the map's storage is
+  // reallocated
+  DebugLoc DL = TermDL[Dominator];
+  TermDL[Flow] = std::move(DL);
+
   DT->addNewBlock(Flow, Dominator);
   ParentRegion->getRegionInfo()->setRegionFor(Flow, ParentRegion);
   return Flow;


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