[llvm] r289694 - [WinEH] Avoid holding references to BlockColor (DenseMap) entries while inserting new elements

[Andrew Kaylor via llvm-commits]

Author: akaylor
Date: Wed Dec 14 13:30:18 2016
New Revision: 289694

URL: http://llvm.org/viewvc/llvm-project?rev=289694&view=rev
Log:
[WinEH] Avoid holding references to BlockColor (DenseMap) entries while inserting new elements

Differential Revision: https://reviews.llvm.org/D27693


Modified:
    llvm/trunk/lib/CodeGen/WinEHPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/WinEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/WinEHPrepare.cpp?rev=289694&r1=289693&r2=289694&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/WinEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/WinEHPrepare.cpp Wed Dec 14 13:30:18 2016
@@ -1202,8 +1202,12 @@ void WinEHPrepare::replaceUseWithLoad(Va
       Goto->setSuccessor(0, PHIBlock);
       CatchRet->setSuccessor(NewBlock);
       // Update the color mapping for the newly split edge.
+      // Grab a reference to the ColorVector to be inserted before getting the
+      // reference to the vector we are copying because inserting the new
+      // element in BlockColors might cause the map to be reallocated.
+      ColorVector &ColorsForNewBlock = BlockColors[NewBlock];
       ColorVector &ColorsForPHIBlock = BlockColors[PHIBlock];
-      BlockColors[NewBlock] = ColorsForPHIBlock;
+      ColorsForNewBlock = ColorsForPHIBlock;
       for (BasicBlock *FuncletPad : ColorsForPHIBlock)
         FuncletBlocks[FuncletPad].push_back(NewBlock);
       // Treat the new block as incoming for load insertion.