From 8f520a73b2b7c721c494662949ca9dde1e013bad Mon Sep 17 00:00:00 2001 From: Justin Bogner Date: Mon, 30 Jan 2017 18:29:46 +0000 Subject: SDAG: Update ChainNodesMatched during UpdateChains if a node is replaced Previously, we would hit UB (or the ISD::DELETED_NODE assert) if we happened to replace a node during UpdateChains, because it would be left in the list we were iterating over. This nulls out the pointer when that happens so that we can avoid the issue. Fixes llvm.org/PR31710 llvm-svn: 293522 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 508ba73315c..d9d8d0c1fd1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -2308,7 +2308,7 @@ GetVBR(uint64_t Val, const unsigned char *MatcherTable, unsigned &Idx) { /// to use the new results. void SelectionDAGISel::UpdateChains( SDNode *NodeToMatch, SDValue InputChain, - const SmallVectorImpl &ChainNodesMatched, bool isMorphNodeTo) { + SmallVectorImpl &ChainNodesMatched, bool isMorphNodeTo) { SmallVector NowDeadNodes; // Now that all the normal results are replaced, we replace the chain and @@ -2320,6 +2320,11 @@ void SelectionDAGISel::UpdateChains( // Replace all the chain results with the final chain we ended up with. for (unsigned i = 0, e = ChainNodesMatched.size(); i != e; ++i) { SDNode *ChainNode = ChainNodesMatched[i]; + // If ChainNode is null, it's because we replaced it on a previous + // iteration and we cleared it out of the map. Just skip it. + if (!ChainNode) + continue; + assert(ChainNode->getOpcode() != ISD::DELETED_NODE && "Deleted node left in chain"); @@ -2332,6 +2337,11 @@ void SelectionDAGISel::UpdateChains( if (ChainVal.getValueType() == MVT::Glue) ChainVal = ChainVal.getValue(ChainVal->getNumValues()-2); assert(ChainVal.getValueType() == MVT::Other && "Not a chain?"); + SelectionDAG::DAGNodeDeletedListener NDL( + *CurDAG, [&](SDNode *N, SDNode *E) { + std::replace(ChainNodesMatched.begin(), ChainNodesMatched.end(), N, + static_cast(nullptr)); + }); CurDAG->ReplaceAllUsesOfValueWith(ChainVal, InputChain); // If the node became dead and we haven't already seen it, delete it. -- cgit v1.2.3