Make ISelPosition a local variable.
Now that multiple DAGUpdateListeners can be active at the same time,
ISelPosition can become a local variable in DoInstructionSelection.
We simply register an ISelUpdater with CurDAG while ISelPosition exists.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155249 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index aa2b843..e2735de 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -263,8 +263,6 @@
// SelectionDAGISel code
//===----------------------------------------------------------------------===//
-void SelectionDAGISel::ISelUpdater::anchor() { }
-
SelectionDAGISel::SelectionDAGISel(const TargetMachine &tm,
CodeGenOpt::Level OL) :
MachineFunctionPass(ID), TM(tm), TLI(*tm.getTargetLowering()),
@@ -703,6 +701,25 @@
CurDAG->clear();
}
+namespace {
+/// ISelUpdater - helper class to handle updates of the instruction selection
+/// graph.
+class ISelUpdater : public SelectionDAG::DAGUpdateListener {
+ SelectionDAG::allnodes_iterator &ISelPosition;
+public:
+ ISelUpdater(SelectionDAG &DAG, SelectionDAG::allnodes_iterator &isp)
+ : SelectionDAG::DAGUpdateListener(DAG), ISelPosition(isp) {}
+
+ /// NodeDeleted - Handle nodes deleted from the graph. If the node being
+ /// deleted is the current ISelPosition node, update ISelPosition.
+ ///
+ virtual void NodeDeleted(SDNode *N, SDNode *E) {
+ if (ISelPosition == SelectionDAG::allnodes_iterator(N))
+ ++ISelPosition;
+ }
+};
+} // end anonymous namespace
+
void SelectionDAGISel::DoInstructionSelection() {
DEBUG(errs() << "===== Instruction selection begins: BB#"
<< FuncInfo->MBB->getNumber()
@@ -719,9 +736,13 @@
// a reference to the root node, preventing it from being deleted,
// and tracking any changes of the root.
HandleSDNode Dummy(CurDAG->getRoot());
- ISelPosition = SelectionDAG::allnodes_iterator(CurDAG->getRoot().getNode());
+ SelectionDAG::allnodes_iterator ISelPosition (CurDAG->getRoot().getNode());
++ISelPosition;
+ // Make sure that ISelPosition gets properly updated when nodes are deleted
+ // in calls made from this function.
+ ISelUpdater ISU(*CurDAG, ISelPosition);
+
// The AllNodes list is now topological-sorted. Visit the
// nodes by starting at the end of the list (the root of the
// graph) and preceding back toward the beginning (the entry
@@ -748,10 +769,8 @@
// If after the replacement this node is not used any more,
// remove this dead node.
- if (Node->use_empty()) { // Don't delete EntryToken, etc.
- ISelUpdater ISU(*CurDAG, ISelPosition);
+ if (Node->use_empty()) // Don't delete EntryToken, etc.
CurDAG->RemoveDeadNode(Node);
- }
}
CurDAG->setRoot(Dummy.getValue());
@@ -1680,8 +1699,6 @@
bool isMorphNodeTo) {
SmallVector<SDNode*, 4> NowDeadNodes;
- ISelUpdater ISU(*CurDAG, ISelPosition);
-
// Now that all the normal results are replaced, we replace the chain and
// glue results if present.
if (!ChainNodesMatched.empty()) {