[EscapeAnalysis] handle value delete notifications.

Needed for malloc/free instruction allocation method.

Author: eeckstein

include/swift/SILAnalysis/EscapeAnalysis.h

@@ -499,6 +499,11 @@ class EscapeAnalysis : public BottomUpIPAnalysis {
     /// Propagates the escape states through the graph.
     void propagateEscapeStates();
 
+    /// Removes a value from the graph.
+    /// It does not delete its node but makes sure that the value cannot be
+    /// lookup-up with getNode() anymore.
+    void removeFromGraph(ValueBase *V) { Values2Nodes.erase(V); }
+
   public:
 
     /// Gets or creates a node for a value \p V.
@@ -719,6 +724,10 @@ class EscapeAnalysis : public BottomUpIPAnalysis {
 
   virtual void invalidate(SILFunction *F, InvalidationKind K);
 
+  virtual void handleDeleteNotification(ValueBase *I) override;
+
+  virtual bool needsNotifications() override { return true; }
+
   virtual void verify() const {
 #ifndef NDEBUG
     for (auto Iter : Function2Info) {

lib/SILAnalysis/EscapeAnalysis.cpp

@@ -1523,6 +1523,18 @@ void EscapeAnalysis::invalidate(SILFunction *F, InvalidationKind K) {
   }
 }
 
+void EscapeAnalysis::handleDeleteNotification(ValueBase *I) {
+  if (SILBasicBlock *Parent = I->getParentBB()) {
+    SILFunction *F = Parent->getParent();
+    if (FunctionInfo *FInfo = Function2Info.lookup(F)) {
+      if (FInfo->isValid()) {
+        FInfo->Graph.removeFromGraph(I);
+        FInfo->SummaryGraph.removeFromGraph(I);
+      }
+    }
+  }
+}
+
 SILAnalysis *swift::createEscapeAnalysis(SILModule *M) {
   return new EscapeAnalysis(M);
 }