Use ValueBase instead of SILInstructions for delete notifications.

This enables e.g. notifications about the removal of SILArguments.

include/swift/SIL/Notifications.h

@@ -15,7 +15,7 @@
 
 namespace swift {
 
-class SILInstruction;
+class ValueBase;
 
 /// A protocol (or inferface) for handling instruction deletion notifications.
 ///
@@ -29,7 +29,7 @@ struct DeleteNotificationHandler {
   virtual ~DeleteNotificationHandler() {}
 
   /// Handle the invalidation message for the value \p Value.
-  virtual void handleDeleteNotification(swift::SILInstruction *Instr) { }
+  virtual void handleDeleteNotification(swift::ValueBase *Value) { }
 };
 
 } // end swift namespace

include/swift/SIL/SILModule.h

@@ -204,9 +204,9 @@ public:
   /// Remove the delete notification handler \p Handler from the module context.
   void removeDeleteNotificationHandler(DeleteNotificationHandler* Handler);
 
-  /// Send the invalidation message that \p Inst is being deleted to all
+  /// Send the invalidation message that \p V is being deleted to all
   /// registered handlers. The order of handlers is deterministic but arbitrary.
-  void notifyDeleteHandlers(SILInstruction *Inst);
+  void notifyDeleteHandlers(ValueBase *V);
 
   /// \brief Get a uniqued pointer to a SIL type list.
   SILTypeList *getSILTypeList(ArrayRef<SILType> Types) const;

include/swift/SILAnalysis/AliasAnalysis.h

@@ -22,6 +22,7 @@ namespace swift {
 
 class SILValue;
 class SILInstruction;
+class ValueBase;
 class SideEffectAnalysis;
 
 /// This class is a simple wrapper around an alias analysis cache. This is
@@ -82,7 +83,7 @@ private:
   bool typesMayAlias(SILType T1, SILType T2);
 
 
-  virtual void handleDeleteNotification(SILInstruction *I) override {
+  virtual void handleDeleteNotification(ValueBase *I) override {
   }
 
 public:

lib/SIL/SILModule.cpp

@@ -676,7 +676,7 @@ removeDeleteNotificationHandler(DeleteNotificationHandler* Handler) {
   NotificationHandlers.remove(Handler);
 }
 
-void SILModule::notifyDeleteHandlers(SILInstruction *Item) {
+void SILModule::notifyDeleteHandlers(ValueBase *Item) {
   for (auto *Handler : NotificationHandlers) {
     Handler->handleDeleteNotification(Item);
   }

lib/SILPasses/SILCombiner/SILCombine.cpp

@@ -355,7 +355,7 @@ class SILCombine : public SILFunctionTransform {
     }
   }
 
-  virtual void handleDeleteNotification(SILInstruction *I) override {
+  virtual void handleDeleteNotification(ValueBase *I) override {
   }
 
   StringRef getName() override { return "SIL Combine"; }