[region-isolation] Define getIsolationRegionInfo(Element elt) on PartitionOpEvaluator.

This will let me look up the dynamic isolation region associated with \p elt
while performing dataflow.

Author: gottesmm

include/swift/SILOptimizer/Utils/PartitionUtils.h

@@ -1220,6 +1220,10 @@ struct PartitionOpEvaluator {
     return asImpl().isActorDerived(elt);
   }
 
+  ValueIsolationRegionInfo getIsolationRegionInfo(Element elt) const {
+    return asImpl().getIsolationRegionInfo(elt);
+  }
+
   bool isTaskIsolatedDerived(Element elt) const {
     return asImpl().isTaskIsolatedDerived(elt);
   }
@@ -1429,6 +1433,12 @@ struct PartitionOpEvaluatorBaseImpl : PartitionOpEvaluator<Subclass> {
   /// isolated value.
   bool isTaskIsolatedDerived(Element elt) const { return false; }
 
+  /// Returns the information about \p elt's isolation that we ascertained from
+  /// SIL and the AST.
+  ValueIsolationRegionInfo getIsolationRegionInfo(Element elt) const {
+    return ValueIsolationRegionInfo();
+  }
+
   /// Check if the representative value of \p elt is closure captured at \p
   /// op.
   ///

lib/SILOptimizer/Mandatory/TransferNonSendable.cpp

@@ -1355,6 +1355,10 @@ struct DiagnosticEvaluator final
     return info->getValueMap().getIsolationRegion(element).getKind();
   }
 
+  ValueIsolationRegionInfo getIsolationRegionInfo(Element element) const {
+    return info->getValueMap().getIsolationRegion(element);
+  }
+
   bool isClosureCaptured(Element element, Operand *op) const {
     auto value = info->getValueMap().maybeGetRepresentative(element);
     if (!value)