Optimize getField by caching a closure generated from a specialized function kind.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 6158a02500f739b5527248a257a37994bdacf38a..b7139ab91bb38fa949bc45382c1993dd59a347fa 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -4743,6 +4743,12 @@ const char* Function::KindToCString(RawFunction::Kind kind) {
     case RawFunction::kInvokeFieldDispatcher:
       return "kInvokeFieldDispatcher";
       break;
+    case RawFunction::kGetFieldClosure:
+      return "kGetFieldClosure";
+      break;
+    case RawFunction::kSetFieldClosure:
+      return "kSetFieldClosure";
+      break;
     default:
       UNREACHABLE();
       return NULL;
@@ -5035,6 +5041,8 @@ intptr_t Function::NumImplicitParameters() const {
     }
   }
   if ((kind() == RawFunction::kClosureFunction) ||
+      (kind() == RawFunction::kGetFieldClosure) ||
+      (kind() == RawFunction::kSetFieldClosure) ||
       (kind() == RawFunction::kSignatureFunction)) {
     return 1;  // Closure object.
   }
@@ -5043,6 +5051,8 @@ intptr_t Function::NumImplicitParameters() const {
     // marked as non-static, but they do not have a receiver.
     // Closures are handled above.
     ASSERT((kind() != RawFunction::kClosureFunction) &&
+           (kind() != RawFunction::kGetFieldClosure) &&
+           (kind() != RawFunction::kSetFieldClosure) &&
            (kind() != RawFunction::kSignatureFunction));
     return 1;  // Receiver.
   }
@@ -5505,7 +5515,9 @@ RawFunction* Function::New(const String& name,
   result.set_optimized_call_site_count(0);
   result.set_is_optimizable(is_native ? false : true);
   result.set_is_inlinable(true);
-  if (kind == RawFunction::kClosureFunction) {
+  if ((kind == RawFunction::kClosureFunction) ||
+      (kind == RawFunction::kGetFieldClosure) ||
+      (kind == RawFunction::kSetFieldClosure) ) {
     const ClosureData& data = ClosureData::Handle(ClosureData::New());
     result.set_data(data);
   }
@@ -5988,6 +6000,12 @@ const char* Function::ToCString() const {
     case RawFunction::kInvokeFieldDispatcher:
       kind_str = "invoke-field-dispatcher";
       break;
+    case RawFunction::kGetFieldClosure:
+      kind_str = "get-field-closure";
+      break;
+    case RawFunction::kSetFieldClosure:
+      kind_str = "set-field-closure";
+      break;
     default:
       UNREACHABLE();
   }