[runtime] Change return type of TransitionsAccessor::FindTransitionToField().

... to MaybeHandle<Map> and add TransitionsAccessor::FindTransitionToDataProperty()
which will be used in follow-up CLs.

Bug: v8:7310
Change-Id: I98cc4fe16dc1ef335885101aa457f27c90ecf1a4
Reviewed-on: https://chromium-review.googlesource.com/968222Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52018}

src/json-parser.cc

@@ -419,9 +419,10 @@ Handle<Object> JsonParser<seq_one_byte>::ParseJsonObject() {
         key = ParseJsonString();
         if (key.is_null()) return ReportUnexpectedCharacter();
 
-        target = TransitionsAccessor(map).FindTransitionToField(key);
         // If a transition was found, follow it and continue.
-        transitioning = !target.is_null();
+        transitioning =
+            TransitionsAccessor(map).FindTransitionToField(key).ToHandle(
+                &target);
       }
       if (c0_ != ':') return ReportUnexpectedCharacter();
 

src/transitions.cc

@@ -303,15 +303,19 @@ bool TransitionsAccessor::IsSpecialTransition(Name* name) {
          name == heap->strict_function_transition_symbol();
 }
 
-Handle<Map> TransitionsAccessor::FindTransitionToField(Handle<Name> name) {
+MaybeHandle<Map> TransitionsAccessor::FindTransitionToDataProperty(
+    Handle<Name> name, RequestedLocation requested_location) {
   DCHECK(name->IsUniqueName());
   DisallowHeapAllocation no_gc;
-  Map* target = SearchTransition(*name, kData, NONE);
-  if (target == nullptr) return Handle<Map>::null();
+  PropertyAttributes attributes = name->IsPrivate() ? DONT_ENUM : NONE;
+  Map* target = SearchTransition(*name, kData, attributes);
+  if (target == nullptr) return MaybeHandle<Map>();
   PropertyDetails details = target->GetLastDescriptorDetails();
-  DCHECK_EQ(NONE, details.attributes());
-  if (details.location() != kField) return Handle<Map>::null();
+  DCHECK_EQ(attributes, details.attributes());
   DCHECK_EQ(kData, details.kind());
+  if (requested_location == kFieldOnly && details.location() != kField) {
+    return MaybeHandle<Map>();
+  }
   return Handle<Map>(target);
 }
 

src/transitions.h

@@ -67,7 +67,13 @@ class TransitionsAccessor {
   // or frozen/sealed transitions.
   static bool IsSpecialTransition(Name* name);
 
-  Handle<Map> FindTransitionToField(Handle<Name> name);
+  enum RequestedLocation { kAnyLocation, kFieldOnly };
+  MaybeHandle<Map> FindTransitionToDataProperty(
+      Handle<Name> name, RequestedLocation requested_location = kAnyLocation);
+
+  MaybeHandle<Map> FindTransitionToField(Handle<Name> name) {
+    return FindTransitionToDataProperty(name, kFieldOnly);
+  }
 
   Handle<String> ExpectedTransitionKey();
   Handle<Map> ExpectedTransitionTarget();

src/value-serializer.cc

@@ -1913,9 +1913,9 @@ Maybe<uint32_t> ValueDeserializer::ReadJSObjectProperties(
           key =
               isolate_->factory()->InternalizeString(Handle<String>::cast(key));
           // Don't reuse |transitions| because it could be stale.
-          target = TransitionsAccessor(map).FindTransitionToField(
-              Handle<String>::cast(key));
-          transitioning = !target.is_null();
+          transitioning = TransitionsAccessor(map)
+                              .FindTransitionToField(Handle<String>::cast(key))
+                              .ToHandle(&target);
         } else {
           transitioning = false;
         }