[Map::TransitionToDataProperty speed] Remove a branch in TransitionsAccessor::SearchTransition

We checked against kNotFound twice; once in
TransitionsAccessor::SearchTransitions and once in TransitionArray::Search. It's
unnecessary to check twice.

In local tests, this speeds up searching for a non-existent transition in a
2-element TransitionArray by ~20%.

BUG=v8:8547

Change-Id: Ic220c4c0bfeeacd9b81953efad212ed15168437e
Reviewed-on: https://chromium-review.googlesource.com/c/1361167Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58038}

src/transitions.cc

@@ -224,9 +224,7 @@ Map TransitionsAccessor::SearchTransition(Name name, PropertyKind kind,
       return map;
     }
     case kFullTransitionArray: {
-      int transition = transitions()->Search(kind, name, attributes);
-      if (transition == kNotFound) return Map();
-      return transitions()->GetTarget(transition);
+      return transitions()->SearchAndGetTarget(kind, name, attributes);
     }
   }
   UNREACHABLE();
@@ -605,6 +603,29 @@ int TransitionArray::SearchDetails(int transition, PropertyKind kind,
   return kNotFound;
 }
 
+Map TransitionArray::SearchDetailsAndGetTarget(int transition,
+                                               PropertyKind kind,
+                                               PropertyAttributes attributes) {
+  int nof_transitions = number_of_transitions();
+  DCHECK(transition < nof_transitions);
+  Name key = GetKey(transition);
+  for (; transition < nof_transitions && GetKey(transition) == key;
+       transition++) {
+    Map target = GetTarget(transition);
+    PropertyDetails target_details =
+        TransitionsAccessor::GetTargetDetails(key, target);
+
+    int cmp = CompareDetails(kind, attributes, target_details.kind(),
+                             target_details.attributes());
+    if (cmp == 0) {
+      return target;
+    } else if (cmp < 0) {
+      break;
+    }
+  }
+  return Map();
+}
+
 int TransitionArray::Search(PropertyKind kind, Name name,
                             PropertyAttributes attributes,
                             int* out_insertion_index) {
@@ -613,6 +634,15 @@ int TransitionArray::Search(PropertyKind kind, Name name,
   return SearchDetails(transition, kind, attributes, out_insertion_index);
 }
 
+Map TransitionArray::SearchAndGetTarget(PropertyKind kind, Name name,
+                                        PropertyAttributes attributes) {
+  int transition = SearchName(name, nullptr);
+  if (transition == kNotFound) {
+    return Map();
+  }
+  return SearchDetailsAndGetTarget(transition, kind, attributes);
+}
+
 void TransitionArray::Sort() {
   DisallowHeapAllocation no_gc;
   // In-place insertion sort.

src/transitions.h

@@ -302,6 +302,9 @@ class TransitionArray : public WeakFixedArray {
   int Search(PropertyKind kind, Name name, PropertyAttributes attributes,
              int* out_insertion_index = nullptr);
 
+  Map SearchAndGetTarget(PropertyKind kind, Name name,
+                         PropertyAttributes attributes);
+
   // Search a non-property transition (like elements kind, observe or frozen
   // transitions).
   inline int SearchSpecial(Symbol symbol, int* out_insertion_index = nullptr);
@@ -309,6 +312,8 @@ class TransitionArray : public WeakFixedArray {
   inline int SearchName(Name name, int* out_insertion_index = nullptr);
   int SearchDetails(int transition, PropertyKind kind,
                     PropertyAttributes attributes, int* out_insertion_index);
+  Map SearchDetailsAndGetTarget(int transition, PropertyKind kind,
+                                PropertyAttributes attributes);
 
   inline int number_of_transitions() const;