deps: V8: cherry-pick 00f6e834029f

Original commit message:

    [runtime] always sort transition arrays during rehashing

    After rehashing, the arrays are no longer in hash-sorted order.
    In this case, we need to force a re-sort even for small arrays,
    so that subsequent linear searches can find the correct transition
    and avoid inserting duplicates.

    Refs: nodejs#61898 (comment)
    Change-Id: Ia813d1fb9d23e08012811d672052d235c0e0bf4d
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7723678
    Commit-Queue: Joyee Cheung <[email protected]>
    Reviewed-by: Igor Sheludko <[email protected]>
    Cr-Commit-Position: refs/heads/main@{#106255}

Refs: v8/v8@00f6e83

Author: joyeecheung

deps/v8/src/objects/objects.cc

@@ -2284,7 +2284,7 @@ void HeapObject::RehashBasedOnMap(IsolateT* isolate) {
       Cast<DescriptorArray>(*this)->Sort();
       break;
     case TRANSITION_ARRAY_TYPE:
-      Cast<TransitionArray>(*this)->Sort();
+      Cast<TransitionArray>(*this)->Sort(true);
       break;
     case SMALL_ORDERED_HASH_MAP_TYPE:
       DCHECK_EQ(0, Cast<SmallOrderedHashMap>(*this)->NumberOfElements());

deps/v8/src/objects/transitions.cc

@@ -799,12 +799,15 @@ void TransitionArray::ForEachTransitionTo(
   }
 }
 
-void TransitionArray::Sort() {
+void TransitionArray::Sort(bool force) {
   DisallowGarbageCollection no_gc;
   // In-place insertion sort.
   int length = number_of_transitions();
-  // Sorting matters only for binary search.
-  if (length <= kMaxElementsForLinearSearch) return;
+  // After rehashing, the arrays are no longer in hash-sorted order.
+  // In this case, we need to force a re-sort even for small arrays,
+  // so that subsequent linear searches can find the correct transition
+  // and avoid inserting duplicates.
+  if (!force && length <= kMaxElementsForLinearSearch) return;
 
   ReadOnlyRoots roots = GetReadOnlyRoots();
   for (int i = 1; i < length; i++) {

deps/v8/src/objects/transitions.h

@@ -341,7 +341,7 @@ class TransitionArray : public WeakFixedArray {
   V8_EXPORT_PRIVATE bool IsSortedNoDuplicates();
 #endif
 
-  V8_EXPORT_PRIVATE void Sort();
+  V8_EXPORT_PRIVATE void Sort(bool force = false);
 
   void PrintInternal(std::ostream& os);
 

deps/v8/test/cctest/test-transitions.cc

@@ -464,5 +464,116 @@ UNINITIALIZED_TEST(TransitionArray_InsertToBinarySearchSizeAfterRehashing) {
   FreeCurrentEmbeddedBlob();
 }
 
+UNINITIALIZED_TEST(TransitionArray_RehashNoDuplicatesWithinLinearSearchSize) {
+  v8_flags.rehash_snapshot = true;
+  v8_flags.hash_seed = 42;
+  v8_flags.allow_natives_syntax = true;
+  DisableEmbeddedBlobRefcounting();
+  v8::StartupData blob;
+  // Stay within linear search size.
+  constexpr int initial_size = TransitionArray::kMaxElementsForLinearSearch / 2;
+
+  {
+    v8::Isolate::CreateParams testing_params;
+    testing_params.array_buffer_allocator = CcTest::array_buffer_allocator();
+    v8::SnapshotCreator creator(testing_params);
+    v8::Isolate* isolate = creator.GetIsolate();
+    {
+      v8::HandleScope handle_scope(isolate);
+      v8::Local<v8::Context> context = v8::Context::New(isolate);
+      v8::Context::Scope context_scope(context);
+      Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+      v8::Local<v8::Object> obj = v8::Object::New(isolate);
+      DirectHandle<Map> first_map =
+          direct_handle(v8::Utils::OpenDirectHandle(*obj)->map(), i_isolate);
+
+      {
+        TestTransitionsAccessor transitions(i_isolate, first_map);
+        CHECK_EQ(0, transitions.NumberOfTransitions());
+      }
+
+      // Insert transitions that will be rehashed on deserialization.
+      v8::Local<v8::Value> null_value = v8::Null(isolate);
+      v8::LocalVector<v8::Value> objects(isolate);
+      for (int i = 0; i < initial_size; i++) {
+        std::string prop_name = "prop_" + std::to_string(i);
+        v8::Local<v8::String> name =
+            v8::String::NewFromUtf8(isolate, prop_name.c_str(),
+                                    v8::NewStringType::kNormal)
+                .ToLocalChecked();
+        v8::Local<v8::Object> new_obj = v8::Object::New(isolate);
+        new_obj->Set(context, name, null_value).Check();
+        objects.push_back(new_obj);
+      }
+      context->Global()
+          ->Set(context, v8_str("objects_for_transitions"),
+                v8::Array::New(isolate, objects.data(), objects.size()))
+          .Check();
+
+      creator.SetDefaultContext(context);
+
+      TestTransitionsAccessor transitions(i_isolate, first_map);
+      CHECK_EQ(initial_size, transitions.NumberOfTransitions());
+    }
+    blob =
+        creator.CreateBlob(v8::SnapshotCreator::FunctionCodeHandling::kClear);
+    CHECK(blob.CanBeRehashed());
+  }
+
+  // Deserialize with a different hash seed to trigger rehashing.
+  v8_flags.hash_seed = 1337;
+  v8::Isolate::CreateParams testing_params;
+  testing_params.array_buffer_allocator = CcTest::array_buffer_allocator();
+  testing_params.snapshot_blob = &blob;
+  v8::Isolate* isolate = v8::Isolate::New(testing_params);
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    CHECK_EQ(static_cast<uint64_t>(1337),
+             HashSeed(reinterpret_cast<Isolate*>(isolate)).seed());
+    v8::HandleScope handle_scope(isolate);
+    v8::Local<v8::Context> context = v8::Context::New(isolate);
+    CHECK(!context.IsEmpty());
+    v8::Context::Scope context_scope(context);
+
+    Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+    v8::Local<v8::Object> obj = v8::Object::New(isolate);
+    DirectHandle<Map> first_map =
+        direct_handle(v8::Utils::OpenDirectHandle(*obj)->map(), i_isolate);
+
+    // Collect existing transition keys from the rehashed array.
+    Handle<String> keys[initial_size];
+    {
+      TestTransitionsAccessor transitions(i_isolate, first_map);
+      CHECK_EQ(initial_size, transitions.NumberOfTransitions());
+      for (int i = 0; i < initial_size; i++) {
+        keys[i] = handle(Cast<String>(transitions.GetKey(i)), i_isolate);
+      }
+    }
+
+    // For each existing transition, create a fresh map and re-insert it with
+    // the same field name.
+    for (int i = 0; i < initial_size; i++) {
+      Handle<Map> new_map =
+          Map::CopyWithField(i_isolate, first_map, keys[i],
+                             FieldType::Any(i_isolate), NONE,
+                             PropertyConstness::kMutable,
+                             Representation::Tagged(), OMIT_TRANSITION)
+              .ToHandleChecked();
+      TransitionsAccessor::Insert(i_isolate, first_map, keys[i], new_map,
+                                  PROPERTY_TRANSITION);
+    }
+
+    // Verify no duplicates were created.
+    {
+      TestTransitionsAccessor transitions(i_isolate, first_map);
+      CHECK_EQ(initial_size, transitions.NumberOfTransitions());
+    }
+  }
+
+  isolate->Dispose();
+  delete[] blob.data;
+  FreeCurrentEmbeddedBlob();
+}
+
 }  // namespace internal
 }  // namespace v8