[runtime] Avoid @@isConcatSpreadable lookup for fast path Array.prototype.concat

src/lookup.cc

Index: src/lookup.cc
diff --git a/src/lookup.cc b/src/lookup.cc
index 3df8752c01a7108ce145875a55d51bdab4185293..e36d31a501a0d56cdf397e8d275dae59973ac9a3 100644
--- a/src/lookup.cc
+++ b/src/lookup.cc
@@ -158,47 +158,39 @@ void LookupIterator::ReloadPropertyInformation() {
   DCHECK(IsFound() || !holder_->HasFastProperties());
 }
 
-bool LookupIterator::HolderIsInContextIndex(uint32_t index) const {
-  DisallowHeapAllocation no_gc;
-
-  Object* context = heap()->native_contexts_list();
-  while (!context->IsUndefined()) {
-    Context* current_context = Context::cast(context);
-    if (current_context->get(index) == *holder_) {
-      return true;
-    }
-    context = current_context->get(Context::NEXT_CONTEXT_LINK);
-  }
-  return false;
-}
-
 void LookupIterator::InternalUpdateProtector() {
   if (isolate_->bootstrapper()->IsActive()) return;
-  if (!isolate_->IsArraySpeciesLookupChainIntact()) return;
 
   if (*name_ == heap()->constructor_string()) {
+    if (!isolate_->IsArraySpeciesLookupChainIntact()) return;
     // Setting the constructor property could change an instance's @@species
     if (holder_->IsJSArray()) {
       isolate_->CountUsage(
           v8::Isolate::UseCounterFeature::kArrayInstanceConstructorModified);
       isolate_->InvalidateArraySpeciesProtector();
     } else if (holder_->map()->is_prototype_map()) {
+      DisallowHeapAllocation no_gc;
       // Setting the constructor of Array.prototype of any realm also needs
       // to invalidate the species protector
-      if (HolderIsInContextIndex(Context::INITIAL_ARRAY_PROTOTYPE_INDEX)) {
+      if (isolate_->IsInContextIndex(*holder_,
+                                     Context::INITIAL_ARRAY_PROTOTYPE_INDEX)) {
         isolate_->CountUsage(v8::Isolate::UseCounterFeature::
                                  kArrayPrototypeConstructorModified);
         isolate_->InvalidateArraySpeciesProtector();
       }
     }
   } else if (*name_ == heap()->species_symbol()) {
+    if (!isolate_->IsArraySpeciesLookupChainIntact()) return;
     // Setting the Symbol.species property of any Array constructor invalidates
     // the species protector
-    if (HolderIsInContextIndex(Context::ARRAY_FUNCTION_INDEX)) {
+    if (isolate_->IsInContextIndex(*holder_, Context::ARRAY_FUNCTION_INDEX)) {
       isolate_->CountUsage(
           v8::Isolate::UseCounterFeature::kArraySpeciesModified);
       isolate_->InvalidateArraySpeciesProtector();
     }
+  } else if (*name_ == heap()->is_concat_spreadable_symbol()) {
+    if (!isolate_->IsArrayIsConcatSpreadableLookupChainIntact()) return;
+    isolate_->InvalidateArrayIsConcatSpreadableProtector();
   }
 }