Introduce a code stub version of Array.prototype.push

src/builtins.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins.h"
 
 #include "src/api.h"
 #include "src/api-arguments.h"
 #include "src/api-natives.h"
 #include "src/base/once.h"
@@ skipping 402 matching lines @@
             ? index < static_cast<uint32_t>(String::cast(*object)->length())
             : key->Equals(isolate->heap()->length_string()));
   } else if (object->IsNull() || object->IsUndefined()) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kUndefinedOrNullToObject));
   }
 
   return isolate->heap()->false_value();
 }
 
-BUILTIN(ArrayPush) {
+namespace {
+
+Object* DoArrayPush(Isolate* isolate,
+                    BuiltinArguments<BuiltinExtraArguments::kNone> args) {
   HandleScope scope(isolate);
   Handle<Object> receiver = args.receiver();
   if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, &args, 1)) {
     return CallJsIntrinsic(isolate, isolate->array_push(), args);
   }
   // Fast Elements Path
   int to_add = args.length() - 1;
   Handle<JSArray> array = Handle<JSArray>::cast(receiver);
   int len = Smi::cast(array->length())->value();
   if (to_add == 0) return Smi::FromInt(len);
 
   // Currently fixed arrays cannot grow too big, so we should never hit this.
   DCHECK_LE(to_add, Smi::kMaxValue - Smi::cast(array->length())->value());
 
   if (JSArray::HasReadOnlyLength(array)) {
     return CallJsIntrinsic(isolate, isolate->array_push(), args);
   }
 
   ElementsAccessor* accessor = array->GetElementsAccessor();
   int new_length = accessor->Push(array, &args, to_add);
   return Smi::FromInt(new_length);
 }
 
+}  // namespace
+
+BUILTIN(ArrayPush) { return DoArrayPush(isolate, args); }
+
+// TODO(verwaest): This is a temporary helper until the FastArrayPush stub can
+// tailcall to the builtin directly.
+RUNTIME_FUNCTION(Runtime_ArrayPush) {
+  DCHECK_EQ(2, args.length());
+  Arguments* incoming = reinterpret_cast<Arguments*>(args[0]);
+  // Rewrap the arguments as builtins arguments.
+  BuiltinArguments<BuiltinExtraArguments::kNone> caller_args(
+      incoming->length() + 1, incoming->arguments() + 1);
+  return DoArrayPush(isolate, caller_args);
+}
 
 BUILTIN(ArrayPop) {
   HandleScope scope(isolate);
   Handle<Object> receiver = args.receiver();
   if (!EnsureJSArrayWithWritableFastElements(isolate, receiver, nullptr, 0)) {
     return CallJsIntrinsic(isolate, isolate->array_pop(), args);
   }
 
   Handle<JSArray> array = Handle<JSArray>::cast(receiver);
   DCHECK(!array->map()->is_observed());
@@ skipping 4058 matching lines @@
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 }  // namespace internal
 }  // namespace v8