[ESnext] Implement Object spread

src/full-codegen/x64/full-codegen-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/full-codegen/full-codegen.h"
 #include "src/ast/compile-time-value.h"
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
@@ skipping 1180 matching lines @@
     DCHECK(!property->is_computed_name());
     if (property->IsCompileTimeValue()) continue;
 
     Literal* key = property->key()->AsLiteral();
     Expression* value = property->value();
     if (!result_saved) {
       PushOperand(rax);  // Save result on the stack
       result_saved = true;
     }
     switch (property->kind()) {
+      case ObjectLiteral::Property::SPREAD:
       case ObjectLiteral::Property::CONSTANT:
         UNREACHABLE();
       case ObjectLiteral::Property::MATERIALIZED_LITERAL:
         DCHECK(!CompileTimeValue::IsCompileTimeValue(value));
         // Fall through.
       case ObjectLiteral::Property::COMPUTED:
         // It is safe to use [[Put]] here because the boilerplate already
         // contains computed properties with an uninitialized value.
         if (key->IsStringLiteral()) {
           DCHECK(key->IsPropertyName());
@@ skipping 1560 matching lines @@
   DCHECK_EQ(
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64