[ESnext] Implement Object spread

src/full-codegen/mips/full-codegen-mips.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_MIPS
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 1223 matching lines @@
     DCHECK(!property->is_computed_name());
     if (property->IsCompileTimeValue()) continue;
 
     Literal* key = property->key()->AsLiteral();
     Expression* value = property->value();
     if (!result_saved) {
       PushOperand(v0);  // Save result on stack.
       result_saved = true;
     }
     switch (property->kind()) {
+      case ObjectLiteral::Property::SPREAD:
       case ObjectLiteral::Property::CONSTANT:
         UNREACHABLE();
       case ObjectLiteral::Property::MATERIALIZED_LITERAL:
         DCHECK(!CompileTimeValue::IsCompileTimeValue(property->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 1629 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OnStackReplacement()->entry()));
   return ON_STACK_REPLACEMENT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS