Fix issue with __proto__ when using ES6 object literals

src/ast.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/ast.h"
 
 #include <cmath>  // For isfinite.
 #include "src/builtins.h"
 #include "src/code-stubs.h"
 #include "src/contexts.h"
@@ skipping 165 matching lines @@
       SharedFunctionInfo* shared = SharedFunctionInfo::cast(obj);
       if (shared->start_position() == start_position()) {
         shared_info_ = Handle<SharedFunctionInfo>(shared);
         break;
       }
     }
   }
 }
 
 
-ObjectLiteralProperty::ObjectLiteralProperty(Zone* zone,
-                                             AstValueFactory* ast_value_factory,
+ObjectLiteralProperty::ObjectLiteralProperty(Expression* key, Expression* value,
+                                             Kind kind, bool is_static,
+                                             bool is_computed_name)
+    : key_(key),
+      value_(value),
+      kind_(kind),
+      emit_store_(true),
+      is_static_(is_static),
+      is_computed_name_(is_computed_name) {}
+
+
+ObjectLiteralProperty::ObjectLiteralProperty(AstValueFactory* ast_value_factory,
                                              Expression* key, Expression* value,
                                              bool is_static,
                                              bool is_computed_name)
     : key_(key),
       value_(value),
       emit_store_(true),
       is_static_(is_static),
       is_computed_name_(is_computed_name) {
   if (!is_computed_name &&
       key->AsLiteral()->raw_value()->EqualsString(
           ast_value_factory->proto_string())) {
     kind_ = PROTOTYPE;
   } else if (value_->AsMaterializedLiteral() != NULL) {
     kind_ = MATERIALIZED_LITERAL;
   } else if (value_->IsLiteral()) {
     kind_ = CONSTANT;
   } else {
     kind_ = COMPUTED;
   }
 }
 
 
-ObjectLiteralProperty::ObjectLiteralProperty(Zone* zone, bool is_getter,
-                                             Expression* key,
-                                             FunctionLiteral* value,
-                                             bool is_static,
-                                             bool is_computed_name)
-    : key_(key),
-      value_(value),
-      kind_(is_getter ? GETTER : SETTER),
-      emit_store_(true),
-      is_static_(is_static),
-      is_computed_name_(is_computed_name) {}
-
-
 bool ObjectLiteral::Property::IsCompileTimeValue() {
   return kind_ == CONSTANT ||
       (kind_ == MATERIALIZED_LITERAL &&
        CompileTimeValue::IsCompileTimeValue(value_));
 }
 
 
 void ObjectLiteral::Property::set_emit_store(bool emit_store) {
   emit_store_ = emit_store;
 }
 
 
 bool ObjectLiteral::Property::emit_store() {
   return emit_store_;
 }
 
 
 void ObjectLiteral::CalculateEmitStore(Zone* zone) {
   ZoneAllocationPolicy allocator(zone);
 
   ZoneHashMap table(Literal::Match, ZoneHashMap::kDefaultHashMapCapacity,
                     allocator);
+  bool seen_prototype = false;
   for (int i = properties()->length() - 1; i >= 0; i--) {
     ObjectLiteral::Property* property = properties()->at(i);
     if (property->is_computed_name()) continue;
     Literal* literal = property->key()->AsLiteral();
     if (literal->value()->IsNull()) continue;
     uint32_t hash = literal->Hash();
     // If the key of a computed property value is in the table, do not emit
     // a store for the property later.
     if ((property->kind() == ObjectLiteral::Property::MATERIALIZED_LITERAL ||
          property->kind() == ObjectLiteral::Property::COMPUTED) &&
         table.Lookup(literal, hash, false, allocator) != NULL) {
       property->set_emit_store(false);
+    } else if (property->kind() == ObjectLiteral::Property::PROTOTYPE) {
+      // Only emit a store for the last prototype property. Make sure we do not
+      // clobber the "__proto__" name for instance properties (using method or
+      // literal shorthand syntax).
+      property->set_emit_store(!seen_prototype);
+      seen_prototype = true;
     } else {
       // Add key to the table.
       table.Lookup(literal, hash, true, allocator);
     }
   }
 }
 
 
 bool ObjectLiteral::IsBoilerplateProperty(ObjectLiteral::Property* property) {
   return property != NULL &&
@@ skipping 765 matching lines @@
 // static
 bool Literal::Match(void* literal1, void* literal2) {
   const AstValue* x = static_cast<Literal*>(literal1)->raw_value();
   const AstValue* y = static_cast<Literal*>(literal2)->raw_value();
   return (x->IsString() && y->IsString() && *x->AsString() == *y->AsString()) ||
          (x->IsNumber() && y->IsNumber() && x->AsNumber() == y->AsNumber());
 }
 
 
 } }  // namespace v8::internal