ES6 computed property names

src/preparser.h

 // 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.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
@@ skipping 69 matching lines @@
         log_(log),
         mode_(PARSE_EAGERLY),  // Lazy mode must be set explicitly.
         stack_limit_(stack_limit),
         scanner_(scanner),
         stack_overflow_(false),
         allow_lazy_(false),
         allow_natives_(false),
         allow_harmony_arrow_functions_(false),
         allow_harmony_object_literals_(false),
         allow_harmony_sloppy_(false),
+        allow_harmony_computed_property_names_(false),
         zone_(zone) {}
 
   // Getters that indicate whether certain syntactical constructs are
   // allowed to be parsed by this instance of the parser.
   bool allow_lazy() const { return allow_lazy_; }
   bool allow_natives() const { return allow_natives_; }
   bool allow_harmony_arrow_functions() const {
     return allow_harmony_arrow_functions_;
   }
   bool allow_harmony_modules() const { return scanner()->HarmonyModules(); }
   bool allow_harmony_scoping() const { return scanner()->HarmonyScoping(); }
   bool allow_harmony_numeric_literals() const {
     return scanner()->HarmonyNumericLiterals();
   }
   bool allow_harmony_classes() const { return scanner()->HarmonyClasses(); }
   bool allow_harmony_object_literals() const {
     return allow_harmony_object_literals_;
   }
   bool allow_harmony_templates() const { return scanner()->HarmonyTemplates(); }
   bool allow_harmony_sloppy() const { return allow_harmony_sloppy_; }
   bool allow_harmony_unicode() const { return scanner()->HarmonyUnicode(); }
+  bool allow_harmony_computed_property_names() const {
+    return allow_harmony_computed_property_names_;
+  }
 
   // Setters that determine whether certain syntactical constructs are
   // allowed to be parsed by this instance of the parser.
   void set_allow_lazy(bool allow) { allow_lazy_ = allow; }
   void set_allow_natives(bool allow) { allow_natives_ = allow; }
   void set_allow_harmony_arrow_functions(bool allow) {
     allow_harmony_arrow_functions_ = allow;
   }
   void set_allow_harmony_modules(bool allow) {
     scanner()->SetHarmonyModules(allow);
@@ skipping 12 matching lines @@
   }
   void set_allow_harmony_templates(bool allow) {
     scanner()->SetHarmonyTemplates(allow);
   }
   void set_allow_harmony_sloppy(bool allow) {
     allow_harmony_sloppy_ = allow;
   }
   void set_allow_harmony_unicode(bool allow) {
     scanner()->SetHarmonyUnicode(allow);
   }
+  void set_allow_harmony_computed_property_names(bool allow) {
+    allow_harmony_computed_property_names_ = allow;
+  }
 
  protected:
   enum AllowEvalOrArgumentsAsIdentifier {
     kAllowEvalOrArguments,
     kDontAllowEvalOrArguments
   };
 
   enum Mode {
     PARSE_LAZILY,
     PARSE_EAGERLY
@@ skipping 339 matching lines @@
   // Parses an identifier and determines whether or not it is 'get' or 'set'.
   IdentifierT ParseIdentifierNameOrGetOrSet(bool* is_get,
                                             bool* is_set,
                                             bool* ok);
 
   ExpressionT ParseRegExpLiteral(bool seen_equal, bool* ok);
 
   ExpressionT ParsePrimaryExpression(bool* ok);
   ExpressionT ParseExpression(bool accept_IN, bool* ok);
   ExpressionT ParseArrayLiteral(bool* ok);
-  IdentifierT ParsePropertyName(bool* is_get, bool* is_set, bool* is_static,
+  ExpressionT ParsePropertyName(IdentifierT* name, bool* is_get, bool* is_set,
+                                bool* is_static, bool* is_computed_name,
                                 bool* ok);
   ExpressionT ParseObjectLiteral(bool* ok);
   ObjectLiteralPropertyT ParsePropertyDefinition(ObjectLiteralChecker* checker,
                                                  bool in_class, bool is_static,
+                                                 bool* is_computed_name,
                                                  bool* has_seen_constructor,
                                                  bool* ok);
   typename Traits::Type::ExpressionList ParseArguments(bool* ok);
   ExpressionT ParseAssignmentExpression(bool accept_IN, bool* ok);
   ExpressionT ParseYieldExpression(bool* ok);
   ExpressionT ParseConditionalExpression(bool accept_IN, bool* ok);
   ExpressionT ParseBinaryExpression(int prec, bool accept_IN, bool* ok);
   ExpressionT ParseUnaryExpression(bool* ok);
   ExpressionT ParsePostfixExpression(bool* ok);
   ExpressionT ParseLeftHandSideExpression(bool* ok);
@@ skipping 83 matching lines @@
 
  private:
   Scanner* scanner_;
   bool stack_overflow_;
 
   bool allow_lazy_;
   bool allow_natives_;
   bool allow_harmony_arrow_functions_;
   bool allow_harmony_object_literals_;
   bool allow_harmony_sloppy_;
+  bool allow_harmony_computed_property_names_;
 
   typename Traits::Type::Zone* zone_;  // Only used by Parser.
 };
 
 
 class PreParserIdentifier {
  public:
   PreParserIdentifier() : type_(kUnknownIdentifier) {}
   static PreParserIdentifier Default() {
     return PreParserIdentifier(kUnknownIdentifier);
@@ skipping 413 matching lines @@
                                        int literal_index,
                                        int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewArrayLiteral(PreParserExpressionList values,
                                       int literal_index,
                                       int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewObjectLiteralProperty(bool is_getter,
+                                               PreParserExpression key,
                                                PreParserExpression value,
-                                               int pos, bool is_static) {
+                                               int pos, bool is_static,
+                                               bool is_computed_name) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewObjectLiteralProperty(PreParserExpression key,
                                                PreParserExpression value,
-                                               bool is_static) {
+                                               bool is_static,
+                                               bool is_computed_name) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewObjectLiteral(PreParserExpressionList properties,
                                        int literal_index,
                                        int boilerplate_properties,
                                        bool has_function,
                                        int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewVariableProxy(void* variable) {
@@ skipping 165 matching lines @@
   static PreParserExpression GetPropertyValue(PreParserExpression property) {
     return PreParserExpression::Default();
   }
 
   // Functions for encapsulating the differences between parsing and preparsing;
   // operations interleaved with the recursive descent.
   static void PushLiteralName(FuncNameInferrer* fni, PreParserIdentifier id) {
     // PreParser should not use FuncNameInferrer.
     UNREACHABLE();
   }
+
   static void PushPropertyName(FuncNameInferrer* fni,
                                PreParserExpression expression) {
     // PreParser should not use FuncNameInferrer.
     UNREACHABLE();
   }
+
   static void InferFunctionName(FuncNameInferrer* fni,
                                 PreParserExpression expression) {
     // PreParser should not use FuncNameInferrer.
     UNREACHABLE();
   }
 
   static void CheckFunctionLiteralInsideTopLevelObjectLiteral(
       PreParserScope* scope, PreParserExpression property, bool* has_function) {
   }
 
@@ skipping 740 matching lines @@
   Expect(Token::RBRACK, CHECK_OK);
 
   // Update the scope information before the pre-parsing bailout.
   int literal_index = function_state_->NextMaterializedLiteralIndex();
 
   return factory()->NewArrayLiteral(values, literal_index, pos);
 }
 
 
 template <class Traits>
-typename ParserBase<Traits>::IdentifierT ParserBase<Traits>::ParsePropertyName(
-    bool* is_get, bool* is_set, bool* is_static, bool* ok) {
-  Token::Value next = peek();
-  switch (next) {
+typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParsePropertyName(
+    IdentifierT* name, bool* is_get, bool* is_set, bool* is_static,
+    bool* is_computed_name, bool* ok) {
+  Token::Value token = peek();
+  int pos = peek_position();
+
+  // For non computed property names we normalize the name a bit:
+  //
+  //   "12" -> 12
+  //   12.3 -> "12.3"
+  //   12.30 -> "12.3"
+  //   identifier -> "identifier"
+  //
+  // This is important because we use the property name as a key in a hash
+  // table when we compute constant properties.
+  switch (token) {
     case Token::STRING:
       Consume(Token::STRING);
-      return this->GetSymbol(scanner_);
+      *name = this->GetSymbol(scanner());
+      break;
+
     case Token::NUMBER:
       Consume(Token::NUMBER);
-      return this->GetNumberAsSymbol(scanner_);
+      *name = this->GetNumberAsSymbol(scanner());
+      break;
+
+    case Token::LBRACK:
+      if (allow_harmony_computed_property_names_) {
+        *is_computed_name = true;
+        Consume(Token::LBRACK);
+        ExpressionT expression = ParseAssignmentExpression(true, CHECK_OK);
+        Expect(Token::RBRACK, CHECK_OK);
+        return expression;
+      }
+
+    // Fall through.
     case Token::STATIC:
       *is_static = true;
-      // Fall through.
+
+    // Fall through.
     default:
-      return ParseIdentifierNameOrGetOrSet(is_get, is_set, ok);
+      *name = ParseIdentifierNameOrGetOrSet(is_get, is_set, CHECK_OK);
+      break;
   }
-  UNREACHABLE();
-  return this->EmptyIdentifier();
+
+  uint32_t index;
+  return this->IsArrayIndex(*name, &index)
+             ? factory()->NewNumberLiteral(index, pos)
+             : factory()->NewStringLiteral(*name, pos);
 }
 
 
 template <class Traits>
-typename ParserBase<Traits>::ObjectLiteralPropertyT ParserBase<
-    Traits>::ParsePropertyDefinition(ObjectLiteralChecker* checker,
-                                     bool in_class, bool is_static,
-                                     bool* has_seen_constructor, bool* ok) {
+typename ParserBase<Traits>::ObjectLiteralPropertyT
+ParserBase<Traits>::ParsePropertyDefinition(ObjectLiteralChecker* checker,
+                                            bool in_class, bool is_static,
+                                            bool* is_computed_name,
+                                            bool* has_seen_constructor,
+                                            bool* ok) {
   DCHECK(!in_class || is_static || has_seen_constructor != NULL);
   ExpressionT value = this->EmptyExpression();
+  IdentifierT name = this->EmptyIdentifier();
   bool is_get = false;
   bool is_set = false;
   bool name_is_static = false;
   bool is_generator = allow_harmony_object_literals_ && Check(Token::MUL);
 
   Token::Value name_token = peek();
   int next_pos = peek_position();
-  IdentifierT name =
-      ParsePropertyName(&is_get, &is_set, &name_is_static,
-                        CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+  ExpressionT name_expression = ParsePropertyName(
+      &name, &is_get, &is_set, &name_is_static, is_computed_name,
+      CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
-  if (fni_ != NULL) this->PushLiteralName(fni_, name);
+  if (fni_ != NULL && !*is_computed_name) {
+    this->PushLiteralName(fni_, name);
+  }
 
   if (!in_class && !is_generator && peek() == Token::COLON) {
     // PropertyDefinition : PropertyName ':' AssignmentExpression
-    if (checker != NULL) {
+    if (!*is_computed_name && checker != NULL) {
       checker->CheckProperty(name_token, kValueProperty,
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
     Consume(Token::COLON);
     value = this->ParseAssignmentExpression(
         true, CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
   } else if (is_generator ||
              (allow_harmony_object_literals_ && peek() == Token::LPAREN)) {
     // Concise Method
@@ skipping 17 matching lines @@
       if (*has_seen_constructor) {
         ReportMessageAt(scanner()->location(), "duplicate_constructor");
         *ok = false;
         return this->EmptyObjectLiteralProperty();
       }
 
       *has_seen_constructor = true;
       kind = FunctionKind::kNormalFunction;
     }
 
-    if (checker != NULL) {
+    if (!*is_computed_name && checker != NULL) {
       checker->CheckProperty(name_token, kValueProperty,
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
 
     value = this->ParseFunctionLiteral(
         name, scanner()->location(),
         false,  // reserved words are allowed here
         kind, RelocInfo::kNoPosition, FunctionLiteral::ANONYMOUS_EXPRESSION,
         FunctionLiteral::NORMAL_ARITY,
         CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
   } else if (in_class && name_is_static && !is_static) {
     // static MethodDefinition
-    return ParsePropertyDefinition(checker, true, true, NULL, ok);
+    return ParsePropertyDefinition(checker, true, true, is_computed_name, NULL,
+                                   ok);
 
   } else if (is_get || is_set) {
     // Accessor
+    name = this->EmptyIdentifier();
     bool dont_care = false;
     name_token = peek();
-    name = ParsePropertyName(&dont_care, &dont_care, &dont_care,
-                             CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+
+    name_expression = ParsePropertyName(
+        &name, &dont_care, &dont_care, &dont_care, is_computed_name,
+        CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
     // Validate the property.
     if (is_static && this->IsPrototype(name)) {
       ReportMessageAt(scanner()->location(), "static_prototype");
       *ok = false;
       return this->EmptyObjectLiteralProperty();
     } else if (in_class && !is_static && this->IsConstructor(name)) {
       ReportMessageAt(scanner()->location(), "constructor_special_method");
       *ok = false;
       return this->EmptyObjectLiteralProperty();
     }
-    if (checker != NULL) {
+    if (!*is_computed_name && checker != NULL) {
       checker->CheckProperty(name_token,
                              is_get ? kGetterProperty : kSetterProperty,
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
 
     typename Traits::Type::FunctionLiteral value = this->ParseFunctionLiteral(
         name, scanner()->location(),
         false,  // reserved words are allowed here
         FunctionKind::kNormalFunction, RelocInfo::kNoPosition,
         FunctionLiteral::ANONYMOUS_EXPRESSION,
         is_get ? FunctionLiteral::GETTER_ARITY : FunctionLiteral::SETTER_ARITY,
         CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
-    return factory()->NewObjectLiteralProperty(is_get, value, next_pos,
-                                               is_static);
+
+    // Make sure the name expression is a string since we need a Name for
+    // Runtime_DefineAccessorPropertyUnchecked and since we can determine this
+    // statically we can skip the extra runtime check.
+    if (!*is_computed_name) {
+      name_expression =
+          factory()->NewStringLiteral(name, name_expression->position());
+    }
+
+    return factory()->NewObjectLiteralProperty(
+        is_get, name_expression, value, next_pos, is_static, *is_computed_name);
 
   } else if (!in_class && allow_harmony_object_literals_ &&
              Token::IsIdentifier(name_token, strict_mode(),
                                  this->is_generator())) {
     value = this->ExpressionFromIdentifier(name, next_pos, scope_, factory());
 
   } else {
     Token::Value next = Next();
     ReportUnexpectedToken(next);
     *ok = false;
     return this->EmptyObjectLiteralProperty();
   }
 
-  uint32_t index;
-  LiteralT key = this->IsArrayIndex(name, &index)
-                     ? factory()->NewNumberLiteral(index, next_pos)
-                     : factory()->NewStringLiteral(name, next_pos);
-
-  return factory()->NewObjectLiteralProperty(key, value, is_static);
+  return factory()->NewObjectLiteralProperty(name_expression, value, is_static,
+                                             *is_computed_name);
 }
 
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseObjectLiteral(
     bool* ok) {
   // ObjectLiteral ::
   // '{' (PropertyDefinition (',' PropertyDefinition)* ','? )? '}'
 
   int pos = peek_position();
   typename Traits::Type::PropertyList properties =
       this->NewPropertyList(4, zone_);
   int number_of_boilerplate_properties = 0;
   bool has_function = false;
+  bool has_computed_names = false;
 
   ObjectLiteralChecker checker(this, strict_mode());
 
   Expect(Token::LBRACE, CHECK_OK);
 
   while (peek() != Token::RBRACE) {
     if (fni_ != NULL) fni_->Enter();
 
     const bool in_class = false;
     const bool is_static = false;
+    bool is_computed_name = false;
     ObjectLiteralPropertyT property = this->ParsePropertyDefinition(
-        &checker, in_class, is_static, NULL, CHECK_OK);
+        &checker, in_class, is_static, &is_computed_name, NULL, CHECK_OK);
+
+    if (is_computed_name) {
+      has_computed_names = true;
+    }
 
     // Mark top-level object literals that contain function literals and
     // pretenure the literal so it can be added as a constant function
     // property. (Parser only.)
     this->CheckFunctionLiteralInsideTopLevelObjectLiteral(scope_, property,
                                                           &has_function);
 
     // Count CONSTANT or COMPUTED properties to maintain the enumeration order.
-    if (this->IsBoilerplateProperty(property)) {
+    if (!has_computed_names && this->IsBoilerplateProperty(property)) {
       number_of_boilerplate_properties++;
     }
     properties->Add(property, zone());
 
     if (peek() != Token::RBRACE) {
       // Need {} because of the CHECK_OK macro.
       Expect(Token::COMMA, CHECK_OK);
     }
 
     if (fni_ != NULL) {
@@ skipping 775 matching lines @@
       DCHECK(IsAccessorAccessorConflict(old_type, type));
       // Both accessors of the same type.
       parser()->ReportMessage("accessor_get_set");
     }
     *ok = false;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H