[es6] implement spread calls

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 72 matching lines @@
         zone_(zone),
         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),
         allow_harmony_rest_params_(false),
+        allow_harmony_spreadcalls_(false),
         allow_strong_mode_(false) {}
 
   // 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_;
   }
   bool allow_harmony_rest_params() const {
     return allow_harmony_rest_params_;
   }
+  bool allow_harmony_spreadcalls() const { return allow_harmony_spreadcalls_; }
 
   bool allow_strong_mode() const { return allow_strong_mode_; }
 
   // 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;
   }
@@ skipping 20 matching lines @@
   }
   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;
   }
   void set_allow_harmony_rest_params(bool allow) {
     allow_harmony_rest_params_ = allow;
   }
+  void set_allow_harmony_spreadcalls(bool allow) {
+    allow_harmony_spreadcalls_ = allow;
+  }
   void set_allow_strong_mode(bool allow) { allow_strong_mode_ = allow; }
 
  protected:
   enum AllowEvalOrArgumentsAsIdentifier {
     kAllowEvalOrArguments,
     kDontAllowEvalOrArguments
   };
 
   enum Mode {
     PARSE_LAZILY,
@@ skipping 397 matching lines @@
   ExpressionT ParseExpression(bool accept_IN, bool* ok);
   ExpressionT ParseArrayLiteral(bool* ok);
   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(
       ObjectLiteralCheckerBase* checker, bool in_class, bool has_extends,
       bool is_static, bool* is_computed_name, bool* has_seen_constructor,
       bool* ok);
-  typename Traits::Type::ExpressionList ParseArguments(bool* ok);
+  typename Traits::Type::ExpressionList ParseArguments(
+      Scanner::Location* first_spread_pos, 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);
   ExpressionT ParseMemberWithNewPrefixesExpression(bool* ok);
   ExpressionT ParseMemberExpression(bool* ok);
   ExpressionT ParseMemberExpressionContinuation(ExpressionT expression,
@@ skipping 91 matching lines @@
   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_;
   bool allow_harmony_rest_params_;
+  bool allow_harmony_spreadcalls_;
   bool allow_strong_mode_;
 };
 
 
 class PreParserIdentifier {
  public:
   PreParserIdentifier() : type_(kUnknownIdentifier) {}
   static PreParserIdentifier Default() {
     return PreParserIdentifier(kUnknownIdentifier);
   }
@@ skipping 72 matching lines @@
   friend class PreParserExpression;
 };
 
 
 class PreParserExpression {
  public:
   static PreParserExpression Default() {
     return PreParserExpression(TypeField::encode(kExpression));
   }
 
+  static PreParserExpression Spread(PreParserExpression expression) {
+    return PreParserExpression(TypeField::encode(kSpreadExpression));
+  }
+
   static PreParserExpression FromIdentifier(PreParserIdentifier id) {
     return PreParserExpression(TypeField::encode(kIdentifierExpression) |
                                IdentifierTypeField::encode(id.type_));
   }
 
   static PreParserExpression BinaryOperation(PreParserExpression left,
                                              Token::Value op,
                                              PreParserExpression right) {
     bool valid_arrow_param_list =
         op == Token::COMMA && !left.is_parenthesized() &&
@@ skipping 113 matching lines @@
 
   // At the moment PreParser doesn't track these expression types.
   bool IsFunctionLiteral() const { return false; }
   bool IsCallNew() const { return false; }
 
   bool IsNoTemplateTag() const {
     return TypeField::decode(code_) == kExpression &&
            ExpressionTypeField::decode(code_) == kNoTemplateTagExpression;
   }
 
+  bool IsSpreadExpression() const {
+    return TypeField::decode(code_) == kSpreadExpression;
+  }
+
   PreParserExpression AsFunctionLiteral() { return *this; }
 
   bool IsBinaryOperation() const {
     return TypeField::decode(code_) == kBinaryOperationExpression;
   }
 
   bool is_parenthesized() const {
     return ParenthesizationField::decode(code_) != kNotParenthesized;
   }
 
@@ skipping 12 matching lines @@
   void set_parenthesized() {}
 
   int position() const { return RelocInfo::kNoPosition; }
   void set_function_token_position(int position) {}
 
  private:
   enum Type {
     kExpression,
     kIdentifierExpression,
     kStringLiteralExpression,
-    kBinaryOperationExpression
+    kBinaryOperationExpression,
+    kSpreadExpression
   };
 
   enum Parenthesization {
     kNotParenthesized,
     kParanthesizedExpression,
     kMultiParenthesizedExpression
   };
 
   enum ExpressionType {
     kThisExpression,
     kThisPropertyExpression,
     kPropertyExpression,
     kCallExpression,
     kSuperExpression,
     kNoTemplateTagExpression
   };
 
   explicit PreParserExpression(uint32_t expression_code)
       : code_(expression_code) {}
 
   V8_INLINE bool IsValidArrowParams() const {
     return IsBinaryOperation()
                ? IsValidArrowParamListField::decode(code_)
                : (IsIdentifier() && AsIdentifier().IsValidArrowParam());
   }
 
-  // The first four bits are for the Type and Parenthesization.
-  typedef BitField<Type, 0, 2> TypeField;
+  // The first five bits are for the Type and Parenthesization.
+  typedef BitField<Type, 0, 3> TypeField;
   typedef BitField<Parenthesization, TypeField::kNext, 2> ParenthesizationField;
 
   // The rest of the bits are interpreted depending on the value
   // of the Type field, so they can share the storage.
   typedef BitField<ExpressionType, ParenthesizationField::kNext, 3>
       ExpressionTypeField;
   typedef BitField<bool, ParenthesizationField::kNext, 1> IsUseStrictField;
   typedef BitField<bool, IsUseStrictField::kNext, 1> IsUseStrongField;
   typedef BitField<bool, ParenthesizationField::kNext, 1>
       IsValidArrowParamListField;
@@ skipping 180 matching lines @@
   PreParserExpression NewCall(PreParserExpression expression,
                               PreParserExpressionList arguments,
                               int pos) {
     return PreParserExpression::Call();
   }
   PreParserExpression NewCallNew(PreParserExpression expression,
                                  PreParserExpressionList arguments,
                                  int pos) {
     return PreParserExpression::Default();
   }
+  PreParserExpression NewCallRuntime(const AstRawString* name,
+                                     const Runtime::Function* function,
+                                     PreParserExpressionList arguments,
+                                     int pos) {
+    return PreParserExpression::Default();
+  }
   PreParserStatement NewReturnStatement(PreParserExpression expression,
                                         int pos) {
     return PreParserStatement::Default();
   }
   PreParserExpression NewFunctionLiteral(
       PreParserIdentifier name, AstValueFactory* ast_value_factory,
       Scope* scope, PreParserStatementList body, int materialized_literal_count,
       int expected_property_count, int handler_count, int parameter_count,
       FunctionLiteral::ParameterFlag has_duplicate_parameters,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::IsFunctionFlag is_function,
       FunctionLiteral::IsParenthesizedFlag is_parenthesized, FunctionKind kind,
       int position) {
     return PreParserExpression::Default();
   }
 
+  PreParserExpression NewSpreadOperation(PreParserExpression expression,
+                                         int pos) {
+    return PreParserExpression::Spread(expression);
+  }
+
   // Return the object itself as AstVisitor and implement the needed
   // dummy method right in this class.
   PreParserFactory* visitor() { return this; }
   int* ast_properties() {
     static int dummy = 42;
     return &dummy;
   }
 };
 
 
@@ skipping 292 matching lines @@
       PreParserIdentifier name, Scanner::Location function_name_location,
       bool name_is_strict_reserved, FunctionKind kind,
       int function_token_position, FunctionLiteral::FunctionType type,
       FunctionLiteral::ArityRestriction arity_restriction, bool* ok);
 
   PreParserExpression ParseClassLiteral(PreParserIdentifier name,
                                         Scanner::Location class_name_location,
                                         bool name_is_strict_reserved, int pos,
                                         bool* ok);
 
+  PreParserExpressionList PrepareSpreadArguments(PreParserExpressionList list) {
+    return list;
+  }
+
+  inline void MaterializeUnspreadArgumentsLiterals(int count);
+
+  inline PreParserExpression SpreadCall(PreParserExpression function,
+                                        PreParserExpressionList args, int pos);
+
+  inline PreParserExpression SpreadCallNew(PreParserExpression function,
+                                           PreParserExpressionList args,
+                                           int pos);
+
  private:
   PreParser* pre_parser_;
 };
 
 
 // Preparsing checks a JavaScript program and emits preparse-data that helps
 // a later parsing to be faster.
 // See preparse-data-format.h for the data format.
 
 // The PreParser checks that the syntax follows the grammar for JavaScript,
@@ skipping 119 matching lines @@
                                         bool* ok);
 };
 
 
 void PreParserTraits::MaterializeTemplateCallsiteLiterals() {
   pre_parser_->function_state_->NextMaterializedLiteralIndex();
   pre_parser_->function_state_->NextMaterializedLiteralIndex();
 }
 
 
+void PreParserTraits::MaterializeUnspreadArgumentsLiterals(int count) {
+  for (int i = 0; i < count; ++i) {
+    pre_parser_->function_state_->NextMaterializedLiteralIndex();
+  }
+}
+
+
+PreParserExpression PreParserTraits::SpreadCall(PreParserExpression function,
+                                                PreParserExpressionList args,
+                                                int pos) {
+  return pre_parser_->factory()->NewCall(function, args, pos);
+}
+
+PreParserExpression PreParserTraits::SpreadCallNew(PreParserExpression function,
+                                                   PreParserExpressionList args,
+                                                   int pos) {
+  return pre_parser_->factory()->NewCallNew(function, args, pos);
+}
+
+
 PreParserStatementList PreParser::ParseEagerFunctionBody(
     PreParserIdentifier function_name, int pos, Variable* fvar,
     Token::Value fvar_init_op, FunctionKind kind, bool* ok) {
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
 
   ParseStatementList(Token::RBRACE, ok);
   if (!*ok) return PreParserStatementList();
 
   Expect(Token::RBRACE, ok);
   return PreParserStatementList();
@@ skipping 626 matching lines @@
   return factory()->NewObjectLiteral(properties,
                                      literal_index,
                                      number_of_boilerplate_properties,
                                      has_function,
                                      pos);
 }
 
 
 template <class Traits>
 typename Traits::Type::ExpressionList ParserBase<Traits>::ParseArguments(
-    bool* ok) {
+    Scanner::Location* first_spread_arg_loc, bool* ok) {
   // Arguments ::
   //   '(' (AssignmentExpression)*[','] ')'
 
+  Scanner::Location spread_arg = Scanner::Location::invalid();
   typename Traits::Type::ExpressionList result =
       this->NewExpressionList(4, zone_);
   Expect(Token::LPAREN, CHECK_OK_CUSTOM(NullExpressionList));
   bool done = (peek() == Token::RPAREN);
+  bool was_unspread = false;
+  int unspread_sequences_count = 0;

[rossberg, 2015/02/25 14:28:18]

A brief comment explaining what this actually counts would be useful. I gather
it's the number of non-empty sequences of non-spread arguments?

[caitp (gmail), 2015/02/25 14:49:08]

That's right --- will add a comment

   while (!done) {
+    bool is_spread = allow_harmony_spreadcalls() && (peek() == Token::ELLIPSIS);
+    int start_pos = peek_position();
+    if (is_spread) Consume(Token::ELLIPSIS);
+
     ExpressionT argument = this->ParseAssignmentExpression(
         true, CHECK_OK_CUSTOM(NullExpressionList));
+    if (is_spread) {
+      if (!spread_arg.IsValid()) {
+        spread_arg.beg_pos = start_pos;
+        spread_arg.end_pos = peek_position();
+      }
+      argument = factory()->NewSpreadOperation(argument, start_pos);
+    }
     result->Add(argument, zone_);
+
+    if (is_spread) {
+      was_unspread = false;
+    } else if (!was_unspread) {
+      was_unspread = true;
+      unspread_sequences_count++;
+    }
+
     if (result->length() > Code::kMaxArguments) {
       ReportMessage("too_many_arguments");
       *ok = false;
       return this->NullExpressionList();
     }
     done = (peek() == Token::RPAREN);
     if (!done) {
       // Need {} because of the CHECK_OK_CUSTOM macro.
       Expect(Token::COMMA, CHECK_OK_CUSTOM(NullExpressionList));
     }
   }
   Expect(Token::RPAREN, CHECK_OK_CUSTOM(NullExpressionList));
+  *first_spread_arg_loc = spread_arg;
+
+  if (spread_arg.IsValid()) {
+    Traits::MaterializeUnspreadArgumentsLiterals(unspread_sequences_count);
+  }
+
   return result;
 }
 
 // Precedence = 2
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN, bool* ok) {
   // AssignmentExpression ::
   //   ConditionalExpression
   //   ArrowFunction
@@ skipping 294 matching lines @@
           // should not point to the closing brace otherwise it will intersect
           // with positions recorded for function literal and confuse debugger.
           pos = peek_position();
           // Also the trailing parenthesis are a hint that the function will
           // be called immediately. If we happen to have parsed a preceding
           // function literal eagerly, we can also compile it eagerly.
           if (result->IsFunctionLiteral() && mode() == PARSE_EAGERLY) {
             result->AsFunctionLiteral()->set_parenthesized();
           }
         }
-        typename Traits::Type::ExpressionList args = ParseArguments(CHECK_OK);
+        Scanner::Location spread_pos;
+        typename Traits::Type::ExpressionList args =
+            ParseArguments(&spread_pos, CHECK_OK);
 
         // Keep track of eval() calls since they disable all local variable
         // optimizations.
         // The calls that need special treatment are the
         // direct eval calls. These calls are all of the form eval(...), with
         // no explicit receiver.
         // These calls are marked as potentially direct eval calls. Whether
         // they are actually direct calls to eval is determined at run time.
         this->CheckPossibleEvalCall(result, scope_);
-        result = factory()->NewCall(result, args, pos);
+
+        if (spread_pos.IsValid()) {
+          args = Traits::PrepareSpreadArguments(args);
+          result = Traits::SpreadCall(result, args, pos);
+        } else {
+          result = factory()->NewCall(result, args, pos);
+        }
         if (fni_ != NULL) fni_->RemoveLastFunction();
         break;
       }
 
       case Token::TEMPLATE_SPAN:
       case Token::TEMPLATE_TAIL: {
         int pos;
         if (scanner()->current_token() == Token::IDENTIFIER) {
           pos = position();
         } else {
@@ skipping 50 matching lines @@
     int new_pos = position();
     ExpressionT result = this->EmptyExpression();
     if (peek() == Token::SUPER) {
       const bool is_new = true;
       result = ParseSuperExpression(is_new, CHECK_OK);
     } else {
       result = this->ParseMemberWithNewPrefixesExpression(CHECK_OK);
     }
     if (peek() == Token::LPAREN) {
       // NewExpression with arguments.
+      Scanner::Location spread_pos;
       typename Traits::Type::ExpressionList args =
-          this->ParseArguments(CHECK_OK);
-      result = factory()->NewCallNew(result, args, new_pos);
+          this->ParseArguments(&spread_pos, CHECK_OK);
+
+      if (spread_pos.IsValid()) {
+        args = Traits::PrepareSpreadArguments(args);
+        result = Traits::SpreadCallNew(result, args, new_pos);
+      } else {
+        result = factory()->NewCallNew(result, args, new_pos);
+      }
       // The expression can still continue with . or [ after the arguments.
       result = this->ParseMemberExpressionContinuation(result, CHECK_OK);
       return result;
     }
     // NewExpression without arguments.
     return factory()->NewCallNew(result, this->NewExpressionList(0, zone_),
                                  new_pos);
   }
   // No 'new' or 'super' keyword.
   return this->ParseMemberExpression(ok);
@@ skipping 389 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H