WIP: Implement ES6 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 535 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,
                                                 bool* ok);
   ExpressionT ParseArrowFunctionLiteral(int start_pos, ExpressionT params_ast,
                                         bool* ok);
   ExpressionT ParseTemplateLiteral(ExpressionT tag, int start, bool* ok);
   void AddTemplateExpression(ExpressionT);
   ExpressionT ParseSuperExpression(bool is_new, bool* ok);
 
   // Checks if the expression is a valid reference expression (e.g., on the
   // left-hand side of assignments). Although ruled out by ECMA as early errors,
   // we allow calls for web compatibility and rewrite them to a runtime throw.
   ExpressionT CheckAndRewriteReferenceExpression(
       ExpressionT expression,
       Scanner::Location location, const char* message, bool* ok);
 
+  ExpressionT MaybeSpread(ExpressionT expression, bool is_spread, int pos) {
+    if (is_spread) {
+      return factory()->NewSpreadOperation(scope_, expression, pos);
+    }
+    return expression;
+  }
+
   // Used to validate property names in object literals and class literals
   enum PropertyKind {
     kAccessorProperty,
     kValueProperty,
     kMethodProperty
   };
 
   class ObjectLiteralCheckerBase {
    public:
     explicit ObjectLiteralCheckerBase(ParserBase* parser) : parser_(parser) {}
@@ skipping 164 matching lines @@
   friend class PreParserExpression;
 };
 
 
 class PreParserExpression {
  public:
   static PreParserExpression Default() {
     return PreParserExpression(TypeField::encode(kExpression));
   }
 
+  static PreParserExpression Spread(PreParserExpression expression) {
+    DCHECK(!expression.IsSpreadExpression() || expression.is_parenthesized());
+    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;
+  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 196 matching lines @@
       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(
+      Scope* scope, 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 287 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);
 
+  static void MarkSpreadCall(PreParserExpression call) {}
+
  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 768 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, bool* ok) {
   // Arguments ::
   //   '(' (AssignmentExpression)*[','] ')'
-
+  Scanner::Location spread_loc = Scanner::Location::invalid();
   typename Traits::Type::ExpressionList result =
       this->NewExpressionList(4, zone_);
   Expect(Token::LPAREN, CHECK_OK_CUSTOM(NullExpressionList));
   bool done = (peek() == Token::RPAREN);
   while (!done) {
+    bool is_spread = peek() == Token::ELLIPSIS;
+    bool first_spread = false;
+    int spread_pos = -1;
+    if (is_spread) {
+      spread_pos = peek_position();
+      first_spread = spread_loc.beg_pos < 0;
+      if (first_spread) {
+        spread_loc.beg_pos = spread_pos;
+      }
+      Consume(Token::ELLIPSIS);
+    }
     ExpressionT argument = this->ParseAssignmentExpression(
         true, CHECK_OK_CUSTOM(NullExpressionList));
-    result->Add(argument, zone_);
+    if (first_spread) {
+      spread_loc.end_pos = peek_position();
+    }
+    result->Add(MaybeSpread(argument, is_spread, spread_pos), zone_);
     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 = spread_loc;
   return result;
 }
 
 // Precedence = 2
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN, bool* ok) {
   // AssignmentExpression ::
   //   ConditionalExpression
   //   ArrowFunction
@@ skipping 283 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()) {
+          Traits::MarkSpreadCall(result);
+        }
         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);
+          this->ParseArguments(&spread_pos, CHECK_OK);
+
+      // TODO(caitp): support spread-calls in CallNew()
+      if (spread_pos.IsValid()) {
+        Traits::ReportMessageAt(spread_pos, "spreadcall_construct");
+        *ok = false;
+        return Traits::EmptyExpression();
+      }
+
       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.
@@ skipping 392 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H