[es6] implement spread calls

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 9f8fc13653a893d8c2adc7fcc2884773f2fd8f34..1ffd2ced47604d62a2df5394dc33072751aa0166 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -90,6 +90,7 @@ class ParserBase : public Traits {
         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
@@ -117,6 +118,7 @@ class ParserBase : public Traits {
   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_; }
 
@@ -157,6 +159,9 @@ class ParserBase : public Traits {
   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:
@@ -558,7 +563,8 @@ class ParserBase : public Traits {
       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);
@@ -670,6 +676,7 @@ class ParserBase : public Traits {
   bool allow_harmony_sloppy_;
   bool allow_harmony_computed_property_names_;
   bool allow_harmony_rest_params_;
+  bool allow_harmony_spreadcalls_;
   bool allow_strong_mode_;
 };
 
@@ -766,6 +773,10 @@ class PreParserExpression {
     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_));
@@ -899,6 +910,10 @@ class PreParserExpression {
            ExpressionTypeField::decode(code_) == kNoTemplateTagExpression;
   }
 
+  bool IsSpreadExpression() const {
+    return TypeField::decode(code_) == kSpreadExpression;
+  }
+
   PreParserExpression AsFunctionLiteral() { return *this; }
 
   bool IsBinaryOperation() const {
@@ -931,7 +946,8 @@ class PreParserExpression {
     kExpression,
     kIdentifierExpression,
     kStringLiteralExpression,
-    kBinaryOperationExpression
+    kBinaryOperationExpression,
+    kSpreadExpression
   };
 
   enum Parenthesization {
@@ -958,8 +974,8 @@ class PreParserExpression {
                : (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
@@ -1160,6 +1176,12 @@ class PreParserFactory {
                                  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();
@@ -1176,6 +1198,11 @@ class PreParserFactory {
     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; }
@@ -1482,6 +1509,16 @@ class PreParserTraits {
                                         bool name_is_strict_reserved, int pos,
                                         bool* ok);
 
+  PreParserExpressionList PrepareSpreadCallArguments(
+      PreParserExpression function, PreParserExpressionList list) {
+    return list;
+  }
+
+  PreParserExpressionList PrepareSpreadCallNewArguments(
+      PreParserExpression function, PreParserExpressionList list) {
+    return list;
+  }
+
  private:
   PreParser* pre_parser_;
 };
@@ -2257,17 +2294,29 @@ typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseObjectLiteral(
 
 template <class Traits>
 typename Traits::Type::ExpressionList ParserBase<Traits>::ParseArguments(
-    bool* ok) {
+    Scanner::Location* 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);
   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 (result->length() > Code::kMaxArguments) {
       ReportMessage("too_many_arguments");
@@ -2281,6 +2330,7 @@ typename Traits::Type::ExpressionList ParserBase<Traits>::ParseArguments(
     }
   }
   Expect(Token::RPAREN, CHECK_OK_CUSTOM(NullExpressionList));
+  *spread_arg_loc = spread_arg;

[arv (Not doing code reviews), 2015/02/18 15:07:06]

I'm not sure why we need to return a Location for this? Also, why is only the
first location interesting and not all of them?

Maybe a boolean is sufficient?

[caitp (gmail), 2015/02/18 15:32:08]

It's a hold-over from the other patch, where the location was used to report an
error if used in construct calls or intrinsics. So it depends whether you think
it's worth issuing an error or not, I guess

   return result;
 }
 
@@ -2590,7 +2640,9 @@ ParserBase<Traits>::ParseLeftHandSideExpression(bool* ok) {
             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.
@@ -2600,7 +2652,14 @@ ParserBase<Traits>::ParseLeftHandSideExpression(bool* ok) {
         // 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::PrepareSpreadCallArguments(result, args);
+          result = factory()->NewCallRuntime(
+              ast_value_factory()->spread_call_string(), NULL, args, pos);
+        } else {
+          result = factory()->NewCall(result, args, pos);
+        }
         if (fni_ != NULL) fni_->RemoveLastFunction();
         break;
       }
@@ -2671,9 +2730,17 @@ ParserBase<Traits>::ParseMemberWithNewPrefixesExpression(bool* 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::PrepareSpreadCallNewArguments(result, args);
+        result = factory()->NewCallRuntime(
+            ast_value_factory()->spread_call_new_string(), NULL, 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;