ES6: Desugaring of instanceof to support @@hasInstance

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index e75e87a65a427da96e9382f58b0a9a8c33fa8460..539209e985d4e9120075b1f041f476ec62408bfa 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -2246,12 +2246,15 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN,
           *ok = false;
           return this->EmptyExpression();
         }
-        x = factory()->NewCompareOperation(cmp, x, y, pos);
-        if (cmp != op) {
-          // The comparison was negated - add a NOT.
-          x = factory()->NewUnaryOperation(Token::NOT, x, pos);
+        if (FLAG_harmony_instanceof && op == Token::INSTANCEOF) {

[rossberg, 2016/02/12 14:11:31]

Nit: make this and 'else if'. Also, s/op/cmp/

[mvstanton, 2016/02/18 02:12:17]

Done.

+          x = Traits::RewriteInstanceof(x, y, pos);
+        } else {
+          x = factory()->NewCompareOperation(cmp, x, y, pos);
+          if (cmp != op) {
+            // The comparison was negated - add a NOT.
+            x = factory()->NewUnaryOperation(Token::NOT, x, pos);
+          }
         }
-
       } else {
         // We have a "normal" binary operation.
         x = factory()->NewBinaryOperation(op, x, y, pos);