Implement experimental exponentiation operator

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 54e4c7cec15b1ed18f2fedcf36db47fb8ed6a126..4c0f8c94e5860f5ff5f72eaa789ee658c7644cde 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -511,6 +511,11 @@ bool ParserTraits::ShortcutNumericLiteralBinaryExpression(
         *x = factory->NewNumberLiteral(value, pos);
         return true;
       }
+      case Token::EXP: {
+        double value = power_helper(x_val, y_val);
+        *x = factory->NewNumberLiteral(value, pos);
+        return true;
+      }
       default:
         break;
     }
@@ -815,6 +820,7 @@ Parser::Parser(CompilationInfo* info, uintptr_t stack_limit, uint32_t hash_seed,
   set_allow_harmony_computed_property_names(
       FLAG_harmony_computed_property_names);
   set_allow_harmony_rest_params(FLAG_harmony_rest_parameters);
+  set_allow_harmony_exponentiation(FLAG_harmony_exponentiation);
   set_allow_strong_mode(FLAG_strong_mode);
   for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
        ++feature) {
@@ -4033,6 +4039,8 @@ PreParser::PreParseResult Parser::ParseLazyFunctionBodyWithPreParser(
         allow_harmony_computed_property_names());
     reusable_preparser_->set_allow_harmony_rest_params(
         allow_harmony_rest_params());
+    reusable_preparser_->set_allow_harmony_exponentiation(
+        allow_harmony_exponentiation());
     reusable_preparser_->set_allow_strong_mode(allow_strong_mode());
   }
   PreParser::PreParseResult result = reusable_preparser_->PreParseLazyFunction(