[parser] Fail early for two-byte intrinsic calls

Don't just DCHECK that intrinsic calls are one-byte, but explicitly
check and return (a failure) when they are not.

Bug: chromium:948248
Change-Id: If2c16f337e9c97e5a585d21a51a985f4abbe1c29
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1547857
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60565}

src/parsing/parser.cc

@@ -347,7 +347,12 @@ Expression* Parser::NewV8Intrinsic(const AstRawString* name,
     GetClosureScope()->ForceEagerCompilation();
   }
 
-  DCHECK(name->is_one_byte());
+  if (!name->is_one_byte()) {
+    // There are no two-byte named intrinsics.
+    ReportMessage(MessageTemplate::kNotDefined, name);
+    return FailureExpression();
+  }
+
   const Runtime::Function* function =
       Runtime::FunctionForName(name->raw_data(), name->length());
 

test/mjsunit/regress/regress-948248.js

+// Copyright 2017 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.
+
+// Flags: --allow-natives-syntax
+
+// Non-ascii intrinsic calls shouldn't crash V8.
+assertThrows("%ಠ_ಠ()", SyntaxError);