Narrowly address async function stack overflow parsing case

src/parsing/parser.cc

 // 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.
 
 #include "src/parsing/parser.h"
 
 #include "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 1080 matching lines @@
            is_strict(info->language_mode()));
     DCHECK(info->language_mode() == shared_info->language_mode());
     FunctionLiteral::FunctionType function_type =
         ComputeFunctionType(shared_info);
     bool ok = true;
 
     if (shared_info->is_arrow()) {
       bool is_async = allow_harmony_async_await() && shared_info->is_async();
       if (is_async) {
         DCHECK(!scanner()->HasAnyLineTerminatorAfterNext());
-        Consume(Token::ASYNC);
-        DCHECK(peek_any_identifier() || peek() == Token::LPAREN);
+        if (!Check(Token::ASYNC)) {
+          CHECK(stack_overflow());
+          return nullptr;
+        }
+        if (!(peek_any_identifier() || peek() == Token::LPAREN)) {
+          CHECK(stack_overflow());
+          return nullptr;
+        }
       }
 
       // TODO(adamk): We should construct this scope from the ScopeInfo.
       Scope* scope =
           NewScope(scope_, FUNCTION_SCOPE, FunctionKind::kArrowFunction);
 
       // These two bits only need to be explicitly set because we're
       // not passing the ScopeInfo to the Scope constructor.
       // TODO(adamk): Remove these calls once the above NewScope call
       // passes the ScopeInfo.
@@ skipping 5879 matching lines @@
 
 #ifdef DEBUG
 void Parser::Print(AstNode* node) {
   ast_value_factory()->Internalize(Isolate::Current());
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8