Using type feedback, eliminate store barriers for indexed stores.

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
 #include "vm/flags.h"
@@ skipping 2251 matching lines @@
   node->value()->Visit(&for_value);
   Append(for_value);
   Value* value = NULL;
   if (result_is_needed) {
     value = Bind(BuildStoreExprTemp(for_value.value()));
   } else {
     value = for_value.value();
   }
   arguments->Add(PushArgument(value));
 
-  const intptr_t checked_argument_count = 1;
+  const intptr_t checked_argument_count = 3;
   const String& name =
       String::ZoneHandle(Symbols::New(Token::Str(Token::kASSIGN_INDEX)));
   InstanceCallInstr* store = new InstanceCallInstr(node->token_pos(),
                                                    name,
                                                    Token::kASSIGN_INDEX,
                                                    arguments,
                                                    Array::ZoneHandle(),
                                                    checked_argument_count);
   if (result_is_needed) {
     Do(store);
@@ skipping 348 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart