Separate mutex for megamorphic cache tables lookup in the background compiler.

runtime/vm/isolate.cc

 // Copyright (c) 2013, 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/isolate.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/text_buffer.h"
@@ skipping 779 matching lines @@
       debugger_(NULL),
       resume_request_(false),
       last_resume_timestamp_(OS::GetCurrentTimeMillis()),
       has_compiled_code_(false),
       random_(),
       simulator_(NULL),
       mutex_(new Mutex()),
       symbols_mutex_(new Mutex()),
       type_canonicalization_mutex_(new Mutex()),
       constant_canonicalization_mutex_(new Mutex()),
+      lookup_mutex_(new Mutex()),

[Cutch, 2016/07/01 17:16:18]

where is this mutex deleted?

[siva, 2016/07/01 17:39:29]

Yes we need to delete it in the destructor.

[Florian Schneider, 2016/07/01 19:31:58]

Done.

[Florian Schneider, 2016/07/01 19:31:58]

Done.

       message_handler_(NULL),
       spawn_state_(NULL),
       is_runnable_(false),
       gc_prologue_callback_(NULL),
       gc_epilogue_callback_(NULL),
       defer_finalization_count_(0),
       deopt_context_(NULL),
       is_service_isolate_(false),
       stacktrace_(NULL),
       stack_frame_index_(-1),
@@ skipping 2006 matching lines @@
 void IsolateSpawnState::DecrementSpawnCount() {
   ASSERT(spawn_count_monitor_ != NULL);
   ASSERT(spawn_count_ != NULL);
   MonitorLocker ml(spawn_count_monitor_);
   ASSERT(*spawn_count_ > 0);
   *spawn_count_ = *spawn_count_ - 1;
   ml.Notify();
 }
 
 }  // namespace dart