Moves the top_ and end_ words of the Scavenger into mutator thread.

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 2640 matching lines @@
     // Now get a free Thread structure.
     thread = thread_registry()->GetFreeThreadLocked(this, is_mutator);
     ASSERT(thread != NULL);
 
     thread->ResetHighWatermark();
 
     // Set up other values and set the TLS value.
     thread->isolate_ = this;
     ASSERT(heap() != NULL);
     thread->heap_ = heap();
+    thread->top_ = *(heap()->new_space()->TopAddress());

[rmacnak, 2017/06/22 22:31:50]

Since we don't yet have background new-space allocation, only the mutator thread
should copy top from the semispace, and the helper threads should have 0s so
allocation fails.

[danunez, 2017/06/30 20:35:57]

Done.

+    thread->end_ = *(heap()->new_space()->EndAddress());
     thread->set_os_thread(os_thread);
     ASSERT(thread->execution_state() == Thread::kThreadInNative);
     thread->set_execution_state(Thread::kThreadInVM);
     thread->set_safepoint_state(0);
     thread->set_vm_tag(VMTag::kVMTagId);
     ASSERT(thread->no_safepoint_scope_depth() == 0);
     os_thread->set_thread(thread);
     if (is_mutator) {
       mutator_thread_ = thread;
     }
@@ skipping 275 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